Production and characterization of functional substances from a by-product of rice bran oil and protein production by a compressed hot water treatment

A by-product of rice bran oil and protein production was treated with water and compressed hot water at 20 degrees C to 260 degrees C for 5 min, and at 200 degrees C and 260 degrees C for 5 to 120 min. Each extract was evaluated for its yield, radical scavenging activity, carbohydrate, protein, total phenolic and furfural contents, molecular-mass distribution and antioxidative activity. The maximum yield was obtained at 200 degrees C. The radical scavenging activity and the protein, total phenolic and furfural contents of the extract increased with increasing temperature. However, the carbohydrate content abruptly decreased when treated at above 200 degrees C. The extract treated at 260 degrees C for 5 min exhibited suppressive activity toward the autoxidation of linoleic acid. Each extract obtained at temperatures lower than or equal to 200 degrees C exhibited emulsifying ability.     

The antioxidative property of green tea against iron-induced oxidative stress in rat brain

The antioxidative property of green tea against iron-induced oxidative stress was investigated in the rat brain both in vivo and in vivo. Incubation of brain homogenates at 37 degrees C for 4 hours in vitro increased the formation of Schiff base fluorescent products of malonaldehyde, an indicator of lipid peroxidation. Auto-oxidation (without exogenous iron) of brain homogenates was inhibited by green tea extract in a concentration-dependent manner. Moreover, incubation with iron (1 microM) elevated lipid peroxidation of brain homogenates after 4-hour incubation at 37 degrees C. Co-incubation with green tea extract dose-dependently inhibited the iron-induced elevation in lipid peroxidation. For the in vivo studies: ferrous citrate (iron, 4.2 nmoles) was infused intranigrally and induced degeneration of the nigrostriatal dopaminergic system of rat brain. An increase in lipid peroxidation in substantia nigra as well as a decrease in dopamine content in striatum was observed seven days after the iron infusion. Intranigral infusion of green tea extract alone did not increase, and in some cases, even decreased lipid peroxidation in substantia nigra. Co-infusion of green tea extract prevented oxidative injury induced by iron. Both iron-induced elevation in lipid peroxidation in substantia nigra and iron-induced decrease in dopamine content in striatum were suppressed. Oral administration of green tea extract for two weeks did not prevent the iron-induced oxidative injury in nigrostriatal dopaminergic system. Our results suggest that intranigral infusion of green tea extract appears to be nontoxic to the nigrostriatal dopaminergic system. Furthermore, the potent antioxidative action of green tea extract protects the nigrostriatal dopaminergic system from the iron-induced oxidative injury.     

Antioxidants from steamed used tea leaves and their reaction behavior

The most efficient steaming conditions below 200 degrees C for extracting antioxidants from used tea leaves and their reaction behavior during the steaming treatment were investigated. The antioxidative activity of the steamed extracts increased with increasing steaming temperature, and the yield of the ethyl acetate extract fraction from each steamed extract showing the greatest antioxidative activity also increased. Caffeine, (-)-catechin, (-)-epicatechin, (-)-gallocatechin, (-)-epigallocatechin, (-)-catechin gallate, (-)-epicatechin gallate, (-)-gallocatechin gallate, (-)-epigallocatechin gallate and gallic acid were identified from the ethyl acetate extract fraction. Quantitative analyses demonstrated that the catechins with a 2,3-cis configuration decreased with increasing steaming temperature, whereas the corresponding epimers at the C-2 position increased. Each pair of epimers showed similar antioxidative activity to each other, indicating that the epimerization reaction did not contribute to the improved antioxidative activity. It is concluded from these results that the improvement in antioxidative activity at higher steaming temperatures was due to the increased yield of catechins and other antioxidants.     

