Laboratory scale studies were conducted to determine temperature distribution in the traditional parboiling process using a rice cooker. A sample holder with a wire-mesh bottom was used to keep the sample from the hot water. The material temperature and the qualities of parboiled rice (hardness, color, lightness and head rice yield) were determined for different layers. The thickness of each layer was about 20 mm. The temperature distribution in this parboiling process (pre-steaming and steaming) was found to be uneven. The change of material temperature was faster for the first (bottom layer; beneath which steam started to penetrate the paddy mass), next was the second (middle) and last was the third (top) layer. The greater the thickness of the material, the lower was the material temperature. The hardness and the head rice yield were found to be the highest for the first, with the second and third layers following in that order; this might be affected by the material temperature. Difference in color intensity and lightness value was insignificant among the layers. The hardness, color intensity and lightness value were about 70 N, 24, and 57, respectively, corresponding to the maximum head rice yield (67%, first layer) which is considered to be the suitable quality of parboiled rice.
The pressure range that prevents growth of microorganisms (two yeast, three lactic acid bacteria, E. coli, three bacilli and one clostridium) was investigated in order to apply it to food processing. The growth of the microorganisms could be restrained in a pressure range of 40-70 MPa depending on the species of microorganism. Growth of Lactobacillus plantarum was inhibited at 70 MPa, and two kinds of yeast at 40 MPa. The pressurization treatment is presumed to induce the germination of the spores of Bacillus and Clostridium, and the germination of B. subtilis and B. stearothermophilus were especially remarkable. Most of the germinated spores were killed at the optimum growth temperature of each microorganism under pressurized conditions. Practical usefulness of these results was verified in the autolysis process of fish meat without decomposition. Growth inhibition and inactivation of spores by pressurization treatment at less than 100 MPa can be utilized as a new technique for killing microorganisms and for producing food.
The solubility of oleic and linoleic acids in water was measured in the range from 60°C to 230°C at 15 MPa. The solubility of oleic acid was almost the same as that of linoleic acid in this range, and the solubility of the fatty acids was higher at higher temperature. The logarithm of the solubility of the fatty acids was related to the reciprocal of the absolute temperature by a linear equation with a negative slope at temperatures above 150°C, and the enthalpy of the solution of each fatty acid in the liquid state in water was estimated to be 122 kJ/mol.
The bread-making quality of rice flour was evaluated by conducting baking tests using strong wheat flours blended with various quantities of rice flour containing 15% gluten (rice flour). The dough properties and bread qualities obtained from these blends were analyzed. The characteristics of dough and bread changed according to the increase in the blended percentage of rice flour used. The water absorption of blends increased rapidly and the Farinograph characteristics were similar to those of weak flour in that the dough became less pliable and more fragile. The gas retention properties of the dough evaluated using the vacuum expansion method and gassing power after 2 h of fermentation decreased greatly. The appearance and crumb grain of the bread became rough, and the specific loaf volume (SLV) decreased. The upper crust was slightly reddish white, and the crumb grain was somewhat dusty. The sugar and amino acid contents in the bread decreased and the amount of maltose, glutamate, glycine, alanine, and phenylalanine decreased drastically. The texture of the bread was very soft at first, however, the bread rapidly hardened when stored. During the storage, the bread had high cohesiveness and showed high recovery when compressed.
Potato pulp is an agricultural by-product of the starch industry. To use it for bread-making, experiments were conducted to evaluate the bread-making quality of doughs to which intact potato pulp (IPP) and potato pulp fermented by Rhizopus oryzae NBRC 4707 (FPP) had been added. The use of IPP significantly decreased the baking quality of wheat flour by degrading the dough's physical properties and lowering the gas retention of the dough. The bread-making quality of dough to which potato pulp that had been fermented for 2 days by R. oryzae had been added was significantly better than that of dough to which IPP had been added. In particular, the bread quality, such as specific loaf volume (SLV), aspect and crumb grain, except for staling and color, were good. Increase of the dough's gas retention and gassing power were the primary reasons for its improvement. They seemed to be related to the decomposition of starch and fiber in potato pulp and the moderate pH lowering of potato pulp by organic acid formed in the fermentation process by R. oryzae. These results suggested that the fermentation with R. oryzae was useful because it improved the utility of potato pulp for bread-making.
