N. Bakhshi - Department of Food Science and Technology, College of Agriculture, Isfahan University of Technology, Isfahan, ۸۴۱۵۶-۸۳۱۱۱, Islamic Republic of Iran.
M. Sheikh-Zeinoddin - Department of Food Science and Technology, College of Agriculture, Isfahan University of Technology, Isfahan, ۸۴۱۵۶-۸۳۱۱۱, Islamic Republic of Iran.
S. Soleimanian-Zad - Department of Food Science and Technology, College of Agriculture, Isfahan University of Technology, Isfahan, ۸۴۱۵۶-۸۳۱۱۱, Islamic Republic of Iran.|Research Institute for Biotechnology and Bioengineering, Isfahan University of Technology, Isfahan, ۸۴۱۵۶-

Given the growing interest in the production of new and low cost bioemulsifiers, the rice and wheat bran and straw were investigated in this study for the production of bioemulsifier by Lactobacillus plantarum subsp. plantarum PTCC ۱۸۹۶ (probiotic). The strain produced bioemulsifier only in the rice bran hydrolysate medium. The bioemulsifier amount reached around ۰.۷ g L-۱ for ۷۲ hours of fermentation. The new biomolecule was extracted, purified, and its structural and thermal properties were evaluated. The functional groups and the structure of the molecule were revealed by GPC, FT-IR, ۱HNMR and ۱۳CNMR techniques. The bioemulsifier was a water soluble extracellular high molecular weight (>۱۰۷ Da) α-glucan (۸۱.۷۴%) bound with protein (۱۸.۱۸%). Thermal behavior was studied using DSC and TG analysis. Thermal analysis showed the bioemulsifier broke down above ۲۱۱.۷۴°C, and the melting point was ۱۸۲.۰°C with the enthalpy value of ۱۰۱.۷ J g-۱. These results might provide incentives for the industrial production of the biodegradable and safe bioemulsifier introduced in this study, which seems to offer potential applications in the food and medical industries.

Probiotic, Rice bran hydrolysate, Structural properties, Thermal analysis