Effect of germination temperature on characteristics of phytase production from barley

The effects of germination temperature on the growth of barley seedlings for phytase production were studied at 15, 20 and 25 degrees C for 6-10 days. The growth rate of the barley seedlings was increased as the germination temperature was increased. The initial rate of total protein production was closely coupled to that of the barley growth, and the rate of total protein production tended to increase as the germination temperature was increased. SDS-PAGE analysis of total protein from the barley seedlings showed time-dependent appearance and disappearance of protein bands. Although no significant phytase activity was detected at zero time of germination, a significant increase in phytase activity up to 7.9-fold occurred during the first several days of germination then decreased. Phosphate production (viz. phytate degradation) in the barley seedlings occurred rapidly at the beginning of germination. However, the rate of production continued to decrease with further germination. A time lag of about 1-2 days between the rate of total protein production and that of phytase production was observed. Unlike the extent of total protein production, that of phytase production was similar irrespective of germination temperature. Partial purification of a crude enzyme extract by hydrophobic interaction chromatography resulted in two phytase fractions (PI and PII). Zymogram analysis demonstrated that PI had two bands with molecular masses of about 66 and 123 kDa while PII had one band corresponding to a molecular mass of about 96 kDa. The optimal temperature for PI was found to be 55 degrees C, while it was 50 degrees C for PII. The enzyme fraction PI had a pH optimum at 6.0, whereas the optimum pH for PII was found to be 5.0. Addition of 0.1% (v/v) Tween 80 was found to increase enzyme activity significantly (i.e., 167% for PI and 137% for PII). Phytate in cereals including barley, rice, corn and soybean degraded effectively by the treatment of the barley phytases.     

产β—葡聚糖酶菌种T199的选育及发酵条件

大麦为啤酒酿造原料 ,含有由葡萄糖残基通过β 1 ,3 和 1 ,4 糖甙键连接而成的β 葡聚糖。在麦芽汁制备过程中 ,热不稳定的大麦葡聚糖酶不能充分降解β 葡聚糖 ,残留的 β 葡聚糖不仅影响麦芽汁分离和啤酒过滤 ,而且将成为成品啤酒出现混浊和沉淀的因素之一。微生物 β 葡聚糖酶能改善啤酒加工工艺和提高产品质量[1,2 ] 。谷类饲料含有不同于纤维素的 β 葡聚糖[2 ] ,作为抗营养因子 ,β 葡聚糖使饲料具有粘性 ,不能很好的消化利用。β 葡聚糖酶作为饲料添加剂加入到饲料中 ,可以将 β 葡聚糖降解 ,从而提高饲料利用率 ,改善营养吸收。相关…     

Natural occurrence of the mycotoxin viomellein in barley and the associated quinone-producing penicillia

In a batch of barley associated with field cases of mycotoxic porcine nephropathy and containing ochratoxin A and citrinin, the mycoflora were isolated by parallel incubation at 10 and 25 degrees C. Subsequently, the isolated cultures were checked for production of nephrotoxins (xanthomegnin, viomellein, ochratoxin, and citrinin). The nephrotoxin producers, all isolated by incubation at 10 degrees C, were comprised of one culture of Penicillium viridicatum, five cultures of Penicillium cyclopium, and one culture of Penicillium crustosum, all producing xanthomegnin and viomellein. One culture of P. cyclopium produced citrinin. Viomellein was detected in the barley at a concentration of approximately 1 mg/kg. The method of analysis for xanthomegnin and viomellein included extraction with chloroform, partitioning in hexane-acetone, and thin-layer chromatographic separation and identification. The identity of the xanthomegnin and viomellein produced by the isolated fungi and of viomellein detected in the barley was supported by infrared spectroscopy. This is the first report of viomellein as a natural contaminant of foodstuffs.     

Natural occurrence of the mycotoxin viomellein in barley and the associated quinone-producing penicillia.

In a batch of barley associated with field cases of mycotoxic porcine nephropathy and containing ochratoxin A and citrinin, the mycoflora were isolated by parallel incubation at 10 and 25 degrees C. Subsequently, the isolated cultures were checked for production of nephrotoxins (xanthomegnin, viomellein, ochratoxin, and citrinin). The nephrotoxin producers, all isolated by incubation at 10 degrees C, were comprised of one culture of Penicillium viridicatum, five cultures of Penicillium cyclopium, and one culture of Penicillium crustosum, all producing xanthomegnin and viomellein. One culture of P. cyclopium produced citrinin. Viomellein was detected in the barley at a concentration of approximately 1 mg/kg. The method of analysis for xanthomegnin and viomellein included extraction with chloroform, partitioning in hexane-acetone, and thin-layer chromatographic separation and identification. The identity of the xanthomegnin and viomellein produced by the isolated fungi and of viomellein detected in the barley was supported by infrared spectroscopy. This is the first report of viomellein as a natural contaminant of foodstuffs.     