With the objective of minimizing aokusami (beany flavor), which is an undesirable aspect of soymilk flavor, we studied the effects of heating on lipid peroxide content, a factor contributing to the beany flavor. We also prepared various desserts containing soymilk using this heating process, and evaluated the effects of heating by sensory test. The lipid peroxide content of soymilk prepared from soaked and swollen soybeans steamed at 75°C in a relative humidity of 80-90% for 10 minutes was substantially lower than that in soymilk prepared from soybeans which lacked lipoxygenase and was 14% or less that of non-heat-treated soybeans. Additionally, the lipid peroxide content of soymilk prepared by blanching soaked and swollen soybeans in boiling water for 30 seconds was comparable to that found in soymilk prepared from lipoxygenase-lacking soybeans. The beany flavor of custard pudding, Bavarian cream, and Annin tofu prepared with soymilk obtained from heat-treated soybeans was significantly improved.
Our blueberry cultured cells produce anthocyanins in high quantity (Nawa et al., Biosci. Biotech. Biochem., 57, 770-774, 1993). Using high performance liquid chromatography/mass spectrometry (LC-MS), 14 anthocyanins in the red cells derived from leaves of rabbiteye blueberry cv. Tifblue (Vaccinium ashei Reade) were identified as 3-galactoside (gal), 3-glucoside (glc) and 3-arabinoside (ara) of cyanidin (Cy), delphinidin (Dp), petunidin (Pe), peonidin (Pn) and malvidin (Mv), except for Mv 3-ara. The fruits additionally contained 15 anthocyanins and Mv 3-ara, as a main anthocyanin. The autumn red leaves contained Cy 3-gal, Cy 3-ara and Cy 3-glc. In the red cells and the leaves, derivatives of Cy were the most abundant at 85.7% (Cy 3-gal 49.1%, Cy 3-glc 5.8%, Cy 3-ara 30.9%) and 100% (Cy 3-gal 51.0%, Cy 3-glc 6.5%, Cy 3-ara 42.5%) of the total anthocyanins, respectively. In contrast, the fruits contained Mv derivatives as main components that amounted to 50.9% of the total anthocyanins; Mv 3-gal, Mv 3-ara and Mv 3-glc constituted 21.2, 15.3 and 14.4%, respectively. Cy derivatives in fruit anthocyanins amounted to 18.0%. The red cells produced 107 mg of anthocyanin/100 g fr wt, which was slightly lower than that of the fruits (129 mg). LC-MS analysis also suggested the presence of quercetin (Q) 3-glc, Q 3-rutinoside, and glycosides of myricetin (M) and Q in the red cells. This analysis showed the presence of (+)-catechin (C) and (−)-epicatechin (EC) in these cells as well as of (+)- C, (−)-EC and chlorogenic acid in the red leaves. These flavonoids and phenolics were also some of the main components in the leaves.
The effect of mannooligosaccharides (MOS) obtained from coffee mannan on cecal microbiota and short chain fatty acid production was examined in male Sprague-Dawley rats. The rats were given water and a dietary treatment containing 5% MOS ad libitum for 28 days. The body weight of those fed the MOS diet showed no significant difference compared with rats that consumed the control diet. The consumption of MOS increased the concentration of bifidobacteria (p<0.05) and the ratio of bifidobacteria to total microbes (p<0.05). The addition of MOS resulted in a significantly higher (p<0.05) concentration of short chain fatty acids in the cecal contents compared with the control diet. The concentrations of acetate, propionate and butyrate were higher (p<0.05) in rats fed the MOS diet compared with the control diet. These results suggest that MOS in the 5% diet promotes bifidobacteria growth and increased production of short chain fatty acids in rats.
Juices prepared from 42 crabapples (Malus spp.) were studied attempting to explore their antiproliferative activity. Most of the juices examined showed strong inhibition of the proliferation of HL-60 human leukemia cells. The amounts of total phenolics and total anthocyanins, as well as DPPH radical scavenging activity were measured. The antiproliferative effect was more correlated to the amount of polyphenol than of anthocyanins. Generally speaking, the stronger was the DPPH radical scavenging activity, the higher was the antiproliferation shown of HL-60. The colors and sizes of fruit and the colors of flower were not strongly correlated to antiproliferative activity, although all of the middle size (1 to 3 cm in diameter) fruits examined showed strong HL-60 antiproliferative and DPPH radical scavenging activities. The results suggested that utilizing crabapple juice as a processed food and beverage contributes to the maintenance of good health.
