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GABA (γ-aminobutyric acid) production, antioxidant activity in some germinated dietary seeds and the effect of cooking on their GABA content


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Germinated grains have been known as sources of Gamma-aminobutyric acid (GABA) that provide beneficial effects for human health. This study was aimed to investigate GABA production, dietary fiber, antioxidant activity, and the effect of cooking on GABA loss in germinated legumes and sesame. The highest GABA content was found in germinated mung bean, (0.8068 g kg-1, 24 h incubation) followed by germinated soybean, germinated black bean and soaked sesame. Beside GABA, dietary fiber content also increased in all grains during germination where the insoluble dietary fiber fractions were always found in higher proportions to soluble dietary fiber fractions. Our results also confirmed that germinated mung bean is a rich source of GABA and dietary fibers. Microwave cooking resulted in the smallest loss of GABA in mung bean and sesame, while steaming led to the least GABA content loss in soybean and black bean. Therefore microwave cooking and steaming are the most recommended cooking processes to preserve GABA in germinated legumes and sesame.
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Food Sci. Technol, Campinas, 1
Food Science and Technology ISSN 0101-2061
1 Introduction
Gamma-aminobutyric acid (GABA) is a four carbon amino
acid that is produced by the decarboxylation of L-glutamic acid that
catalyzed by glutamate decarboxylase enzyme (Komatsuzakietal.,
2007). GABA is an inhibitory neurotransmitter in the sympathetic
nervous system (Wangetal., 2006) and is widely distributed
in nature. GABA provides many benecial eects for human
health such as decreasing blood pressure, controlling stress
(Chungetal., 2009), diuretic eect, tranquilizer eect, while
germinated brown rice with enhanced levels of GABA can inhibit
cancer cell proliferation (Oh & Oh, 2004). Many kinds of food
such as germinated grains have high content of GABA. During
germination process, the biochemical activities of germinated
grains produce essential compounds for the formation of the
seedling. Accordingly, these processes lead to increasing amounts
of simple sugars, peptides and amino acids in germinated
seeds, such as in wheat (Moongngarm & Saetung, 2010), barley
(Chungetal., 2009), and rice (Samanetal., 2008). In addition,
many enzymes are activated, which may produce minor nutrients
such as GABA and vitamins. Germinated cereal grains have been
widely studied for GABA production such as in germinated barley
(Chungetal., 2009), germinated rice (Komatsuzakietal., 2007;
Zhangetal., 2007; Thuwapanichayananetal., 2015; Kimetal.,
2015) and soybean (Xu & Hu, 2014).
Legumes and sesame seed are highly nutritious food
ingredients. Mung bean is an excellent source of protein, rich in
vitamins, especially thiamin, riboavin and niacin, and minerals.
Soybean proteins are considered high quality proteins, rich
in lysine, and their amino acid prole resemble that of cereal
proteins (Castrorubioetal., 2006). It was reported that GABA
levels in soybean sprouts were rapidly increased during the
early stage of germination (Matsuyamaetal., 2009). Blackbean
is also a rich source of proteins, bers, several vitamins and
essential minerals such as calcium and iron (Girishetal., 2012).
Sesame seeds contain many compounds that have antioxidant
activity such as sesamin, sesamolin, sesamol, and sesaminol
(Hahmaetal., 2009; Rangkadiloketal., 2010). On the other
hand, legumes and sesame have been reported to possess
antinutritional factors such as trypsin inhibitor, phytic acid, and
tannins (Siddhurajuetal., 2002). Cooking is usually useful to
inactivate heat-labile antinutritional factors. However, cooking
processes cause considerable losses in vitamins and minerals
(Alajaji and El-Adawy, 2006; Mubarak, 2005). A previous study
reported that germination process enhances the nutritive value of
legumes by reducing the antinutritional and indigestible factors
in legumes (Bauetal., 1997). However, only a few studies have
reported the accumulation of GABA and nutritional composition
during germination (Matsuyamaetal., 2009; Oh & Choi, 2001;
Martínez-Villaluengaetal., 2006; Shenetal., 2015) and the eect
of cooking process on GABA loss in germinated legumes and
sesame (Sirisoontaralaketal., 2015).
Therefore, the aim of this research was to study the
appropriate germination condition of grains, which were
mung bean (Vignaradiata), soybean (Glycine max), black bean
(Vignamungo), and sesame (Sesamum indicum) in producing
GABA (γ-aminobutyric acid) production, antioxidant activity in some germinated
dietary seeds and the eect of cooking on their GABA content
Received 25 Nov., 2015
Accepted 11 Apr., 2016
Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, ailand
Center of Excellence on Agricultural Biotechnology – AG-BIO/PERDO-CHE, Bangkok, ailand
Institute of Food Research and Product Development, Kasetsart University, Bangkok, ailand
Science Division, International College, Mahidol University, Salaya, Nakhonpathom, ailand
*Corresponding author:
Germinated grains have been known as sources of Gamma-aminobutyric acid (GABA) that provide benecial eects for human
health. is study was aimed to investigate GABA production, dietary ber, antioxidant activity, and the eect of cooking on
GABA loss in germinated legumes and sesame. e highest GABA content was found in germinated mung bean, (0.8068 g kg
24 h incubation) followed by germinated soybean, germinated black bean and soaked sesame. Beside GABA, dietary ber
content also increased in all grains during germination where the insoluble dietary ber fractions were always found in higher
proportions to soluble dietary ber fractions. Our results also conrmed that germinated mung bean is a rich source of GABA
and dietary bers. Microwave cooking resulted in the smallest loss of GABA in mung bean and sesame, while steaming led to
the least GABA content loss in soybean and black bean. erefore microwave cooking and steaming are the most recommended
cooking processes to preserve GABA in germinated legumes and sesame.
Keywords: gamma-aminobutyric acid; legume; sesame; cooking eect.
Practical Application: Germinated mung bean can potentially be used to enrich foods with GABA and dietary bers.
GABA content in dietary seeds
Food Sci. Technol, Campinas, 2
GABA. Also, physicochemical composition, dietary ber content
and antioxidant activity of germinated legumes and sesame were
investigated. Additionally, the eect of domestic traditional
cooking such as boiling, steaming, microwave cooking and
open pan roasting on the GABA content of germinated grains
was evaluated.
2 Materials and methods
2.1 Grains samples
e grains used in this study were mung bean (Vigna radiata),
soybean (Glycine max), black bean (Vigna mungo), and sesame
(Sesamum indicum). ey were obtained from Institute of Food
Research and Product Development, Kasetsart University,
Bangkok, ailand.
