**3. Pomegranate pomace**

Pomegranate (*Punica granatum* L.) is a member of the Punicaceae family and an important native product of subtropical Asia (**Figure 4**) [20, 21].

Pomegranate fruit has approximately 48% peel and 52% fruit (w/w), which is the edible part of fruit and consists of 78% juice and 22% seeds [22, 23]. Pomegranate is rich in vitamins A, B, C, and E, minerals potassium, and iron, which have healing properties. It is also a rich source of folic acid and antioxidants. This fruit contains a significant amount of phenolic compounds such as anthocyanins, punicalin, and various flavonols, which have antimicrobial, antibacterial, and anti-inflammatory properties and increase the immune system in vitro and in vivo [24]. Pomegranate peel contains 55.4% non-fibrous carbohydrates (NFC), 8.4% crude protein (CP),

#### *New Advances in Postharvest Technology: An Overview for Feed Production from Postharvest… DOI: http://dx.doi.org/10.5772/intechopen.111539*

16.7% lignin, 34.5% neutral detergent fiber (NDF), and 0.84–1.0% total condensed tannins [25]. Pomegranate pomace is a by-product of the pomegranate juice industry, which has strong antioxidant power, anti-inflammatory compounds, vitamin E, sterols, phenols, and natural estrogens [26]. Pomegranate by-products offer excellent nutritional value as ruminant feed and can be utilized efficiently to substitute grains in ruminant diets. Feeding cattle calves and a fresh pomegranate peel diet improved feed intake and plasma alpha-tocopherol amount [27]. The antioxidants in pomegranate peel prevent diseases in lambs and have been useful in improving the quality of meat [28]. Substitution of a portion of grain in the diet with dry pomegranate seed pulp had no effect on growth performance, carcass traits, and nutrient digestibility, but it reduced the cost of meat production and increased the antioxidant capacity of lambs. As the pomegranate seed pulp was increased in the diet, it caused a decrease in kidney fat and a tendency to increase the apparent digestion of crude fat [29]. In fattening lambs, it has also been shown that pomegranate pomace silage can significantly replace a part of the fodder, which will result in a reduction in production costs and saving environment from the waste pollution coming from pomegranate processing industries. In another study, dairy goats fed a diet supplemented with dry pomace pomegranate seeds at 14% instead of cereal grain with no detrimental effects on animals. Therefore, it was suggested that pomegranate seed pomace, as a cheap by-product, can be replaced in the diet as an energy source [30]. Dairy cows fed diets supplementing with concentrated pomegranate extract at 1 and 2% based on dry matter, revealed increased the antioxidant activity of milk by 15 and 17.2%, respectively, and compared to the control group [31]. As a new feed for beef cattle, the antioxidant potential and nutrients of fresh and ensiled pomegranate by-products (pomegranate peel) were investigated. The results of this experiment showed that fresh pomegranate peel caused a significant increase in feed intake and alpha-tocopherol concentration in plasma [31]. Inclusion of wet fresh pomegranate peels in diets of bull calves promoted an increase in feed intake, with a tendency to increased weight gain [27]. In contrast, Oliveira et al. [32] found that feeding a pomegranate extract to young calves for the first 70 d of life did not change the digestibility of dry matter, organic matter, or starch, but it suppressed the intake of grain and whole tract digestibility of fat and crude protein, likely because of its high tannin content.

## **4. Tomato pomace**

Tomato (*Lycopersicon esculentum*) has an annual global production of 170 million tons, of which 127.5 million tons are used for fresh consumption and 42.5 million tons for industrial processing [33] (**Figure 5**). Asia produces 61.1% of the world's tomatoes, whereas Europe, the Americas, and Africa provide 13.5, 13.4, and 11.8% of total tomato yield, respectively [34].

Tomato pomace is a by-product of tomato processing that refers to the skin (peel) and seeds of tomatoes and accounts for 10–40% of all processed tomatoes (**Figure 6**) [35]. Tomato pomace contains approximately 33% seeds, 27% peel, and 40% pulp, while dry pulp contains approximately 44% seeds and 56% peel and pulp [36] which average protein is 21.9% in tomato pomace and 38.7% in fat-free tomato seeds [37]. Tomato pulp is a good source of lycopene, carotene, vitamin E, vitamin C

**Figure 5.** *Tomato plant (fruit).*

**Figure 6.** *Tomato pomace.*

and nucleosides [38], carotenoids, lycopene, flavonoids, and soluble dietary fiber (**Figure 7**) [40, 41].

Tomato pomace is used as an ingredient in small ruminant diets due to its chemical composition and good animal acceptability [42]. In feeding ruminants, tomato pomace is sometimes considered as a concentrate due to the high content of nutrients and sometimes as forage because of its high content of the cell wall [43].

Recently, studies have been conducted using tomato residues in the form of silage and considering tomatoes along with other industrial residues in goat diets [44]. Silage of tomato pomace with 10% of wheat straw can be a good quality forage source for sheep when the forage is not available [45]. In a research, dietary replacing 10% of corn silage with ensiled tomato pomace had a positive effect on the vitamin content of *New Advances in Postharvest Technology: An Overview for Feed Production from Postharvest… DOI: http://dx.doi.org/10.5772/intechopen.111539*

#### **Figure 7.** *Processing and uses of tomato pomace [39].*

milk, antioxidant function, and immunity in early lactating cows [46]. Ruminants fed diets containing tomato pomace showed higher nutritional intake as well as apparent digestibility, organic matter, dry matter (DM), and crude protein indices [47]. Tomato pomace, if properly preserved, can be included in a significant portion of animal rations for a longer period of time and can also be used as a protein and energy supplement in feeding ruminants [48]. Up to 15% of the diets supplied to sheep can be substituted with dried tomato pomace without having any negative impact on growth [49]. The substitution of barley grain diet with tomato and cucumber waste was studied on rumen fermentation and microbial communities in goats and found that up to 250 grams per kilogram of tomato waste can replace the barley grain diet [50]. Supplement consumption increased milk quality and fat content by 20 and 40%, respectively. This demonstrated that, despite the fact that TP decreased the body weight of breastfeeding goats, it might enhance the quality and fat content of their milk, which may be related to the TP's own energy content and fatty acid composition [39]. In a study, supplementation of different levels of tomato pomace had no effect on the body weight of goats and sheep, carcass length, blood sugar, total protein, urea, or cholesterol [51].

Tomato pomace has also been used in poultry diets, so feeding 5% tomato pomace to chickens at the age of 1–28 days can increase body weight and production index, also increase the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and reduce HDL cholesterol and serum triglyceride concentrations [52]. The results of another study revealed that dietary inclusion of tomato pomace at 12% can significantly improve the immune system function, antioxidant enzymes, and digestive enzymes of Japanese quails [53]. The concentrate mixture in the feed of male buffaloes can be substituted with sun-dried tomato pomace without having any negative effects on urinary purine derivatives, DM intake, nutritional digestibility, microbial protein synthesis, or production of volatile fatty acids in the rumen [54].

**Figure 8.** *Fodder beet plant.*