The effects of harvesting time on sweetness of cooked rice and activity of starch-degradation enzymes of rice grains were examined. In both Koshihikari and Nakateshinsenbon, the content of free sugars in cooked rice was the highest in the rice harvested extremely early (28 days after heading, DAH), and it decreased as the harvesting time was delayed. Maltotriose and maltotetraose were detected in the cooked rice when harvested early (28-34 DAH). On the contrary, in the cooked rice when harvesting time was standard (40 DAH) or late (43-49 DAH), maltoligosaccharides were not detected. In both varieties, α-amylase activity in rice grains of early harvesting (31 DAH) was higher than that of standard (40 DAH) and late harvesting (49 DAH). These findings suggested that the early harvesting of rice grains is an effective method of increasing the sweetness of cooked rice, because it activate α-amylase activity in rice grains.
Many studies have examined the protective effects of antioxidative agents against diabetic nephropathy, using various models. 6-Methylsulfinylhexyl isothiocyanate (6-MSITC) isolated from wasabi (Wasabia japonica MATUM) induces glutathione S-transferase in vitro, thus 6-MSITC may act as an antioxidant in vivo. The aim of this study was to examine whether wasabi powder (WP) and 6-MSITC suppress oxidative stress in vivo and inhibit the impairment of renal function and diabetic nephropathy, using type 2 diabetic mice. KK-Ay type 2 diabetic mice were assigned to three groups (n = 10 each); control mice were fed normal chow (CRF-1) and two experimental groups were fed CRF-1 containing 0.5% WP or 0.03% 6-MSITC for 4 wk. Urine volume, urinary albumin excretion, and creatinine clearance were significantly lower in the 6-MSITC group than in the control group. There was statistically no difference in TBARS or other biomarkers of oxidative stress among the three groups. However, urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG), one of the markers of oxidative stress tended to be lower in the 6-MSITC group than in the control group. In conclusion, the present results show that a sufficient supply of dietary 6-MSITC may prevent or delay renal dysfunction in diabetes by protecting against oxidative stress, and that dietary 6-MSITC may have beneficial effects on diabetic complications in type 2 diabetic mice.
Free (FL) and bound lipids (BL) of germinated quinoa seeds were extracted sequentially with n-hexane and hot water-saturated butanol (WSB), respectively. The total lipid contents containing these free and bound lipids were 8.4% (6.0 and 2.4%) for 0 hr (control), 8.1% (6.0 and 2.1%) for 24 hr, 7.2% (4.3 and 2.9%) for 48 hr and 8.8% (4.0 and 4.8%) in 72 hr of germination. The nonpolar lipids (NL), glycolipids (GL) and phospholipids (PL) in the bound lipids changed to: 50.0-61.0%, 23.4-30.4% and 26.5-8.7%, respectively. The ratio of NL to POL (GL + PL) was 1.04, 1.13, 1.56 and 1.56 for control, 24, 48 and 72 hr of germination, respectively. Linolenic acid (18:3) was the major fatty acid of GL for the control quinoa, but linoleic (18:2), and oleic (18:1) and palmitic (16:0) acids were the major fatty acid of NL, GL and PL during the germination. During germination, oleic acid increased, but linoleic acid decreased in NL, GL and PL. The ratio of saturated, monounsaturated and polyunsaturated fatty acids of NL, and PL approached 3:4:3. After 72 hr germination, the ratio of ω3/ω6 became 0.25 in GL.
We studied the role of ethanol in the improvement of bacterial cellulose (BC) production, primarily using 13C NMR. 13C-labeled BC was biosynthesized by Acetobacter xylinum ATCC 10245 using culture media containing D-(1-13C), (2-13C), and (6-13C)glucose. The introduction of (1-13C) ethanol was also investigated. Ethanol was not utilized as a carbon source for BC production, but was oxidized to acetic acid. The consumption rate of glucose and the extracellular conversion of glucose into gluconic acids were suppressed by the ethanol supplementation. The direct polymerization of the glucose into BC was accelerated; in contrast, the participation of the Entener-Doudoroff pathway was reduced by the ethanol supplementation. These results support the hypothesis that the improvement of BC production by ethanol supplementation can be achieved by the effective use of glucose. Ethanol could be used as a substitute for glucose and gluconic acids, and a source for metabolites in the tricarboxylic acid cycle.
