**7. Sensory evaluation**

Cooked burgers from each treatment were evaluated by 18 panelists from the sensory evaluation team at the Department of Nutrition and Food Technology. The panelists were both male and female, and were of different ages; they were requested to taste each sample separately without comparing it with other samples. Panelists were familiarized with the questionnaire form used. The samples were evaluated for desirability in appearance, color, tenderness, flavor, juiciness and overall acceptability using a 9-hedonic scale test as described by LARMOND (1991), varying from 9 (like extremely) to 1 (dislike extremely). Pieces of bread and water were used to neutralize the taste between samples.

The sensory evaluation results showed that all the sensory characteristics did not exceed the range like moderately, or fell to dislike slightly*.* This low score given by the panelists for all samples might be attributed to the fact that the prepared burgers were free of any added ingredients or additives that are usually added to these type of products such as spices, salt, protein derivatives of vegetable origin, dietary fibers, antioxidants, flavor enhancers and other additives which result in enhancing the sensory characteristics and the stability of the meat products.

Since the fat content of all burger treatments was about 15%, these products might contain up to 20-30% of fat to give the desirable succulence and texture.

Mixing of chicken with beef meat enhanced the sensory characteristics of the beef. In general, mixed sample had sensory scores higher than beef sample, and were close to the chicken sample. Mixed formulation was the most stable with respect to the sensory characteristics during the storage period. Freshly prepared mixed formulation samples had appearance and color scores (6.94 and 6.89, respectively) higher than those of the beef and chicken samples.(6.11 and 6.83, respectively for appearance) and (5.67 and 6.61, respectively for color). This may be due to the dilution of the redness color of beef meat as well as the dilution of the yellowness of the chicken meat which resulted in moderate appearance and color between beef and chicken meats (between redness and yellowness), since beef meat contains more myoglobin than chicken.

Appearance and color are related sensory qualities, so this modification in color of the mixed treatment affected the appearance, which in role affected the panelist's evaluation.

Tenderness evaluation of meat and meat products by panelists is correlated mainly with juiciness. Therefore, close scores of tenderness and juiciness of beef chicken and mixed treatments were observed. Tenderness and juiciness scores of the mixed formulations were significantly higher than those of beef, and very close to those of chicken. This indicated that tenderness and juiciness are strongly related to the type of meat more than to other factors.

Meat Fat Replacement with Olive Oil 445

Substitution of meat fat in beef and chicken samples with olive oil, in general, did not affect the sensory characteristics, since no significant differences were found between the sensory scores of the samples with and without olive oil. Beef with olive oil showed lower sensory scores after three months of storage compared to the beef sample with tallow, whereas the sensory

Although chicken with olive oil treatment showed lower cooking loss compared with the chicken treatment The tenderness and juiciness scores of these two treatments were not

Storage time did not significantly affect the sensory evaluation scores of each treatment, except for chicken in which the appearance, color and overall acceptability at the end of storage were lower than the initial values. Appearance, color, flavor and overall acceptability of beef with olive oil also were affected by storage time. This decline in sensory

In conclusion, it could be observed that the addition of olive oil did not affect the sensory properties of chicken burger, but it had a slight negative effect on these properties of beef burger, and addition of chicken meat to beef burger improved their sensory properties, which was very close to those of chicken sample. In addition, although, the fatty acid oxidation measured by TBARS of all treatments during storage and by grilling was relatively high, but it didn't affect significantly the sensory properties of their samples.

As a result of this research, it is recommended to introduce olive oil in burgers and other potential meat products to improve their nutritional value and to reduce their cholesterol content, and also to produce burger by mixing chicken and beef meat to enhance the sensory properties of the beef and to improve the oxidative stability of the chicken. However, Further studies are needed to determine the most suitable ratio of chicken/beef meat and fat

Chritopherson, S. and Giass, R. (1969). Preparation of milk fat methyl esters by alcoholysis in an essentially nonalcoholic solution. *Journal of Dairy Science,* 52, 1289-1290. Fernández, J., Pérez-Alvarez, J. and Fernández-López, J. (1997). Thiobarbituric acid test for

Faustman, C., Yin, M. and Nadeau, D. (1992). Color stability, lipid stability, and nutrient composition of red and white veal. *Journal of Food Science*, 57, 302-304. Jordanian Institute for Standards and Metrology, The Hashemite Kingdom of Jordan. (2002).