2.2 Germination condition
Grain samples were soaked in distilled water (1:5, w/v) for
6h at room temperature. Samples were then incubated in plastic
container and placed between of moist cloth layers at room
temperature. As germination progressed germinated grains
were randomly selected for analysis at dierent incubation
times, which were 0 (immediately aer soaking), 6, 12, 24, 36
and 48h. esample grains were then dried in hot air oven
at 50 °C for 8h and subjected to further analysis for GABA
content, proximal food composition, dietary ber content and
antioxidant activity.
2.3 GABA content analysis
e GABA content measurement was carried out by the modied
method of Srisangetal. (2011). e germinated grains were nely
ground and extracted with 3% sulfosalicylic acid (0.5g/200 mL)
for 1.5 h at room temperature. e extracts were centrifuged at
5,000 × g for 10 min and the supernatant was collected and run
through derivatization process. 50µL supernatant was mixed
with 50 µL NaHCO
and 200 µL dimethylaminoazobenzene
and incubated at 70 °C for 10min. 250 µL ethanol and 250 µL
were added and the solution was ltered through 0.45µm
pore-size nylon lters. e derivative solution was analyzed by
HPLC (Agilent 1100 Series, Agilent Technologies, California,
USA) equipped with Supelcosil-LC-DABS column, where the
detector was set at 465 nm. Acetonitrile was used as a mobile
phase with a ow rate 1 mL/min. e column temperature was
controlled at 35 °C.
2.4 Proximate analysis of food components
e Kjeldahl method was used for the analysis of total
nitrogen content, which then was utilized to calculate the protein
content (N×6.25) (Association of Official Analytical Chemists,
1990b). Determination of total fat content was performed by
gravimetric solvent extraction using Soxhlet extraction system
and petroleum ether as extraction solvent (Association of Official
Analytical Chemists, 2000). Ash was determined by combustion
of the sample in a mue furnace at 550 °C (Association of
Official Analytical Chemists, 1990a) and total carbohydrate
content was calculated by subtracting % protein, % ash, and %
fat contents from total dry weight (100%). All proximal values
were reported as the average value of three replications.
2.5 Dietary ber content Determination
e contents of total (TDF), soluble (SDF) and insoluble
dietary ber (IDF) were determined by the enzymatic-gravimetric
method modied from AACC methods 32-05 and 32-21 using
Total Dietary Fiber Assay Kit (Megazyme). e defatted sample
was gelatinized with 50 µL heat stable α-amylase in 50 mL
phosphate buer (0.08 mol L
, pH 6.0). e sample was further
digested with 100 µL protease and 200 µL amyloglucosidase.
ereaer, the solution was ltered; the residue was washed,
dried and weighed to determine insoluble dietary ber content.
e ltrate was precipitated by adding four times volume of
60°C 95% ethanol. en, the precipitates were ltered, washed,
dried and weighed to determine soluble dietary ber content.
Determination of ashes and proteins in residues was carried out
for corresponding corrections. Kjeldahl nitrogen and ash contents
were assayed according to standard procedures (Association
of Official Analytical Chemists, 1990b). e total dietary ber
content was calculated as the sum of insoluble dietary ber and
soluble dietary ber contents.
2.6 DPPH radical scavenging assay
e extracts used for determination of 2,2-Diphenyl-1-
picrylhydrazyl (DPPH) radical scavenging and total phenolics
content was prepared by reuxing the germinated grains powder
with distilled water (10 g/100 mL). e reuxed material was ltered
and the supernatant was collected for analysis. efree-radical
scavenging capacity of each extract was evaluated according
to the procedure of Butsat & Siriamornpun (2010) with some
modications. Briey, 100 µL of the extract was added to freshly
prepared 0.1 mM DPPH solution (1.9 mL), and the mixture
was kept at room temperature in dark environment for 30 min.
eabsorbance was measured at 517 nm and the antioxidant
activity was calculated by the following Equation 1:
DPPH scavenging activity (%) = [(A
517 control
– A
517 extract
517 control
2.7 Total phenolics assay
The total phenolics content was determined by the
Folin-Ciocalteu method modied by Randhir & Shetty (2007).
Briey, 1 mL of the sample extract was transferred into a test
tube and mixed with 1 mL of 95% ethanol and 5 mL of distilled
water. Folin-Ciocalteu reagent was added to each sample to a
nal concentration of 50% (v/v) and mixed. Aer 5 min, 1 mL
of 5% Na
was added and the reaction mixture was allowed
to stand for 60 min. e absorbance was measured at 725 nm.
e standard curve was established using various concentrations
of gallic acid in 95% methanol, and the result was expressed
as mg of gallic acid equivalent per gram of dry weight sample
(dry weight).
2.8 e eect of cooking process on GABA content
e germinated grains were soaked in distilled water
(1:5, w/v) for 3 h at room temperature to soen the grains. en,
they were rinsed twice with distilled water, and cooked by the
methods described below:
Food Sci. Technol, C ampinas, 3
a. Boiling: Soaked grains were boiled in distilled water
(98-100 ºC) in the ratio of 1:10 (w/v). Grains were cooked
for 20 min and then rinsed again with distilled water.
b. Steaming: Soaked grains were cooked in steaming pot
for 40 min.
c. Microwave cooking: Soaked grains were placed in a plastic
box with distilled water (1:5, w/v) and then cooked in a
microwave oven (Sharp R276) with 2450 MHz, 800 W
(IEC 60705) for 10 min.
d. Open pan roasting: Non soaked germinated grains were
roasted in open pan (90-95°C). e grains of mung bean,
soybean, and black bean were roasted for 10 min, while
germinated sesame was roasted for 5 min.
Cooking treatments were replicated three times. Aer
the germinated grains were subjected to the cooking process,
they were analyzed for their GABA content and compared to
uncooked germinated grains.
2.9 Statistical analysis
All analyses were performed in triplicate. Statistical analyses
were carried out with Duncans multiple test (p < 0.05) using
statistical soware SPSS V. 17 (SPSS Institute Inc., Cary, NC).
3 Results and discussion
3.1 GABA content in germinated legumes and sesame
Aer soaking and incubation, GABA content in germinated
grains was generally higher than in non germinated grains
(Figure1). is indicated that the storage protein in grains was
decomposed at least partially and supplied to the growing part
of the seedlings and within this process glutamate decarboxylase
enzyme was activated which converted glutamic acid to GABA.
is result agrees with a previous report which found that the
GABA contents in ve cultivars of brown rice (Oryza sativa L.
ssp. Japonica: Haiminori, Oou 359, Koshihikari, Yumetsukushi
and Nipponbare) were signicantly increased during soaking
Figure 1. GABA contents of germinated grains at dierent incubation periods. NG denotes non germinated grains. (a) GABA content in germinated
mung bean. (b) GABA content in germinated soybean. (c) GABA content in germinated black bean. And (d) GABA content in germinated sesame.
