Purification and characterization of a phytate-degrading enzyme from germinated oat (Avena sativa)

A phytate-degrading enzyme (myo-inositol hexakisphosphate phosphohydrolase) has been purified about 5,400-fold from germinated oat seedlings to apparent homogeneity. The molecular mass of the native monomeric enzyme was estimated to be about 67 kDa. Optimal pH for degradation of phytate was 5.0 and the optimal temperature 38 °C. Kinetic parameters for the hydrolysis of Na-phytate are K_M 30 µM and k_cat 356 s⁻¹ at 35 °C and pH 5.0. The oat phytase exhibits a broad affinity for various phosphorylated compounds and hydrolyses phytate in a stepwise manner. The first hydrolysis product was identified as D /L -l(1,2,3,4,5) P₅. © 1999 Society of Chemical Industry     

Polar lipid fraction from oat (Avena sativa): characterization and use as an o/w emulsifier

Oat seeds have an oil content of up to 13?%, of which up to 34?% can be polar lipids (glycolipids and phospholipids). Because of their amphiphilic structure, these polar lipids are potential emulsifiers. In this study, polar lipid fraction from oat produced by a supercritical fluid extraction process was fractionated into different polar lipid classes by HPLC and the lipid classes in subfractions were identified by comparing retention times with reference compounds and performing co-injections. The oat polar lipid fraction contained monogalactosyldiacylglycerol, digalactosyldiacylglycerol, steryl glycoside, and phosphatidyl choline, and also possibly phosphatidyl inositol. The polar lipid fraction was also used as an emulsifier to produce oil-in-water emulsions with different amounts of emulsifier and oil, and the stability and other properties of emulsions were studied. Emulsions were formed quite easily, but they were prone to rapid creaming even after a couple of days of storage at ambient conditions. Droplet size and droplet size distribution of the emulsions seemed to be slightly smaller with smaller amount of oil and larger amount of emulsifier. Generally, the droplet size of the emulsions was in the range of 0.2?C4???m, and with the largest amount of oil (5?%, w/v) up to 10???m. The upper phase of creamed emulsions contained slightly larger droplets, up to 30???m, while the lower phase retained smaller droplets. Microscopic investigation revealed that the increase in droplet size of the upper phase was mainly due to aggregation, which implies that these emulsions may be stable against coalescence to some extent.     

An electron spin resonance study of radicals induced by radiation in oat (Avena sativa L.)

A detailed electron spin resonance (ESR) investigation of the spectroscopic features and kinetic behaviours over a range of temperatures of the long‐life free radicals induced in a sample of ground oat that had been irradiated with γ‐radiation is reported. Unirradiated ground oat exhibited a weak, broad single‐line ESR spectra centered at g = 2.0048 ± 0.0008. The structure of this radical is unknown and is assigned as radical III in this work. The γ‐irradiation of oats yields radical III and other radical species. Although all these species are stable at 77 K, some of them are very unstable at room temperature. A model based on three radical species (designated I, II and III) was used to describe the room temperature spectra of their decay at room and at high temperatures. Annealing studies at six different temperatures were used to determine the kinetic behaviour and activation energies of the radicals induced by radiation. A dose–response curve was also constructed and it was concluded that ground oat is potentially a good dosimetric material. The presence of an ESR signal after a storage time of 90 days was interpreted as providing an opportunity to distinguish irradiated from unirradiated oats.     

Unmalted triticale cultivars as brewing adjuncts: effects of enzyme activities and composition on beer wort quality

The applicability of three selected triticale cultivars (Trinidad, Lamberto, Fidelio) for use as brewing adjuncts was investigated in comparison with wheat adjunct and barley malt. Fermentable substance, crude protein and arabinoxylan levels of starchy materials were determined as well as their native potencies (amylolytic, proteolytic, pentosolytic) to solubilise and degrade grain components during mashing. Laboratory‐scale experiments were performed to evaluate the influence of the adjuncts (composition, enzyme potency) on beer wort quality by mashing mixed (1:1) grists of malt and adjunct. Barley malt was rated as the superior raw material, possessing considerably higher enzyme activities and yielding the lowest wort viscosity. Among the triticale cultivars cv Trinidad was identified as the most suitable to serve as a brewing adjunct due to its improved starch solubilisation properties and its ability to generate low wort viscosities. Compared with the potent malt enzymes, the enzyme activities of unmalted triticale (such as amylases, pentosanases and proteases) had little affect on the composition of the sweet worts. In contrast, the contents of crude protein and fermentable substance of the triticale varieties greatly affected wort quality. Furthermore, the adjunct moiety determined the level of wort viscosity when mashing a combination of malt and triticale. In general, the brewing properties of triticale cv Trinidad were comparable with those of wheat. Copyright © 2004 Society of Chemical Industry     

