Combined microwave and enzymatic treatment improve the release of insoluble bound phenolic compounds from the grapefruit peel insoluble dietary fiber. (September 2021)

• Record Type: Journal Article
• Authors: Peng, Guanyi; Gan, Jiapan; Dong, Ruihong; Chen, Yi; Xie, Jianhua; Huang, Ziyan; Gu, Yue; Huang, Danfei; Yu, Qiang
• Is Part Of: Lebensmittel-Wissenschaft + Technologie =. Volume 149(2021)
• Publication Date: 2021-09
• Subjects: Enzymatic hydrolysis -- Structural analysis -- Qualitative and quantitative analysis -- Antioxidant capacities -- α-Glucosidase inhibition; Food industry and trade -- Periodicals; Food -- Composition -- Periodicals; Microbiology -- Periodicals; Nutrition -- Periodicals; 664.005
• DOI: 10.1016/j.lwt.2021.111905
• Languages: English
• ISSNs: 0023-6438

Abstract

Abstract: Increasingly attention has been paid to the active substances in grapefruit peel. In this study, insoluble bound phenolic compounds (BP) were released from grapefruit peel insoluble dietary fiber (GP-IDF) by microwave extraction (M-BP), enzymatic hydrolysis (E-BP) and combined microwave and enzymatic treatment (ME-BP). The results showed that the yield of ME-BP was the highest (148.856 ± 0.620 GAE mg/100 g), and conditions of microwave treatment (microwave power, temperature, time) were 600 W, 85 °C, and 37 min, while that of enzymatic treatment were 8% addition, 60 °C, and 2 h. Scanning electron microscopy displayed that GP-IDF became looser by ME. ME mainly resulted in the removal of lignin in IDF from X-ray diffraction, which was consistent with FT-IR. Twenty seven BP were identified by UPLC-ESI-QTOF-MS/MS. The high content of gallic acid (42.50 ± 3.21 μg/g DW), ferulic acid (18.46 ± 1.65 μg/g DW) and protocatechuic acid (6.16 ± 0.72 μg/g DW) was quantified by LC-ESI-QqQ-MS/MS. Furthermore, ME-BP showed stronger antioxidant capacities than that of others (ABTS, oxygen and DPPH free radical scavenging ability), and showed good inhibition of α-glucosidase. Our results demonstrated that combined microwave and enzymatic treatment was an effective treatment for improving the release of BP. Highlights: Combined microwave and enzymatic treatment (ME) released bound phenolic compounds. Optimal condition was 600 W, 85 °C for 37 min and 8% enzyme dosage, 60 °C for 2 h. ME-IDF (insoluble dietary fiber) was more seriously disintegrated than others. Composition and content of ME-BP (bound phenolic compounds) was analyzed. ME-BP exhibited higher antioxidant capacities and α-glucosidase inhibition.