Data reported are the mean ± SD of triplicate determinations.
Means of each grain type with dierent letters are signicantly dierent (p < 0.05).
GABA content in dietary seeds
Food Sci. Technol, Campinas, 4
and germination (Komatsuzakietal., 2007). Similarly, GABA
content in germinated barley and soy bean were found higher
than in non germinated grains as reported by Chungetal. (2009)
that in germinated barley steeping was found to contribute to
the increasing of GABA content. Wangetal. (2015) also found
that GABA content of Chinese soybean cultivar ZH 13 was
increased 36.7-fold in day 5 of germination comparing to non
germinated soybean.
e concentrations of GABA were 0.1325, 0.1222, 0.0438
and 0.0907 g kg
dry matter in non germinated mung bean,
soybean, black bean and sesame, respectively. Aer germination,
the amount of GABA signicantly increased especially in mung
bean. GABA content in germinated mung bean increased up to
0.8068 g kg
dry matter at 24 h of incubation period, however there
was no further increase aer 24 h (Figure1a). econcentration
of GABA in germinated soybean exponentially increased up
to 0.4977 g kg
dry matter at 6 h of incubation period then
decreased to 0.2638 and 0.1659 g kg
dry matter at 12 h and
24h, respectively (Figure1b). Aer 6 h soaking (0 h incubation),
the GABA content in germinated black bean was found to be
0.6773 g kg
dry matter and increased up to 0.7430 g kg
matter at 6 h of incubation period (Figure1c). Aer that the
GABA content decreased to 0.3526 and 0.1645 g kg
dry matter
at 12 h and 24 h, respectively. In sesame seeds, 6 h soaking alone
increased the GABA content up to 0.1649 g kg
dry matter
(Figure1d). However it slightly decreased aerwards. Soaking
leads to water absorption which activate the germination processes
including glutamate decarboxylase enzyme that convert glutamic
acid to GABA (Komatsuzakietal., 2007). Rapid accumulation
of GABA in early stage of soaking and germination of soybean
and black bean has been suggested to be a probable response to
water stress by young tissues (Matsuyamaetal., 2009). Based on
our results, the optimal incubation period for GABA production
in germinated soybean and black bean was 6 h. Interestingly,
the highest GABA content in sesame was obtained aer only
soaking for 6 h without incubation period. However, it is dicult
to compare the actual GABA content found in grains with
dierence in plant varieties and germination conditions. As in
the study of Zhangetal. (2014) found that GABA production
in indica and japonica germinated brown rice were dierent
and inuenced by genotypes and condition of soaking and
germination. Ourstudy supports the fact that soaking and
germination were ecient processes to increase the levels of
GABA in legumes and sesame. In general, legumes have higher
protein content than sesame; as a result germinating legumes
could produce more GABA than sesame.
3.2 Physicochemical composition of germinated legumes and
Germination process affected the physicochemical
composition of germinated grains (Table1). e protein
content of non germinated mung bean and black bean was
0.2457 and 0.2625 g kg
(dry weight basis), respectively. Aer
soaking and incubation, the protein content increased with
incubation time and reached up to 0.2940 and 0.2760 g kg
dry weight basis at 48 h in germinated mung bean and black
bean, respectively. eseresults are in agreement with other
works where an increase of crude protein content during
germination were reported in mung bean (Mubarak, 2005) and
tigernut (Chinmaetal., 2009). e increasing protein content by
germination could be attributed to synthesis of several enzymes
and resulted in the production of some non-protein nitrogen
containing compounds (Moongngarm & Saetung, 2010). On the
other hand the protein content in soybean and sesame increased
only slightly during germination. ese ndings are similar to
that of Donangeloetal. (1995) observing that 48 h germination
of soybean led to only a small increase in crude protein, while
crude protein remained almost unchanged throughout the
germination period in sesame (Hahmaetal., 2009). e recent
study of Shenetal. (2015) found that most of free amino acids
signicantly increased in brown rice aer germination in
anaerobic condition for 10 h, whereas the serine and threonine
contents remained unchanged, the content of aspartic acid and
glutamic acid decreased. ese changes can be explained by
accumulation of free amino acids from the assimilation of the
nitrate stored during the early stage of anaerobic germination
of seeds and later probably come from the breakdown of storage
protein followed by the translocation of amino acids.
Concerning fat content in germinated grains, incubation
periods did not have any eect on it in germinated mung bean,
soybean and black bean. is appears to be similar to that
of found by Moongngarm & Saetung (2010) in brown rice.
However in germinated sesame, fat content decreased during
germination period (Table1). is is could be attributed to the
use of fat as an energy source to start germination as described by
Hahmaetal. (2009). Fat could be hydrolysed during germination
and used to produce the necessary energy for the biochemical
and physicochemical modications that occur throughout the
e incubation period aected the ash content in all
germinated grains. It was found that ash content signicantly
decreased during germination. ese results are in agreement
with the decreasing ash content during germination found in
mung bean (Mubarak, 2005), legumes such as green gram, cow
pea, lentil and chick pea (Ghavidel & Prakash, 2007). It was
suggested that solid matter leaching from the seeds during the
soaking process could be the reason for signicant reduction
of minerals in germination.
Carbohydrate amount in legumes and sesame were also
estimated. Considering the non germinated grains, mung bean
and black bean had higher carbohydrate content than soybean and
sesame. As incubation periods lengthened, decreasing amount
of carbohydrates was found in germinated mung bean. is is
possibly due to their use as an energy source to fuel germination.
During germination of grains and legumes, biochemical activities
produce simple molecules such as sugars, amino acids and minerals
from more complex chemical constituents for the formation and
growth of seedling (Samanetal., 2008). In addition, increasing
α-amylase activity during germination could also be a possible
explanation for the carbohydrate loss. On the other hand, there
was no signicant change in carbohydrate content of germinated
soybean, black bean and sesame. ese ndings are similar to
that of reported in germinated rough rice and brown rice by
Moongngarm & Saetung (2010).
