Deproteinase Effect of Hydrocolloid Flour Made of “Gembili Tuber†(Dioscorea esculenta L.) on Chemical and Technical Functional Properties

Abstract

Hydrocolloid flour extracted of gembili tuber studied in this research to know the chemical and technical functional properties. Hydrocolloid flour extracted directly with distilled water (HFC) and hydrocolloid flour which has reduced protein (deproteinase) by hydrolysis with 0.05% protease of Aspergillus oryzae (HFD). Compared to the chemical properties and technical functional properties covering proximate test, total sugars, solubility, power and emulsion stability, power and  foaming stability, water holding capacity (WHC), oil holding capacity (OHC), viscosity to changes in temperature and viscosity to changes in pH. The results showed that different test t-test (α = 0.05) moisture content, ash content and fat content between HFC and HFD not significant, while the levels of protein and carbohydrates are significant. Deproteinase the process of hydrocolloid  flour made of  gembili tuber with 0.05% protease enzyme use in the extraction able to lower protein content by 49.57% and increase of carbohydrates by 11.39%.   In addition, the process deproteinase effect the technical functional properties of hydrocolloid flour increase solubility, emulsion stability, foam stability, WHC and OHC. Increasing in the temperature by  10-90 °C lower the viscosity by 70%  (56.33 ± 0.19mp to 17.05 ± 0.03 mp) of HFC and  73% (26.16 ± 1.28 mp to 7 , 08 ± 0.79 mp) of HFD. The highest viscosity hydrocolloids flour (HFC and HFD) contained at pH 7 and decrease with acidic or alkaline conditions.