燕麦油的精制及其抗过敏性与抗氧化性功效检测

通过脱胶、脱酸和脱色三步对燕麦粗油进行精制,并对燕麦油精制前后酸价、游离脂肪酸含量、碘价和皂化值进行测定.通过透明质酸酶体外抑制实验和大豆色拉油抗氧化实验对燕麦油抗过敏性和抗氧化性进行检测,证明其具有一定的抗过敏性和抗氧化性.     

Europium uptake and partitioning in oat (Avena sativa) roots as studied by laser-induced fluorescence spectroscopy and confocal microscopy profiling technique

The uptake of Eu3+ by elongating oat roots was studied by fluorescence spectroscopy, fluorescence lifetime measurement, and a laser excitation time-resolved confocal fluorescence profiling technique. The results of this work indicated that initial uptake of Eu3+ was highest within the undifferentiated cells of the root tip just behind the root cap, a region of maximal cell growth and differentiation and with incomplete formation of the Casparian strip around the central vascular cylinder. Distribution of assimilated Eu3+ within the root's differentiation and elongation zone was nonuniform. Higher concentrations of Eu3+ were observed within the vascular cylinder, specifically in the phloem and developing xylem parenchyma. Elevated levels of the metal were also observed in the root hairs of the mature root zone. Fluorescence spectroscopic characteristics of the assimilated Eu3+ suggested that the Eu3+ exists as inner-sphere mononuclear complexes inside the root. This work also demonstrated the effectiveness of a time-resolved Eu3+ fluorescence spectroscopy and confocal fluorescence profiling techniques for the in vivo, real-time study of metal [Eu3+] accumulation by a functioning intact plant root. This approach can prove valuable for basic and applied studies in plant nutrition and environmental uptake of actinide radionuclides.     

Inhibition of Fusarium graminearum growth in flour gel cultures by hexane-soluble compounds from oat (Avena sativa L.) flour

Fusarium head blight, incited by the fungus Fusarium graminearum, primarily affects wheat (Triticum aestivum) and barley (Hordeum vulgarum), while oat (Avena sativa) appears to be more resistant. Although this has generally been attributed to the open panicle of oats, we hypothesized that a chemical component of oats might contribute to this resistance. To test this hypothesis, we created culture media made of wheat, barley, and oat flour gels (6 g of flour in 20 ml of water, gelled by autoclaving) and inoculated these with plugs of F. graminearum from actively growing cultures. Fusarium growth was measured from the diameter of the fungal plaque. Plaque diameter was significantly smaller on oat flour cultures than on wheat or barley cultures after 40 to 80 h of growth. Ergosterol concentration was also significantly lower in oat cultures than in wheat cultures after growth. A hexane extract from oats added to wheat flour also inhibited Fusarium growth, and Fusarium grew better on hexane-defatted oat flour. The growth of Fusarium on oat flour was significantly and negatively affected by the oil concentration in the oat, in a linear relationship. A hexane-soluble chemical in oat flour appears to inhibit Fusarium growth and might contribute to oat's resistance to Fusarium head blight. Oxygenated fatty acids, including hydroxy, dihydroxy, and epoxy fatty acids, were identified in the hexane extracts and are likely candidates for causing the inhibition.     

Amylase isozymes of oats (Avena sativa L.)

Amylase isozymes were studied in six varieties of Avena sativa L. using agar gel electrophoresis. Three distinct zymograms were detected in aqueous extracts of endosperm of 4 to 5-day old seedlings. No intravarietal variation was observed. These results indicate that amylase zymograms may be useful markers for helping in the identification of oat varieties. Using the varieties Maris Tabard and Maris Titan it was found that all the isozymes in 4 to 5-day old seedlings, except one, had the properties of α-amylase. The zymograms of extracts from ungerminated grains of these two varieties, although apparently identical to those of 4 to 5-day old seedlings, differed in that all the α-isozymes in the former were found to be heat labile whereas in the latter they were heat stable.     