Food Sci. Technol, C ampinas, 5
3.3 Dietary bers in germinated legumes and sesame
Dietary bers play an important role in prevention of
cardiovascular diseases, cancer, diabetes and others (Girishetal.,
2012). Each fraction of insoluble dietary ber (IDF) and soluble
dietary ber (SDF) has dierent physiological eect. e IDF
relates to both water absorption and intestinal regulation, whereas
SDF associates with cholesterol in blood and diminishes its
intestinal absorption. Mostly, total dietary ber (TDF) content
in the tested grains increased during germination (Table2).
eIDF, SDF and TDF contents in non germinated mung
bean were 0.1464, 0.0066 and 0.1530 g kg
dry weight basis,
respectively, indicating that the IDF is the main dietary ber
fraction in mung bean. e IDF content increased up to 0.1640,
0.1874, 0.1990 and 0.2057 g kg
dry weight basis aer soaking
and incubation for 6 h, 12 h and 24 h, respectively. Aerwards
the IDF content slightly decreased to 0.1965 and 0.1896 g kg
dry weight basis at 36 h and 48 h, respectively. Besides, SDF
and TDF amounts also increased during germination. e SDF
content in germinated mung bean reached up to 0.0179 g kg
dry weight basis at 48h. While the TDF content increased
from 0.1783 to 0.2036 and 0.2212 g kg
dry weight basis aer
6 and 24 h, respectively.
e SDF content in germinated soybean changed only slightly
during germination. However, the amount of IDF and TDF in
germinated soybean was signicantly increased. e highest
IDF (0.2073 g kg
dry weight basis) and TDF (0.2467 g kg
weight basis) contents in germinated soybean were obtained aer
12hours of incubation. e SDF content in black bean increased
gradually during germination up until 36 h, whereas IDF and
TDF were slightly changed. e IDF, SDF, and TDF contents of
germinated sesame were also increased during germination period.
e results suggested that the germination process increased the
dietary bers (IDF, SDF and TDF) content of germinated grains.
Our ndings also reveal that the IDF contents were higher than
the SDF contents in germinated legumes and sesame. us,
the incorporation of these germinated legumes’ bers in food
could be useful particularly in the development of foods with
improved digestibility, as suggested by Martin-Cabrejasetal.
(2008). Aguerreetal. (2015) also reported that the combination
of germination and ensiling resulted in changes in the chemical
composition and improved the digestibility of sorghum grains.
Table 1. Eect of incubation periods on the physicochemical composition of germinated grains (g kg
dry weight basis).
Samples Incubation periods (h) Protein Fat Ash Carbohydrate
Mung bean
NG (0.246 ± 0.001)
(0.017 ± 0.002)
(0.036 ± 0.001)
(0.699 ± 0.005)
0 (0.243 ± 0.005)
(0.017 ± 0.003)
(0.032 ± 0.001)
(0.707 ± 0.005)
6 (0.252 ± 0.002)
(0.017 ± 0.003)
(0.032 ± 0.001)
(0.698 ± 0.005)
12 (0.263 ± 0.008)
(0.016 ± 0.003)
(0.032 ± 0.001)
(0.687 ± 0.005)
24 (0.268 ± 0.011)
(0.016 ± 0.002)
(0.032 ± 0.001)
(0.681 ± 0.012)
36 (0.264 ± 0.002)
(0.017 ± 0.002)
(0.032 ± 0.001)
(0.686 ± 0.001)
48 (0.294 ± 0.005)
(0.017 ± 0.003)
(0.032 ± 0.001)
(0.656 ± 0.035)
NG (0.445 ± 0.011)
(0.212 ± 0.015)
(0.051 ± 0.001)
(0.292 ± 0.012)
0 (0.446 ± 0.002)
(0.204 ± 0.004)
(0.041 ± 0.001)
(0.308 ± 0.006)
6 (0.450 ± 0.011)
(0.208 ± 0.012)
(0.043 ± 0.001)
(0.318 ± 0.022)
12 (0.443 ± 0.014)
(0.206 ± 0.005)
(0.040 ± 0.001)
(0.312 ± 0.014)
24 (0.445 ± 0.012)
(0.205 ± 0.017)
(0.040 ± 0.001)
(0.310 ± 0.004)
36 (0.448 ± 0.011)
(0.210 ± 0.017)
(0.035 ± 0.001)
(0.307 ± 0.007)
48 (0.449 ± 0.012)
(0.208 ± 0.010)
(0.035 ± 0.001)
(0.308 ± 0.023)
Black bean
NG (0.263 ± 0.001)
(0.017 ± 0.001)
(0.036 ± 0.001)
(0.685 ± 0.001)
0 (0.265 ± 0.001)
(0.017 ± 0.001)
(0.035 ± 0.001)
(0.685 ± 0.011)
6 (0.272 ± 0.002)
(0.017 ± 0.001)
(0.033 ± 0.002)
(0.678 ± 0.009)
12 (0.272 ± 0.005)
(0.015 ± 0.003)
(0.033 ± 0.001)
(0.680 ± 0.013)
24 (0.272 ± 0.002)
(0.015 ± 0.001)
(0.033 ± 0.001)
(0.680 ± 0.003)
36 (0.272 ± 0.008)
(0.014 ± 0.001)
(0.034 ± 0.002)
(0.679 ± 0.008)
48 (0.276 ± 0.002)
(0.015 ± 0.001)
(0.034 ± 0.002)
(0.676 ± 0.009)
NG (0.215 ± 0.003)
(0.574 ± 0.027)
(0.051 ± 0.001)
(0.160 ± 0.029)
0 (0.220 ± 0.005)
(0.569 ± 0.021)
(0.050 ± 0.001)
(0.162 ± 0.026)
6 (0.219 ± 0.280)
(0.562 ± 0.020)
(0.048 ± 0.001)
(0.171 ± 0.021)
12 (0.223 ± 0.008)
(0.554 ± 0.010)
(0.048 ± 0.001)
(0.176 ± 0.011)
24 (0.221 ± 0.006)
(0.557 ± 0.017)
(0.048 ± 0.001)
(0.175 ± 0.020)
36 (0.220 ± 0.002)
(0.546 ± 0.017)
(0.048 ± 0.002)
(0.186 ± 0.015)
48 (0.224 ± 0.005)
(0.533 ± 0.012)
(0.047 ± 0.002)
(0.195 ± 0.016)
NG denotes non germinated grains; Data expressed as means ± SD of three independent experiments;
Means in the same column of each grain type with dierent letters are
signicantly dierent (p < 0.05).
GABA content in dietary seeds
Food Sci. Technol, Campinas, 6
3.4 DPPH radical scavenging activity and total phenolics in
germinated legumes and sesame
e DPPH radical is considered to be a model of a stable
lipophilic radical. Antioxidants react with DPPH radical, reducing
the number of DPPH molecules equal to the number of their
available hydroxyl groups. erefore, the absorption at 517 nm
is proportional to the amount of residual DPPH (Xuetal., 2005).
Also, phenolic compounds are known to exhibit free-radical
scavenging (antioxidant) activity, which is determined by their
reactivity as hydrogen or electron donors (Fernandez-Orozcoetal.,
2008). DPPH activity and total phenolics of non germinated and
germinated grains are shown in Figure2. In mung bean, the
DPPH activity slightly decreased and total phenolics content
showed no signicant change during germination (Figure2a).