Kyoichi. O., Takehiro, K., Koji, Y. and Michihiro, S. (1993). Oxidation of cholesterol by

Larmond, E. (1991). *Laboratory Methods for Sensory Evaluation of Food*, (2nd ed). Ottawa:

Mattson, F. H. and Grundy, S. M. (1985). Comparison of dietary saturated,

Standard No. JS: 1334/2002, (2nd ed). Meat and Meat Products: *Poultry-Chilled* 

monounsaturated and polyunsaturated fatty acids on plasma lipids and

to be used in burger formulas which give the best chemical and sensory properties.

monitoring lipid oxidation in meat. *Food Chemistry,* 59(3), 345-353.

*and/or Frozen Chicken /or Burger.* Amman, Jordan. (In Arabic).

heating. *Journal of the American Chemists' Society,* 41, 1198-1202.

Canadian Department of Agriculture Publication.

lipoproteins in man. *Journal of Lipid Research,* 26, 194-203.

characteristics of the chicken with olive oil remained stable during the storage period.

parameters of these samples should be attributed to oxidation

significantly different.

**8. References** 


Means in the same column with the same subscripts denote no significant differences among treatments of burger (p> 0.05) according to LSD.

Means in the same row with different superscripts denote significant differences among treatments of burger (p< 0.05) according to LSD.

Means are the average of 18 reading.

Table 7. Effect of formulation and storage time on sensory evaluation scores for the burger samples.


\* Correlation is significant at the 0.05 level

Table 8. Pearson's correlation coefficients between the sensory scores for the burger formulations.

a6.83a ab6.22ab b5.50b

a6.61ab ab6.00ab b5.11b

> a6.56a a6.33a a6.22a

a6.33a a5.88ab a5.50ab

a6.44a a5.61a a5.61a

a6.52a ab6.06ab b5.51a

Means in the same column with the same subscripts denote no significant differences among treatments

Means in the same row with different superscripts denote significant differences among treatments of

Table 7. Effect of formulation and storage time on sensory evaluation scores for the burger

scores Appearance Color Tenderness Flavor Juiciness Overall

Appearance 1.00 0.95\* 0.60\* 0.79\* 0.72\* 0.90\* Color 0.95\* 1.00 0.59\* 0.71\* 0.70\* 0.85\* Tenderness 0.60\* 0.59\* 1.00 0.78\* 0.96\* 0.79\* Flavor 0.79\* 0.71\* 0.78\* 1.00 0.84\* 0.92\* Juiciness 0.72\* 0.70\* 0.96\* 0.84\* 1.00 0.88\*

acceptability 0.90\* 0.85\* 0.79\* 0.92\* 0.88\* 1.00

Table 8. Pearson's correlation coefficients between the sensory scores for the burger

Treatment

a6.94a a7.00a a6.83a

a6.89a a7.00a a6.44a

a6.10a a6.72a a6.67a

a5.78ab a6.28a a5.94a

a6.11a a5.67a a5.83a

a6.39ab a6.50a a6.00a

olive oil

a6.00a a5.33b b4.16c

a5.88b a5.39c b4.00c

a4.27b a4.50b a4.33b

a5.06b ab4.72c b3.94c

a4.44b a4.22b a3.56c

a5.39b ab4.44c b3.72b

Chicken with olive oil

> a6.56a a5.61b a5.72b

a6.67ab a5.61bc a5.61ab

a6.44a a6.50a a6.17a

a6.06a a5.12bc a5.63ab

a6.17a a5.44a a5.50ab

a6.10ab a5.17bc a5.83a

acceptability

Beef Chicken Mixed Beef with

Characteristic

Appearance

Color

Tenderness

Flavor

Juiciness

Overall acceptability

samples.

Sensory

Overall

formulations.