Production of ochratoxin A in barley by Aspergillus ochraceus and Penicillium viridicatum: effect of fungal growth, time, temperature, and inoculum size.

Moistened barley was inoculated with 1.4 x 10(3) and 1.4 x 10(5) spores, respectively, from ochratoxin A-producing strains of Aspergillus ochraceus and Penicillium varidicatum. To estimate fungal tissue in the barley, the amount of glucosamine was followed for 28 days at 10 and 25 degrees C. Ochratoxin A was also followed during the same period and under the same conditions. The data show that ochratoxin A could be detected 4 to 6 days after inoculation at 25 degrees C, and the maximal accumulation of ochratoxin A was observed 28 days after inoculation. After 28 days at 25 degrees C, the quantities of ochratoxin A were between 7 and 46 micrograms/g of grain. At 10 degrees C only P. viridicatum produced ochratoxin A. The results indicated that production of ochratoxin A is not associated with rapid increase of glucosamine in the barley.     

Induction of cellular DNA synthesis in G0-specific ts mutant, tsJT60, following Infection with SV40 and adenoviruses

tsJT60 cells, a temperature-sensitive G0 mutant of a Fischer rat cell line, grew normally in an exponential growth phase at both permissive (34 degrees C) and nonpermissive (39.5 degrees C) temperatures, but when stimulated with fetal bovine serum in the growth-arrested state (G0 phase) they entered S phase at 34 degrees C but not at 39.5 degrees C. Infection of G0-arrested tsJT60 cells with SV40, adenovirus (Ad) 5 wild type and its E1B mutant dl313, and Ad12 wild type and its E1B mutants in205B, in205C, dl205, and in206B induced DNA synthesis at both temperatures. The DNA synthesized after virus infection was shown to be cellular by Hirt separation of DNA from SV40-infected cells and by CsCl equilibrium density gradient centrifugation of DNA from Ad5-infected cells.     

Antioxidative activities of aroma extracts isolated from natural plants

Natural leaves and flowers containing numerous aroma chemicals are widely used in aromatherapy since ancient times. In addition to their pleasant smells, aroma chemicals might have some beneficial health effects. Aroma extracts, isolated from coffee beans, soybeans, and mung beans by steam distillation under mild conditions (55 degrees C and 85 mm Hg) were examined for their antioxidative activities. The inhibitory effect of these extracts toward hexanal/hexanoic acid conversion was measured in the testing solution over prolonged time periods. The inhibitory effects of these extracts toward malonaldehyde formation from lipids oxidized by Fenton's reagent were also measured. The antioxidative activity of these extracts, in particular coffee bean extract, was consistent with that of BHT or alpha-tocopherol (vitamin E). Soybeans and mung beans extract contained maltol, which inhibits hexanal oxidation significantly. Eugenol, which is one of the major constituents of mung bean extract, exhibited potent antioxidative activity in an aldehyde/carboxylic acid assay. Antioxidants such as eugenol and maltol may play an important role in the pharmaceutical activities of natural plant extracts used for aromatherapy.     

Recovery of catechin compounds from Korean tea by solvent extraction

Catechin compounds from Korean green tea as potential sources of anticancer and antioxidant components were target materials in this work. The methodologies of solvent extraction and partition were utilized to recover catechin compounds from green tea. The optimum experimental condition was obtained by optimizing operating factors, such as, the extraction solvent, extraction time and operating temperature. After extracting the green tea with water at 80 degrees C for 40 min, the extract was partitioned with water/chloroform, which was best suited to remove caffeine impurity from the extract. Further, the resulting extract was partitioned water/ethyl acetate to deeply purify the catechin compounds of EGC, EC, EGCG and ECG. The experimental result in this work could be extended to preparative HPLC to obtain EGCG on commercial scale.     

