**New Nutritional Strategies for Improving the Quality of Meat**

Akbar Taghizadeh and Jamal Seifdavati

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.78041

### **Abstract**

Few studies of using locally legume grains in lamb nutrition have been studied that their use had no negative impact on meat quality such as fatty acid composition. One of the strategies of increasing functional food availability is to increase polyunsaturated fatty acids, especially the ω-3 series, conjugated linoleic acid (CLA) level and reduce saturated fatty acids in animal products. The CLA isomers appear to be concentrated in intramuscular and subcutaneous fat of meat ruminants and the concentration of c9, t11-CLA being greater than the concentration of t10, and c12-CLA in all tissues. To increase the CLA yield in lamb meat, it is essential to provide lamb an appropriate substrate for the formation of CLA.-The provision of source of dietary linoleic acid appears to increase the CLA concentration to the greatest extent. Regarding the recommended daily intake for the appreciation of health benefits in humans (3500mg/d), this amount of CLA supplied to meat lamb will partially provide the CLA requirement for everyone under certain conditions; deposition of CLA in the tissues using the provision of modest amounts of locally legume grains is more conducive to CLA synthesis rather than high levels of grain.-

**Keywords:** conjugated linoleic acid, local legume grains, meat quality, ruminants, nutrition manipulation, ruminal biohydrogenation

### **1. Introduction**

The protein sources form the largest and most cost-effective part of animal feed, and large quantities of these resources are exported annually for use in animal feed production. Not only does this impose a heavy currency burden on the country, it also causes a lot of problems, in which case the quality of the purchased materials, the distances, transportation problems and the probability of their pollution can be pointed out [1]. Therefore, recognizing

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locally feedstuffs and replacing them with imported food sources have a significant contribution to economic self-sufficiency. The leguminous family is widely distributed globally, so that various species of chickling vetch are present in the Canary Islands, Germany, East Asia, Nepal, China, the Middle East, North Africa, southern Europe, North America and the Mediterranean, with moderate climates and moderate rainfall as a source of plant protein for animal nutrition [2].-

 In recent years, the limitations in the use of animal by-products, such as meat meal due to government regulations, and consumer demand have led to an increase in the use of plant protein sources. Soybean meal is the main plant protein source used in animal feeding and it is largely- imported from Brazil, which has recently been questioned. In addition, in the livestock feeds- industry, all efforts are made to reduce feed and feed costs; therefore,an important objective- of world farmers has been to increase the use of plant protein sources preferably from local feedstuffs. Few studies of using locally legume grains in lamb nutrition have been studied.- Several reports seemed to suggest that their use had no negative impact on meat quality such- as fatty acid composition [3, 4]. Locally produced legumes as alternative protein sources in the- diets of ruminants are commonly used worldwide like peas, field beans, types of vetch and- rapeseed. Types of vetch, such as bitter vetch (*Vicia ervilia* L.), common vetch (*Vicia sativa* L.)- and chickling vetch (*Lathyrus sativus* L.) grains, are the legume seeds available in the- Mediterranean and Western Asia areas and especially in the west-north area of Iran and are- comparatively cheap despite its relatively high nutritional value. One of the strategies of- increasing functional food availability is to increase polyunsaturated fatty acids, especially- the ω-3 series, conjugated linoleic acid (c9,t11-CLA) level and reduce saturated fatty acids in- animal products [4, 5]. Although there is a vast amount of literature available about the CLA- content of milk, a few research trials focusing on the CLA content of meat are limited. The- CLA isomers appear to be concentrated in the intramuscular and subcutaneous fat of meat- ruminants and the concentration of c9, t11-CLA being greater than the concentration of t10,- c12-CLA in all tissues, but the proportion of the latter CLA isomer is greater in subcutaneous fat [6]. Of the many isomers identified, the cis-9, trans-11 CLA isomer (rumenic acid)- accounts for up to 80–90% of the total CLA in ruminant products [7]. However, the amount- of the CLAs found in milk and meat are small, relative to the recommended daily intake for- the appreciation of health benefits in humans, which is 3500mg/d [6]. There is little data- available on the effects of feeding types of vetch grains on lamb intramuscular fatty acid- composition. The objective of the present chapter is to evaluate the effect of totally replacing- dietary soybean meal and nutrition manipulation of the diet of the livestock to produce- high-quality and healthy meat.-

### **2. Nutrition manipulation for the production of high-quality and healthy meat**

New nutritional strategies for feeding livestock and poultry focus on the increase of unsaturated fatty acids (especially n-3) and conjugated linoleic fatty acids and the reduction of saturated fatty acids in animal food products [5, 8]. To increase the CLA in animal meat, it is essential to provide a suitable base for its formation. Therefore, the inclusion of the source of linoleic acid in the ruminant animal diet will be most effective in increasing the concentration of CLA in meat products. Forage foods such as grasses or legumes (alfalfa) are suitable for facilitating the accumulation of CLA and increasing the precipitate and forming it in the tissue of the animals. Therefore, the use of plant sources such as plants in the marine ecosystem and dry areas is one of the first and most important sources of unsaturated fatty acids. Aquatic plants have a special ability to produce fatty acids (18: 3 n-3), which are the building blocks for the production, refinement and nonsaturation of a series of fatty acids, which ultimately produce docosahexaenoic acid and eicosapentaenoic acid. These two fatty acids are consumed by fish from aquatic plants and can be used to produce a wide variety of fatty acids, especially in fish oil, in fish tissues [5]. Plant sources and dry forages such as clover have a high proportion of unsaturated fatty acids (75–50%), such as alpha linoleic acid, which can be considered as a suitable substitute for the supply of fatty acid in some regions. However, the transfer of this type of fatty acids in ruminant meat depends on two important processes for increasing the level of these fatty acids in fodder (resulting in the animal) and reducing the amount of ruminal bovine fermentation [5]. However, providing a moderate amount of granular material in the diet concentrate instead of high levels leads to more CLA synthesis. Specific breeds of cattle tend to have more fat storage in the muscle and more CLA in the adipose tissue that is suitable for offering to the consumer. CLA levels of muscle can be increased by increasing the consumption of food items such as fresh fodder, silage, rangeland nutrition and the use of vegetable oils and fish oils, all of which have high levels of linoleic acid [9]. The production of CLA in the ruminant tissue is such that in the pathway of unsaturated fatty acid biosynthesis, the increase in the activity of the delta-9-dosacharase enzyme occurs and ultimately leads to the production of trans-vaccenic acid (**Figure 1**), which is the acid of the domestic production source; CLA is in the tissue, so that a linear relationship is obtained between the concentration of CLA and trans-vaccenic acid [9]. According to researchers (**Table 1**), CLA levels in beef ranged from 2.1 to 5.12mg/g of fat [10].-