Implementation of commercial oat and sorghum flours in brewing

Brewing with commercial flours has the potential to reduce mashing times and improve brewhouse efficiency. At present, however, no studies are available assessing the application of commercial oat and sorghum flours as brewing adjuncts. Therefore, the objectives of this study were to evaluate the quality and processability of mashes/worts produced with 10–90 % oat or sorghum flour as well as to reveal the advantages and limitations of their use as a substitute for barley malt. For these purposes, both flour types were fully analyzed in terms of brewing-relevant characteristics using standard methods, Lab-on-a-Chip capillary electrophoresis, and scanning electron microscopy. Laboratory-scale mashing trials were performed to assess the effect of up to 90 % flour adjunct on mash/wort quality. Equivalent factors were introduced to determine the performance efficiency of different oat/sorghum flour concentrations. Commercial oat flour sourced in Ireland exhibited significantly more protein, β-glucan, and fat, less starch, ash, and polyphenols, as well as a lower starch gelatinization temperature than commercial sorghum flour obtained from the USA. Worts produced with 10–90 % oat or sorghum flour had lighter colors, higher pH values, and lower concentrations of foam-positive proteins as well as free amino nitrogen compared to 100 % barley malt worts. In terms of extract yields, the use of up to 70 % oat flour and 50 % sorghum flour, respectively, has proven economically beneficial. Worts containing up to 70 % oat flour showed a very good or good fermentability, those containing 30–50 % sorghum flour resulted, however, in a lower alcohol production.     

Avena sativa (Oat), A Potential Neutraceutical and Therapeutic Agent: An Overview

The aim of the present review article is to summarize the available information related to the availability, production, chemical composition, pharmacological activity, and traditional uses of Avena sativa to highlight its potential to contribute to human health. Oats are now cultivated worldwide and form an important dietary staple for the people in number of countries. Several varieties of oats are available. It is a rich source of protein, contains a number of important minerals, lipids, β-glucan, a mixed-linkage polysaccharide, which forms an important part of oat dietary fiber, and also contains various other phytoconstituents like avenanthramides, an indole alkaloid-gramine, flavonoids, flavonolignans, triterpenoid saponins, sterols, and tocols. Traditionally oats have been in use since long and are considered as stimulant, antispasmodic, antitumor, diuretic, and neurotonic. Oat possesses different pharmacological activities like antioxidant, anti-inflammatory, wound healing, immunomodulatory, antidiabetic, anticholesterolaemic, etc. A wide spectrum of biological activities indicates that oat is a potential therapeutic agent.     

A comparative study on free and bound phenolic acid content and their antioxidant activity in bran of rice (Oryza sativa L.) cultivars of Eastern Himalayan range

In our study, seven most prevailing but unexplored indigenous rice cultivars of northeast India, situated in the Eastern Himalayan Range, were investigated for their phenolic acid profile, total phenolic content (TPC) and antioxidant capacities in free and bound phenolic extracts of their bran. HPLC studies showed the presence of ferulic, p‐coumaric, sinapic, caffeic, chlorogenic and vanillic acids, with ferulic and p‐coumaric acids being the dominant phenolic acids in the bound form. The lower EC₅₀ values of the bound extracts than the free extracts suggested the better radical scavenging activity of the bound extracts. Significant correlations were observed between TPC and phenolic acid content (HPLC‐DAD) of bound extracts, and between Trolox equivalents antioxidant capacity (TEAC) and phenolic acid content (HPLC‐DAD) of both free and bound extracts. The findings suggest that phenolic acids in the rice cultivars investigated were exclusively present in bound form and contribute significantly towards their antioxidant capacity.     

Screening of rice cultivars for brewing high quality turbid rice wine

To screen proper rice cultivars for brewing high quality turbid rice wine, 5 high-yield rice cultivars, 9 high-eating-quality rice cultivars and 5 glutinous rice cultivars were collected. At the end of fermentation, significant differences (p < 0.05) were observed in the fermentation properties, sensory properties and suspension stability of the original fermented mash (OFM) among individual rice cultivars. The assayed fermentation properties of OFM included pH value, total acidity, amino acidity, reducing sugar, alcohol yield, fusel alcohols and ethyl acetate. Seven rice cultivars were screened out for producing high quality wine by the comparative analysis. This research provided the basic scientific data for producing potential high quality turbid rice wine.     

