DIMETHYL SULPHIDE FORMATION IN MALT—EFFECT OF MALTING CONDITIONS

The dimethyl sulphide (DMS) content of kilned malt, and, presumably, the level of precursor in green malt, is significantly affected by malting conditions. Increasing proteolysis favours increased DMS formation in the malt, particularly when induced by higher germination temperatures. The additives gibberellic acid and potassium bromate have opposing effects, some increase being caused by the former and significant reduction being achieved by the latter.     

THE EFFECTS OF DIFFERENT STEEPING REGIMES ON WATER UPTAKE,GERMINATION RATE,MILLING ENERGY AND HOT WATER EXTRACT

Five spring cultivars and one winter barley cultivar have been assessed for aspects of malting quality following four different steeping regimes. There were significant effects of cultivar and steeping regime for all characters and cultivar X steeping regime interaction for germination rate and hot water extract. Moisture content after steep was the best guide to the optimum steeping regime. Malting quality was best predicted, in genotypes which germinated rapidly, by determining grain hardness following steeping and 24 hrs germination.     

Quantifying cyanogenic glycoside production in the acrospires of germinating barley grains

Ethyl carbamate is an undesirable trace component in distilled beverages and its content in Scotch whisky is largely determined by the cyanogenic pre‐cursor, epi‐heterodendrin (EPH) from malted barley. A rapid colorimetric procedure can identify cultivars that do not produce EPH and attempts were made to quantify this test, to determine differing levels of production. Using a given fresh weight of acrospire tissue from germinated grain, it was possible to distinguish between genotypes but differences between replicates were substantial. Acrospire length was not a reliable indicator of EPH production and genotypes differed not only in the quantity of EPH produced but in the rate and pattern of production. © 1999 Society of Chemical Industry     

Towards improving the nutrition and health of the aged: the role of sprouted grains and encapsulation of bioactive compounds in functional bread – a review

Aging reduces the absorption of nutrients. Literature related to functional bread processing techniques including sprouting of grains and the application of encapsulation technology and the bioavailability of bioactives was reviewed. Functional ingredients including sprouted/germinated grain particularly brown rice and wheat flours enhance the bioactive properties of functional bread. Ingredients with high polyphenol content such as lavender and melissa by-products, tea-extracts and aronia powder enhance the bioactive content and appear to have a favourable effect on the shelf-life of bread and antioxidant status of consumers. Incorporation of encapsulated bioactive compounds into bread have a huge potential to improve the bread quality and increase the bioavailability and bioaccessibility of bioactive compounds including polyphenols. More investigations and new areas of research should focus on sprouted grain flours and the application of encapsulation technologies especially nanoencapsulation to optimize the bioactivity, storage, bioavailability and nutritional profile of bread to improve nutrition and health with aging.     

THE USE OF MILLING ENERGY TO PREDICT INCREASES IN HOT WATER EXTRACT IN RESPONSE TO THE ADDITION OF GIBBERELLIC ACID DURING STEEPING

Addition of gibberellic acid at 2 ppm during steeping of six spring barley cultivars was found to enhance both hot water extract and loss of grain hardness, as measured by malt milling energy. The rate of water uptake and percentage germination after 24 hrs were unaffected, greatly limiting their usefulness in predicting extract. Milling energy after 24 hrs germination correlated extremely well with extract after both 4 and 5 days germination, in five of the cultivars, so constitutes a very useful screening system in most instances. Extending the germination period may be necessary, however, to select progeny of parents with very hard endosperms but with the potential to modify extensviely during malting.     

STUDIES ON DEBRANCHING ENZYMES. PART I THE LIMIT DEXTRINASE ACTIVITY OF EXTRACTS OF CERTAIN HIGHER PLANTS AND COMMERCIAL MALTS

Using pullulan as the substrate, the limit dextrinase activity of protein extracts from higher plants and from commercial malts has been measured. Extracts of ungerminated barley, rye, maize and wheat show low levels of activity which increase markedly on germination. By contrast, extracts of ungerminated oats have a high level of activity which does not increase during germination. Gibberellic acid has a significant effect on the rate of development of limit dextrinase activity in barley. Commercial samples of malt show varying amounts of limit dextrinase activity which does not correlate with the diastatic power. For comparative purposes, the α-amylase and maltotriase activities of all the protein extracts have also been measured.     

Two Lipoxygenases from Germinated Barley-Heat and Kilning Stability

Using ammonium sulfate precipitation followed by hydrophobic and ion exchange chromatography, two lipoxygenase isoenzymes, LOX 1 and LOX 2, were 18.3- and 44.5-fold purified from germinated barley, with 18 and 24% recovery of activity respectively. LOX 1 and LOX 2 were characterized by isoelectric points 4.9 and 6.4, and molecular weights of 90 kd and 110 kd, respectively. Apparent Km values for linoleic acid were 0.06 mM for LOX 1 and 0.18 mM for LOX 2. LOX 1 converted linoleic acid to 9 and 13 hydroperoxides at about 4:1, whereas the 13 hydroperoxide was the major product formed by LOX 2 (ratio 3:7). For both isoforms, thermal inactivation data indicated first order kinetics with activation energies influenced by ionic strength and pH. Isoenzymes composition was analyzed for three kilning schemes: the 1:3 ratio between LOX 1 and LOX 2 observed in germinated barley increased during the course of kilning.     