**Figure 1.** The major route of 18-carbon unsaturated fatty acid biohydrogenation [11].-

These researchers have identified the variation in the concentration of CLA in beef, depending on the system used and the diet. In these reports, the factors affecting the content of CLA in beef have been compared with pasture forage and that the diet contains oil or whole grains, and even the composition of the fatty acid content of the grains and the ratio of the concentrate to the forage are also evaluated. Lanza etal. [3] in their research showed that the replacement of a variety of legumes with soybean meal and corn grain significantly increases the CLA in lamb meat. Scerra etal. [4] in their research examined the effects of some legume seeds on the composition of fatty acids and intramuscular CLA and showed that feeding some legumes over soybean meal saved omega 3, omega 6 and CLA fatty acids in muscle tissue. Abdollah etal. [12] in their study showed that the replacement of beet seed at different levels of 0, 5, 10 and 15% with soybean meal did not affect the characteristics, carcass traits and performance of lambs and it has been replaced without negative effects and has reduced the cost of the diet. At the 10% level, daily gain was higher than other levels and control group. The amount of crude protein, NDF, ADF and crude fat was estimated to be 23.1, 21.3, 6.9 and 1.6%, respectively, and researchers have proposed a 10% level for replacing soybean meal. In the study by Gül etal. [13] the authors used different levels of vetch (0, 15 and 25%) in the diet of avocado lambs and found that in 60 days of the feeding period, the daily gain and feed conversion ratio was 1.716, 0.26 and 6.06kg for the level of 0 and 1.756, 0.28 and 6.27kg for the level of 15% and 1.806, 0.29 and 6.23kg for the level of 25% ration lambs. The growth traits, carcass quality and meat quality were approximately the same among treatments, and supplementation of up to 25% of levels of vetch did not have a significant effect on fattening performance and consumable carcass parts. However numerical improvement was observed in the food conversion ratio.-


**Table 1.** CLA levels in cattle meat based on various breeding and feeding systems (mg/g fat).-

### **2.1. Chemical composition and fatty acid composition of meat-**

 The results of the chemical composition of the meat samples are reported in findings by Seifdavati and Taghizadeh [14]. The chemical composition of lamb samples fed with different diets showed a significant difference in crude fat and crude protein (P-<-0.01). Unlike crude fats, the raw protein content of lamb meat was higher in soybean meal diet and slightly higher than in other groups. Although the crude protein content of common vetch was higher than the rest of the seeds, the lower carcase protein could be due to its low digestibility of undigested protein in the rumen, which is based on the results of digestion intestinal experiments from the methods of Gargallo etal. [15] and McNiven etal. [16], (for more details, refer to the references [17, 18].-However, there was no increase in the digestible protein content of the total gastrointestinal tract between the tested samples either in their raw state or autoclaved, except for common vetch grain. Even with the autoclave of the common vetch grain, its protein was too protected and was not digested. According to the findings of Seifdavati and Taghizadeh [14], the composition of their experimental diets containing bitter vetch seed and soybean meal, had higher C16: and C18:0 fatty acids compared to the diets of common vetch group and chickling vetch group. The diets of common vetch and chickling vetch group were rich in linoleic (C18:2) and linolenic (C18:3) as essential fatty acids, compared to bitter vetch diets and soybean meal diets. However, the total of these two fatty acids was in all their experimental diets ranging from 56.6 to 57.05 grams per gram of methylated fatty acids. The results according to Seifdavati and Taghizadeh [14] among the saturated fatty acids showed a significant difference in the C16:0 content of the meat samples of the groups and soybean meal group was higher in lamb meat group (P-<-0.05). Also, among the soybean meal groups, the level of palmitic acid C16:0in lamb meat was higher than soybean meal (P-<-0.01). The most abundant fatty acid in meat was oleic acid among legumes and its amount was significantly different between treatments (P-<-0.01). Linolenic acid was higher in common vetch group lamb meat than in dietary containing bitter vetch seed, chickling vetch seed and soybean meal (P-<-0.05). Similar results for this fatty acid were observed by Lanza etal. [3], Wood etal. [8] and Scerra etal. [4] for other legumes used in the dietary concentrate section. Generally, linolenic acid in common vetchgroup lamb meat was higher than in dietary containing bitter vetch seed, chicklingvetch seed and soybean meal group (P-<-0.01). Lamb meat in dietary containing chickling vetch showed higher levels of linolenic acid than lamb meat in soybean meal group (P-<-0.01). The fatty acid composition of the muscle of the lambs moderately reflects the composition of the fatty acid in the diet. Ruminants, unlike nonruminants, do not store fat in tissues as much as they receive in the diet. This is because ruminal microorganisms hydrolyze glycerides and subsequently cause hydrogen to combine with unsaturated fatty acids derived from dietary feeds [19, 20]. Therefore, ruminants have more ratios of saturated to unsaturated fatty acids comparedto nonruminants. The reduction of palmitic acid and stearic acid in lamb meat with diets containing chickling vetch and common vetch, respectively, compared with other diets, showed the potential of these two diets to reduce harmful effects on health (P-<-0.01). These two acids can be responsible for increasing total cholesterol and low-density lipoprotein in the plasma and increasing the risk of human health [5, 20]. In sheep and lamb meats, the ratio of these two fatty acids is more similar. There is a small variation in the ratio of fatty acids present in different body parts of the lamb. An alternative strategy

 to improve health indicators of humans in relation to consumption of lamb meat is reducing the level of stearic acid in the tissue by increasing the activity of the enzyme, stearoyl-CoA desaturase-Δ9, although the response of the animal to this manipulation is often relatively small [21]. In terms of fatty acid content, sheep meat is rich in saturated and poor fatty acids from unsaturated fatty acids, which is thought to be harmful for humans [21]. Despite the initial hypothesis [22], the effects of dietary lipids on human health, there were some issues and ambiguities in the concepts of saturated fatty acids that led to an increase in blood cholesterol and coronary artery disease. In a meta-analysis of Hunter etal. [23] on available scientific documentation from 2000 onwards, it resulted in a systematic review of all previous findings on the concepts of saturated fatty acids. The researchers, in a review with contributions from scientists, focused on the topic that the effect of stearic acid as saturated fatty acid on the risk of vascular disease in the heart depends on the fact that this fatty acid is to be replaced with other saturated fatty acids, trans-fatty acids, fatty acids with a double bond and fatty acids with multiple bonds or with sugary substances. One of the goals and main concern of advanced livestock nutrition research is the study of the possible nutritional manipulation of fatty acid composition of the lamb meat to reduce the concentration of saturated fatty acids and increase the concentration of fatty acids (C18:1, C18:2, C18:3), as cholesterol-lowering serum [20, 21]. However, in the study by Seifdavati and Taghizadeh [14], the concentration of palmitic saturated fatty acid in soybean and bitter vetch group meat was higher than other experimental groups (P-<-0.01). The higher levels of these two fatty acids (palmitic and stearic acid) in the soybean and bitter vetch group meat can be attributed to the higher levels of these two fatty acids in their diets than those of diets containing chickling vetch and common vetch. The level of oleic fatty acid was lower in raw chickling vetch group than in other experimental groups. The amount of oleic fatty acid in the intramuscular fat was higher than that of the ration levels in the meat of all groups. Fortunately, farm animal cells are capable of synthesizing oleic acid and its derivatives from stearic acid. Oleic acid is obtained by unsaturation or loss of hydrogen in stearic acid. In farm animals especially ruminants, secretion of the Δ9-desaturase enzyme make stearic acid easily into oleic acid [24]. But linoleic acid in lamb fat was much less than its dietary fat [14]. This indicates that biohydrogenation is a major part of the rumen [25]. Larger amounts of linoleic acid in the fat of lamb in the chickling vetch group are likely to correlate with the high level of this acid in the chickling vetch group compared to the rest of the group. Among the remaining groups, the amount of linoleic acid in the fat of lamb meat was higher than soybean meal group. The internal biosynthesis of linolenic acid is shown in the studies of Zhou and Nilsson [26]. This acid is a precursor to omega-3 fatty acids that have a wide range of biological activities with beneficial effects on human health [27–29]. Linolenic acid level, similar to linoleic acid in lamb fat, was less than its dietary fat, indicating a major part of its transformation and hydrogenation in the rumen [25].-

