A Study on Enzymatic Hydrolysis on Chicken Skin Protein Hydrolysates: Comparison Between Defatted Freeze Dried and Fresh Chicken Skin

Lee, Ling Jun (2019) A Study on Enzymatic Hydrolysis on Chicken Skin Protein Hydrolysates: Comparison Between Defatted Freeze Dried and Fresh Chicken Skin. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Chicken skin considered as a functional waste or by-product which can be utilized and believed that it can be incorporate into the medicine as the antihypertensive agents. It can be found abundantly in the poultry industry among Malaysia. The objectives of this study were to evaluate antioxidant activity of protein hydrolysates by enzymatic hydrolysis on the defatted freeze dried and fresh chicken skin, determine retention of nutrient content in enzyme treated and untreated chicken skin through proximate analysis and to determine the potential in vitro anti-oxidative properties of CSPHs. Chicken skin protein hydrolysates (CSPH) were prepared via enzymatic hydrolysis to investigate its antioxidant activity. Two types of enzymatic hydrolysis which are alcalase and pepsin with pancreatin were used in this research and CSPH had been hydrolysed using defatted freeze dried and defatted fresh chicken skin. Antioxidant activities were measured using DPPH and Ferric Reducing Antioxidant Power Assay. For the antioxidant assay from this research, CSPH hydrolysed with Alcalase showed higher reducing power ability compared to Pepsin with Pancreatin while Pepsin with Pancreatin showed higher free radical scavenging activity compared to Alcalase. The highest antioxidant activity for Alcalase was in defatted freeze dried chicken skin for FRAP assay (Ferrous equivalent = 0.055 ± 0.004a μM/mL) and in defatted oven dried chicken skin for DPPH assay (Ascorbic acid equivalent = 1.916 ± 0.049b ppm VCE). While for Pepsin with Pancreatin, the highest antioxidant activity was in defatted freeze dried chicken skin with FRAP assay (Ferrous equivalent = 0.048 ± 0.006a μM/mL) and in defatted raw chicken skin for DPPH assay (Ascorbic acid equivalent = 2.143 ± 0.077a ppm VCE). Furthermore, the degree of hydrolysis of CSPH with different skin type by Alcalase and pepsin with Pancreatin were also evaluated. In conclusion, there is significant difference between protein and antioxidant content in defatted freeze dried and fresh chicken skin and showed that defatted freeze dried chicken skin retained highest protein content and provide more antioxidative properties after enzymatic hydrolysis. Keyword: Chicken skin, Freeze dried, Alcalase, Pepsin with Pancreatin, Antioxidant activities