Beans germination as a potential tool for GABA-enriched tofu production

Abstract

Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter that can be found in many plants, especially beans. Beans are normally used for producing vegetarian foods, such as bean milks, bean sprouts, and tofu. Thus, the aims of this study were to determine the GABA content in various germinated beans (yellow beans, black beans, green beans, and red beans) as well in tofu products made from different types of germinated beans. The results showed that soaking and germination significantly contributed to an increase in GABA production. The GABA content increased to a maximum value of 0.89, 3.09, 3.93 and 4.78 mg/g in yellow beans, red beans, green beans, and black beans, respectively. Moreover, due to the bean characteristics, green beans, red beans, and black beans were collected at 6 h after germination while yellow beans were collected at 0 h after germination. As a result, only yellow bean sprouts could be used for tofu production since they are composed of a high amount of proteins and a low amount of carbohydrates. The GABA content in tofu was 0.55 mg/g, which was lower than that in soybean milk (0.65 mg/g), likely due to the filtration and pressing processes of tofu production.

Transcriptome Analysis Reveals the Molecular Mechanism of GABA Accumulation during Quinoa (Chenopodium quinoa Willd.) Germination

“…Therefore, it is important to observe the changing patterns of GABA during germination using quinoa varieties with different GABA contents. Numerous studies have shown that the GABA content of seeds such as buckwheat, soybean , beans, and brown rice increase remarkably after germination. In our work, the results of changes in the GABA content during quinoa germination were similar to those of the previous study .…”

“…Most studies about GABA biosynthesis have mainly focused on the GABA shunt, , only a few reports on the polyamine degradation pathways . Plants are able to accumulate a large amount of GABA through the polyamine degradation pathway to resist stress .…”

“…As one kind of plant enrichment, germination, an important approach to improve the nutritional value and bioactive compound contents (especially for GABA) of cereals and vegetables, has been successfully applied in quinoa, soybean, mung bean, broccoli, and Chinese wild rice . Numerous studies have reported that the levels of GABA significantly increase during soybean, buckwheat, beans, and brown rice germination. It is worth noting that a 29.1-fold increase in the GABA content was observed during kiwicha germination using response surface analysis .…”

Optimization of γ-Aminobutyric Acid (GABA) Accumulation in Germinating Adzuki Beans (Vigna angularis) by Vacuum Treatment and Monosodium Glutamate, and the Molecular Mechanisms

“…Immersion of beans and cereals seeds in solution could release dormancy and restore physiological functions. Previous studies have demonstrated that different soaking conditions have varying effects on GABA enrichment in germinating beans ( 16 , 29 ). In the present study, when the soaking time was <16 h, GABA contents in adzuki beans increased as soaking time increased ( Figure 1A ), which indicated that metabolism was induced following water imbibition, in addition to the activation of endogenous enzymes and GAD in the reaction system produces GABA secondary metabolites and other nutrients ( 7 , 30 ).…”

Impact of Bacillus in fermented soybean foods on human health

“…The FSF such as natto, miso, tauco, gochujang, douchi, cheonggukjang, doenjang, tofu, tempeh, meju, and bean curd are commercially available in retail markets across the East and Southeast Asian countries like Japan, China, Indonesia, and Korea. Some soybean foods like tofu are also available in countries like the USA and India (Chen et al 2012 ; Vann et al 2020 ). These commercially available fermented foods are fermented by using starter cultures such as Bacillus subtilis for preparing kinema, tungrymbai, bekang, and natto (Tamang 2015 ).…”