### **2.2. CLA of lamb's muscle**

The CLA values in the musclesof the lambs in different groups are shown in findings of Seifdavati etal. [17]. According to these findings in the lamb meat samples of the diet group consisting of common vetch seed, chickling vetch seed, bitter vetch seed and soybean meal, the amount of CLA was 2.23, 1.41, 1.94 and 1.15 g per methylated fatty acid, respectively, and

 so CLA in the diet group containing common vetch seed was significantly more than lamb meat of others dietary groups (P-<-0.01). However, except for the soybean meal group, CLA levels of meat were not significantly different between lambs fed with diets containing raw legumes and processed with autoclave moist heat (P-<-0.01). It is likely that the difference between the dietary groups of the contents of the tested legumes and the soybean meal composition group (control) is related to the specific effect of common vetch, chickling vetch, bitter vetch seeds in expressing the gene and increasing the activity of the Δ9-desaturase enzyme for the production of CLA precursors. Priolo etal. [30] showed that farm animals, especially ruminants, by secreting this enzyme easily convert stearic acid into oleic acid. Priolo etal. [24] found that, by replacing some kind of legumes, the CLA increased in the meat of lambs than soybean meal in lamb diet. The findings of Seifdavati etal. [17] are consistent with the results of Priolo etal. [24]. French etal. [31] reported that CLA levels of calf meat fed with different levels of concentrate and basic forage were different. In this study, the amount of CLA in meat were in the diet of the group (4kg of concentrate + free forage), 0.47 g per 100 g of muscle fatty acid, diet group (8kg of concentrate +1kg of hey), 0.37g per 100g of muscle fatty acid, diet group (6kg of grass fodder +5kg of concentrate), 0.54g per 100g of muscle fatty acid), diet group (12kg of grass fodder +2.5kg of concentrate), 0.66g per 100g of muscle fatty acid and finally diet group (Only 22kg of grass fodder), 1.08g per 100g of muscle fatty acid. Franch etal. [31] concluded that by increasing the level of concentrate, the level of CLA in meat was reduced. De La Torre etal. [32] in a report showed that the base ration and supplementation with oily grains were one of the effective ways to increase the amount of CLA in meat and the use of flaxseed (22 to 36%) in the ration was increased the amount of CLA meat. The researchers explained that the basic forage with concentrates, especially whole grains in the ration of livestock, reduced the severity of the unsaturated fatty acid dehydrogenation in the rumen, and this resulted in the production of optimal trans-vaccenic acid for the synthesis of CLA and its accumulation in meat. McNiven etal. [20] showed that the use of toasted soybean seed instead of its crude soybean seed in feeding calves with base ration did not have an effect on the amount of CLA in meat, and its rate in this report was 0.32–0.35 g per 100 g of fatty acid muscle. Despite the negative effects of rumen metabolism on the intramuscular fat structure of the livestock, the process of biohydrogenation is often carried out incompletely and produces several intermediates that affect human health. One of these compounds is the rumenic acid known as CLA (one of the linoleic acid isomers). Increasing interest in this compound has been attributed to anticancer, coronary heart disease and anti-hyperglycemia and prevents lipid accumulation in the body [20, 33, 34]. In animal experiments, CLA has been shown to inhibit cancer, diabetes and atherosclerosis [35–38]. In addition, McGuire and his colleagues [39] reviewed some of the potential effects of CLA on human health. These researchers have recommended that the increase in the accumulation of CLA in human consumption is realized by manipulation of the dietary intake of ruminants, especially sheep, for the purpose of enriching meat, in order to show the beneficial effects of this compound on health. In the study of Seifdavati etal. [17], CLA levels in meat from lamb fed with the diet group containing common vetch seed were higher than soybean meal group (P-<-0.01) and numerically higher than chickling vetch and bitter vetch seed groups. This can be attributed to a high level of linoleic acid in the content of common vetch seed diet. This fact is shown in the report by Scerra etal. [4], which investigated the effects of some legume seeds on intramuscular CLA,

