Dietary effects of soy and citrus flavonoid on antioxidation and microbial quality of meat in broilers
Flavonoids and especially their subgroups isoflavones (soy flavonoids) and flavanones (citrus flavonoids) exhibit well‐recognized antioxidant activities and could act as health promoting agents due to their multidimensional biological functions (free radicals scavenger, inflammation attenuation and antimicrobial properties) (Kamboh et al., 2015).
Oxidation by free radicals is one of the primary mechanisms of quality deterioration in food products especially in meat. Oxidation of muscle membrane lipids causes the production of hydroperoxides, which are further oxidized to secondary products such as oxygenated compounds, aldehydes and other short‐chain ketones. These secondary metabolites may adversely affect carbohydrates, proteins, lipids and vitamins, thus limiting the overall nutritional value and shelf life of meat (Goliomytis et al., 2015). Research on ruminants and non‐ruminants have shown that dietary inclusion of citrus and soy flavonoids have improved the quality, shelf life and antioxidant status of meat without any negative effects on the product and/or environment (Kamboh & Zhu, 2013; Marzoni et al., 2014; Yanishlieva‐Maslarova, 2001). In recent years, scientific community have shown a growing interest into application of antioxidant plants as dietary supplement to enhance shelf life of refrigerated meat by reducing microbial load. For this purpose, rosemary leaves (O'Grady, Maher, Troy, Moloney, & Kerry, 2006), oregano oil (Soultos, Tzikas, Christaki, Papageorgiou, & Steris, 2009) and thyme leaves (Nieto, Díaz, Bañón, & Garrido, 2010a) have already been used and significant effects have been reported. However, practical application of these plant parts/products is often limited because of several thousand‐fold variances in their antioxidant contents due to difference in growing conditions, growing season, cultivation, etc. (Carlsen et al., 2010). Hence, it is important to use these plant antioxidants in purified (extracted) form to examine their actual effects and to launch their practical application in the meat industry.
In the last decade, substantial interest has arisen in the use of purified natural antioxidants in animal production. These natural compounds have great consumer acceptance due to their natural origin and because they do not leave any residue in the product. Nutritional approaches considered more effective that direct addition of the antioxidant to the muscle food as the compound is preferably and evenly deposited where it is most required (Ahossi, Dougnon, Kiki, & Houessionon, 2016). To our knowledge, significant work has not been conducted on health and meat quality effects of supplemental purified soy flavonoid genistein and citrus flavonoid hesperidin in broiler chickens. Therefore, the objective of present study was to investigate the dietary effects of individual and a mix of soy genistein and citrus hesperidin (CH) on meat composition, antioxidant status and microbial growth of meat during refrigeration.