以玉米为原料酿造清酒的工艺研究

实验探讨了以玉米为单一原料酿制清酒的工艺。将玉米在亚硫酸溶液中浸泡50 h,脱胚去皮后进行蒸料,以米曲霉作为糖化剂,利用酵母进行发酵,7 d后结束。结果显示:玉米经处理后,其蛋白质含量和脂肪含量明显减少,各物质含量与大米更加接近。在25℃,pH5.0条件下使用安琪酵母菌发酵成的酒,其酒精度12.5%,氨基酸含量0.41 mg/ml。在活性炭添加量0.8 mg/ml条件下脱色24 h,所得清酒酒体清亮透明,具有特有的清香味。     

中国啤酒制造业发展概览(2001-2002年度)

据国家统计局公布的数据显示:我国啤酒产量在连续9年名列世界第二后,2002年以2386.83万吨超过了美国的2200多万吨的产量,位居世界第一.2003年国内啤酒消费量达到2500万吨,成为世界上最大的啤酒消费市场.     

归芪养生醋酿造工艺的研究

研究以青藏高原生产的青稞、玉米为原料,配以岷县当归、黄芪等地道名贵中药材,采用固态发酵工艺,通过实验研究,确定最佳工艺条件:液化醪糖度15～18°Bx,pH4～4.5,干酵母添加量0.3%,温度30℃,液态发酵6 d,酒精发酵结束后酒精度6%、外观糖度0.5°Bx以下时进行醋酸发酵,酷温控制在40℃,固态发酵10 d左右;最后经调配、澄清过滤后修饰得到营养丰富、澄清透明的归芪养生醋.     

The apparent ileal digestibility of amino acids and the digestible energy content of naked oats (Avena sativa cv Bandicoot) fed to growing pigs

An experiment was conducted to determine the apparent ileal digestibility of amino acids and the digestible energy (DE) content of two samples of naked oats (Avena sativa cv Bandicoot) and to compare these parameters in wheat (Triticum aestivum cv Machete) and dehulled oats (groats; Avena sativa cv Echidna). Four Large White male pigs were fitted with simple T-piece ileal cannulae and allocated to experimental diets in a 4×4 Latin square design. Amino acid digestibility coefficients were determined after continuous eight hour collections of digesta over two consecutive days using acid-insoluble ash as an indigestible marker. Digestible energy was determined using grab samples of faeces. No significant difference between the four test cereals was found in the digestibility of all amino acids, except for proline and lysine. The apparent ileal digestibility of lysine in wheat (0·87) and two samples of naked oats (0·89 and 0·82, respectively) was lower (P<0·05) than dehulled oats (0·91). The mean DE value of the naked oats samples was 16·96 MJ kg⁻¹ (air-dry basis). The results suggest that Bandicoot naked oats and dehulled oats are superior amino acid and DE sources to wheat and have potential for use in weaner and grower pig diets. © 1998 SCI.     

柑桔白酒的酿造工艺初探

该文以柑桔为主要原料,辅以高梁、米糠等辅料,采用传统固态发酵工艺生产柑桔白酒,通过对原料配比、发酵条件、蒸馏工艺的优化,辅以勾兑调配,酿成果香、酒香优雅,醇厚、协调,典型性较强的柑桔白酒,旨在开辟柑桔深加工的新途径,同时满足市场多元化的要求.     

Inflorescences of Brassicacea species as source of bioactive compounds: A comparative study

Two Brassica oleracea varieties (B. oleracea L. var. costata DC and B. oleracea L. var. acephala) and Brassica rapa L. var. rapa inflorescences were studied for their chemical composition and antioxidant capacity. Phenolic compounds and organic acids profiles were determined by HPLC–DAD and HPLC–UV, respectively. B. oleracea var. costata and B. oleracea L. var. acephala inflorescences presented a similar qualitative phenolic composition, exhibiting several complex kaempferol derivatives and 3-p-coumaroylquinic acid, while B. rapa var. rapa was characterized by kaempferol and isorhamnetin glycosides and several phenolic acids derivatives. B. oleracea L. var. costata and B. rapa var. rapa showed the highest phenolics content. The three Brassica exhibited the same six organic acids (aconitic, citric, pyruvic, malic, shikimic and fumaric acids), but B. oleracea L. var. acephala presented a considerably higher amount. Each inflorescence was investigated for its capacity to act as a scavenger of DPPH radical and reactive oxygen species (superoxide radical, hydroxyl radical and hypochlorous acid), exhibiting antioxidant capacity in a concentration dependent manner against all radicals. These samples were also studied for its antimicrobial potential against Gram-positive and Gram-negative bacteria and fungi, displaying antimicrobial capacity only against Gram-positive bacteria.