Analysis of protein composition in rice cultivar used for sake brewing, and their effects on nitrogen compounds in sake

Abstract

Background and objectives Protein composition analysis of 81 rice samples was performed on three cultivars harvested different regions in Japan, and the effects of the protein composition on the nitrogen composition in sake. Findings Crude protein content showed a significant positive correlation with glutelin content. Yamadanishiki cultivars showed lower crude protein and glutelin contents compared with Gohyakumangoku cultivars harvested from the same field. Total nitrogen content in the enzyme digest of steamed rice grains showed a significant positive correlation with the crude protein and glutelin contents. Ten polished (70%) white rice samples were investigated in a small‐scale sake brewing test. Total nitrogen compounds, bitter‐tasting peptides, and free amino acids in the brewed sake positively correlated with the glutelin content of the rice samples. There were no clear correlations between α‐amylase and acid proteinase activities with the nitrogen compounds in the sake. Conclusions The results indicated that the glutelin content in the cultivar rice affects sake quality through taste‐active and other nitrogen‐containing compounds produced from rice glutelin in the sake brewing process. Significance and novelty We revealed that the glutelin content in the milled rice grains is important to brew high quality of sake clearly. The present results would be useful for cultivation or breeding of sake rice.

Nitrogenous compounds and Chinese baijiu: a review

“…The rice for making sake is white, polished rice. Studies have found that the 'polishing' of white rice can affect the content of nitrogenous compounds and the quality and taste of sake (75)(76)(77)(78).…”

Peptides in Brewed Wines: Formation, Structure, and Function

“…41 Sake is made from rice with a polishing rate of ∼65% 38 and a crude protein content ∼5%. 23,41 These remaining proteins can be hydrolyzed by sake koji enzymes; about 50% of total nitrogen of sake (0.78−1.21 g/L) 23 is composed of free amino acids (∼30%) and peptides (∼20%). 82 Three ACEI peptides VY (IC 50 of 7.1 μM), HY (26.1 μM), and YGGY (16.2 μM), were identified from sake.…”

“…28,29 However, there is scanty information on the study of peptides in brewed wines. The contents of peptides range from 15 to 230 mg/L, from 156 to 242 mg/L, and from 1770 to 4210 mg/L in grape wine, 30 sake, 23 wine, 24,31 respectively. However, little is known about their structural and functional characteristics, their formation mechanisms, and their health-promoting activities.…”

“…Food fermentation uses microorganisms to decompose and transform food components in the raw materials into a wide range of metabolites . Protein is a major macromolecular substance of grape wine, Japanese sake, and Chinese rice wine (also called Chinese Huangjiu or Chinese yellow wine in China) . In addition to contributing to the flavor, aroma, and mouthfeel of alcoholic beverages, proteins are also involved in the development of brewed wine turbidity .…”

“…They are also partially converted into corresponding small-molecule metabolites by fermentation, which impart organoleptic properties, for example, bitter, umami, sweet, and/or astringent taste, or exert beneficial effects on human health. , The sensory and functional properties of peptides in fermented dairy products, such as yogurt and cheese, fermented meat products, and fermented soybean products, have been widely studied in the literature. , However, there is scanty information on the study of peptides in brewed wines. The contents of peptides range from 15 to 230 mg/L, from 156 to 242 mg/L, and from 1770 to 4210 mg/L in grape wine, sake, and Chinese rice wine, , respectively. However, little is known about their structural and functional characteristics, their formation mechanisms, and their health-promoting activities.…”