Isolation and Physicochemical Properties of Rice Bran Protein from Heat-Stabilized Rice Bran

Inneke Kusumawaty; Dedi Fardiaz; Nuri Andarwulan; Sri Widowati; Slamet Budijanto

Inneke Kusumawaty
Dedi Fardiaz Departement of Food Science and Technology, Faculty of Agricultural Technology, Bogor Agricultural University, Bogor, Indonesia; Southeast Asia Food and Agricultural Science and Technology (SEAFAST) Center, Bogor Agricultural University, Bogor, Indonesia
Nuri Andarwulan Departement of Food Science and Technology, Faculty of Agricultural Technology, Bogor Agricultural University, Bogor, Indonesia; Southeast Asia Food and Agricultural Science and Technology (SEAFAST) Center, Bogor Agricultural University, Bogor, Indonesia
Sri Widowati Indonesian Center for Agricultural Postharvest Research and Development, Agricultural Ministry of Indonesia, Bogor, Indonesia
Slamet Budijanto Departement of Food Science and Technology, Faculty of Agricultural Technology, Bogor Agricultural University, Bogor, Indonesia

Abstract

Isolation and the physicochemical properties of rice bran protein concentrate (RBPC) produced from unstabilized and heat-stabilized Pandanwangi and Ciherang rice bran were studied. Rice bran stabilization process optimization done on previous research resulted in the extrusion conditions at a temperature of 130.96oC and screw speed 26.65 Hz. Kjeldahl analysis showed that protein content of unstabilized rice bran protein concentrates (URBPC) and stabilized rice bran protein concentrates (SRBPC) of Pandanwangi and Ciherang were 60.76%, 61.38%, 60.19%, and 60.23% respectively. Amino acid composition showed that polar amino acid composition of RBPC Ciherang was higher than that in Pandanwangi leading to its solubility. The protein percentage of acid-soluble glutelin of Pandanwangi was higher than that in Ciherang rice bran protein concentrate. The molecular weight were in range from 11.19 to 60.29 kDa. Glutelin differentiated into α-glutelin (30-39 kDa) and β-glutelin (19-25 kDa). The RBPCs from two varieties had similar denaturation temperatures (77.22 - 77.99oC) with enthalpy ranged between 109.72 J/g and 200.98 J/g. Foaming stability and emulsion activities had similiar pattern with solubilities profile and showed no significant difference between varieties (p> 0.05). This finding shows potential protein concentrate of both heat-stabilized and unstabilized rice bran as food ingredient.

Keywords: Heat-stabilized rice bran, rice bran protein, physicochemical properties