• Korean Journal of Food Science and Technology
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• v.36 no.5
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• pp.761-764
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• 2004

Effects of pretreatment conditions on ${\gamma}-aminobutyric$ acid (GABA) contents of brown rice and germinated brown rice were investigated. As steeping time increased, GABA contents of brown rices increased gradually. The highest GABA content, 3.33mg/100g, was found in brown rice steeped at $40^{\circ}C$ for 8 hr. GABA content of brown rice decreased significantly at pH 8 (p<0.05), but changed slightly at pH of steeping solution ranging 4-7. Steeping of brown rices in glutamate solution increased GABA contents. Brown rice steeped in glutamate solution at 200-300 ppm showed GABA content between $4.09{\pm}0.48-4.11{\pm}0,47mg/100g$, which was much higher than that of untreated brown rice. Anaerobic treatment of brown rices using $N_2$ gas increased GABA contents, ranging from $4,70{\pm}0.49\;to\;4.92{\pm}0.83mg/100g$. Germinated brown rice steeped in glutamate solution under anaerobic condition had GABA content of $5.92{\pm}0.72mg/100g$, two-fold higher than that of untreated brown rice, $3.05{\pm}0.67mg/100g$. Optimum pretreatment condition established in this study could significantly increase GABA content in germinated brown rice.

• Food Science and Biotechnology
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• v.14 no.4
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• pp.518-522
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• 2005

Yogurt containing high ${\gamma}$-aminobutyric acid (GABA) was developed using lactic acid bacteria and germinated brown rice. Lactobacillus acidophilus, L. plantarum, and L. brevis OPY-1 strains were inoculated into Lactobacillus MRS broth for use as yogurt starter. After treatment with 5% monosodium glutamate in MRS broth, L. brevis OPY-1 strain isolated from Kimchi produced GABA concentration of 8,003.28 nmol/mL. Starter was inoculated into fermentation substrate mixture containing germinated brown rice extract and blend of powdered whole milk and skim milk. Samples were incubated, and viable cell colonies were counted. Highest number of lactic acid bacteria was reached between 16 and 20 hr. Concentrated rice milk fermented with high GABA-producing strain contained GABA concentrations of $137.17\;{\mu}g/g$ D.W., whereas concentrated fermented milk prepared by conventional method contained GABA of $1.29\;{\mu}g/g$ D.W. Sensory evaluation panelists gave favorable ratings to fermented rice milk containing high GABA concentration.

• Preventive Nutrition and Food Science
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• v.8 no.1
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• pp.75-78
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• 2003

We analyzed the ${\gamma}$-aminobutyric acid (GABA) content of a selection of uncooked foods. Foods with GABA concentrations in excess of 100 nmole per g dry weight included: brown rice germ, brown rice sprouts, barley sprouts, bean sprouts, beans, corn, barley, brown rice, spinach, potatoes, sweet potatoes, yams, kale and chestnuts. Cereals included: brown rice germ, brown rice sprouts, barley sprouts, bean sprouts, beans, corn, barley, and brown rice and had GABA concentrations of 718, 389, 326, 302, 250, 199, 190, and 123 nmole per g dry weight (DW), respectively. The vegetables: spinach, potatoes, sweet potatoes, yams and kale contained 414, 166, 137, 129, 122 nmole GABA per g DW, respectively. The GABA concentration of chestnut was 188 nmole per g DW. However, oatmeal, adlay, broccoli, squash, carrots, onion, apples, lentinus edodes, green laver, and lactobacillus had GABA concentrations of less than 100 nmole per g DW. These results show that brown rice germ, sprouted cereals and spinach are good sources of plant-derived GABA. These data will be useful in selecting foods for the manufacturing of uncooked foods containing a relatively high concentrations of GABA.