Contradictory, in soybean the DPPH activity increased but
total phenolics changed only marginally during germination
(Figure2b). In black bean the trend of DPPH activity and
total phenolics was similar to that of germinated mung bean
(Figure2c). Interestingly, DPPH activity of sesame decreased
dramatically aer soaking and then slightly increased again as
the germination progressed. However, there was no signicant
change in the total phenolics content found in germinated
sesame (Figure2d).
e results suggested that the germination process only
slightly aected the total phenolics content of germinated
grains in this study. Although the DPPH activity in germinated
soybean and sesame increased, it decreased in germinated
mung bean and black bean. However, the study of Shenetal.
(2015) showed that in germinated brown rice using anaerobic
treatment phenolics content and DPPH activity were found to
be increased throughout germination period. It was explained by
the anaerobic treatment, as one of the stress factors, may activate
phenylalanine ammonia lyase that responsible for the synthesis
of phenolics and resulted in an increase of total phenolics during
germination. Wangetal. (2015) also found that total phenolics
content was increased inconsistently in germinated soybean of the
three cultivars. is indicates that genetics can be an important
factor for phenolic compound synthesis during germination.
In this study, the trend of total phenolics content cannot
absolutely predict the activity of DPPH scavenging in germinated
grains. As in a previous research, Randhir & Shetty (2007)
suggested that the antioxidant attribute of mung bean extract
may depend on the qualitative characteristics of phenolic prole
and not just on the total amount of phenolics. However, changes
of antioxidant activities during germination in grains have not
been fully understood yet.
Table 2. Insoluble, soluble, and total dietary ber content in germinated grains (g kg
dry weight basis).
Samples Incubation periods (h) IDF SDF TDF
Mung bean
NG (0.146 ± 0.007)
(0.007 ± 0.001)
(0.153 ± 0.008)
0 (0.164 ± 0.009)
(0.014 ± 0.001)
(0.178 ± 0.009)
6 (0.187 ± 0.010)
(0.016 ± 0.002)
(0.204 ± 0.012)
12 (0.199 ± 0.90)
(0.015 ± 0.001)
(0.214 ± 0.010)
24 (0.206 ± 0.008)
(0.016 ± 0.001)
(0.221 ± 0.008)
36 (0.197 ± 0.007)
(0.017 ± 0.001)
(0.213 ± 0.006)
48 (0.190 ± 0.006)
(0.018 ± 0.002)
(0.208 ± 0.006)
NG (0.196 ± 0.003)
(0.038 ± 0.001)
(0.234 ± 0.004)
0 (0.199 ± 0.005)
(0.038 ± 0.001)
(0.237 ± 0.006)
6 (0.201 ± 0.005)
(0.039 ± 0.002)
(0.240 ± 0.007)
12 (0.207 ± 0.005)
(0.040 ± 0.002)
(0.247 ± 0.007)
24 (0.194 ± 0.010)
(0.038 ± 0.001)
(0.232 ± 0.011)
36 (0.197 ± 0.005)
(0.040 ± 0.002)
(0.237 ± 0.004)
48 (0.199 ± 0.003)
(0.040 ± 0.001)
(0.239 ± 0.004)
Black bean
NG (0.198 ± 0.001)
(0.005 ± 0.002)
(0.203 ± 0.003)
0 (0.200 ± 0.002)
(0.007 ± 0.002)
(0.208 ± 0.003)
6 (0.199 ± 0.007)
(0.011 ± 0.001)
(0.210 ± 0.006)
12 (0.120 ± 0.004)
(0.011 ± 0.002)
(0.210 ± 0.005)
24 (0.215 ± 0.002)
(0.016 ± 0.001)
(0.230 ± 0.002)
36 (0.224 ± 0.002)
(0.017 ± 0.001)
(0.240 ± 0.002)
48 (0.225 ± 0.003)
(0.017 ± 0.001)
(0.242 ± 0.003)
NG (0.135 ± 0.004)
(0.029 ± 0.004)
(0.164 ± 0.008)
0 (0.137 ± 0.002)
(0.033 ± 0.002)
(0.170 ± 0.004)
6 (0.138 ± 0.003)
(0.031 ± 0.001)
(0.170 ± 0.004)
12 (0.147 ± 0.001)
(0.035 ± 0.002)
(0.181 ± 0.003)
24 (0.152 ± 0.001)
(0.035 ± 0.001)
(0.187 ± 0.003)
36 (0.161 ± 0.002)
(0.048 ± 0.001)
(0.209 ± 0.003)
48 (0.162 ± 0.001)
(0.053 ± 0.001)
(0.215 ± 0.002)
NG denotes non germinated grains; Data expressed as means ± SD of three independent experiments;
Means in the same column of each grain type with dierent letters are
signicantly dierent (p < 0.05).
Food Sci. Technol, C ampinas, 7
3.5 e eect of cooking process on GABA content in
germinated legumes and sesame
e cooking processes chosen in this study were mainly
based on Eastern traditional and household cooking methods
for legumes and sesame. e condition of each cooking method
was established for laboratory scale in order to obtain cooked
legumes and sesame. e GABA contents of non-processed and
processed germinated grains are presented in Table3. GABA
contents were signicantly (p<0.05) decreased by all cooking
methods. In germinated mung bean, all the cooking processes
decreased the concentrations of GABA. e remaining amounts
of GABA were 0.0634, 0.1778, 0.2184 and 0.1834 g kg
matter aer the boiling, steaming, microwave cooking and open
pan roasting process, respectively. is suggests that microwave
cooking process in germinated mung bean is the least harmful on
GABA. In case of germinated soybean, it appears that steaming
allowed the highest GABA content to remain. Similar result was
obtained in germinated black bean, where steaming aected
only about 25% of the GABA content. In germinated sesame,
the GABA content was 0.0716, 0.0730, 0.1584 and 0.0928 g kg
dry matter aer boiling, steaming, microwave cooking and open
pan roasting process, respectively. Although microwave cooking
retained the highest GABA content in germinated sesame, the
second least harmful was open pan roasting which generated
a roasted odor, a specic characteristic of roasted sesame and
that may be important, as roasting is common process for
sesame in Asia.
Our results suggest that microwave cooking is recommended
for germinated soybean and black bean preparation. Also, both
steaming and microwave cooking process generated the so
texture of grains, which is suitable for semi-moist food such as
salad or soup. On the other hand, open pan roasting provided
drier texture of grains and roasted odor that are suitable for use
as an ingredient in cereal products, particularly in cereal bar.
Figure 2. DPPH scavenging activity (bar ) and total phenolics (line ▬▬) of germinated grains for dierent incubation periods, NG denotes
non germinated grains. (a) Germinated mung bean. (b) Germinated soybean. (c) Germinated black bean. (d) Germinated sesame. Data reported
are the mean ± SD of triplicate determinations.
Means of each grain type with dierent letters are signicantly dierent (p < 0.05).
