Effect of natural extracts obtained from food industry by-products on nutritional quality and shelf life of chicken nuggets enriched with organic Zn and Se provided in broiler diet

Abstract

This study investigated the influence of an organic mineral-supplemented broiler diet on the quality of nuggets. The resulting chicken nuggets were enriched with inorganic and organic forms of Zn and Se. The nuggets were processed by incorporating extracts from food industry by-products (rosemary [R_H and R_L], hydroxytyrosol [HYT], pomegranate [P], grape [GS], and Harpagophytum [H]). The physiochemical, microbiological, and sensory characteristics of the chicken nuggets were evaluated over a 12-month period of frozen storage. The addition of natural extracts did not affect the pH, proximate composition, or color (CIELab) of the nuggets among samples. However, significative differences were found between month of analysis (range from pH 6.16 to 6.63; luminosity from 62.51 to 84.74; redness from 0.16 to 7.14; and yellowness from 10.80 to 33.77). In addition, the combination of phenolic compounds with Zn and Se retarded microbial growth and reduced protein and lipid oxidation, thus maintaining the sensory quality and extending the shelf life of this product. For instance, the combination of R_L + GS reduced in 75% the microbiological growth regarding the control sample (C), while samples that incorporated R_H + P or HYT + P + H presented 50% less than C. In addition, upon only incorporating organic minerals Zn and Se, microbiological deterioration is reduced in 15%. This mix was significantly effective at reducing the oxidative reactions of lipids and proteins by 40% and 50%, as measured after 9 and 12 mo of frozen storage, respectively. The addition of the natural extracts and Zn and Se did not adversely affect the acceptability of the meat product.

Keywords: antioxidant activity; broiler; meat quality; nugget; organic mineral-supplemented diet.

Figure 1

Results of lipid oxidation, TBARs (mg MDA/kg) (A); protein oxidation, thiol groups (nmol thiol/mg protein) (B); and sensory evaluation (C: at time 0 and D: at month 12) of chicken frozen nuggets for 12 mo of storage. Mean values (n=8) for each sensory descriptor by chicken nuggets. The relevant significance is reported for each descriptor (*P < 0.05). C, control; C_RH+P, 1000 ppm rosemary extract + 1500 ppm pomegranate extract; C_RL+GS, 1000 ppm Nutrox OS + 1500 ppm grape seed extract; C_HYT+P+H, 1500 ppm pomegranate extract + 750 ppm hydroxytyrosol + 500 ppm Harpagophytum; GS, grape seed; H, Harpagophytum; HYT, hydroxytyrosol; MDA, malondialdehyde; P, pomegranate; R_H, rosemary extract; R_L, rosemary extract (Nutrox OS); SZ, control fortified with Zn and Se meat; SZ_RH+P, 1000 ppm rosemary extract + 1500 ppm pomegranate extract; SZ_RL+GS, 1000 ppm Nutrox OS + 1500 ppm grape seed extract; SZ_HYT+P+H, 1500 ppm pomegranate extract + 750 ppm hydroxytyrosol + 500 ppm Harpagophytum; TBAR, thiobarbituric acid reactive substance.