The distribution of starch-degrading enzymes in dormant rice grains was investigated with specific antibodies against α-glucosidases, α-amylases, and β-amylases. The α-glucosidases were predominantly localized in the inner endosperm. The α-amylases were mainly localized in the outer layers, and the β-amylases were distributed in whole grains. We propose a model to demonstrate how these enzymes degrade starch during rice cooking.
The apparent distribution coefficients, Kapp, of some mono-, di- and trisaccharides onto cation-exchange resins in the sodium-ion form and having the divinylbenzene (DVB) contents of 4, 6 and 8% were measured at 25°C. A method for simultaneously estimating the swelling pressures of the resins and the binding constants, B, of the saccharides to the sodium ion was proposed. By applying the method to the Kapp values of mono- and disaccharides, the swelling pressures of the resins having the DVB contents of 4, 6 and 8% were estimated to be 18.9, 30.8 and 37.8 MPa, respectively, and the B values of the mono- and disaccharides were also estimated simultaneously. The B values of the trisaccharides were calculated using the estimated swelling pressures. The B values ranged from 0.24 to 2.2 L/mol. The tri-, di- and monosaccharides had higher B values in this order. There was a tendency that the solute, which can form a tridentate complex with the sodium ion, contains high numbers of axial-equatorial and equatorial-equatorial complexing hydroxyl groups.
The purpose of this study was to investigate effect of fermentation time on the proteins of steamed soybean inoculated with Bacillus subtilis (natto). The result was found that the contents of trichloroacetic acid soluble nitrogen (TCA-N) and drgree of hydrolysis (DH) of protein increased with the fermentation time increased, but the protein solubility was declined with increasing the fermentation time in advance, then increased. The most bands of soy proteins were found to disappear from the Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) electrophoretogram after 24 h of fermentation. Some of nonessential amino acids were found to remarkedly decline, but some of them were remained unchanged after 24-48 h of fermentation., However the most essential amino acids were found to declined after 36h of fermentation, then all of them increased after 48 h of fermentation except histidine.
This study aims to maximize the yield of gamma-linolenic acid (GLA) by a filamentous fungus, Mucor racemosus, using fermentation Douchi. Optimized fermentation conditions includes inoculum size and temperature. GLA content in Douchi by M. racemosus greatly varied in terms of fermentation temperature, from zero to 3.38% in total fatty acids, which means apart from fermentation temperature some other factors must affect GLA content in Douchi. The optimal amount of inoculums was 5.30 × 107 spores/10 g cooked soybean. The optimal temperature for fermentation was about 26°C. Under the optimal fermentation conditions, the GLA production of M. racemosus could be enhanced by optimizing the Douchi fermentation condition. Douchi, which contains GLA, may be directly absorbed through diet. Thus, Douchi may be a good kind of healthy food for people.
In this paper we report on the antioxidant components and activities of the edible parts of Gnetum gnemon (young and mature leaves, seed skin and endosperm), as well as their ability to inhibit DNA damage. Since Gnetum gnemon is usually consumed daily as a boiled vegetable, we also measured the effect of boiling on the antioxidant components and activities. The mature leaves contain the greatest levels of antioxidant components, followed by the young leaves. Accordingly, the mature and young leaves possess the highest antioxidant component and DNA damage prevention activities. However, the endosperm also has significant activity in ORAC, peroxyl radical-scavenging activity and DNA damage prevention activity at higher concentrations. Boiling decreased the amount of antioxidant components as well as the antioxidant activities in all edible parts examined, except for the seed skin. The results presented here indicate that the edible parts of G. gnemon are a potential source of natural antioxidants and can be beneficial, consumed as a daily vegetable or processed into an extract for use as a food additive.
In this study, raw and cooked chickpea flours (CPF) were used in erişte formulation at different levels (10, 20, 30, 40 and 50% w/w) with and without whole egg addition. Some selected properties of erişte, such as, color, weight and volume increase, cooking loss, ash, protein, minerals, phytic acid (PA) contents, and sensory properties were determined. Erişte containing cooked CPF without egg showed the darkest color. While egg addition improved the cooking quality, CPF over 20% addition level decreased weight and volume increase values significantly (p<0.05). Ash, protein, Ca, K and P contents increased with egg addition, and increasing amount of CPF. Usage of cooked CPF decreased the PA content from 376.4 to 320.2 mg/100 g. However, CPF substitution increased the PA content up to 515.3 mg/100 g. Erişte made with 30-40% raw CPF and egg showed the highest overall acceptability score. As a result, raw CPF at a level of 20-30% with egg combination can be used in erişte formulation for nutritional enrichment with minimum adverse affect on color and technologic properties.