• BMB Reports
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• v.36 no.3
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• pp.319-325
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• 2003

Changes in the concentrations of $\gamma$-aminobutyric acid (GABA), soluble calcium ions, glutamic acid, and the activity of glutamate decarboxylase (GAD) were investigated in non-germinated vs. germinated brown rice. Brown rice was germinated for 72 h by applying each of the following solutions: (1) distilled water, (2) 5 mM lactic acid, (3) 50 ppm chitosan in 5 mM lactic acid, (4) 5 mM glutamic acid, and (5) 50 ppm chitosan in 5 mM glutamic acid. GABA concentrations were enhanced in all of the germinated brown rice when compared to the non-germinated brown rice. The GABA concentration was highest in the chitosan/glutamic acid that germinated brown rice at 2,011 nmol/g fresh weight, which was 13 times higher than the GABA concentration in the non-germinated brown rice at 154 nmol/g fresh weight. The concentrations of glutamic acid were significantly decreased in all of the germinated rice, regardless of the germination solution. Soluble calcium and GAD were higher in the germinated brown rice with the chitosan/glutamic acid solution when compared to the rice that was germinated in the other solutions. GAD that was partially purified from germinated brown rice was stimulated about 3.6-fold by the addition of calmodulin in the presence of calcium. These data show that the germination of brown rice in a chitosan/glutamic acid solution can significantly increase GABA synthesis activity and the concentration of GABA.

• Korean Journal of Food Science and Technology
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• v.42 no.5
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• pp.632-636
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• 2010

The level of ${\gamma}$-aminobutyric acid (GABA) in pigmented rice was quantitatively and qualitatively determined by high pressure liquid chromatography/fluorescence detection (HPLC/FLD). In this study, the recovery rate and limit of detection (LOD) of GABA were 122.4${\pm}$2.4% and 0.23 ${\mu}g/g$, respectively. The geminating pigmented rice samples, which were harvested in Paju, Korea, were soaked in water at $18^{\circ}C$ for 20 hr. After soaking, the samples were germinated at $30^{\circ}C$ for about 24 hr. GABA content was highest (293.0 ${\mu}g/g$) in the germinated red rice. Furthermore, GABA levels in the germinated rice increased significantly by up to 11.1 and 24.7-fold as compared to non-germinated rice and milled rice, respectively. The GABA concentrations of non-germinated rice, with the exception of red rice, were significantly higher than those of milled rice by 7.6-20.6-fold.

• Korean Journal of Food Science and Technology
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• v.42 no.6
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• pp.688-692
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• 2010

The aim of this study was to investigate the effects of molecular weight and concentrations of chitosan on the germination of brown rice. Brown rice was germinated at $30^{\circ}C$ for three days in various chitosan solutions. The germination rate of the brown rice increased with increasing concentrations of chitosan solution, and was higher in the chitosan solution than in water. GABA content increased with increasing germination time and chitosan solution concentration. As the molecular weight of the chitosan decreased, germination rate and GABA content increased in the brown rice. The GABA content of germinated brown rice using low molecular weight chitosan A in a 100 ppm solution was 5145.5 nmole/g. This is approximately a five times higher value than that of the water-germinated brown rice. Texture properties were enhanced in all the germinated brown rice samples in chitosan solution compared to the brown rice germinated in water. These results indicate that chitosan solution treatment can increase germination rate and GABA synthesis activity in brown rice during germination, and can also improve the texture properties of brown rice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.2
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• pp.274-280
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• 2010

This study was to investigate the quality characteristics of noodles prepared with germinated brown rice and rice bran, and to determine the changes in GABA content and antioxidant activity of the noodles. These noodles were evaluated for cooking properties (cooking loss, swelling index, water holding capacity), total polyphenols, antioxidant activities (radical scavenging of ABTS and DPPH), and GABA contents. The addition of germinated rice bran in the range of 5, 10, and 15% showed a significant influence on cooking loss, although no effect on swelling index was observed. The raw and cooked noodles containing germinated brown rice and rice bran contained more GABA contents (2751.6~4176.7 and 5522.0~9617.8 nmol/20 g of fresh noodle, respectively) than those of non-germinated brown rice and rice bran. Noodles made with germinated brown rice and rice bran had similar total polyphenolics contents and antioxidant activities compared to noodles made with non-germinated brown rice and rice bran. Overall, the germinated brown rice could be used as a good ingredient to increase the nutritional value and antioxidant properties of wheat flour noodle without affecting the cooking properties.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.8
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• pp.1201-1206
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• 2010

