Physicochemical and functional properties of buckwheat protein product

This study was conducted to compare the physicochemical and functional properties of buckwheat protein product (BWP), soy protein isolate (SPI), and casein. BWP was prepared from buckwheat flour by the method including alkaline extraction and isoelectric precipitation. The amino acid composition of BWP was very similar to that of buckwheat flour. The protein solubility (PS) of BWP was much greater than that of SPI at all pH levels (pH 2-10) but lower than that of casein at pH 7-10. The isoelectric point of BWP was around pH 4. The higher aromatic hydrophobicities (ARH) of BWP, SPI, and casein were obtained at lower pH levels (pH 2-3). The emulsifying stability (ES) of BWP was lower than those of SPI and casein at high pH levels (pH 7-10). At all pH levels, BWP formed a thin emulsion. Regression analysis showed that the ARH of BWP was significantly associated with the ES. Although the water holding capacity of BWP was quite lower than that of SPI, its fat absorption capacity was slightly higher than those of SPI and casein. These results indicated that the physicochemical properties of BWP were different from those of SPI or casein. Thus, BWP is a potential source of functional protein for possible food application.     

Pigments in green tea leaves (Camellia sinensis) suppress transformation of the aryl hydrocarbon receptor induced by dioxin

Environmental contaminants such as dioxins enter the body mainly through diet and cause various toxicities through transformation of the aryl hydrocarbon receptor (AhR). We previously reported that certain natural flavonoids at the dietary level suppress the AhR transformation induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In this study, we identified lutein and chlorophyll a and b from green tea leaves as the novel antagonists for AhR. These active compounds suppressed AhR transformation dose-dependently with the 50% inhibitory concentration (IC(50)) values against 0.1 nM TCDD-induced AhR transformation at 3.2, 5.0, and 5.9 microM, respectively. (-)-Epigallocatechin gallate, which is the most abundant flavonoid in green tea leaves, also showed stronger suppressive effects than did other major tea components, with the IC(50) value of 1.7 microM. Thus, these pigments of green tea leaves have the potential to protect from dioxin toxicity through the suppression of AhR transformation.     

Isolation of pentachlorophenol decomposing bacteria from soil

The bacteria capable of degrading pentachlorophenol (PCP) were isolated from soil. In the soil perfused with 40 ppm PCP solution, PCP was decomposed and five chlorine atoms of PCP were liberated as chloride ion after about 3 weeks. Re-addition of PCP after its degradation, accelerated the rate of PCP degradation and de-chlorination. After the addition of PCP to the soil three times, bacteria which grew on PCP agar were counted to be about 2 × 10⁷ per gram dry soil. In the liquid medium inoculated with the perfused soil, PCP degradation and complete de-chlorination were found. In this case, multiplication of bacteria capable of growing on PCP agar was found. The bacteria capable of growing on and degrading PCP in the medium with inorganic salts and 40 ppm PCP as a sole source of carbon were isolated from the agar plates for enumeration of the bacteria. From the morphological and physiological properties of the isolated bacteria, the genus of the bacteria was considered to be Pseudomonas or a closely related one. In the culture medium with PCP and inorganic salts, the bacteria degraded PCP and completely de-chlorinated it. The de-chlorination process corresponded approximately to PCP disappearance. Pathways of PCP metabolism are not yet elucidated.     

Contents of heavy metal elements in copper mosses: Scopelophila ligulata,Scopelophila cataractae,and Mielichhoferia japonica and their substrates

Scopelophila ligulata (Spruce) Spruce, S. cataractae (Mitt.) Broth., and Mielichhoferia japonica Besch. (Mielichhoferia mielichhoferi (Hook.) Wijk et Marg. var. japonica (Besch.) Wijk et Marg.) are well known “copper mossess” which show peculiar ecological characteristics consisting of a preference for metal-rich soils, lithosols, rocks, etc. as their substrates. The total and water-soluble element contents in the substrates and heavy metal contents in the moss body were analyzed in this study. The results of these chemical analyses were as follows: The iron contents in the moss body and substrate of S. ligulata were higher than those of S. cataractae and M. japonica. On the contrary the copper contents of the former were lower than those of the latter. The pH values of substrate of S. ligulata were lower than those of S. cataractae and M. japonica. The concentrations of water-soluble iron and sulfate in the substrate of S. ligulata were higher than those of S. cataractae and M. japonica. On the contrary, the water-soluble copper concentrations in the substrate of S. ligulata were lower than those of the others. Although in the substrate of S. cataractae the iron content was several times higher than the copper content, in the moss body the copper content was higher than iron content.     

