Characteristics and in vitro Anti-diabetic Properties of the Korean Rice Wine, Makgeolli Fermented with Laminaria japonica

Abstract

New in vitro anti-diabetes makgeolli was produced from rice by adding various quantities of Laminaria japonica, and the fermentation characteristics of the L. japonica makgeolli during the fermentation process were investigated. The contents of alcohol and reducing sugar, and viable count of yeast, of L. japonica makgeolli were not significantly changed when the proportion of L. japonica was increased. The total acid content decreased with an increase in L. japonica concentration; the pH and total bacterial cell count increased in proportion with the increase in L. japonica concentration. The L. japonica makgeolli contents of free sugars, such as fructose, glucose, and sucrose, and of organic acids, such as acetic acid, citric acid, succinic acid, and lactic acid, were altered during fermentation and showed various patterns. The effects of the quantity of L. japonica added on the acceptability and anti-diabetes activities of L. japonica makgeolli were also investigated. In a sensory evaluation, L. japonica makgeolli brewed by adding 2.5 or 5% L. japonica to the mash showed the best overall acceptability; the 12.5% L. japonica sample was least favored due to its seaweed flavor. L. japonica addition did not increase the peroxynitrite-scavenging activity of makgeolli. L. japonica makgeolli showed potent anti-diabetes activity, particularly that containing >7.5% L. japonica. Therefore, L. japonica makgeolli may represent a new functional makgeolli with anti-diabetes properties.

Keywords: Laminaria japonica; anti-diabetes activity; makgeolli; quality characteristics; rice wine.

Fig. 1

Changes in (A) ethanol content, (B) pH, (C) total acid content, and (D) reducing sugar content during makgeolli fermentation in L. japonica makgeolli containing 0.0% (•), 2.5% (○), 5.0% (▼), 7.5% (▽), 10.0% (■), or 12.5% (□) of L. japonica powder. All measurements were performed in triplicate, and values are the means of three replicates. Means with different letters (a–f) among samples in the same fermentation period are significantly different at P<0.05 by Duncan’s multiple range test.

Fig. 2

Changes in (A) bacterial count, and (B) yeast count during makgeolli fermentation in L. japonica makgeolli containing 0.0% (•), 2.5% (○), 5.0% (▼), 7.5% (▽), 10.0% (■), or 12.5% (□) of L. japonica powder. All measurements were performed in triplicate, and values are the means of three replicates. Means with different letters (a–f) among samples in the same fermentation period are significantly different at P <0.05 by Duncan’s multiple range test.

Fig. 3

Peroxynitrite-scavenging activity (A) and anti-diabetes activity (B) of L. japonica makgeolli. All measurements were performed in triplicate, and values are means of three replicates. All measurements were performed in triplicate, and values are the means of three replicates. Means with different letters (a–c) above the bars are significantly different at P <0.05 by Duncan’s multiple range test.