Processing affects (decreases or increases) metabolites, flavonoids, black rice pigment, and total antioxidant capacity of purple glutinous rice grains

Jinyan Zhu; Qiang Shi; Changhui Sun; Jinlong Hu; Nianbing Zhou; Haiyan Wei; Haohua He; Dahu Zhou; Hongcheng Zhang; Qiangqiang Xiong

doi:10.1016/j.fochx.2022.100492

Processing affects (decreases or increases) metabolites, flavonoids, black rice pigment, and total antioxidant capacity of purple glutinous rice grains

Food Chem X. 2022 Oct 25:16:100492. doi: 10.1016/j.fochx.2022.100492. eCollection 2022 Dec 30.

Authors

Jinyan Zhu^{1

2}, Qiang Shi¹, Changhui Sun¹, Jinlong Hu^{1

2}, Nianbing Zhou^{1

2}, Haiyan Wei^{1

2}, Haohua He³, Dahu Zhou³, Hongcheng Zhang^{1

2}, Qiangqiang Xiong^{1

2

4}

Affiliations

¹ Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Cultivation and Physiology, Agricultural College of Yangzhou University, Yangzhou 225009, China.
² Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China.
³ College of Agronomy, Jiangxi Agricultural University, Nanchang 330045, China.
⁴ Jiangxi Irrigation Experiment Central Station, Nanchang 330201, China.

Abstract

The objective of this study was to understand the effects of processing on metabolites, flavonoids, black rice pigments and total antioxidant capacity of purple grains. The biochemical indicators and metabolites were determined before and after processing of purple grains. The results showed that the total antioxidant capacity, total phenol (TP), flavonoid (PD), oligomeric proanthocyanidin (OPC), ascorbic acid (AsA), cyanidin-3-O-glucoside (C3OG), peonidin 3-glucoside (P3G) contents of purple grains were greatly decreased after brown rice grains were processed into polished rice grains. The TP, PD, OPC, AsA, C3OG, and P3G of Yangzinuo No.1 brown rice (YZN1_B) or polished rice grains (YZN1_H) were higher than those of Yangzinuo No.2 brown rice (YZN2_B) or polished rice grains (YZN2_H). 154 differential metabolites (DMs) were identified between YZN1_B and YZN1_H. 52 DMs were identified between YZN2_B and YZN2_H. Citric acid and isocyanate are key metabolites affected during processing and have good correlations with various biochemical indicators.

Keywords: Black rice pigment; Flavonoids; Metabolomic; Purple rice; Total antioxidant capacity.