\* Correlation is significant at the 0.05 level

Time of storage (month)

> 0 1 3

> 0 1 3

> 0 1 3

> 0 1 3

> 0 1 3

> 0 1 3

of burger (p> 0.05) according to LSD.

burger (p< 0.05) according to LSD. Means are the average of 18 reading.

a6.11a a6.06ab a5.94ab

a5.67b a5.56bc a6.33a

a4.44b a4.55b a4.60b

a4.94b a5.06bc a4.83bc

a4.17b a4.27b a4.44b

a5.38b a5.00c a5.22a Substitution of meat fat in beef and chicken samples with olive oil, in general, did not affect the sensory characteristics, since no significant differences were found between the sensory scores of the samples with and without olive oil. Beef with olive oil showed lower sensory scores after three months of storage compared to the beef sample with tallow, whereas the sensory characteristics of the chicken with olive oil remained stable during the storage period.

Although chicken with olive oil treatment showed lower cooking loss compared with the chicken treatment The tenderness and juiciness scores of these two treatments were not significantly different.

Storage time did not significantly affect the sensory evaluation scores of each treatment, except for chicken in which the appearance, color and overall acceptability at the end of storage were lower than the initial values. Appearance, color, flavor and overall acceptability of beef with olive oil also were affected by storage time. This decline in sensory parameters of these samples should be attributed to oxidation

In conclusion, it could be observed that the addition of olive oil did not affect the sensory properties of chicken burger, but it had a slight negative effect on these properties of beef burger, and addition of chicken meat to beef burger improved their sensory properties, which was very close to those of chicken sample. In addition, although, the fatty acid oxidation measured by TBARS of all treatments during storage and by grilling was relatively high, but it didn't affect significantly the sensory properties of their samples.

As a result of this research, it is recommended to introduce olive oil in burgers and other potential meat products to improve their nutritional value and to reduce their cholesterol content, and also to produce burger by mixing chicken and beef meat to enhance the sensory properties of the beef and to improve the oxidative stability of the chicken. However, Further studies are needed to determine the most suitable ratio of chicken/beef meat and fat to be used in burger formulas which give the best chemical and sensory properties.

#### **8. References**


**24** 

*1Philippines 2USA* 

**Biocatalyzed Production of** 

Laura J. Pham1 and Patrisha J. Pham2

**Structured Olive Oil Triacylglycerols** 

*1BIOTECH, University of the Philippines at Los Baños College, Los Baños, Laguna, 2Dave C. Swalm School of Chemical Engineering Mississippi State University,* 

Functional properties of fats and oils do not depend only on their fatty acid composition but also on the distribution of these fatty acids in the three positions of the glycerol backbone. This gives the fat or oil its commercial value. (Zhao,2005) There is a growing demand for lipids with desired characteristics ,thus researches have given way to these demands by the development of structured lipids with triacylglycerols that have predetermined composition and distribution of fatty acids. Structured lipids are now considered as alternatives to conventional fats not on the basis of saturate/polyunsaturate ratios but rather on their impact on cholesterol deposition. With the advances in the biotechnology and chemistry of fats and oils it is now possible to design fats and oils with properties that are desired. Recent years have seen great interest in the biotechnological modification and synthesis of structured triacylglycerols. Modification of fats and oil triacylglycerols to improve functionality have been carried out with various oils including olive oil. Olive oil enjoys a privileged position amongst edible oils and is still a buoyant commerce because of the large consumption of Mediterranean inhabitants (Oh et al,2009). It is one of the most expensive vegetable oils and of all the vegetable oils, olive oil is the best source of the monounsaturated fatty acid, oleic acid (72-83%)Risk factors for cardiovascular disease such as the level of homocysteine and total and low density lipoprotein (LDL) cholesterol in plasma have been reported to be reduced by oleic acid (Baro et al,2003). Olive oil is more than just oleic acid and because of its properties and qualities, it is used almost entirely in

dietary consumption and even new markets have been created for this oil.

Triacylglycerols are by far the most abundant single lipid class and virtually all important fats and oils of plant or fat origin and most animal depot fats consist almost entirely of this lipid.

Glycerol is a trihydric alcohol (containing three **-OH** hydroxyl groups) that can combine with up to three fatty acids to form monoacylglycerols, diacylglycerols, and triacylglycerols.

**2. Triacyglycerol structure and characteristics** 

**2.1 Triacylglycerol structure** 

**1. Introduction** 

