The Volatile Compounds and Aroma Description in Various Rhizopus oligosporus Solid-State Fermented and Nonfermented Rice Bran

Retno Dwi Astuti,Dody Dwi Handoko,Hitoshi Shirakawa,Slamet Budijanto,Dwi Larasatie Nur Fibri,Wahyudi David,Ardiansyah Ardiansyah

doi:10.3390/fermentation8030120

Abstract

Rice bran is known to have beneficial nutrients. Current studies suggest that solid-state fermentation affects the rice bran’s volatile profile. The aim of this study is to identify the volatile compounds and aroma description of fermented and nonfermented rice bran (FRB and NFRB) of Ciherang, Inpari30, IR64 and Inpari42. The fermentation was conducted using Rhizopus oligosporus solid-state fermentation. Headspace-solid phase microextraction coupled with GC/MS was performed, and the aroma was translated by 10 trained panelists through quantitative descriptive analysis (QDA). The result showed that 72 and 68 compounds were identified in FRB and NFRB, respectively. They are aldehydes, ketones, alcohols, acids, esters, fatty acid, phenol, benzenes, furan, thiazole, pyrazines, pyridine, lactones, terpenes, and hydrocarbons. The PCA showed that FRB was dominated by alcohols, whereas NFRB was dominated by aldehydes. The QDA described nine aromas, i.e., rancid, smoky, musty, grassy, green, earthy, cereal, and sweet in NFRB. The fermentation process added fermented attributes to the aroma description to FRB and enhanced the rancid, smoky, and musty aromas. These studies indicated that fermented rice bran might increase the volatile compound of rice bran. Thus, it may provide opportunities to develop the production of fermented rice bran as a functional ingredient.

Highlights

Rice bran (RB) is a by-product of milling rice that is produced in an estimated million tons per year
Volatiles of Fermented and Nonfermented Rice Bran pounds were identified in fermented rice bran (FRB) and nonfermented rice bran (NFRB) volatile compounds, respectively
Volatile compounds from the fermentation process showed more diverse compounds than NFRB

Summary

Introduction

Rice bran (RB) is a by-product of milling rice that is produced in an estimated million tons per year. This high production has a great potential to be developed as functional ingredients, due to its high nutritional and bioactive compounds such as dietary fiber, vitamins, minerals, lipids, protein, γ-oryzanol, ferulic acid, and tocopherol [1]. The sensory profiles of RB odor are the most decisive in terms of acceptance. Volatile compounds are chemical compounds that play an essential role in regulating odors in food. The volatile compounds of RB have been detailed by a few investigators utilizing GC-MS to identify the compounds. The main volatiles of RB are aldehydes, ketones, acids, esters, hydrocarbons, alcohols, and alkanes, among which hydrocarbons, acids, and aldehydes

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