GABA content in dietary seeds
Food Sci. Technol, Campinas, 8
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4 Conclusions
In conclusion, during germination process, there was a
signicant increase in GABA amounts in mung bean, black
bean, soy bean and sesame. Germinated mung bean provided
the highest content of GABA at 24 h (0.8068 g kg
dry weight).
Ingeneral, total crude protein, fat and carbohydrate contents were
dierent in each kind of seed and sampling time. It was clearly
found that the concentration of crude protein in germinated
mung bean and black bean increased during germination.
Ashcontent was found decreased in all germinated grains.
Mostly, total dietary ber content increased during germination.
Ourimportant nding was that germinated legumes and sesame
especially mung bean could be potential nutritional sources of
GABA and dietary bers. Additionally, all the cooking processes
were found to decrease GABA contents in germinated grains.
However, steaming was found to be the least destructive for
GABA contents in black bean and soybean, whereas microwave
cooking allowed the smallest loss of GABA contents in mung
bean and sesame.
is research has been granted by the Center of Excellence
on Agricultural Biotechnology, Science and Technology
Postgraduate Education and Research Development Oce,
Oce of Higher Education Commission, Ministry of Education
(AG-BIO/PERDO-CHE), ailand.
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Table 3. Eect of some cooking processes on the GABA content (g kg
dry weight basis) of germinated grains at optimal incubation time.
Cooking Process
GABA content (g kg
dry weight basis)
Germinated mung bean at 24 h Germinated soy bean at 6 h Germinated black bean at 6 h Germinated sesame at 0 h
Uncooked (0.807 ± 0.026)
(0.498 ± 0.012)
(0.743 ± 0.010)
(0.165 ± 0.003)
Boiling (0.063 ± 0.021)
(0.204 ± 0.006)
(0.310 ± 0.012)
(0.072 ± 0.005)
Steaming (0.178 ± 0.005)
(0.407 ± 0.020)
(0.558 ± 0.024)
(0.073 ± 0.001)
Microwave cooking (0.218 ± 0.007)
(0.191 ± 0.005)
(0.455 ± 0.021)
(0.158 ± 0.001)
Open pan roasting (0.183 ± 0.014)
(0.306 ± 0.012)
(0.386 ± 0.020)
(0.093 ± 0.005)
Data expressed as means ± SD of three independent experiments;
Means in the same column with dierent letters are signicantly dierent (p < 0.05).
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... Besides, germination also enhanced bioactive compounds such as γ-aminobutyric acid (GABA) (Cáceres et al., 2017;Ohtsubo et al., 2005;Zhang et al., 2014). GABA, a nonprotein amino acid, play important role as neurotransmitter in the brain and has some essential physiological functions such as antihypertensive and anti-stress effects on human health (Cáceres et al., 2017;Tiansawang et al., 2016;Watchararparpaiboon et al., 2010). ...
... The increase of GABA content during germination was reported in seeds and legumes, including in brown rice (Mohan et al., 2010;Tiansawang et al., 2016;Zhang et al., 2014). Accumulation of GABA was closely related to the activation of some enzymes that converts glutamate to succinate via GABA, called GABA shunt, which converts L-glutamic acid into GABA by glutamate decarboxylase enzyme (GAD). ...
... After 24 h steeping time, both TPC and antioxidant capacity of five germinated brown rice decreased significantly. The results are agreed with the results in brown rice Indica SLF09 and some different grains after soak for 24 h and 6 h, respectively (Cáceres et al., 2017;Tiansawang et al., 2016). During the soaking process and changing the soaking water, some phenolic compounds might leach out to the water soaking. ...
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Germination can alter the physicochemical, nutritional, and nutraceutical value of brown rice. This study aimed to evaluate some characteristic changes from five Indonesian brown rice varieties during germination. The germination was carried out through a complete soaking method for up to 120 h, and the samples were taken and analyzed every 24 h. The results showed that germination increased GABA (γ-aminobutyric acid) content in brown rice. The highest level of GABA, up to 126.55 mg/100 g, obtained in rice var. Inpari 43, after 120 h. Germination also affected the changes in phenolic content, antioxidant capacity, and γ-oryzanol, while fatty acid compositions showed no changes. The pasting properties changed significantly after germination, especially in peak viscosity, final viscosity, breakdown, and setback. In conclusion, the changes in brown rice characteristics during germination, especially for increased GABA content and shifting of pasting properties, are valuable information for developing functional rice-based food products.
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The level of γ-aminobutyric acid (GABA) in nongerminated adzuki bean seeds is low, but it increases substantially during germination and sprouting. In this study, three seed treatments, including soaking (S), high voltage electric field (HVEF), and soaking plus HVEF (SHVEF), were used to examine their effects on sprout growth, sprout GABA content, sprout glutamate decarboxylase (GAD), and diamine oxidase (DAO) activities and microbial loads on 6-day-old adzuki bean sprouts. All the treatments enhanced sprout growth, increased sprout’s GABA, and increased sprouts’ GAD and DAO activities. The examined seed treatments also significantly reduced the microbial loads of the produced 6-day-old adzuki bean sprouts. The most effective treatment that improved the morphological and biochemical traits and reduced microbial loads on produced sprouts was the SHVEF treatment. SHVEF treatment also achieved a 5-log reduction in the microbial loads of total aerobic bacterial counts, total coliform counts, and total mold counts on the produced adzuki bean sprouts. Therefore, SHVEF is effective for increasing adzuki bean sprout production. It can also be used to improve nutritional quality and provide an intervention technique against microbial contamination on produced sprouts.
... Since GABA is mainly formed by the decarboxylation of glutamate, the product is not BA but an amino acid [64]. Unlike BAs, which are formed by decarboxylation, GABA is nutritionally desirable, and various approaches using selected MO even in combination with germination [65] have been shown to be efficient in increasing GABA content. The use of chickpea sourdough for the preparation of experimental bread resulted in significantly higher GABA content in the final product in compared to commercial artisan breads, which were presumably prepared with sourdough starters based on cereal flour [35]. ...