The fatty acid distribution, proximate composition, physicochemical characteristics and levels (ppm) of selected trace metals (Fe, Mn, Cu, Pb, Cd and Zn) and macro nutrients (Na, K, Mg and Ca) were determined in the seeds and seed oils of D. regia and P. pterocarpum. The oil yield was found to be 7.0% in D. regia and 8.10% in P. pterocarpum. D. regia has a higher carbohydrate content (39.5%) than P. pterocarpum (38.3%). The crude protein is high, 45.2% for D. regia and 44.1% for P. pterocarpum. Neutral lipids were the dominant lipid fraction in the oils with linoleic as the most abundant fatty acid in both the oils. Hydrocarbons, stigmasterol, phytol, sitosterol, ergost-4-en-3-one and ergost-5-en-3-ol were identified in the unsaponifiables of these oils. The physicochemical characterization as well as the fatty acid profile of the oils suggests good industrial application of these oils.
Effect of sourdough fermentation, by different starter culture (lactic acid bacteria Lactococcus lactis ssp. Lactis, Weissella confusa, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus helveticus, and yeast Kluyveromyces marxianus subsp. Marxianus), on antioxidant capacity of rye dough and bread was determined and compared with spontaneous fermentation. The total phenolic content and antioxidant activities assessed using Trolox equivalent antioxidant capacity (TEAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity expressed in terms of Trolox equivalents and of percentage of discoloration, were measured. The results indicate that antioxidant activity of the rye sourdough highly depends on the type of inoculum used for fermentation and the levels of bioactive compounds change during the bread making process. Fermentation process and type of starter culture are tools to increase the bioactive compounds with antioxidant activities of the rye bread.
This study was conducted to determine antioxidant activities in acetone, ethanol, methanol, and water extracts from the seeds of 4 persimmon cultivars. Antioxidant activities were evaluated on the basis of DPPH (1,1-diphenyl-2-picrylhydrazyl) radical-scavenging activity (RSA), ABTS (2,2-azino-bis [3-ethylbenzothiazoline-6-sulfonic acid]) RSA, and reducing power. Cheongdobansi seed extracts showed significantly higher antioxidant activities and phenolic contents than did Bongok, Fuyu, and Nishimurawase seed extracts. Ethanol was more effective for the extraction of antioxidant compounds from persimmons than other solvents. Palmitic acid, oleic acid, and linoleic acid were the main fatty acids found in persimmon seeds. Fuyu seeds contained the highest levels of fatty acids, and the unsaturated fatty acid contents of persimmon seeds range from 70.4% to 78.3%. All persimmon seed extracts, with the exception of the water extract of Nishimurawase seeds, inhibited DNA damage induced by H2O2.
Thaumatin, an intensely sweet-tasting protein used as a sweetener, was secreted by the methylotrophic yeast Pichia pastoris. Approximately 100 mg L-1 of recombinant thaumatin I was obtained using an expression vector which possesses three copies of the thaumatin gene containing the 22-amino acid pre-sequence. Expression yield was about three-fold higher than when the α-factor secretion signal from Saccharomyces cerevisiae was used. The circular dichroism and tryptophan fluorescence spectra for recombinant thaumatin I were almost the same as those for plant thaumatin. Large amounts of homogeneous recombinant thaumatin allowed for preparation of high-quality crystals in the presence of cryoprotective glycerol used in high-resolution x-ray structural analysis to help further understand the perception of the sweet taste of thaumatin.
The viability of production of good quality and acceptable bread with substitution of wheat flour with Dolichos lab lab (Lab lab purpureus) was investigated. The bread was analyzed for protein, moisture, general bread quality and sensory properties. The protein content of bread was elevated by up to about 20% and the moisture content reduced by about 10% without significant changes in bread taste, odor, volume and general bread quality. Substitution levels of up to 10% produced bread with quality characteristics not significantly different from the control. Sensory evaluation showed no significant differences between the control bread and the Dolichos supplemented breads up to 15% in the sensory attributes of aroma, crumb appearance, texture, crust colour, loaf shape, taste and general acceptability (p < 0.05). The crumb colour changed from creamish white to dull brown and a gradual hardening of crumb texture was observed as the addition of Dolichos lab lab bean flour increased. Above 15% substitution levels, the acceptability declined because of the compact texture of the crumb and the strong beany flavor of the product. Results indicate that acceptable breads can be produced by substitution of up to 15% wheat flour with dolichos bean flour.
RAG2 is a member of the rice 14-16 kDa α-amylase/trypsin inhibitors, which are the main allergens in rice grains. Recombinant RAG2 protein was expressed in Escherichia coli, and polyclonal antisera were prepared against the protein. The polyclonal antisera specifically bound with 14-16 kDa α-amylase/trypsin inhibitors from husked brown, red and black rice. No cross-reaction was observed between the polyclonal antisera and saline-soluble proteins from other tested cereal grains. By immunoblotting with the polyclonal antisera, 14-16 kDa α-amylase/trypsin inhibitors were found to be distributed throughout the endosperm of brown rice and their contents were estimated. Moreover, 14-16 kDa α-amylase/trypsin inhibitors were also detected in processed foods. Thus, the polyclonal antisera prepared against recombinant RAG2 protein could be used to compare the content of 14-16 kDa α-amylase/trypsin inhibitors in rice samples and probe the presence of the allergen in processed foods.
