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Effect of alkali extraction on the digestibility and bioavailability of rice protein
Author(s) -
Kubota Masatoshi,
Saito Yuhi,
Masumura Takehiro,
Kumagai Takehisa,
Watanabe Reiko,
Fujimura Shinobu,
Kadowaki Motoni
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1013.33
Subject(s) - prolamin , bioavailability , rice protein , chemistry , food science , starch , extraction (chemistry) , casein , protein digestibility , digestion (alchemy) , agronomy , storage protein , biochemistry , chromatography , biology , gene , bioinformatics
Since a manufacturing method was developed for rice protein, a novel plant protein food material, its digestibility and bioavailability were investigated. The products from two different methods were compared: rice protein by alkali extraction (AE‐RP) and by starch degradation through heat‐stable alpha‐amylase (SD‐RP). To estimate their bioavailability, a growth study with male Wistar rats was performed for 4 weeks: AE‐RP was superior to SD‐RP and comparable to casein in PER. The digestibility of rice protein is not superb for prolamin, which is notoriously indigestible in rice, but AE‐RP was dramatically improved, compared to that of SD‐RP when analyzed by western blotting analysis of gastrointestinal contents and feces. Next, an in vitro digestion study with pepsin and pancreatin was conducted to clarify the mechanism improving prolamin digestibility in AE‐RP. It was clarified that particle structures of protein body‐I in which prolamin accumulates and the heat process affected prolamin digestibility. In conclusion, alkali extraction to prepare rice protein gives a higher digestibility and bioavailability, when compared to starch‐degradation by heat‐stable alpha‐amylase, which is typical for cooked rice. This study was supported by grants to MK from the Japan Science and Technology Agency Innovation Satellite Niigata, Nagaoka, Japan.