芽菜生产中利用电生功能水控制微生物污染的研究

芽菜中的微生物主要由生产芽菜所用种子带入,人们误食被病原菌污染的芽菜后会出现食物中毒现象。研究采用电生功能水对黄豆、绿豆、苜蓿和萝卜4种芽菜种子进行浸泡前处理,达到杀灭种子表面的微生物的目的。实验结果显示:电生功能水可以有效降低种子表面的微生物数量,处理后黄豆和绿豆种子表面的微生物总数均小于1logcfu/g,苜蓿和萝卜种子表面的微生物总数分别为(3.53±0.07)logcfu/g和(2.65±0.14)logcfu/g。对绿豆种子表面的电镜扫描结果显示:碱性水和微酸性水相结合的方式可以严重破坏绿豆种子表层的蜡质层,增强杀菌效果。结果还发现,电生功能水处理使黄豆种子的发芽率由85%提高到89%,萝卜种子的发芽率由62%提高到80%,对绿豆和苜蓿种子的发芽率没有显著影响。     

谷物制品的生物加工研究进展

谷物类食品含有丰富的碳水化合物、脂肪、蛋白质、膳食纤维等营养成分,在我国居民的膳食结构中占有重要的地位.已有研究表明,对谷物进行适当的生物加工处理会显著提高其制品的营养价值、增加其在人体的消化吸收利用率,并且能改善谷物制品的风味和食用品质、增强其功能活性.本文仔细研究了近年来国内外有关谷物加工的文献报道,分别从发酵、酶...     

EFFECT OF GERMINATION CONDITIONS,WITH OPTIMISED STEEPING,ON SORGHUM MALT QUALITY—WITH PARTICULAR REFERENCE TO FREE AMINO NITROGEN

Using optimised steeping conditions for sorghum, the effect of various germination parameters (time, temperature and moisture) on the quality of sorghum malt for brewing purposes (in terms of diastatic power, free amino nitrogen and hot water extract) and on the associated malting losses, was investigated. Over the range studied (2, 4 and 6 days), the quality of the malt and the losses incurred during malting increased with increasing germination time. In general, the optimum germination temperature was between 25 and 30°C, and 18°C was found to be sub-optimal for the development of malt diastatic power. The quality of the finished malt and the associated malting losses were significantly correlated with the moisture content of the green malt. The root and shoot portion of the malt was found to be rich in free amino nitrogen (more than four times richer than the berry portion). Although a relatively small proportion of the total weight of the whole malt, the roots and shoots were found to contribute a substantial amount (as much as 61% under certain circumstances) to the whole-malt free amino nitrogen.     

HORDEIN POLYPEPTIDE PATTERN IN RELATION TO MALTING QUALITY AND THE VARIETAL IDENTIFICATION OF MALTED BARLEY GRAIN

A procedure is described for the extraction of hordein fractions from single seeds of barley and determination of their polypeptide composition by SDS-PAGE. Varietal differences in the hordein polypeptide pattern occur, and on the basis of this character the 28 varieties which are most widely grown in the U.K. can be divided into 11 groups. Whereas several of these groups contain varieties with similar malting quality, other groups contain both good and poor quality varieties. Examination of pilot scale malts and germinating seeds showed little change in the hordein polypeptide pattern during malting or the early stages of germination. Thus the procedure is suitable for use in the identification of malted grain as well as dry seed.     

种植密度对酿造专用大麦原麦品质的影响

针对甘肃省啤酒大麦均一性差、发芽不整齐的品质现状,研究论证了种植密度对蛋白质、千粒重、饱满度、发芽率等原麦品质的影响,为指导大面积生产提供科学依据.试验表明随种植密度加大,发芽率变幅不大,但千粒重降低,当种植密度达50万/666.7m2以上时,原麦蛋白质和饱满度下降到二级标准.结合产量及品质分析结果,提出甘肃河西石羊河流域啤酒大麦推荐播种密度应以30万/666.7m2～40万/666.7m2为宣.     

QUANTITATIVE DETERMINATION OF α-AMYLASE ENZYMES IN GERMINATED BARLEY AFTER SEPARATION BY ISOELECTRICFOCUSING1

Quantitative extraction of malt and germinated barley α-amylases from polyacrylamide gels after isoelectricfocusing was achieved using bovine serum albumin (2 mg/ml) in the extracting medium. Sharp bands of activity were obtained when extracts from polyacrylamide gels were re-focused on another gel. This technique demonstrated that α-amylase III was the major component in malt and germinated barley extracts. This enzyme was converted to α-amylase II when such extracts were heated at 70°C.     

谷物早餐食品研究进展

该文介绍几种典型谷物早餐食品加工工艺原理和技术,谷物早餐食品研究现状及新型谷物早 餐食品开发。     

MICROMALTING TRITICALE

A sample of ‘Lasko’ triticale, a wheat × rye hybrid cereal, was micro-malted in a variety of ways. The grain was adequately steeped in under 24 h, and was relatively unaffected by high steeping temperatures, or the use of air-rests. Malts with exceptionally high extracts (about 340 1°/kg dry) and diastatic powers were obtained with malting losses of about 8% after 4 days germination. However, levels of soluble nitrogen were also high, even when potassium bromate had been employed. Malts made from this cereal could be of value in mixed brewing grists and in the manufacture of some malt extracts.