Potencialidade do resíduo de cervejaria na terminação de bovinos e como fonte de compostos bioativos para incrementar a qualidade da carne

Abstract

Food quality is defined in terms of consumer acceptability, so efforts to reduce oxidation have increased. The incorporation of natural antioxidants into meat can be clone by direct contact on the surface or by supplementing. In the animal diet with antioxidants and metabolic deposition in the meat being to exert its protective activity. B w ’ ent grain (BSG) is the most abundant by-product of the brewing industry.It is available at low cost as a valuable source of phenolic acids. Thus, the objective was to evaluate different extraction conditions for the characterization and identification of BSG polyphenols and their effect on the performance and quality attributes of beef under feedlot. In order to characterize the BSG and other ingredients used in the diets (corn silage, rice bran, corn bran and wheat bran), chemical composition, determination of total phenolics, total flavonoids, and in vitro antioxidant activity of the extracts were performed. Extracts were obtained by conventional extraction and assisted by microwave. using solvent 50% acetone, 50% methanol, or 0.75% NaOH. Samples were studied in natura or deffated. Using HPLC-DAD, monomers of phenolic compounds from all samples were identified and quantified. Four formulations were tested by varying the replacement level of corn silage by BSG at the termination of beef cattle in a completely randomized design (DIC) with five replicates in each treatment. During feedlot, the average daily consumption of the animals and the average daily weight gain were evaluated. The digestibility of dietary nutrients and levels of phenolic compounds and endogenous antioxidant enzymes in bovine blood. Longissimus thoracis muscle was analyzed 24 hours after slaughter through temperature, pH, chemical composition, fatty acid profile, color, cooking loss, texture profile, water activity, oxidative, protein and microbiological stability, besides the acceptability of products throughout its shelf life for 75 days of vacuum-packed refrigerated storage. The comparison between BSG and other ingredients used in the experimental diets of the animals revealed that this residue has the highest concentration of polyphenols identified and bioavailable with consequent higher antioxidant potential. The BSG in replacement of corn silage up to 35% in the finishing diet of cattle feedlot allows excellent production performance and a significant reduction in production costs, considering the market values currently practiced. Regarding the final product, beef with the inclusion of BSG in the animals' diet presents a higher amount of fatty acids that are beneficial to the health of the consumers. Moreover, meat has hight oxidative stability and increased tenderness. The inclusion of up to 35% BSG in the cattle finishing diets as a forage source did not promote any undesirable effect during the shelf life evaluation under commercial conditions. The use of BSG to replace corn silage in beef cattle diets can be adopted as a strategy to reduce feed costs. Furthemore, it is also a source of polyphenols from a material that needs to be recycled. Those substances have show that are able to improve important attributes related to meat quality, as: tenderness, fatty acid profile, and oxidative stability.