Cysts propagated by the agar block method with heat-killed Escherichia coli as nutrient overlay were inoculated into Perna viridis broth (PVB) and phosphate-buffered saline (PBS) prior to exposure to 60, 75 and 100°C for 0, 3, 5, and 10 min. The heat resistance of Acanthamoeba sp. cysts expressed in of D- and Z- values were found to be greater in the complex organic PVB than in the aqueous PBS. The established D- values in the PVB were 81.20, 44.59, and 8.83 min at 60, 75, and 100°C, respectively. The calculated Z-value of Acanthamoeba sp. cysts in PVB was 40.28°C.
The microbiology of kwek-kwek as a Philippine emerging streetfood made from boiled quail eggs, which have been battered and fried was studied. The process of water-cooling and manual peeling of the boiled shell eggs were shown to increase the TPCs, and coliform and staphylococci counts of the product. The batter was also shown to contribute to microbial contamination of the product. The microbial profile of ready-to-eat kwek-kwek during vending was: 104-106 cfu/g TPC; ≤102 MPN/g coliform count; ≤104 MPN/g coagulase-positive staphylococci count; and presence of Salmonella sp. per 25 g sample. The flour-based sauces of kwek-kwek were found to contain higher microbial contaminants than the vinegar-based sauce. It was recommended that good manufacturing procedures within the boundary of streetfood trade economics be fully considered in the preparation and vending of the product.
In this research, refined sunflower oil was packed at various packaging materials namely: yellow PET (polyethylene terephtalate) bottles, clear PET bottles, yellow HDPE (high density polyethylene) containers and metal cans. Randomly selected packaged sunflower oils samples were packed in carton as dark condition and secondary container. The samples were stored at room temperature (26.9°C) for 365 days. At 45 days intervals, the peroxide values of stored samples were determined. Every 180 days the samples were analyzed for TBA and anisidine values. In order to determine the effect of storage temperature, some samples were stored at 38°C under dark condition for a period of 56 days. At 7 days intervals, the peroxide value of samples was determined. The results indicate that at room temperature, increase in peroxide value, thio-barbituric acid (TBA), anisidine value and totax value were significantly (p < 0.05) higher in sunflower oil stored in HDPE containers as compared to PET (yellow, clear) bottles and metal cans. No significant differences were observed in the capability of PET bottles and metals cans to protect the oil against the deterioration effect of primary and secondary oxidation. At 38°C, significant differences on peroxide value of sunflower oil in HDPE containers in comparison to the other packaging materials were observed (p < 0.05). The results indicate that, the estimated shelf life for sunflower oil in HDPE containers at room temperature were less than 180 days and decreased to 35 days at 38°C. Where as, the shelf life of sunflower oil in PET (yellow, clear) bottles and metal cans were estimated to be more than 365 days at room temperature. It seems that PET bottles and metal cans are suitable containers for sunflower oil that protect oil against oxidative deterioration, where as the HDPE container with the low oxidative stability is unsatisfactory.
To evaluate fish as free radical scavengers in the human diet, we examined the radical-scavenging activity of some marine fish tissue commonly consumed in Japan, using the 1,1-diphenyl-2-picrylhydrazyl (DPPH)-HPLC and 2'-deoxyguanosine oxidation method. All fishes showed high DPPH (259-2225 μmol Trolox eq./100g) and oxygen (1059-8018 μmol Trolox eq./100g) radical-scavenging activity. Ascorbic acid and tocopherol content were determined as free radical-scavenging compounds and ranged from 0.6-7.8 and 0.5-16.6 mg/100g fresh weight, respectively. Fish liver and skin showed higher contents of these antioxidative compounds than other parts, although their contribution to DPPH radical scavenging activity was negligible. Unlike vegetables some other compounds seem to be responsible for the high scavenging activity of fish.