Characterization of a mutant form of SecA that alleviates a SecY defect at low temperature and shows a synthetic defect with SecY alteration at high temperature

The secY205 mutant is cold-sensitive for protein export, with an in vitro defect in supporting ATP- and preprotein-dependent insertion of SecA into the membrane. We characterized SecA81 with a Gly516 to Asp substitution near the minor ATP-binding region, which suppresses the secY205 defect at low temperature and exhibits an allele-specific synthetic defect with the same SecY alteration at 42 degrees C. The overproduced SecA81 aggregated in vivo at temperatures above 37 degrees C. Purified SecA81 exhibited markedly enhanced intrinsic and membrane ATPase activities at 30 degrees C, while it was totally inactive at 42 degrees C. The trypsin digestion patterns indicated that SecA81 has some disorder in the central region of SecA, which encompasses residues 421-575. This conformational abnormality may result in unregulated ATPase at low temperature as well as the thermosensitivity of the mutant protein. In the presence of both proOmpA and the wild-type membrane vesicles, however, the thermosensitivity was alleviated, and SecA81 was able to catalyze significant levels of proOmpA-stimulated ATP hydrolysis as well as proOmpA translocation at 42 degrees C. While SecA81 was able to overcome the SecY205 defect at low temperature, the SecY205 membrane vesicles could not significantly support the translocation ATPase or the proOmpA translocation activity of SecA81 at 42 degrees C. The inactivated SecA81 molecules seemed to jam the translocase since it interfered with translocase functions at 42 degrees C. Based on these results, we propose that under preprotein-translocating conditions, the SecYEG channel can stabilize and activate SecA, and that this aspect is defective for the SecA81-SecY205 combination. The data also suggest that the conformation of the central region of SecA is important for the regulation of ATP hydrolysis and for the productive interaction of SecA with SecY.     

Response surface methodology to supercritical carbon dioxide extraction of astaxanthin from Haematococcus pluvialis

Experimental design was used to investigate the effect of operating temperature (40-80 degrees C), operating pressure (30-50 MPa), and extraction time (1-4h) of supercritical carbon dioxide (SC-CO2) extraction on astaxanthin yields and the extract antioxidant activity (IC50). The ranges of the factors investigated were 40-80 degrees C for the operating temperature (X1), 30-50 MPa for the operating pressure (X2), and 1-4h for the extraction time (X3). The statistical analysis of the experiment indicated that pressure, extraction time, and the interaction between temperature and pressure (X1X2) had significant effect on astaxanthin yields. The central composite design showed that polynomial regression models were in good agreement with the experimental results with the coefficients of determination of 0.924 and 0.846 for astaxanthin yield and antioxidant activity, respectively. The optimal condition for astaxanthin yield within the experimental range of the variables studied was at 70 degrees C, 50 MPa, and 4h. At this condition, the predicted amount of astaxanthin extracted was 23.04 mg/g (2.3 wt% or 83.78% recovery). For the effect of experimental extraction conditions on antioxidant activity, IC50 was used as an index, which is the concentration that gives a 50% reduction in the absorbance of the ABTS free radical. The analysis of the results showed that the interaction between the operating temperature and operating pressure (X1X2) was the only significant factor affecting the extract antioxidant activity. The statistical model gave the minimum point for antioxidant activity at 67 degrees C, 40.3 MPa, and 1.86 h of extraction, at which the value for 1/IC50 was 0.39 l/mg (or IC50 was 2.57 mg/l).     

gamma-Linolenic acid production by solid-state fermentation of Mucorales strains on cereals

Oleaginous fungi of the genus Mucorales were screened for gamma-linolenic acid (GLA) production on solid substrates containing moistened cereals. Cunninghamella elegans CCF 1318 produced the highest yields of GLA when cultivated on barley. Substrate moisture and cultivation temperature proved critical for effective GLA production. Vegetable oil supplied to the cultures improved GLA production. Rotating bottles and plastic bags were used as cultivation vessels to reproduce the conditions found in rotating drums and tray bioreactors, respectively. After 11 days of cultivation at 21 degrees C, C. elegans produced 14.2 mg of GLA per gram of dry substrate, composed of a mixture of barley, spent malt grains (SMG) and peanut oil. GLA represented 15.6% of the total fatty acids in the lipid extract.     

