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

作者：Okuda Masaki^*; Joyo Midori; Tamamoto Yuki; Sasaki Motoki; Takahashi Kei; Goto Yamamoto Nami; Ikegami Masaru; Hashizume Katsumi

来源：Cereal Chemistry, 2018, 95(2): 320-329.

DOI：10.1002/cche.10036

• glutelin
• nitrogen compound
• rice protein
• sake

Background and objectivesProtein 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.
FindingsCrude 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 -amylase and acid proteinase activities with the nitrogen compounds in the sake.
ConclusionsThe 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 noveltyWe 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.

• 出版日期2018-4