As a means to increase the production and consumption of the brown colored rice with high content of GABA ($\gamma$-aminobutyric acid), this study was conducted to develop brown colored rice tea. After roasting at various temperatures and times, color values and GABA content of the brown colored rice were analyzed. Physicochemical properties such as browning, turbidity, reducing sugar, soluble solid, total polyphenol and pH of brown colored rice tea were determined after the rice powder was put into tea bags and leached in hot water. Sensory characteristics were investigated for three kinds of tea roasted at $170^{\circ}C$ for 10, 20 and 30 min. As the roasting temperature and time increased, L, a and b values decreased as well as GABA content. The brown colored rice roasted at $170^{\circ}C$ for 10 min contained the highest content of GABA. Browning, turbidity, reducing sugar, soluble solid and total polyphenol of the brown colored rice tea increased as the roasting temperature and time increased, on the contrary, pH decreased. The brown colored rice tea roasted for 30 min was preferred the most in color, flavor, taste and overall acceptance. From this result, the brown colored rice tea needs to be manufactured by a combination of the brown colored rice roasted at $170^{\circ}C$ for 10 min and 30 min to satisfy the consumer's preference and high content of GABA.

• The Korean Journal of Food And Nutrition
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• v.23 no.4
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• pp.511-515
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• 2010

It was conducted to assess GABA(${\gamma}$-aminobutyric acid) producing capacity and vitamin contents of germinated brown rice soaked in different soaking solutions. For germination, samples were soaked in 5% glutamic acid solution and 5% lactic acid solution as test group to investigate GABA producing capacity, and samples soaked in the solution without glutamic acid and lactic acid were set as control groups(rice and non-germinated brown rice). The GABA contents of the samples were $44.80\;{\mu}g/g$ for rice, $59.90\;{\mu}g/g$ for non-germinated brown rice, $146.70\;{\mu}g/g$ for germinated brown rice, $203.20\;{\mu}g/g$ for germinated brown rice soaked in glutamic acid solution and $222.5\;{\mu}g/g$ for germinated brown rice soaked in lactic acid solution, resulting in a significant difference(p<0.05). GABA producing capacity was enhanced by the addition of glutamic acid and lactic acid in the soaking solution for brown rice germination. The GABA contents of the germinated brown rice soaked in lactic acid solution greatly increased, along with increases in niacin and vitamin E contents without losing vitamin $B_1$. In conclusion, the addition of lactic acid in soaking solution is most suitable for germination of brown rice.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.5
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• pp.822-829
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• 2015

The purpose of this study was to evaluate the biological activities and quality properties of macaroons made with GABA rice powder and xylose. GABA rice powder was added to macaroons at weight percentages of 0, 2.5, and 3.5%. Hunter's color values ($L^*$, $a^*$, $b^*$), total sugar contents, total phenolics, ABTS and DPPH radical scavenging activities, textures, and sensory characteristics supplemented with different xylose and GABA rice powder contents were measured. As the ratio of GABA rice powder in macaroons increased, total phenol contents and ABTS and DPPH radical scavenging activities increased. In the texture profile analysis, fracturability and brittleness were lower as GABA rice powder content increased. In the sensory evaluation, significant differences (p<0.05) were observed in color, sweetness, texture, and overall acceptability depending on the addition of GABA rice powder to macaroons. Overall qualities of macaroons were different from GABA rice powder and xylose added ones. Therefore, xylose and GABA rice powder may be used to make healthy macaroons.