Combined Treatment of Enzymatic Hydrolysis of Dried Okara with Pectinase and Proteases

Tan, Mei Ching (2024) Combined Treatment of Enzymatic Hydrolysis of Dried Okara with Pectinase and Proteases. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

Okara is a solid byproduct resulting from soybean processing with high protein content. The low solubility of okara protein may poses challenges for its efficient conversion into bioactive peptides. Pretreatment with pectinase before enzymatic hydrolysis of okara can result in improving bioavailability of okara protein, which is essential step to achieve high bioactivity of okara hydrolysate. This study aimed to determine the effects of different types of enzymes (Alcalase and Flavourzyme) and the effect of pectinase pretreatment, concentration of okara suspension (5% and 10%, w/w) and enzyme to substrate (E/S) ratio (0.5%, 1.0% and 2.0%, w/w) on the yield, degree of hydrolysis, soluble protein content, ferric reducing antioxidant powder (FRAP), DPPH free radical scavenging activity, and ABTS free radical scavenging activity of okara hydrolysate. The results showed that the types of enzymes, okara suspension concentration, and E/S ratio significantly affected degree of hydrolysis, soluble protein content, FRAP, DPPH, ABTS (p < 0.0005). Okara hydrolysates obtained from the combined pectinase pretreatment before enzymatic hydrolysis with Alcalase and Flavourzyme showed significantly higher degree of hydrolysis, soluble protein content, FRAP, DPPH, ABTS (p < 0.05) than the okara hydrolysates obtained from the single enzymatic hydrolysis with Alcalase and Flavourzyme, regardless the okara suspension concentration and E/S ratio. The combined pectinase pretreatment with 2.0% of pectinase to substrate ratio, followed by Alcalase enzymatic hydrolysis (2.0% of Alcalase to substrate ratio) in 10% of okara suspension concentration yielded the highest degree of hydrolysis (74.61 ± 0.44%), soluble protein content (59.00 ± 1.02 mg BSA/100 mL), FRAP (56.46 ± 0.97 mg FeSO4E/100 mL), DPPH (3.29 ± 0.34 mg AAE/100 mL) and ABTS (61.53 ± 0.91 mg TE/100 mL) among all the okara hydrolysate samples. Combined pectinase pretreatment and protein hydrolysis of okara by Alcalase presented as a potential technique to recover okara protein as hydrolysate form, which can be source for protein supplementation and antioxidant component in food applications