Effect of cooking pressure on phenolic compounds, gamma-aminobutyric acid, antioxidant activity and volatile compounds of brown rice

• Published in: Journal of cereal science 2021-01, Vol.97, p.103127, Article 103127
• Main Authors: Yu, Chengtao, Zhu, Ling, Zhang, Hao, Bi, Shilin, Wu, Gangcheng, Qi, Xiguang, Zhang, Hui, Wang, Li, Qian, Haifeng, Zhou, Li
• Format: Article
• Language: English
• Subjects: brown rice; Cooking pressure; Phenolic compounds; Volatile compounds
• ISSN: 0733-5210; 1095-9963
• DOI: 10.1016/j.jcs.2020.103127

The cooking method is the key factor influencing the cooking quality of rice. In this study, the effect of different cooking pressures on phenolic compounds, gamma-aminobutyric acid (GABA), antioxidant activity and volatile compounds with an adjustable pressure cooker was investigated. The high-pressure cooking (60, 70 and 105 kPa) resulted in a greater retention of total phenolic content and total antioxidant activity as compared with low-pressure cooking (30, 40 and 50 kPa). Further, UPLC-PDA-MS/MS analysis indicated that high-pressure cooking was more effective in term of free phenolic compounds retention (p-coumaric acid and ferulic acid) and caused the significant increase in two predominant bound phenolic compounds (ferulic acid and isoferulic acid). Besides, with the increase of cooking pressures, the GABA content decreased. GC-MS result suggested that high-pressure cooking (50, 60, 70 and 105 kPa) significantly decreased off-flavor compounds contents (hexanal, 2-pentylfuran and 2,3-dihydrobenzofuran) compared to low-pressure cooking (30 and 40 kPa). This study extended the present knowledge about the effect of cooking pressure on bioactive compounds, antioxidant activity and volatile flavor of brown rice. The obtained results may provide the valuable information on improvement of cooking quality for brown rice. [Display omitted] •High pressures maintained more free phenolic compounds than low pressures.•High pressures significantly increased bound phenolic compounds than before cooking.•With the increase of cooking pressures, the GABA content decreased.•High pressures caused a greater retention of antioxidant activity than low pressures.•High pressures significantly decreased off-flavor compounds than low pressures.