鸭舌草中抗氧化活性物质的分离与鉴定

采用溶剂萃取法将鸭舌草75%乙醇提取物浸膏分成4个不同组分,并用碘量法测定其抗氧化活性.结果表明,高极性组分正丁醇相具有最强的抗氧化活性,与天然抗氧化剂茶多酚和化学合成抗氧化剂BHT的抗氧化活性相当,显著高于对照.利用柱层析技术对具有高抗氧化活性组分正丁醇相进一步分离纯化,并确定为豆甾醇葡萄糖甙.以BHT为对照对羟自由基进行清除试验,结果表明,与对照抗氧化剂BHT相比,它们对羟自由基具有更高的清除率.     

Extraction conditions affecting supercritical fluid extraction (SFE) of lycopene from watermelon

Lycopene, a carotenoid linked to protection against certain forms of cancer, is found in produce such as papaya, red-fleshed tomatoes, grapefruit and watermelon. The preparation of a supercritical CO2 (SC-CO2) watermelon-lycopene extract could serve as a food grade source of this carotenoid. This study established preliminary conditions for enhancing SC-CO2 extraction of lycopene from watermelon. Freeze-dried watermelon was extracted with SC-CO2 and ethanol as an organic co-solvent. The lycopene concentration was determined by HPLC, with absorbance measured at 503 nm. In an initial set of experiments, the effects of extraction temperature (70-90 degrees C), pressure (20.7-41.4 MPa) and co-solvent ethanol addition (10-15%) were evaluated. A lycopene yield of 38 microg per gram of wet weight was obtained at 70 degrees C, 20.7 MPa, and 15% by volume ethanol. The extraction of fresh (non-freeze-dried) watermelon yielded 103+/-6 microg lycopene per gram fresh fruit weight. Of the parameters tested, temperature had the most effect on lycopene yield. Thus, in another set of experiments, the temperature was varied from 60-75 degrees C at an extraction pressure of 20.7 MPa in the presence of 15% ethanol. Studies showed that freeze-dried watermelon flesh loses lycopene in storage. In accounting for lycopene storage losses, lycopene yields at 60 degrees C extraction temperature were 14% greater than those obtained at 70 degrees C.     

Supercritical carbon dioxide extraction of chamomile flowers: extraction efficiency, stability, and in-line inclusion of chamomile-carbon dioxide extract in beta-cyclodextrin

The extraction of chamomile flowers using supercritical carbon dioxide was investigated with respect to extraction efficiency and compared with solvent extraction. The stability of matricine, a sensitive constituent of the essential oil of chamomile, in these extracts was studied during storage at different temperatures over 6 months. Matricine was stable at -30 degrees C. A slight decrease (80-90% recovery) occurred at +5 degrees C, whereas complete decomposition of matricine took place within 3-4 months at room temperature and at +30 degrees C, respectively. An in-line inclusion of chamomile constituents in beta-cyclodextrin (beta-CD) during the extraction process was assessed and inclusion rates between 40 and 95% were obtained depending on the amount of beta-CD and the type of chamomile constituent. No further stabilization of matricine in the carbon dioxide extract/beta-CD complexes was achieved. High residual water contents in the complexes even after freeze-drying were identified as accelerating the decomposition. In addition, the extractability of flavonoids, such as apigenin and apigenin-7-glucoside, was determined. Apigenin-7-glucoside, the more hydrophilic substance, was not extractable with pure carbon dioxide and showed a recovery of 11% using methanol modified carbon dioxide (18%, w/w) at 60 degrees C and 380 bar. Extraction conditions in the two-phase region of the binary mixture carbon dioxide-methanol (70 degrees C, 100 bar) led to a drastic change in fluid polarity and hence extractability increased to 92-95%.     