Enzymatic production of N-acetyl-D-glucosamine (GlcNAc) from chitin was investigated using crude enzyme from the liver of Japanese common squid Todarodes pacificus and cuttlefish Sepia esculenta. The ratio for the activities of endo- and exo-type chitinolytic enzyme, chitinase and β-N-acetylhexosaminidase, in the crude enzyme prepared from the liver of Japanese common squid was 1:19 and those of cuttlefish was 1:20. Both enzyme activities from cuttlefish were about 1.5 time higher than those of Japanese common squid. Crude enzyme of Japanese common squid, corresponding to 2 g of liver weight, produced 26.8 mg of reducing sugar from 50 mg of colloidal chitin during 5 days of incubation at 37°C. In the crude enzyme from cuttlefish, 44.4 mg of reducing sugar was obtained under the same reaction conditions. The main product of the produced reducing sugar, analyzed by HPLC, was GlcNAc. These results suggest that squid liver could be a source of chitinolytic enzyme for the enzymatic production of GlcNAc.
The process of Sake making generates a great deal of secondary product called Sake lees. Part of the Sake lees is disposed of as waste, so finding ways to recycle it are a matter of concern. Because Sake lees contains many nutritious substances derived from both rice and Sake yeast, we studied the physiological effects of these materials on rats. Sprague-Dawley rats were fed one of three experimental diets for two weeks. Rats fed diets containing either 20% Sake lees or 2% Sake yeast (Kyokai 9 yeast) both had higher spontaneous locomotive activity than rats fed a control casein diet. Body weight and food consumption were not different among the three groups. These results suggest that Sake lees and Sake yeast have a reinforcing effect on spontaneous locomotive activity.
Water extracts and 50% ethanol extracts of 14 samples of sufu (fermented tofu) produced in various regions of China were prepared, and their DPPH (α,α-Diphenyl-β-pricryl-hydrazyl) radical-scavenging activity and isoflavone content were determined. Although the extracts showed different radical-scavenging activity levels depending on their color and region of production, all contained highly active components. Radical-scavenging activity in the water extracts ranged from 2.03 to 11.93 μg α-tocopherol/mg, while that for the 50% ethanol extracts ranged from 2.14 to 14.62 μg α-tocopherol/mg. Radical-scavenging activity in extracts from grey sufu was higher than that found in red or white sufu. Samples from the same regions showed similar radical-scavenging activity, but there was no clear directional tendency (north/south, east/west) for the produced sufu to have high activity. Most of the isoflavone in sufu was shown to be in the form of aglycone. Isoflavone aglycones in water extracts ranged from 50.2 to 179.3 μg/g of dry matter, and that in 50% ethanol extracts ranged from 199.0 to 706.9 μg/g of dry matter.
The major glycoalkaloids, α-solanine and α-chaconine, in potato tubers were determined by LC/ESI-MS. The average recoveries from spiked samples by the method used in this study were more than 94% with RSD of analytical values less than 5% for both α-solanine and α-chaconine. The total glycoalkaloid contents in tubers of four potato cultivars distributed in Japan, cv. Irish Cobbler, Touya, May Queen, and Sayaka, were compared. There was no significant difference in glycoalkaloid content between immature and mature tubers among all the cultivars tested. There was also no significant difference among cultivars in glycoalkaloid content at either the immature or mature stage, except for May Queen, which had higher glycoalkaloid contents at both stages. Glycoalkaloid content increased significantly in cv. May Queen and Touya with 7 days of light exposure immediately after harvest. The light exposure increased glycoalkaloid content in the long-term stored tubers of all four cultivars tested and that in the short-term stored tubers, except for Sayaka.
A total of 85 microbial strains from indigenous alcohol starters of some Asian countries were screened for antibacterial and antioxidant activities. From the result of co-incubation, only one strain, M2-1 showed the antibacterial activity against all target bacteria and this strain was selected. Radical scavenging activity of ethyl acetate extract of M2-1 strain was compared with BHA using DPPH. The free radical scavenging activities were 18.0 and 29.5%, respectively, at the concentration of 100 and 200 ppm. The antioxidant activity of extract was determined according to the thiocyanate method using AAPH. The inhibition of peroxidation of extract was 22.4% at 250 ppm concentration. Antibacterial activity of extract was assayed by paper disk method using 450 μg extract per disk. The extract has broad inhibition against all the target bacteria. M2-1 strain was identified as Bacillus sp. on the basis of 16S rDNA sequence.
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