Increased γ-Aminobutyric Acid Content of Germinated Brown Rice Produced in Membrane Reactor

Abstract

Research background. Rice germination is a natural approach to enhance the physical and functional properties of brown rice. Thus, the aim of this study was to investigate the influence of germination methods on functional properties of GBR and evaluate the process feasibility. Experimental approach. Brown rice of IPB 3S was germinated in three (3) different methods, such as (i) complete soaking without water replacement, (ii) complete soaking with water replacement every six hours, and (iii) complete soaking with continuous washing in the developed membrane-facilitated soaking reactor. Results and conclusions. The application of the membrane reactor for producing germinated brown rice could maintain the pH of the soaking solution relatively constant (i.e. 6.8-7.0). This indicated the circumvention of natural fermentation during brown rice germination. Moreover, the concentration of γ-aminobutyric acid in germinated brown rice produced in the membrane reactor was about 4.5-fold higher (169.2 mg/100 mg sample) than brown rice (36.82 mg/100 mg sample), and also higher than that of the other two soaking methods. The γ-oryzanol concentrations and the antioxidant capacities of GBR resulted from the three soaking methods were fluctuated, ranging from 32 to 38 mg/100 mg sample and 18 to 28 mg AEAC/100 g sample, respectively. Within this study, germination could also slightly reduce the transition temperatures of GBR starch gelatinization (to = 73-74 °C, tp = 76-77 °C, and tc = ~ 80 °C). In conclusion, the production of germinated brown rice in the membrane reactor could enhance the γ-aminobutyric acid content of germinated brown rice and reduce wastewater production. Therefore, the production of germinated brown rice in the membrane reactor is considered more feasible. Novelty and scientific contribution. This study demonstrates the feasibility of germinated brown rice production using a membrane-facilitated soaking reactor with better enhancement in bioactive compounds, especially γ-aminobutyric acid, and minimizing wastewater production.

Effects of hydrogen‐rich water on the nutritional properties, volatile profile and texture of germinated brown rice

“…It is well known that the GABA concentration in BR significantly increases after soaking and germination. However, the GABA content in GBR varies with different types of rice and germination processes (Yao et al ., 2008; Munarko et al ., 2021; Sitanggang et al ., 2021; Munarko et al ., 2022).…”

“…Sitanggang et al . (2021) found that germination changes the phenolic content, antioxidant capacity and γ‐oryzanol content. However, more studies on the compositional and functional changes of the bioactive components during germination are still needed.…”

“…Rice germination is a natural approach to enhance the physical and functional properties of BR since it induces numerous changes in the composition and chemical structure of the bioactive components. Sitanggang et al (2021) found that germination changes the phenolic content, antioxidant capacity and γ-oryzanol content. However, more studies on the compositional and functional changes of the bioactive components during germination are still needed.…”

The combined effect of cold plasma pretreatment and germination on nutritional quality and texture properties of brown rice cakes

“…The germination of brown rice can enhance nutritional value and physiological function of brown rice (Munarko et al., 2021; Sitanggang et al., 2021). Germinated brown rice (GBR) is rich in phenolics, GABA, minerals, and other active substances which are superior to that of brown rice and white rice, and has a good effect on the prevention of diabetes, high blood fat, hypertension and other chronic diseases (Munarko et al., 2022; Li et al., 2022a).…”

Bioactive Compounds and Quality Evaluation of Red-Pigmented Rice Processed by Germination and Roasting

“…Germinated brown rice (GBR) has recently gained popularity in Asia. Germinated rice contains higher quantities of phytochemicals, including GABA, tocopherol, 𝛾-oryzanol, and phenolic compounds than non-germinated rice [ 10 , 11 ]. Germinated grain products have been used as new ingredients in the food industry for improving flavor, taste, mineral absorption, and nutritional value.…”