 in their study. So these researchers found that the higher intracellular CLA in peas seed with 0.45 g per 100 g of methylated fatty acid compared with soybean meal (0.20 g per 100 g of methylated fatty acid) was associated with high levels of linoleic acid in the pea seed diet. As mentioned earlier, in nonruminants, the fatty acid structure of their meat is similar to the structure of fatty acid in the diet, both in terms of accumulation and in terms of its secretion and biosynthetics [40]. However, this is a beneficial and similar effect in ruminants by manipulating and benefiting from the biohydrogenation incomplete process of ruminal metabolism on the dietary fat content [41]. However, several studies have shown the difference in the structure of dietary fatty acids with ruminant body tissues (milk or meat) [42–44]. In the study of Seifdavati etal. [17], CLA levels in lamb meat were two to three times higher than those of other researchers, as reviewed by Khanal and Olson [45] and McNiven etal. [20]. The results of Seifdavati et al. [17], also coincided with the findingsof Tilak etal. [46], Valvo etal. [47] and Lanza etal. [3]. In the study of-Lanza etal. [3] reported that the use of pea grain and horse beans grain instead of soybean meal in the diet of lamb fattening did not change the amount of CLA in meat of lambs and its values for all treatments ranged from 0.78 to 0.93 g per 100 g of methylated fatty acids. Not only differences in CLA content of products in an animal but also among species have been reported and received. In general, CLA levels are higher in ruminants compared to nonruminants [6]. Differences in the total amount of CLA in lamb meat in the experiment of Seifdavati etal. [17], with other reports, can be due to several factors such as nutrition from pasture forage as compared to intensive feeding of the high grain content of rations, the nature of nutrient content of dietary concentrate (having intact and complete oily seeds), the composition of fatty acid supplementation, the proportion of concentrate and silage versus hay, seasonal differences, genetics and animal breed, the type and nature of the seed and the breeding system [6, 46]. In the study of Seifdavati etal. [17], wetheating autoclave treatments of legume grains replacing soybean meal in lamb's diet had no effect on the results of CLA levels of lamb meat. This can be due to the inherent nature of the seeds and the difference in the processing method. The findings of McNiven etal. [20] regarding the effect of soybean heat treatment on CLA in meat contradicted Seifdavati etal. [17] conclusion. In contrast to McNeven etal. [20] findings and in accordance with the results of Seifdavati etal. [17] experiment, Mohammed etal. [48] study showed that the content of trans-fatty acid (C18:1) and CLA isomer of cow milk has a strong effect from the type and nature of the source of grain compared to the processing method, and these researchers have shown that intrinsic factors in the type of grain such as anti-nutritional factors like tannin are responsible for the difference and may not be affected by the processing method. Researchers have shown that tannin content of legume or legume seeds (such as common vetch, chickling vetch and bitter vetch seeds) causes the accumulation of trans-vaccenic acid in rumen in both cases, using the live animal and the laboratory methods [49, 50]. Because tannins have the ability to inhibit trans-vaccenic acid in rumen converting bacteria to stearic acid or, in other words, to reduce the action of biodehydrogenation by inhibiting the activity of mentioned bacteria [49, 50], as a result, this process of CLA production increases as an intermediate product of this route [49, 50]. Despite this, Vasta etal. [51] showed that the CLA of tannin (certainly in low-to-moderate concentrations) is less effective than vaccenic acid, which suggests the fact that CLA is also produced and synthesized in the muscle as endogenous. In the experiment of Vasta etal. [51], CLA levels in the control diet muscle (dried alfalfa with concentrate) were 0.73 g per 100 g of methylated fatty acids, and the diet containing tannin-rich carob pulp treated with and without polyethylene glycol was 0.63 and 0.48 g per 100 g of methylated fatty acid. Findings of Di La Torre etal. [32], Franch etal. [31] and Priolo etal. [24] and in results of Seifdavati etal. [17], lambs fed with whole legumes grains and with alfalfa hay as total mixed ration (TMR) and full oily seeds (more fatty common vetch seed compared to the rest of the seeds) mixed with alfalfa (especially the inclusion of common vetch seed instead of soybean meal) showed that it caused and led to an increase in CLA meat from 1.15 g per 100 g of methylated fatty acid (soybean meal ration) to 2.23 g per 100 g of methylated fatty acid (diet of common vetch seed). Based on the per capita consumption of sheep meat at 7.6kg per year in Iran, 37 g a day is consumed [52]. According to these figures, based on the daily requirement of humans (3500mg of CLA) and the amount CLA of sheep meat intake per day, it will range from 1.8 to 7mg and depending on the marble fat inside the muscle and supplementation of diets of lambs with whole oily grains in fattening. The average value of CLA in the muscle fat of sheep in quantitative aspects are not justifiable and can not be interpreted, unless with for enrichment the lamb meat with CLA, it is used appropriate feed in the diet to form CLA.-Preferably, these materials should be rich in linoleic acid. The forage in diet with the consolidation and proliferation of CLA productive and storage microorganisms and forage supplementation with medium amounts of full-fat high-grade whole-grain material in comparison with high levels of grains material for lambs leads to more CLA for accumulation in muscle tissue. Taking into consideration that the daily requirement per person (3500mg) with regard to the CLA for the beneficial effects on health, part of these needs can be achieved by daily consumption of lamb meat and its inclusion in the food pyramid or food basket provided in each household.-

### **2.3. The use of breeds with an increased capacity to deposit CLA in lambs muscle**

 Public health policies recommend population-wide decreases in the consumption of fat, saturated and trans-fatty acids (TFA), and higher intakes of polyunsaturated fatty acids such as increasing in the consumption of the long-chain n-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (20:5n-3, EPA), and docosahexaenoic acid (22:6n-3, DHA) [54]. Another potential pathway to increase PUFAs in ruminant tissues is to utilize breeds with an increased ability to deposit these fatty acids or deposit n-3 PUFAs in preference to those of the n-6 fatty acid series [55]. According to findings of Wachira etal. [56] Suffolk and Soay lambs contained more α-linolenic acid (ALA) than the Friesland lambs, and Soay lambs had higher intramuscular levels for all the major n-6 PUFAs and CLA than Suffolk or Friesland lambs. The LA and ALA were higher in the Suffolk × Lleyn lambs than Scottish Blackface, as consideredin the polar lipids of the semimembranosus muscle [54]. Lambs from Merino dams had about 2mg/100g higher levels of EPA-+-DHA than lambs from cross-bred dams, when the sire breed was Poll Dorset [57].-

#### **2.4. Protected fat as sources of n-3 fatty acids-**

Ferreira etal. [58] showed that stearic acid concentration decreased linearly when fish oil replaced soybean oil. Also, vaccenic acid concentration was higher for lamb-fed fat diets versus control diet with a 10:90 of forage to concentrate ratio. In addition, vaccenic acid increased linearly with fish oil inclusion. The conjugated linoleic acid (CLA) C18:2 cis-9, trans-11 showed a higher concentration in the meat of animal-fed diets containing fish oil compared to controlled diet, but it was not affected by soybean oil inclusion. However, if the fat used in the diet is somehow protected from rumen degradation, the result will be doubled, as shown in the research that the CLA content of lamb longissimus muscle improved 16.7% when 86.6g of Megalac (as fat protected) per kg of diet DM was fed for 10weeks [59]. It is the general opinion that inclusion of protected fat in diet increases the concentration of n-3 and n-6 fatty acids in muscle in some but not all researches [60, 61]. In these studies (as shown in **Table 2**), there was a higher amount of corn in the controlled diet as a replacement of protected fat diet and thus more LA [53]. It should also be noted that it is not obvious if the 18:3 shown is n-3, n-6 or the sum of both, in the study of Castro etal. [60]. In contradiction with the comment, Gómez-Cortés etal. [62] find the fatty acid composition of lamb muscle with a significant difference among diets containing calciumsoap fatty acid (CSFA) compared with extruded linseed for 18:3n-3 (α-linolenic acid, ALA) but with no effect on 18:3n-6 (γ-linolenic acid, GLA). A significant difference among diets for the muscle level of ALA and no effect on GLA was found in research [63]. A recent research showed the ALA, EPA, DPA, DHA and the sum of PUFA levels, in IMF, were higher in lambs fed with extruded linseed than CSFA of palm oil [62]. This could be because of the higher level of ALA in extruded linseed than in calcium soap of palm oil (as shown in **Table 2**), which is the precursor of the n-3 long-chain PUFA.-



**Table 2.** Sources of oleic, linoleic, and linolenic fatty acids in animal feeds.-

### **3. Conclusion**

Higher CLA values in the muscle tissue of intensively finished lambs are not easily explained.- To increase the CLA yield in lamb meat it is essential to provide lamb an appropriate substrate- for the formation of CLA.-The provision of source of dietary linoleic acid appears to increase the- CLA concentration to the greatest extent. Dietary forage such as grass or legume hay appears- to facilitate the establishment of the micro-flora that enhances the formation and depositionof CLA in the tissues; also, the provision of modest amounts of grain is more conducive to- CLA synthesis rather than high levels of grain. Regarding the recommended daily intake for- appreciation of health benefits in humans (3500mg/d), this amount of CLA supplied to meat- lamb will partially provide the CLA requirement for everyone under conditions of this study.-

