VALORIZATION OF CHICKEN GIZZARD FOR OBTAINING PROTEIN HYDROLYSATE USING A COMMERCIAL PROTEASE

The chicken gizzard, an edible visceral organ from poultry slaughter, is rich in macronutrients. It serves as an alternative source of protein in various cultures and can be consumed either directly or as an ingredient in food. With a growing interest in utilizing chicken by-product proteins as a substrate, researchers have explored enzymatic hydrolysis as an alternative and sustainable approach to produce protein hydrolysates that may exhibit bioactivity. The objective of this study was to determine the physicochemical characteristics of chicken gizzard and to assess its potential as a substrate for obtaining enzymatic protein hydrolysate. After slaughtering the poultry, chicken gizzards were collected, manually separated, cleaned to remove excess fat, and stored under refrigeration. The samples were subjected to analyses to determine their moisture, protein, lipids, ash, and hydroxyproline content. The hydrolysate was prepared by using Alcalase® 2.4 L (enzyme:substrate ratio of 5%, w/w), pH 8.00, temperature of 60 °C for 240 min, under continous mechanical stirring. For this purpose, 30 grams of the sample were mixed with ultrapure water in a 1:2 (w/v) ratio. The hydrolysis process took place in a jacketed glass reactor, with temperature control provided by a thermostatic water bath. Aliquots were withdrawn over time. The chicken gizzard contained 79.96, 17.55; 4.12; 0.90, and 2.45 g/100g moisture, protein, fat, ash, and collagen, respectively. These results are consistent with literature values for both chicken gizzards and for other by-products of this origin. The degree of protein hydrolysis was 18.69%, which is in line with findings reported in the literature for studies with combs and wattles (19%), chicken plasma (16.22%), and goat viscera (26.74%), using Alcalase®. Our preliminary findings suggest that chicken gizzard may be a potential source for obtaining protein hydrolysates using Alcalase®. Further investigations are underway to explore the properties of these hydrolysates.