Chlorine water has been widely used to reduce viable bacterial contamination on food surfaces and sanitize processing facilities. The emergence and spread of microorganisms with reduced susceptibility to antimicrobial agents is a major public health problem. This in vitro study was designed to evaluate the possibility that E. coli O157:H7 can acquire chlorine resistance and subsequent induction of cross-resistance to chlorine water. In addition, the occurrence of spontaneous chlorine resistance mutations or a higher mutation rate introduced by chemical mutations as compared to the standard was also examined. Comparisons of bacterial viability, cellular activity and susceptibility to antibiotics before and after repeated cycles of enrichment cultivation were performed. There were no significant changes observed in bactericidal sensitivity during repeated cultivation in both NTG treated and non-treated cells (n = 6, P > 0.05). There were no significant differences in the activity of cellular respiration enzymes, oxidative stress related gene expression and susceptibility to antibiotics observed in both the NaClO treated samples (n=8, P<0.01) as compared to the control. These results suggested that it might be difficult for E. coli O157:H7 to acquire resistance to chlorine solution even though the bacteria were exposed to NaClO and continued to proliferate.
The antioxidative fraction of roasted pearl barley (adlay, Coix lacryma-jobi L. var Ma-yuen Stapf), which is used in commercial tea beverages, was obtained by column chromatography and eluted with 70% ethanol. We investigated the effect of dietary supplementation with pearl barley extract on the formation of thiobarbituric acid-reactive substances in rat serum and ex vivo tissues. We also investigated whether the serum and tissue homogenates were susceptible to lipid peroxidation. Rats that were fed a diet containing 5 g/kg pearl barley extract (antioxidative fraction) for 14 days exhibited no significant reduction in the formation of thiobarbituric acid-reactive substances in the serum. However, compared to controls, liver homogenates from rats fed pearl barley extract showed significantly lower susceptibility to lipid peroxidation (induced by 2,2′-azobis(2-amidinopropane)hydrochloride). These results demonstrate that a diet containing pearl barley extract increases oxidation resistance in ex vivo rat livers.
Water-soluble pigment mixture was extracted from discolored nori seaweed without separating phycoerythrin (PE) and phycocyanin (PC). The stability of this mixture against light irradiation was studied for application as a violet food coloring additive. The PC component showed greater photo-stability than the PE component of the pigment solution (pH 7.0, 20°C) under irradiation at 5,300 and 7,800 Lx. The ratio of the second-order rate constant kPE/kPC which reflects photo-destruction was 9.3 (5,300 Lx) and 7.0 (7,800 Lx). The results were similar to those of a respective pigment separated by gel-chromatography. As for tonal changes, the a* value was decreased and both the b* and L* values were increased with progressing photo-destruction, namely, the violet color changed to pale dark-violet due to de-coloration of the red PE component. A reduction in photo-fading of 6.6% (PE) and 6.9% (PC) was achieved by 7,800 Lx irradiation for 5 h, compared with the control, by adding γ-cyclodextrin to the mixture.
The purpose of this study was to investigate the effect of extruded polished rice (PR), brown rice (BR), and germinated brown rice (GBR) on the behavior of ICR mice in a repeated open field test, as well as their concentrations of plasma lipids, glucose, and minerals. After 4 weeks in the open field test, the locomotion distance was significantly lower in mice fed GBR than those fed PR, but showed no difference in mice fed a diet with the same gamma-aminobutyric acid (GABA) content as GBR. The different rice diets had little influence on plasma lipids and glucose but the plasma calcium content was significantly higher in mice fed BR than those fed PR. These results suggest that the influence of GBR on mice behavior may be related to other components of GBR in addition to GABA and that BR and GBR may have no negative influence on mineral levels.
To effectively recover polymethoxyflavonoids (PMFs) from Citrus depressa fruits, different types of extractors were combined in two types of multi-stage extraction systems. The 2-stage extraction system utilized the caterpillar and twin-screw presses, and the 3-stage extraction system utilized the caterpillar, roller, and twin-screw presses. Material balance and distribution of PMFs, extraction rate, and electric power consumption of each stage and total system were evaluated. Compared with single extraction, multi-stage extraction improved the efficiency of PMF recovery in the juice from the fruit; there was no significant difference between the 2- and 3-stage extraction systems. More than 30% of the PMF content was recovered in the juice by these systems. The multi-stage extraction system for Citrus depressa allows production of second- and third-stage juices which contain higher concentration of PMFs and reduction of extraction residue.