### **Acknowledgements**

The authors would liketo thank the Chairman and staffs of the Institute of Khalat Phoshan Educational and Agricultural Research Station located in University of Tabriz in Iran for the financial support and their technical assistance in the preparation and provision of research information for this chapter; we also thank the University of Mohaghegh Ardabili for providing scholarships. We are grateful to the honorable officials of the Laboratory of the Faculty of Chemistry of the University of Tabriz, the Fellow of the Standard Ardabil Day Institute, the Evonik Manufacturing Company Group and Tehran Pars Biopharmacy Co., who have been collaborating in various analyses of the samples and data.-

### **Author details**

Akbar-Taghizadeh<sup>1</sup> \* and Jamal-Seifdavati<sup>2</sup>

\*Address all correspondence to: ataghius@yahoo.com-

1-Department of Animal Science, Faculty of Agriculture, University of Tabriz, Iran-

2-Department of Animal Science, Faculty of Agriculture, University of Mohaghegh Ardabili, Iran-

### **References**


**Section 4**

**Nutritional Composition of Meat**

**Nutritional Composition of Meat** 

**Chapter 4**

**Provisional chapter**

**Nutritional Composition of Meat**

**Nutritional Composition of Meat**

DOI: 10.5772/intechopen.77045

Meat ranks among one of the most significant, nutritious and favored food item available to masses, which aids in fulfilling most of their body requirements. It has played a vital role in human evolution and is an imperative constituent of a well-balanced diet. It is a good source of proteins, zinc, iron, selenium, and phosphorus followed by vitamin A and B-complex vitamins. Average value of meat protein is about 23% that varies from higher to lower value according to the type of meat source. Meat fat and its fatty acid profile is point to worry, with respect to its consumption, but its moderate usage is always advised by doctors and nutritionists, in order to lead a healthy life. Fat content of animal carcasses ranges between 8 and 20%. Quality traits of meat along with its nutritional composition become dependent upon animal breed type, feeding source (grains, pasture and grass), genetics of animal and post mortem techniques. This chapter will mainly focus on the variant aspects of nutritional constituents of meat including proteins and essential amino acids, fats and fatty acid profile, carbohydrates, vitamins and minerals along with their

**Keywords:** meat, nutritional value, proteins, saturated fats, minerals, vitamins

Ingestion of fresh, healthy and wholesome food materials play a crucial role in maintaining the health status of human beings. The term balanced diet has gained immense popularity globally owing to the increasing awareness regarding the maintenance of health status among the masses. Balanced diet ensures the intake of all the essential nutrients, which are required by the human body to perform the daily life functions [1]. In this scenario, awareness of nutritional composition of the food stuffs has become quite significant in having a balanced meal,

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

Rabia Shabir Ahmad, Ali Imran and

Rabia Shabir Ahmad, Ali Imran and

http://dx.doi.org/10.5772/intechopen.77045

health benefits to human health.

Muhammad Bilal Hussain

Muhammad Bilal Hussain

**Abstract**

**1. Introduction**

**Chapter 4** 

## **Nutritional Composition of Meat**

Rabia Shabir Ahmad, Ali Imran and Muhammad Bilal Hussain

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.77045

### **Abstract**

Meat ranks among one of the most significant, nutritious and favored food item available to masses, which aids in fulfilling most of their body requirements. It has played a vital role in human evolution and is an imperative constituent of a well-balanced diet. It is a good source of proteins, zinc, iron, selenium, and phosphorus followed by vitamin A and B-complex vitamins. Average value of meat protein is about 23% that varies from higher to lower value according to the type of meat source. Meat fat and its fatty acid profile is point to worry, with respect to its consumption, but its moderate usage is always advised by doctors and nutritionists, in order to lead a healthy life. Fat content of animal carcasses ranges between 8 and 20%. Quality traits of meat along with its nutritional composition become dependent upon animal breed type, feeding source (grains, pasture and grass), genetics of animal and post mortem techniques. This chapter will mainly focus on the variant aspects of nutritional constituents of meat including proteins and essential amino acids, fats and fatty acid profile, carbohydrates, vitamins and minerals along with their health benefits to human health.-

**Keywords:** meat, nutritional value, proteins, saturated fats, minerals, vitamins-

### **1. Introduction**

Ingestion of fresh, healthy and wholesome food materials play a crucial role in maintaining the health status of human beings. The term balanced diet has gained immense popularity globally owing to the increasing awareness regarding the maintenance of health status among the masses. Balanced diet ensures the intake of all the essential nutrients, which are required by the human body to perform the daily life functions [1]. In this scenario, awareness of nutritional composition of the food stuffs has become quite significant in having a balanced meal,

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

which in-turn ensures the health status of individuals. Nutritional composition refers to the comprehensive frame of information regarding vital nutritional components of food items and offers energy values. The nutrients are the elements that provide nourishment essential for the maintenance of life and for growth, which includes both the macro- and micronutrient. Macro-nutrients are those that are required by the human body in large amounts and these include proteins, fats and carbohydrates. Micro-nutrients are those elements which are required by the body in small amount and comprising of vitamins, minerals and fiber [2]. All of these are being supplied by number of food stuffs including meat, cereal grains, milk, fruits and vegetables. Among them meat holds a key spot which fulfills most of the protein requirements of the humans. Different types of meats are present including the beef, mutton, lamb, chicken and fish etc. Each and every type of meat is significant in its own value with little differences in its composition [3]. The detailed information regarding its nutritional composition is as follows;-

### **2. Nutritional composition of meat**

Meat ranks among one of the most significant, nutritious and energy-rich natural food product,- utilized by the humans to fulfill their regular body requirements. It is considered quite important in maintaining a healthy and balanced diet, which is essential in accomplishing optimum- human growth and development. Although, few epidemiological studies have also pointed a- possible relationship between its consumption and the elevated risks of having cardiovascular- diseases, various forms of cancers and metabolic disorders but still its role in the human species evolution, specifically in its brain and intellectual development cannot be ignored [4].-

In accordance with European legislation, meat is defined as the edible portions, obtained from domestic animals including caprine, bovine, ovine and porcine, including the poultry meat, farmed and wild animals. It is a rich source of high value proteins, variety of fats including omega-3 polyunsaturated fatty acids, zinc, iron, selenium, potassium, magnesium, sodium, vitamin A, B-complex vitamins and folic acid. Its composition varies with reference to its breed, type of feed being ingested, climatic conditions and also on the meat cut, which imparts a considerable difference on its nutritional and sensorial properties [4].-

From the nutritional point of view, meat is considered as a rich essential amino acids source whereas, mineral contents to a lesser extent. Apart from it, essential fatty acids and vitamins also make a part of it. Organ meat like liver is quite an enriched source of Vitamin A, Vitamin B1 and nicotinic acid. The research is still in progress for the better understanding of the probable differences among the nutritional value of different meat cuts, variant animal species and breeds. It is quite evident from the previous research that the meat having lesser connective tissues is likely to have low scores of digestion and absorption [5]. Moreover, the meat having more connective tissues are supposed to have less contents of essential amino acids, which make them less nutritious as compared to the meat piece having lesser connective tissues and results in more digestibility and nutritional value [3]. Following **Table 1** shows the nutritional composition of different sort of meat products.-