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Citation: Polak, T.; Mejaš, R.; Jamnik, P.; Kralj Cigić, I.; Poklar Ulrih, N.; Cigić, B. Accumulation and Transformation of Biogenic Amines and Gamma-Aminobutyric Acid (GABA) in Chickpea Sourdough. Foods 2021, 10, 2840. 10.3390/foods10112840 Academic Editors: Maria Schirone and Pierina Visciano Abstract: In general, sourdough fermentation leads to an improvement in the technological, nutritional , and sensory properties of bakery products. The use of non-conventional flours with a specific autochthonous microbiota may lead to the formation of secondary metabolites, which may even have undesirable physiological and toxicological effects. Chickpea flours from different suppliers have been used to produce sourdoughs by spontaneous and inoculated fermentations. The content of nutritionally undesirable biogenic amines (BA) and beneficial gamma-aminobutyric acid (GABA) was determined by chromatography. Fenugreek sprouts, which are a rich source of amine oxidases, were used to reduce the BA content in the sourdoughs. Spontaneous fermentation resulted in a high accumulation of cadaverine, putrescine, and tyramine for certain flours. The use of commercial starter cultures was not effective in reducing the accumulation of BA in all sourdoughs. The addition of fenugreek sprouts to the suspension of sourdough with pH raised to 6.5 resulted in a significant reduction in BA contents. Enzymatic oxidation was less efficient during kneading. Baking resulted in only a partial degradation of BA and GABA in the crust and not in the crumb. Therefore, it could be suggested to give more importance to the control of sourdough fermentation with regard to the formation of nutritionally undesirable BA and to exploit the possibilities of their degradation.
... Susamın GABA içeriği ise yalnızca 6 saatlik (0.1649 g/kg) suda bekletme ile bir miktar artmıştır. Araştırmacılar tanelerdeki depo proteinlerinin en azından bir kısmının ayrıştığını ve fidelerin büyüyen kısımları için kullanıldığını ve bu esnada glutamik asidi GABA'ya dönüştüren glutamat dekarboksilaz enziminin aktive edildiğini belirtmiştir [31]. ...
The candied kidney bean contains a vital bioactive compound called γ‐aminobutyric acid (GABA), which could be easily lost in the traditional producing processes like soaking, cooking and candying. The traditional procedure distinctly decreased the GABA content to the GABA retention rate as 34.01% in the candied kidney bean. In this study, the optimum technological methods of soaking, cooking and candying were determined by single factor experiment according to the GABA content. The optimized producing condition was that the kidney bean was soaked at 55°C for 5 h, followed by atmospheric steaming for 35 min, and then subjected to microwaving candying on 150 W for 25 min. By the optimal procedure, the GABA content retention reached to 75.33%. Meanwhile, the texture, nutrients contents and antioxidant capacity were obviously improved in the candied kidney beans produced by the optimal methods.
In this study, proximate, minerals, chlorophyll, amino acids (AAs), phenolics and antioxidant properties of black gram, mung bean and chickpea microgreens grown under different conditions (soil, water and coco‐peat with nutrient solution [CNS])were investigated. The yield, moisture, ash content (AC) and protein content of microgreens extract powder (MEP) varied from 7.31‐11.09%, 5.63‐8.96%, 9.31‐13.63% and 51.07‐60.41%, respectively. The total chlorophyll content (TCC), flavonoid content (TFC), phenolic content (TPC) and antioxidant activity (TAA) ranged from 3.42‐5.23 mg/g, 16.03‐28.18 mg QE/g, 7.46‐12.52 mg GAE/g and 9.51‐14.59 μmol TE/g, respectively. The phenolic acids (protocatechuic, p‐coumaric, chlorogenic, caffeic, gallic and ferulic acids) and flavonoids (epicatechin, catechin, rutin, quercetin, kaempferol, vitexin and isovitexin) were more in soil grown MEP while CNS grown had high AAs. MEP of soil grown chickpea exhibited the highest AC, TCC, minerals (magnesium, potassium and calcium), TPC, TFC and TAA, while CNS grown mung bean MEP had abundant AAs.
Germinated mung beans have been widely used as fresh vegetable or processed healthy foods due to their high amounts of bioactive and nutritional compounds, including γ‐aminobutyric acid (GABA). The objectives of this study were to investigate the effects of different soaking conditions (temperature, ratios of seeds to water, soaking time, pH, addition of L‐glutamic acid (L‐Glu) or gibberellic acid (GA3)) and germination time on accumulation of GABA in the germinated mung bean seeds. The mung bean seeds, soaked at 40 °C for 4 h with ratio of seeds to water of 1:4 (g mL‐1) and then germinated for 7 h, accumulated higher amount of GABA than other soaking conditions and germination time. The addition of GA3 (0.30 mg L‐1) or L‐glu (1,000 mg L‐1) or acidifying to pH 5.5 of the soaking water had high impact on the GABA accumulation. Among them, the soaking water with pH 5.5 was more effective than adding with the L‐Glu or GA3 in the production of GABA (1677 mg/kg powder) and essential amino acids (16.56 g/100g powder) in the germinated mung bean seeds. The findings of this study provide useful information to produce GABA‐enriched and healthy foods from mung beans.
The γ-aminobutyric acid (GABA) content and distribution of mung bean (MB), heat and relative humidity treated MB (HRH-MB) under different cooking and storage conditions were investigated. The quality characteristics of noodles prepared by MB and HRH-MB were evaluated. Results showed that black MB varieties presented a higher average GABA content under HRH treatment than that of green MB varieties. Soaking significantly increased the GABA content of MB (P < 0.05), but, 58.78% of GABA in HRH-MB were distributed in the soaking solution. After cooking, although the GABA of HRH-MB had a slightly degradation, its content was higher than MB. With the increase of storage time, the GABA content in MB increased initially, followed by a decrease, whereas a slower reduction was observed on HRH-MB. Besides, compared with the mixed MB-wheat flour and noodles, the pasting properties of mixed HRH-MB-wheat flour, the color and texture properties of mixed HRH-MB-wheat noodles were improved and closer to wheat flour and noodles, respectively. Furthermore, the mixed HRH-MB-wheat noodles exhibited the highest GABA content (16.56 mg/100 g DW) after cooking. Therefore, HRH-MB may be an ideal material for enhancing GABA and improving the quality characteristic of MB-based foods.
Germinated soybean (GSB) has a high interest in the food industry due to its potential health benefits. However, the understanding of physiochemical properties as well as sensory properties of plant‐based milk made of GSB is very limited. This study, therefore, formulated GSB milk and identified its nutritional value, rheological property and perception of consumers. The obtained result revealed that GSB milk had a high gamma‐aminobutyric acid (GABA) content (127 – 135 mg/L) while its other properties including pH, crude protein content and total soluble solid were equivalent to those of conventional soymilk. Due to the denaturation of protein in germination, GSB milk had a bigger droplet size in comparison with conventional soymilk, resulting in a lower viscosity. For consumer perception, sensory properties of GSB milk were evaluated as better than those of conventional soymilk.
