RESUMEN
Large amounts of collagen-rich by-products are generated in poultry processing. In particular, gelatin from the by-products of turkey processing is limited. Gelatin extraction from turkey and chicken MDRs (mechanically deboning residue) was the purpose of this study. Both materials were modified at the highest swelling pH for chemical denaturation of collagen and hot water extraction of gelatin was performed at the optimum temperature-time, which was determined to be pH 1.0 and 80°C-6 h, respectively. In these conditions, yields of 9.90% turkey gelatin (TG) and 13.85% chicken gelatin (CG) were produced. They demonstrated similar viscosity, gel strength, and lightness values of 72-73 g, 2.5-2.7 mPas, and 31, respectively. These results are close to those of bovine gelatin (BG). TG with 239.78 g Bloom exhibited higher strength than CG (225.27 g) and BG (220.00 g). The melting and gelation temperatures of CG and BG were 21 and 30°C, respectively, while those of TG were 19 and 28°C. Imino acids (proline + hydroxyproline) of TG (22.82%) were higher than those of CG (20.73%). Fourier transform infrared spectroscopy (FTIR) analysis revealed secondary structure and functional groups of CG and TG similar to those of BG. CG displayed a higher thermal transition temperature than BG, while TG exhibited the highest temperature sensitivity, according to the differential scanning calorimetry (DSC) analysis. In conclusion, TG showed higher potential for effective utilization with higher bloom and imino acids. Overall, turkey and chicken MDRs are a promising and potential alternative source to produce gelatin with comparable properties to bovine gelatin for intended food applications as well as for pharmaceutical and cosmetic fields.
RESUMEN
The aims of this research were to investigate the usability of black grape pomace in the production of shalgam juice, which is a traditional fermented Turkish beverage, to transform the pomace into the high value-added product and to enrich the shalgam juice with phenolic compounds. Black grape pomace and black carrot were used as the sources of polyphenols and five different formulations were obtained according to the amounts of black carrot and black grape pomace. During the fermentation, the samples were taken at different periods and analyzed for anthocyanins, phenolic compounds, antioxidant activity, and tannin content. Gentisic, caffeic, ferulic, coumaric, and chlorogenic acids, catechin, glucosides of kaemferol and isorhamnetin, resveratrol, rutin, cyanidin-3-xylosylglucosylgalactoside, cyanidin-3-xylosylgalactoside, cyanidin-3-xylosylglucosylgalactoside acylated with sinapic acid, ferulic acid, or coumaric acid, and glucosides of cyanidin, petunidin, and malvidin were identified in the shalgam juices that contained both black grape pomace and black carrot in their formulation. Some of these polyphenols were not detected detect in the shalgam juices that were produced from only the black carrot or black grape pomace. During the fermentation, a decrease in the amount of anthocyanins originated from black carrots and an increase in the amount of anthocyanins orginated from black grape pomace were determined. Black grape pomace addition to the formulation before the fermentation caused an increase in the amount of tannin in the shalgam juice samples. Consequently, it is thought that black grape pomace can be fruitfully evaluated in shalgam juice production and can be enhanced by polyphenolic profile of shalgam juice.