**Table 1.** Nutritional composition of meat [4, 6].-

### **2.1. Water**

Water is one of the important constituents of all food materials. In general, there are three types of food products depending upon their moisture contents, firstly perishable commodities (having more than 70% moisture content in them), non-perishable commodities (having around 50–60% moisture contents) and stable food materials (with less than 15% moisture). The more the water content of any food material the lesser are the chances of its longer shelf life as micro-organisms have greater chance to grow on them that in turn, limit their lives.-

Meat ranks among the perishable food material, as it contain around more than 70% of moisture in it. Apart from reduction in shelf life, its presence imparts a strong impact on the color, texture and flavor of muscle tissues of meat. Adipose tissues (tissues on the abdominal part of the animal) contain less moisture content, which leads to the fact that if the animal is fatter it will be having lower water content in its carcass and vice versa. Younger and leaner animals exhibited around 72% of moisture content [7].-

Major portion of water contents in meat tissues exist in free- state within muscle fibers and smaller amount of it is present in the connective tissues. During the processing conditions, such as curing and heat treatment followed by the storage, small percentage of the water remains within the muscle fiber which is termed as the "bound water". The three dimensional structure of muscle fiber fortified with the pressure and temperature helps the water to retain in the muscles during the processing conditions, while most of the water "lost" during these circumstances known as "free water". The water holding ability of meat could be altered by the disruptions of its muscle fibers, which resultantly aid in the enhancement of the shelf life of meat products. There are numerous methods involved in this regard containing chopping, grinding, salting, freezing, thawing, breakdown of connective tissues by enzymatic or chemical means, heating application and use of chemicals or organic additives altering the acidity (pH) of meat are the processes that can affect the final water contents of meaty products [8].-

### **2.2. Carbohydrates**

The main source of the carbohydrate in the animal body is its liver, which contains about ½ of the total carbohydrates present in the body. They are stored in the form of "glycogen" mainly in the liver and muscles but also in glands and organs to lesser extent. Its substantial quantities are present in blood in the form of glucose. The glycogen has an indirect impact on the meat color, texture, tenderness and water holding capacity of it. The conversion of stored glycogen to glucose; and from glucose to lactic acid is quite a complex process and all these modifications are governed by the action of hormones and enzymes [9].-

During the early stage of aging, the lactic acid content of musclesincreases, thus lowering the pH.-The pH has a very strong influence on the muscle texture, tenderness, color and also on water-holding capacity. The normal pH of the muscle considers being around 5.6. If an animal suffers from severe stress or exercise just before the slaughter and have no chance to regain its normal glycogen levels, then a minute amount of glycogen will be there to convert into lactic acid causing an elevated pH (i.e. 6.5) and as a result, meat muscles get dark, firm and dry (DFD). This type of meat results from exhaustion and then causes depletion of glycogen before slaughter. This occurs not so often in beef (2%), but also affected the other ones that are called as "Dark Cutters". The main reason for the dark colored meat with high pH is owing to the higher water holding capacity. This causes the muscles to absorb more water, which makes them to absorb the incident light rather than to reflect it from the meat surface, thus causing the darker appearance of the meat. This DFD defect is quite disliked by the retailers and customers, affecting heavily on its sensorial and nutritional properties, so stress and rough handling of animals should be avoided just prior to slaughtering [10].-

A quite speedy postmortem causes a drop in the muscle pH (i.e. 5.0) is recognized by pale, soft- and exudative condition (PSE), which is quite common in pork meat. PSE affected muscle portion is recognized by low water-holding capacity, soft texture and pale yellow color. The softer- muscle structure of PSE meat causes its lower water-holding capacity, which is then accountable for more reflectance of incident light, thus making the color of meat as pale yellow [11].-

All the above mentioned conditions of DFD and PSE relates to the carbohydrate contents of the meat, which has considerable effect on nutritional value of meat.-

### **2.3. Proteins and its amino acids**

Meat ranks among one of the protein-rich foods, providing high biological value to the masses.- Proteins are naturally occurring complex nitrogenous compounds having very high molecularweight consisting of carbon, hydrogen, oxygen and most importantly nitrogen. Few of the proteins also have phosphorousand sulfur in their structures. All these components chemically- linked together to form different types of individual proteins, exhibiting different properties.- These vary from one tissue to the other within a same living organism and also in corresponding- tissues of different species. The proteins are more complex than the carbohydrates and fats from- their size and constituents. The percentage of meat protein component varies extensively in different types of meats [12]. In general, the average value of the meat protein is about 22%, but it- could range from high protein value of 34.5% in chicken breast to as low as 12.3% protein in duck- meat. The protein digestibility-corrected amino acid scores (PDCAAS) which depict the protein- digestibility reveals that meat has high score of 0.92 as compared to other protein sources including lentils, pinto beans, peas and chickpeas scoring 0.57– 0.71 [13]. Protein quality is mainly concerned with the availability of amino acids present in it.-

Amino acids serve as the building blocks of the proteins. The nutritional value of meat can be varied to great deal by the presence or absence of numerous amino acids. One hundred and ninety two are known among which only 20 are used to prepare the proteins. From these 20 amino acids, 08 are considered as the essential amino acids, as these could not be prepared by the human body, so must be taken by the diet. Other 12 are the non-essential amino acids that could be manufactured by the human body but only if their particular dietary sources are being ingested, otherwise, it could result in the protein malnutrition. The **Table 2** shows all non-essential and essential amino acids present in meat.-

The beef meat appears to have higher contents of valine, lysine and leucine as compared to lamb and pork. Studies have revealed that main reason of the difference in essential amino acid proportion lies with the breed, animal age and muscle location. Previous research studies reported that contents of valine, isoleucine, phenylalanine, arginine and methionine in the animal meat increase with its age [16]. The essential amino acid contents also differ with the different parts of the carcass. Their composition could also be affected by the application of processing techniques including heat and ionization radiations, but only when the severe prolonged mode of these conditionsare being applied [17]. In some cases, these amino acids are not being available for the human use. In a study, some researchers found out that only 50% of lysine was available at 160°C, while 90% of it was there at 70°C.-Sometimes the interaction of the other constituents with the proteins has put an effect on the availability of essential amino acids. Smoking and salting of the meat has also played its role in this regard. Apart from the effect of the processing conditions, the storage has also imparted its effect on amino acids, in case of canned meat [18].-

#### **2.4. Fat and fatty acids-**

Fats rank among one of the three major macro-nutrients, including carbohydrates and proteins.- Fat contents are known as triglycerides that are esters of three fatty acid chains and the alcohol- glycerol. Meat contains fatty tissues (fat cells filled with lipids) that have varying amount of fat.- In meat, fat content functions as energy deposits, protective padding in the skin and around- organs especially heart and kidney as well as provides insulation against body temperature- losses [19]. Fat content in animal carcass varies from 8 to 20% (latter is only in pork). The fatty- acid and fat composition of fatty tissue differs significantly in different locations among poultry-


**Table 2.** Amino acid composition in fresh meat [6, 14, 15].-

and other meat products such as offal, sausages and ham etc. External body fat is softer than the- internal fat that surrounds the organs owing to the higher content of unsaturated fat in external- animal parts. Skin is the main fat source in poultry meat. In the main retail cuts, fat content in- chicken and turkey ranges between 1 and 15% and meat cuts with skin have higher percentage.- Cooking can have a significant effect on fatty acid composition and meat fat content. Scientific- evidence reported the considerable losses of fat in numerous meat cuts which were referred to- broiling, grilling and pan-frying without added fat [20].-

