Emulsifying properties of defatted rice bran concentrates enriched in fiber and proteins

BONIFACINO, CARLA; FRANCO FRAGUAS, EUGENIA; LÓPEZ, DÉBORA N.; WAGNER, JORGE R.; CABEZAS, DARÍO M.; PANIZZOLO, LUIS A.; PALAZOLO, GONZALO G.; ABIRACHED, CECILIA

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE

JOHN WILEY & SONS LTD

Año: 2020 vol. 100 p. 1336 - 1343

0022-5142

BACKGROUND: Rice bran (RB), a by-product of rice milling industry, constitutes around10% of the total weight of rough rice. The interest in the use of RB is centered on its nutritionalquality, its low cost and its worldwide extensive production. As RB is commonly used for oilextraction, the defatted rice bran (DRB) is obtained as a second by-product. The aim of thiswork was to obtain a defatted rice bran concentrate (DRBC), enriched in protein and fiber, fromdefatted rice bran flour (DRBF) and to determine its physicochemical and emulsifyingproperties.RESULTS: To obtain the DRBC, the starch was efficiently hydrolyzed (> 98%) with α-amylase and amyloglucosidase, with the concomitant increase of crude protein (from 154.7 to274.3 g kg-1) and total dietary fiber (from 276.1 to 492.3 g kg-1) proportions. DRBC exhibited aloss of protein solubility and increased surface hydrophobicity compared with DRBF. DRBCdispersions with and without previous ultrasound treatment were prepared. The sonication led toan increase in the apparent viscosity. Emulsions were prepared with dispersions with andwithout previous ultrasound treatment and showed high stability in quiescent conditions during28 days. However, the emulsions prepared with dispersions treated with ultrasound resulted inlower D4,3 values and higher elastic and viscous moduli.CONCLUSION: The rice bran concentrate can be used to obtain stable O/W emulsions,including both fractions, soluble and insoluble, in acidic and neutral conditions. Thus, theseinnovative findings contribute to increase the added value of this important by-product of rice millingindustry.