Investigation of the Effect of Rice Bran Content on the Antioxidant Capacity and Related Molecular Conformations of Plant-Based Simulated Meat Based on Raman Spectroscopy

Abstract

At present, plant-based simulated meat is attracting more and more attention as a meat substitute. This study discusses the possibility of partial substitution of rice bran (RB) for soybean protein isolate (SPI) in preparing plant-based simulated meat. RB was added to SPI at 0%, 5%, 10%, 15%, and 20% to prepare RB-SPI plant-based simulated meat by the high moisture extrusion technique. RB-SPI plant-based simulated meat revealed greater polyphenol content and preferable antioxidant capacity (DPPH radical scavenging capacity, ABTS scavenging ability, and FRAP antioxidant capacity) compared to SPI plant-based simulated meat. The aromatic amino acids (tryptophan and tyrosine) of RB-SPI plant-based simulated meats tend to be masked first, and then the hydrophobic groups are exposed as RB content increases and the polarity of the surrounding environment increases due to the change in the disulfide conformation of RB-SPI plant-based simulated meats from a stable gauche–gauche–gauche conformation to a trans–gauche–trans conformation.

Unlocking the potential of rice bran through extrusion: a systematic review

“…This enhanced antioxidant capacity was achieved by forming more unstable t–g–t structures in disulphide bonds and disruptions in the protein's hydrophobic core, exposing hydrophobic amino acids that can react with oxidants. 64 Including DRB (25%, 40%, 55%) in soya protein isolates 30 and 20%, 35%, and 50% DRB in soya protein isolate and rice protein isolate was studied. 69 The conformational change in the protein from a β-sheet to a random coil and α-helix was due to the breakage of chemical bonds between protein molecules and protein denaturation was due to the extrusion process and unfolded protein.…”

“…63 An increase in the DPPH, ABTS, and FRAP suggests the antioxidant activity is due to RB. 64 These are attributed to the presence of bioactive compounds like anthocyanins, flavones and flavanols, ferulic and p -coumaric acid, apigenin and quercetin, phytic acids, alpha-tocopherol, γ -oryzanol and phytosterols which have numerous health benefits (Fig. 6).…”