Among the fatty acid composition, meat contains unsaturated fatty acids; oleic (C-18:1),- linoleic (C-18:2), linolenic (C-18:3) and arachidonic (C-20:4) acid appear to be essential.- They are necessary constituents of mitochondria, cell wall and other active metabolic sites.- Linoleic acid (C-18:2) is abundantly present in vegetable oils such as soya and corn oils with- its concentration 20 times in meat and linolenic acid (C-18:3) occurs abundantly in leafy parts- of plants. Eicosapentaenoic acid (C-20:5) and docosahexaenoic acid (C-22:6) are normallypresent at low concentration in meat tissues, but these are present in high concentrations- in fish and fish oils [21]. Polyunsaturated fatty acids concentrations as well as cholesterol in- muscular and offal tissues of common meat species are shown in **Table 3**.-

It is obvious that the linoleic acid concentration is more in lean meat of pig than in ox or sheep meat. These variations in concentration of fatty acids compositionamong different species are also revealed in kidney and liver fatty acid profile. The liver tissue in all the mentioned animal species is suggested as a rich source of polyunsaturated fatty acids. On the other hand, brain has distinctively high concentration of C-22 polyunsaturated fatty acids. It is tabulated that the concentration of cholesterol in offal tissues, particularly brain is more than the concentration in muscle tissues [26].-

From the number of polyunsaturated fatty acids, omega 3 fatty acids justify their special attention as they play a protective role in general human health particularly cardiovascular diseases.- Seafood is the main source of omega 3 fatty acids. Though, meat can contribute up to 20% of- long chain omega 3 polyunsaturated fatty acids intake. This polyunsaturated omega 3 content- in meat depends on the feeding source and it is higher in forage-based and grass diet. It is also- suggested that polyunsaturated fatty acids of animal fat are indispensable for the development- of brain, particularly in the fetus. When linoleic and linolenic acids are ingested, they can be- digested by animal liver and produce polyunsaturated fatty acids. Furthermore, the chain elongation of linoleic acid gives rise to the prostaglandins which are very important for the regulation of blood pressure. Prostaglandins are mostly found in organs and tissues and synthesized- in the cell from essential fatty acids. They are produced by all nucleated cells and known as- autocrine and paracrine lipid mediators that act on endothelium, uterine and platelet cells [27].-

To avoid the possible harmful effects on health from the consumption of the meat of ruminant animals, there must be introduced a greater potential of unsaturation into their fats and- fatty tissues. Generally, feeding of vegetable fats to sheep and cattle would be nullified because- of the reduction or condensation by rumen bacteria. But, when they are firstly treated with-


**Table 3.** Polyunsaturated fatty acids and cholesterol in lean meat and offal [22–25] (as % total fatty acids).-

formaldehyde, there would be the resistance in reduction and then results in increased potential of unsaturation in fat stores of ruminants. Because of the important role of meat in human- diet, increasing its consumption rate through the years and considerable role in human health,- numerous research studies were concentrated on different ways of fatty acid composition- improvement in meat. Meat fatty acid composition can be changed through animal diet (feeding), certainly in single-stomach poultry and pigs where the alpha-linolenic, linoleic and longchain polyunsaturated fatty acid contents respond suddenly to elevated dietary applications.- Significant difference was found between grain and pasture-fed animal's fatty acid composition- that gives higher polyunsaturated fatty acid concentration in pasture-fed animal groups [28].-

Digestive characteristics of animals may affect composition of meat fatty acids. Microbial enzymes encourage the hydrolysis of unsaturated fatty acids that leads to an increased stearic acid concentration that reaches in small intestine and gets absorbed there. Trans-fatty acids are formed in beef as a result of the bio hydrogenation by rumen bacteria. The most common and well known in meat from ruminant animals is conjugated linoleic acid (CLA), which has been proved to prevent cardiovascular diseases, obesity and diabetes [29].-

### **2.5. Minerals**

Minerals are the nutrients present in food materials that do not contain the element carbon in them and required for the proper growth, development as well as maintenance of human body. They are divided into two categories i.e. macro- and micro-minerals, on the basis of their requirement by the human body. Macro-minerals are those ones, which are required by the body in larger amount. These include sodium, calcium, phosphorus, magnesium, chloride potassium and sulfur, while micro-minerals refers to those who are required in smaller amounts including iron, zinc, iodine, copper, cobalt, manganese, selenium and fluoride [30]. The following **Table 4** represents the micro- and macro-minerals of meat and meat products.-

It is quite evident that potassium is quantitatively quite dominant mineral as compared to others i.e. followed by phosphorus, sodium and magnesium. Meat is also a very good source


**Table 4.** Mineral contents (mg/100g) of meat and meat products [31, 32].- of iron, zinc and selenium. All these minerals perform variant functions for the growth, development and maintenance of human body that are described as follows.-

### *2.5.1. Potassium*

Potassium helps in metabolism, nerve impulses transmission, growth, muscle building and maintaining of acid–base balance in the human body.-

### *2.5.2. Phosphorus*

Phosphorus is an important mineral element that gives energy, forms phospholipids along with Ca, which involves the formation of bones and teeth.-

### *2.5.3. Sodium*

Regulates water content of the body, aids in transport of CO2and maintains osmotic pressure of body fluids.-

### *2.5.4. Magnesium*

Magnesium repairs and improves the growth of human body, maintains blood pressure, prevents tooth decay and helps to keep bones healthy.-

### *2.5.5. Zinc*

Zinc is the part of many enzymes, required for the body immune system, having role in cell division, growth and wound healing.-

### *2.5.6. Selenium*

Prevent cancer, poisonous effect of heavy metals and helps the body after vaccination.-

### *2.5.7. Iron*

Iron is one of the key mineral present in meat, which plays a vital role in human health- and its deficiency causes several hindrances in the normal functioning of human body,- particularly disturbs child growth and development [33]. The mode of metabolism of iron- is quite different from the other mineral contents in the sense, that it is excreted and more- than 90% of it is utilized internally in the body. Obligatory sources of iron and red blood- cells disruption or losses are intestines, urinary tract, skin and also during menstrual- bleeding among females. Its deficiency could be overcome primarily by the diet [34]. Iron- is available in a number of food stuffs and occurs in two forms like heme and non-heme- iron. The former one comes from the hemoglobin and myoglobin, so it is present in animal- foods only and has a high degree of bioavailability that could easily be absorbed in the- intestinal lumen [35].-

### *2.5.7.1. Organ meat as a mineral source*

It is quite evident that the offal organs are quite rich in the mineral contents like iron, zinc, and copper as compared to the minerals that are present in muscular tissues. The children on the fully vegetarian diet could lead them to retarded cognitive activity owing to zinc deficiency, so the ingestion of meat stuff has been emphasized [7]. Mineral contents of offal organs are depicted in **Table 5**.-