Feasibility for use of digested slurry by the pouring method in paddy fields of Southern Vietnam

In this study, we evaluated the feasibility for the use of digested slurry from livestock manure (hereafter, slurry) in paddy fields through field experiments conducted in Southern Vietnam. The pouring method for slurry was used, and a vacuum truck was used for transportation and pouring of the slurry. A prototype slurry tanker was manufactured for transportation and application of slurry, because vacuum trucks are rarely available in rural areas of Vietnam. For evaluation of feasibility, costs and labor for application of slurry and rice production were examined and compared with conventional cultivation methods using chemical fertilizers. As the results, rice production with the use of slurry was 485 g m^?2, which is within the range of on-site conventional cultivation, so slurry may be a good substitute for chemical fertilizers in rice production. Costs for slurry fertilization with a prototype slurry tanker and a vacuum truck were estimated at 0.13 USD m^?2 and 0.10 USD m^?2, respectively. These costs were higher than for conventional cultivation of 0.06 USD m^?2 under the present conditions with T-N concentrations of approximately 400 mg L^?1 in the slurry. However, we clarified that the cost for slurry fertilization can be lower than conventional cultivation when the concentrations of nitrogen in slurry increase from 400 to 2000 mg L^?1. These results show that an increase in nitrogen concentrations in slurry make slurry fertilization feasible if the amounts of water for washing livestock sheds that enter into the biogas digesters are reduced.     

Determination of mechanism of flock sediment formation in tea beverages

The mechanism of sediment formation during the storage of green tea beverage was investigated. Green tea extract was separated by Diaion HP-20 column chromatography, and a sediment-formation test was performed. Results showed that at least one compound of the substance causing flock sediment was contained in each of the HP-20 nonadsorbed and adsorbed fractions. From the following fractionations and structure analyses, the substance in the HP-20 adsorbed fraction was determined to be 1-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl-beta-D-glucose (strictinin), which is one of the ellagitannins. Strictinin was hydrolyzed to ellagic acid by heat-sterilization processes such as retort sterilization or the ultra-high temperature processing used during the manufacturing of tea beverages. Ellagic acid combined with proteins in the HP-20 nonadsorbed fraction to form an irreversible sediment of green tea beverage; ellagic acid and proteins were confirmed to be present in that sediment. The HP-20 adsorbed fraction contained little strictinin and formed hardly any sediment, suggesting that control of the strictinin content is significant in avoiding sediment formation during the manufacturing process of tea beverages.     

Survivals of Vibrio parahaemolyticus and Escherichia coli in a gastropod mollusc, Heminerita japonica.

Vibrio parahaemolyticus strains D-3 and R-13 were found to be cleared within 7 days from a marine neritid gastropod mollusc, Heminerita japonica, maintained in artificial seawater with salinities of 15, 25 and 35 permil (%) at 25 degrees C. Escherichia coli strain YS-2 survived at a level of 10(2) colony forming units per gram in the mollusc maintained in 15% water for up to 14 days and fell to non-detectable level within 7 days in a 35% salinity group. The ability of H. japonica to clear these organisms seems to be less active than that of a marine species. Nerita albicilla, and more active than that of an estuarine species. Clithon retropictus.     

Growth response of cabbage plants to transition elements under water culture conditions

Cabbage plants were water-cultured under 4 levels of titanium (0,0,4,4,20 ppm), vanadium (0, 0.4,4, 20 ppm), chromium (0, 0.2, 2, 10 ppm), manganese (0, 0.4, 4, 20 ppm), and iron (0, 1, 10, 50 ppm), and the effects of the elements supplied on the growth of the plants and on the distribution of the elements in the plants were studied.

The dry weight of a whole plant and of inner leaves (yield) without the addition of Ti, V, and Cr did not decrease, while that without the addition of Mn and Fe decreased slightly. The addition of Ti, V, Cr, Mn, and Fe (more than 0.4, 0.4, 2, 4, and 10 ppm, respectively) decreased the yield. Slight transition element-induced chlorosis was observed in the plots at high levels of Ti, Cr, and Mn.

The contents of the elements in the plants increased with an increase in the concentration of each element in the culture solution. The critical contents of Mn and Fe in plant-tops which resulted in a slight decrease in the yield due to the deficient injury were estimated to be about 10 and l00 ppm. The contents of Ti, V, Cr, Mn, and Fe when the yield decreased by 50% due to the excess injury were 4,6, 20, 3,000, and 300 ppm in outer leaves and 3,000, l,000, 2,000, 15,000, and 50,000 ppm in roots, respectively.     

Growth response of cabbage plants to beryllium and strontium under water culture conditions

Cabbage plants (B. oleracea L. var. capitata L.) were grown for 37 days in culture solutions containing 4 levels (0, 0.5, 5, 25 ppm) of beryllium or strontium with a low or high supply (20 or 200 ppm) of calcium, and the effects of the cations supplied on the growth of the plants were studied.

The total dry weights of the plants decreased successively with increasing levels of Be and Sr in the culture solution, concurrfnt with an increase in the contents of each cation in the plants. The decrease in the yield (dry weight of inner leaves) was most pronounced in the Be treatment with the low Ca supply. The critical contents of Be and Sr which resulted in a 50% decrease in the yield due to the excess injury were estimated to be about 0.0006 and 0.4% on a dry basis in the outer leaves and 0.3 and 0.4% in the roots, respectively, regardless of the Ca supply.