In order to accumulate gamma-aminobutyric acid (GABA), soybean seeds (cultivar Jindou 25) were germinated for 102 h at different temperatures (19,25 and 32 degrees C). The content of GABA, glutamic acid and the activity of the glutamate decarboxylase (GAD) and GABA transaminase (GABA-T) in soybeans during germination were investigated. The results showed that the germination temperature and germination time had great influences on GABA content and the related enzyme activities in soybean seeds. As compared to raw soybeans, an increase in the content of GABA and glutamic acid was observed, as well as GAD activity in soybeans during germination, while germination at 32 degrees C was better for accumulating GABA in soybeans. The GABA-T activity first decreased and then increased at 19 degrees C and 25 degrees C, on the contrary, it first increased and then decreased sharply during germination at 32 degrees C. These results indicate that the increase of GABA content can be attributed to the changes of GAD and GABA-T activities rather than enough glutamic acid resulting from the degradation of protein during germination of Jindou 25 seeds. However, more assays need to be further performed with more soybean cultivars.
The changes in isoflavone and γ-aminobutyric (GABA) contents and antioxidant activity of germinated soybean seeds were investigated. Three Chinese soybean cultivars (ZH 13, 30 and 42) released for high yield and protein content were evaluated. The results showed that the total isoflavone contents at peak level were 86.3, 81.0, and 42.3% higher than that of the un-germinated control for ZH 42, 13 and 30, respectively. GABA content of ZH 13 in particular was a statistically significant 36.7-fold increase in day 5 germinated soybeans as compared to un-germinated soybean. Such increases also led to significantly elevated antioxidant activities. Moreover, germination can significantly suppress IL-8 expression in Caco-2 cells by ZH 13 extract (P < 0.05) without cell apoptosis. Current results suggest that ZH 13 soybean is a cultivar that can be used to develop nutritional and functional foods with important health benefits.
The objective of this study was to evaluate the effects of water addition, germination, ensiling and/or their association with respect to chemical composition and nutritive value of dry sorghum grain. Five commercial paddocks of sorghum grain were harvested dry and evaluated for chemical composition, digestion site and in vitro gas production under six treatment conditions: dry ground (dry), soaked for 24 h (SG), germinated for 5 days (G), germinated for 5 days and then ensiled for 21 days (G&E), ensiled for 21 days as whole grain (EWG) or ensiled for 21 days as ground grain (EGG). Soaked, EWG and G&E treatments led to a lower starch content compared to dry grains (P < 0.05). Reconstituted and ensiled treatments (either as whole or ground grain) decreased the tannin concentration compared to dry grains (P < 0.05). The dry matter (DM) digestion site and total tract digestibility were similar among dry grains, G and EWG. However, compared to these treatments, G&E and EGG increased ruminal and total DM digestibility (P < 0.05). Total tract DM digestibility did not differ between SG and dry grains; however, SG affected DM digestion site (P < 0.05). Starch digestion site and total tract digestibility were similar between dry grains and EGG. Although G&E and EWG had similar total starch digestibility in comparison with dry grains, these treatments affected the digestion site (P < 0.05). Soaked and G treatments reduced total tract digestibility and changed the starch digestion site compared to dry grains (P < 0.05). In vitro fermentation of dry grains was similar to SG and EWG. Although the total in vitro gas production was less for G&E and EGG than dry grains (P < 0.05), these treatments fermented more rapidly than dry grains (P < 0.05). The soaking, the germination process, or the ensiling of whole sorghum grain as sole factors, produced changes in the chemical composition but did not improve the nutritive value of sorghum grain. However, the combination of germination and ensiling resulted in changes in the chemical composition and improved the digestibility of sorghum grains. The grinding of grain before reconstitution and ensiling is an alternative to increase the sorghum grain digestibility and nutritive value.
Enhancement of γ-aminobutyric acid (GABA) in germinated grain could be induced via environmental stresses. Soaking in combination with anaerobic treatment (SA) as well as soaking in combination with anaerobic and heat treatment (SAH) are proposed in this work to increase the GABA content in germinated paddy; the results were compared with that obtained via a conventional germination (soaking) method (CS). The quality of germinated rice prepared from paddy (GP) by CS, SA and SAH after shade drying and fluidized bed drying in terms of the GABA content, number of fissured kernels and textural property was also investigated. The results showed that the GP prepared via SAH had the highest GABA content. The GABA contents in GP prepared by CS, SA and SAH increased 15, 25 and 29 times as compared to that of the un-germinated brown rice, respectively. However, SAH resulted in the higher number of fissured kernels as compared with CS and SA. After fluidized bed drying at 150 °C, the GABA content in GP did not decrease, but the number of fissured kernels of the fluidized bed dried samples was higher than that of the shade-dried samples. However, the head brown rice yield of the fluidized bed dried samples was higher than that of the shade-dried samples. Hardness and stickiness of the fluidized bed dried samples prepared by the three germination methods were not significantly different; exception held nevertheless for the hardness value of the complete kernels obtained via CS.
Process for conveniently prepared rice product was improved to enhance its health benefits. Brown aromatic rice (Kao Dawk Mali 105 cultivar) was soaked in water at 25 °C and 35 °C for 12 h and 24 h, incubated for 24 h and dried. Higher GABA content (15–17 mg/100 g) was observed in germinated brown rice (GBR) with soaking at 25 °C for 24 h and 35 °C for 12 h. Subsequently GBR (soaking at 25 °C for 24 h) was cooked in boiling water or pressure cooker and dried to produce quick cooking germinated brown rice (QCGBR). Cooking time of QCGBR was reduced to 3.6–4.2 times. Pressure cooking provided lighter QCGBR (p < 0.05) and higher hot paste viscosity, cold paste viscosity and setback than those of boiling, however, panelists could not detect any differences of sensorial quality (p ≥ 0.05). GABA content significantly reduced after QCGBR development process (p < 0.05). To improve health benefit of the product, GBR was cooked under pressure and kept at chilling temperature for 24 h and 48 h before drying. Rehydrated QCGBR prepared by chilled storing cooked GBR for 48 h had noticeably more resistant starch of 0.74 g/100 g compared to those of cooked brown rice (0.29 g/100 g) and cooked GBR (0.36 g/100 g).
This study was performed to evaluate the enhancement of functional components of germinated rough rice. Rough rice was germinated at 37°C for 6days, and subjected to a high hydrostatic pressure treatment (HPT) at 30MPa for 24h (HP24) and 48h (HP48). Germinated rough rice without HPT (HP0), HP24, and HP48 were analysed for their functional components. The highest γ-aminobutyric acid, total arabinoxylan, and tricin 4'-O-(threo-β-guaiacylglyceryl) ether contents were 121.21mg/100g, 10.6%, and 85.82μg/g, respectively, after HP48 for 2days. γ-Oryzanol contents increased from 23.19-36.20mg/100g (at HP0) to 31.80-40.32mg/100g (at HP48). The highest vitamin B (60.99mg/100g) and E (4.07mg/100g) contents were observed after HP24 for 5 and 2days, respectively. These results suggest that a combination of HPT and germination efficiently enhances the functional characteristics of rough rice.