Spectrin plus band 4.1 cross-link actin. Regulation by micromolar calcium

A low-salt extract prepared from human erythrocyte membranes forms a solid gel when purified rabbit muscle G- or F-actin is added to it to give a concentration of approximately 1 mg/ml. This extract contains spectrin, actin, band 4.1, band 4.9, hemoglobin, and several minor components. Pellets obtained by centrifugation of the gelled material at 43,000 g for 10 min contain spectrin, actin, band 4.1, and band 4.9. Although extracts that are diluted severalfold do not gel when actin is added to them, the viscosity of the mixtures increases dramatically over that of G-actin alone, extract alone, or F-actin alone at equivalent concentrations. Heat-denatured extract is completely inactive. Under conditions of physiological ionic strength and pH, information of this supramolecular structure is inhibited by raising the free calcium ion concentration to micromolar levels. Low-salt extracts prepared by initial extraction at 37 degrees C (and stored at 0 degree C) gel after actin is added to them only when warmed, whereas extracts prepared by extraction at 0 degree C are active on ice as well as after warming. Preincubation of the 37 degrees C low-salt extract under conditions that favor conversion of spectrin dimer to tetramer greatly enhances gelation activity at 0 degree C. Conversely, preincubation of the 0 degree C low-salt extract under conditions that favor conversion of spectrin tetramer to dimer greatly diminishes gelation activity at 0 degree C. Spectrin dimers or tetramers are purified from the 37 dgrees or 0 degree C low-salt extract by gel filtration at 4 degrees C over Sepharose 4B. The addition of actin to either purified spectrin dimer (at 32 degrees C) or tetramer (at 0 degree C or 32 degrees C) results in relatively small increases in viscosity, whereas the addition of actin to a high-molecular-weight complex (HMW complex) containing spectrin, actin, band 4.1, and band 4.9 results in dramatic, calcium-sensitive increases in viscosity. These viscosities are comparable to those obtained with the 37 degrees or 0 degree C low-salt extracts. The addition of purified band 4.1 to either purified spectrin dimer (at 32 degrees C) or purified spectrin tetramer (at 0 degree C) plus actin results in large increases in viscosity similar to those observed for the HMW complex and the crude extract, which is in agreement with a recent report by E. Ungewickell, P. M. Bennett, R. Calvert, V. Ohanian, and W. B. Gratzer. 1979 Nature (Lond.) 280:811-814. We suggest that this spectrin-actin-band 4.1 gel represents a major structural component of the erythrocyte cytoskeleton.     

Production of 5'-ribonucleotides by enzymatic hydrolysis of RNA.

Study of optimal operational conditions for RNA enzymatic hydrolysis to obtain 5'-ribonucleotides has been carried out. RNA from brewer's yeasts, obtained by ammonium extraction, was hydrolysed by a partially purified 5'-phosphodiesterase from barley rootlets. Temperature of 60 degrees C and pH 7 have been determined as the best operational conditions. Low RNA initial concentration (approximately 0.1%) and reaction time (approximately 1 h) have been identified as necessary to obtain a good yield of 5'-ribonucleotides.     

Cold-induced accumulation of protein in the leaves of spring and winter barley cultivars

Electrophoretic pattern and quantitative changes in soluble proteins were determined in the leaves of spring and winter cultivars of barley (Hordeum vulgare L., cv. Makouei and cv. Reyhan, respectively) exposed to 4 degrees C for 14 d. Seedlings were grown in a controlled growth chamber for 2 weeks at a constant air temperature of 20 degrees C and then transferred to constant 4 degrees C for 14 d followed by returning to 20 degrees C (cold treatment), or they were maintained throughout at 20 degrees C during the experimental period of 40 d (control treatment). Plants were sampled every 48 h for leaf fresh weight measurements. Total leaf soluble proteins were extracted and their concentration was either determined by a colorimetric method, or size-fractionated on SDS-PAGE. Low temperature-induced increases in protein amount occurred over the second week of exposure to cold treatment irrespective of cultivar: the winter cultivar was 2 d prior in this response. The protein patterns and their density showed differences between-cultivars and between-temperature treatments. A new cold-induced polypeptide was recognized in the leaves of winter barley cultivar on day 22 (8 d at 4 degrees C) compared to the control. This polypeptide was produced earlier over the first 48 h of low temperature in the winter cultivar compared with the spring one, recognizing in the leaves of cold-treated seedling until day 26. This more rapid response to a low temperature by the winter barley cultivar indicates a more sensitive response compared with the spring barley, probably cold-shock protein is a component of this cold-induced response.