Physicochemical and functional properties of Alcalase‐extracted protein hydrolysate from oil palm leaves

• Published in: Journal of the science of food and agriculture Vol. 102; no. 1; pp. 233 - 240
• Main Authors: Hau, Eng Huan, Teh, Soek Sin, Yeo, Siok Koon, Mah, Siau Hui
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 15-01-2022; John Wiley and Sons, Limited
• Subjects: degree of hydrolysis; Enthalpy; Food industry; Food plants; Fourier transforms; Functional groups; Hydrolysates; Hydrolysis; Infrared analysis; Leaves; oil palm biomass; Oil palm trees; Oil wastes; protein content; Proteins; Subtilisin; Thermal stability; Vegetable oils; Wastes; Zeta potential
• ISSN: 0022-5142; 1097-0010
• DOI: 10.1002/jsfa.11350

BACKGROUND
The oil palm tree produces 90% of wastes and the limited usage of these wastes causes a major disposal problem in the mills. Nevertheless, these by‐products have a large amount of nutritional components. Thus, the present study aimed to determine the physicochemical and functional properties of protein hydrolysates (PH) from oil palm leaves (OPL) extracted using different concentrations of Alcalase (0–10%) at 2 h of hydrolysis time.
RESULTS
Fourier transform infrared spectral analyses showed that the enzymatic hydrolysis altered functional groups of OPL where a secondary amine was present in the PH. Changes were also observed in the thermal stability where the enthalpy heat obtained for PH (933.93–1142.57 J g−1) was much lower than OPL (7854.11 J g−1). The results showed that the PH extracted by 8% Alcalase exhibited absolute zeta potential, as well as a high emulsifying activity index (70.64 m2 g−1 of protein) and emulsion stability index (60.58 min). Furthermore, this PH showed higher solubility (96.32%) and emulsifying properties compared to other PHs. It is also comparable with commercial plant proteins, indicating that 8% Alcalase is an optimum concentration for hydrolysis.
CONCLUSION
In summary, the physicochemical and functional properties of PH extracted from OPL showed good functional properties, suggesting that it can be used as an alternative plant protein in food industries. © 2021 Society of Chemical Industry.