Further Studies on the Protein Chemistry and Property of Glutathione-Added Rice Bread : Evidence of Glutathionylation of Batter Protein as well as Crumb Structure/Sensory Evaluation

Abstract

Rice is one of the major staple crops in many developing countries, so commercializing rice-based processed foods should help boost their economy. We have recently reported that the addition of glutathione, a natural ubiquitous tri-peptide, to rice batter allows it to retain the carbon dioxide gas in fermentation, whereupon subsequent baking swells the rice bread without the need for added gluten. Although we have just detected this phenomenon, further mechanical and qualitative investigation should accelerate studies for its practical application. We speculate that the swelling is due to the "barrier theory". In short, disulfide-linked protein polymers hinder the adsorption of water by the starch granules. Glutathione may cleave or hinder the formation of the disulfide bonds of the polymers, which boosts starch hydration, resulting in increased viscosity and continuity of the rice batter. In this paper, we have obtained evidence that glutathione modifies the sulfhydryl groups of the barrier proteins (glutathionylation) and increases their solubility, thus fraying the barrier. Although further studies are needed to reveal the complete swelling mechanism, these observations support and extend the hypothesized barrier-linked swelling mechanism of glutathione bread. Moreover, from a bread quality perspective, the fine/coarse property of crumbs is found to be controllable, and the sensory assessment demonstrated that the bread smell is unimpaired by glutathione. All these data will accelerate the practical use of the glutathione bread.

Role of enzymes in improving the functionality of proteins in non-wheat dough systems

“…Similar results were observed also when dissociation of the disulphide linkages between a-and b-subunits of rice glutelins was obtained by addition of glutathione (Yano, 2010). In both cases, the treatments resulted in improved baking quality of rice batters (Renzetti and Arendt, 2009b;Yano, 2010;Yano et al, 2013). Therefore, it remains to be further explored the exact mechanism and the identity of the protein subunits that play a decisive role in the formation of the fine network responsible for improving the expansion of rice batters.…”

Current and forward looking experimental approaches in gluten-free bread making research

“…The pasting behavior of batters/doughs during heating, by Rapid Visco Analyzer (RVA) or Mixolab analysis were studied in ten articles (see Table 1). Protein analysis was done by SDS-PAGE (Hatta et al, 2015;Kawamura-Konishi et al, 2013;Yano, 2010Yano, , 2012Yano et al, 2013). Torbica et al (2010) and Han et al (2012) used differential scanning calorimetry (DSC) to assess starch gelatinization.…”

“…Torbica et al (2010) and Han et al (2012) used differential scanning calorimetry (DSC) to assess starch gelatinization. The batter/dough structure was studied by microscopy (Kawamura-Konishi et al, 2013;Martinez et al, 2014b;Yano et al, 2013). Storck et al (2013) measured batter/dough color.…”

Recent practical researches in the development of gluten-free breads

“…97 Usage of GSSG in breadmaking instead of GSH significantly reduced the generation of these sulfur compounds, 71 and sensory evaluation demonstrated that the aroma of GSSG-added rice bread was almost equivalent to that of non-added bread. 98 However, we sought to develop rice bread without glutathione or any other additives.…”