### **2.6. Vitamins**

Vitamins are a group of organic substances that function in a variety of dimensions in human body. These constituents although required in minute amounts and are very important for the proper growth, development and maintenance of the human body. They are especially required at the early age of life by the children. They partake in various metabolic processes involving series of chemical and biochemical reactions. One of their distinguishing features is that they generally cannot be prepared by the mammalian cells, so must be supplied through the diet [37]. They are generally classified into two groups on the basis of their solubility in water and fat i.e. water soluble vitamins and fat soluble vitamins. Water soluble vitamins include the B-complex vitamins (thiamin, riboflavin, nicotinic acid, pyridoxine, choline, biotin, folic acid, cyanocobalamin, inositol, vitamin-B6and vitamin-B12) and vitamin C.-Fat soluble vitamins of meat including vitamin A, vitamin D and vitamin K also participate in the nutritional importance of meat [38].-

Meat is a good source of five of the B-complex vitamins including thiamin, riboflavin, nicotinic acid, vitamin B6and vitamin B12. It also contains pantothenic acid and biotin, but a poor source of folacin [39]. Vitamin content of various raw meats is illustrated in **Table 6**.-


**Table 5.** Mineral content of offal tissues [22, 36].-

### *2.6.1. Water soluble vitamins*

### *2.6.1.1. Thiamin*

It works along with other B-complex vitamins to carry out numerous chemical reactions required for the growth and maintenance of the human body. They are involved in the metabolic processes necessary for energy production to perform various body functions. Deficiency of thiamine could cause loss of appetite, fatigue, constipation, irritability and depression. Meat in general is a good source of thiamine with especial reference to fish which provides larger quantities of it as compared to other meat sources except pork.-

#### *2.6.1.2. Riboflavin-*

It is essential to release energy from the major food constituents like proteins, fats and- carbohydrates. It helps in retaining good eye sight and healthy skin. It also aids in the- absorption and utilization of iron. Moreover, it is required in the conversion process from- tryptophan to niacin. Poultry meat, lamb and beef are considered among the good sources- of riboflavin.-

### *2.6.1.3. Niacin*

Together with other B-vitamins, niacin functions in a variety of intracellular enzyme systems, including those involved in energy production. Its sources are meat, fish and poultry etc. Its deficiency causes the disease called as "pellagra" which is characterized by the rough or raw skin. Other problems include memory loss, vomiting and diarrhea.-


**Table 6.** Vitamin content of various raw meats [31, 36].-

### *2.6.1.4. Vitamin B6*

Vitamin B6plays a vital role in the functioning of approximately 100 enzymes that catalyze the essential chemical reactions in the human body. It helps in the synthesis of the neurotransmitters and important in the synthesis of heme iron i.e. a component of hemoglobin. Additionally, it also helps in the synthesis of niacin from tryptophan. Important meaty sources of vitamin-B6 are fish, poultry and meat.-

### *2.6.1.5. Vitamin B12*

This vitamin is important for the synthesis of deoxyribonucleic acid (DNA), which is a genecontaining component of cell's nucleus, vital for proper growth and development of the human body. Vitamin-B12is found only in foods of animal origin; therefore, vegans (vegetarians who consume no animal products) might have been needed to supplement their diet with this vitamin. Individuals who have pernicious anemia (inability to absorb vitamin-B12- from food) and do not consume vitamin-B12can be treated successfully with injections of vitamin-B12. Liver, beef, lamb and pork are rich sources of this vitamin. Some other sources are oysters, fish, egg yolk and cheese.-

### *2.6.2. Loss of B complex vitamins during meat processing*

 Vitamins present in the meat get lost during its processing by both methods of conventional- heating and microwave heating especially in case of vitamin B<sup>1</sup> [40]. The retention of both the- vitamins B1 and B2from different kinds of the meat by conventional cooking is shown in the- table. The loss of vitamin B1 was mainly observed by leaching. These losses are about 15–40%- by boiling, 40–50% by frying, 30–60% through roasting, and 50–70% on canning [40]. Other vitamins of B complex family including B6 , B12and pantothenic acid also exhibit same issues like B<sup>1</sup> . Contrary to it, vitamin A has the ability to retain even at the temperature of 80°C.-Loss or retention of B complex vitamins during conventional and microwave cooking is illustrated in **Table 7**.-


**Table 7.** Comparison of cooking losses and vitamin B<sup>1</sup> retention in conventional and microwave cooking [31].-


**Table 8.** Vitamin contents (units/100g raw tissue) of various offal tissues [22, 36].-

### *2.6.3. Fat soluble vitamins*

Vitamin A is a fat-soluble vitamin necessary for the maintenance of healthy tissues and for maintaining the normal vision and eyesight. Green and yellow vegetables provide most of the vitamin A and it occurs in the form of carotene (a precursor which the body converts to vitamin A). Milk and margarine are often fortified with vitamin A.-Liver is suggested as the greatest single food source of vitamin A.-It is also a good source of the other fat-soluble vitamins such as vitamin D and vitamin K [41]. Vitamin contents (water and fat soluble) of various offal organs are shown in **Table 8**.-

### **3. Conclusion**

This chapter concludes that meat and meat products have significant role in fulfillment and maintenance of human health. Studies indicated that strong nutritional composition (fats, proteins and- carbohydrates) with minerals, vitamins and other functional compounds have a preventive role- against major and minor nutrients deficiency diseases. This food material must be included as- important proportion in balanced diet to meet the required health benefits. Proteins and amino- acids are beneficial for growth and building of muscles in humans. Owing to the fats and fatty- acid profile composition of meat, there is a point to be concerned about the consumption of meat- because of the presence of saturated fats that cause coronary heart diseases and elevated cholesterol level if taken in higher than normal amount. Thus, intake of meat in balanced proportion- must be according to the prescription of nutritionist and health practitioners. Additionally, minerals and vitamins including zinc, iron, selenium, sodium, copper, magnesium, calcium, potassium,- phosphorus and vitamin A along with ample amount of B complex vitamins are considered as- important constituents of meat, respectively, that are beneficial for overall human health stratum.-

### **Acknowledgements**

We would like to acknowledge that Government College University Faisalabad and its IT department provided us kind permission to use digital library and access to research data.-

### **Conflict of interest-**

The authors declare no conflict of interest.-

### **Author details**

Rabia Shabir-Ahmad\*, Ali-Imran and Muhammad Bilal-Hussain-

\*Address all correspondence to: rabiaahmad@gcuf.edu.pk-

Institute of Home and Food Sciences, Government College University Faisalabad, Pakistan-

### **References**


## *Edited by Muhammad Sajid Arshad*

Meat holds an important position in human nutrition. Although protein from this source has lower biological value than egg albumin, it is an exclusive source of heme iron and vitamins and minerals. Fat content and faty acid profle from this source are a constant mater of concern. Tough currently meat utilization is linked with an array of maladies, including atherosclerosis, leukemia, and diabetes, meat has a noteworthy role not only for safeguarding proper development and health, but also in human wellbeing. Enormous scientifc investigations have proved that consuming meat has had a benefcial role in cranial/dental and gastrointestinal tract morphologic changes, human upright stance, reproductive atributes, extended lifespan, and maybe most prominently, in brain and cognitive development.

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