Effect of Hydrolysis Temperature on in vitro Bioaccessibility and Antioxidant Properties of Unicorn Leather Jacket (Aluterus monoceros) Skin Collagen Hydrolysates Following Simulated Gastro-Intestinal Digestion

Abstract

The aim of the research was to prepare collagen hydrolysate (CH) from unicorn leatherjacket (Aluterus monoceros) fish skin using papain at different hydrolysis temperature viz. 50C (CH-5), 200C (CH-20), 250C (CH-25) and 500C (CH-50) and to investigate the antioxidant properties (DPPH free radical-scavenging activity, ferric reducing power assay, ferric chelating activity and hydroxyl radical scavenging activity) prior to and after in vitro gastrointestinal (pepsin–pancreatin) simulated digestion in order to assess the bioaccessibility and biofunctional activities. The DH was higher (4.27%) for CH-50 within 300 min of hydrolysis than other CH’s. On contrary, ferric reducing and ferric chelating properties were comparatively higher in CH-5 than other CH’s, corresponding to 33% and 0.32 absorbance units, respectively at 8 mg/mL protein concentration. DPPH free radical-scavenging and hydroxyl radical scavenging activities were more or less similar in all CH’s. Subsequent in vitro gastrointestinal simulated digestion studies showed that the bioaccessibility of CH-50 was higher (54.25) after gastric and pancreatic digestion, but CH-5 exhibited good antioxidative property expressing 90% activity. FTIR spectral analysis further confirmed it through expression of major shifts in amide A, I and II peaks and disappearance of aromatic ring peaks in CH-5. The study thus indicated that CH with good antioxidant activity shall be produced by hydrolysis the skin at 50C, rather than at 500C.