Genotype × environment influence on cowpea (Vigna unguiculata (L) walp) antinutritional factors: 1 – trypsin inhibitors,tannins, phytic acid and haemagglutinin

The relative influence of genotype, environment and genotype×environment effects on four antinutritional factors (g kg⁻¹) of importance in cowpea were studied using 15 local and improved cowpea genotypes grown in 12 environments, comprising three locations over four seasons per location. The locations Ago‐Iwoye (6°58′N4°00′E), Mokwa (9°17′N5°04E) and Kano (12°00′N8°31′E) were representatives of the major agroecological zones where cowpeas are produced. Genotypes effects were strongest in controlling trypsin inhibitor content, while the environment was the major source of variation for tannins, haemagglutinin and phytic acid contents. Thus, the variability in the levels of these antinutritional factors in cowpea seeds depends largely on the environment where they are grown. This implies that a cowpea genotype grown and consumed safely in an environment can be poisonous when grown and consumed in another environment. Genotype×environment effects were significant for tannins, haemagglutinins and trypsin inhibitor contents. Correlation coefficients (pooled data) from the three locations indicated that trypsin inhibitor was positively correlated to phytic acid (r=0.59, 0.001<P<0.05) and haemagglutinins (r=0.64, 0.001<P<0.05) but negatively correlated to tannin contents ( r=−0.79, 0.001<P<0.05). © 1999 Society of Chemical Industry     

利用弱碱性阴离子交换树脂从脱脂米糠中制取植酸的研究

以脱脂米糠为原料,通过酸浸、离子交换吸附、洗脱、精制、浓缩过程利用D318型弱碱性阴离子交换树脂制得植酸。试验结果表明,D318型阴离子交换树脂从脱脂米糠植酸粗溶液中吸脱植酸的最佳工艺条件为:吸附液浓度为10 mg/ml,吸附液流速为1.0 ml/min,NaOH洗脱液的流速为2.0 ml/min,NaOH洗脱液浓度为1.5 mol/L,操作温度为45℃,pH值为2.5左右。     

Quinoa saponins—analysis and preliminary investigations into the effects of reduction by processing

A gas chromatographic method has been developed for the analysis of saponins in quinoa (Chenopodium quinoa Willd). The method, which involves separation and quantitation of the trimethylsilylated sapogenols, has been applied to the analysis of the UK-grown crop obtained by selection from lowland Chilean ecotypes. Total saponin contents of 1·03 and 1·19% were found for material grown in 1987 and 1988. The major aglycone in the quinoa saponin mixture was identified as phytolaccagenic acid (>40% total), with hederagenin (～25%) and oleanolic acid (30%) aglycones also being present. The effects of washing and abrasion on total and individual saponin content were investigated; the data obtained suggest differential cellular locations of the individual saponins. The processing of quinoa led to changes in sensory characteristics; removal of saponins was associated with reductions in bitterness and astringency. Microscopic analysis revealed considerable differences in washed and abraded samples, both before and after cooking; in particular the abraded samples showed a greater degree of cellular disruption.     

Enhancing the Microbiological Stability of Malt and Beer — A Review

While beer provides a very stable microbiological environment, a few niche microorganisms are capable of growth in malt, wort and beer. Growth of mycotoxin‐producing fungi during malting, production of off‐flavours and development of turbidity in the packaged product due to the growth and metabolic activity of wild yeasts, certain lactic acid bacteria (LAB) and anaerobic Gram negative bacteria, impact negatively on beer quality. It follows that any means by which microbial contamination can be reduced or controlled would be of great economic interest to the brewing industry and would serve the public interest. There has been an increasing effort to develop novel approaches to minimal processing, such as the exploitation of inhibitory components natural to raw materials, to enhance the microbiological stability of beer. LAB species, which occur as part of the natural barley microbiota, persist during malting and mashing, and can play a positive role in the beer‐manufacturing process by their contribution to wort bioacidification or the elimination of undesirable microorganisms. Other naturally occurring components of beer that have been valued for their preservative properties are hop compounds. It may be possible to enhance the antimicrobial activities of these compounds during brewing. Some yeast strains produce and excrete extracellular toxins called zymocins, which are lethal to sensitive yeast strains. Yeast strains resistant to zymocins have been constructed. Imparting zymocinogenic activity to brewing yeast would offer a defence against wild yeasts in the brewery. Thus, the antimicrobial properties of naturally occurring components of raw materials can be exploited to enhance the microbial stability of beer.     

Physiological Effects of Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA)—A Review

Marine lipids have long been documented to be the major source of polyunsaturated fatty acids (PUFAs), especially n-3 fatty acids such as eicosapentaenoic acid (EPA; 20:5 n-3) and docosahexaenoic acid (DHA; 22:6 n-3). Both EPA and DHA have been documented to have significant influence on biochemical and physiological changes in the body. Although these long chain PUFA exert positive influences on human nutrition and health, there are also some controversies pertaining to the functioning of these n-3 PUFAs including the extent of their requirement by the body. As marine lipids have been thoroughly reviewed often, the present review mainly focuses on works related to physiological effects of EPA and DHA.     

精炼对牛油主要理化指标及挥发性成分的影响

为研究精炼对牛油过程中理化指标及挥发性成分的影响,对熔油、脱酸、脱色后牛油酸价、过氧化值、碘值、脂肪酸和挥发性成分变化进行测定。结果表明,在整个精炼过程中,酸价呈先降后升的趋势,过氧化值呈递增趋势,碘值呈递减趋势。精炼后牛油的酸价为0.37mg/g,过氧化值为0.057 5g/100g,碘值为12.47g/100g。精炼各阶段的牛油中含有16种脂肪酸,最主要的是油酸、棕榈酸、硬脂酸。应用气相—离子迁移谱研究发现醇类挥发性物质在精炼过程中逐渐减少;脱酸后牛油中醛类挥发性物质达到了最高值。脱色后的牛油成品中醛类挥发性物质有所降低;酯类挥发性物质则在精炼过程中逐渐增多。     

河南烤烟主产区烟叶化学成分的比较分析

对河南4个烟区(豫中、豫西、豫南、豫东)、3个等级(B2F,C3F,X2F)共计120个烤烟样本的主要化学成分进行了分析和评价,并与巴西、津巴布韦烤烟品质相比较.结果表明:1)河南烤烟普遍存在烟叶钾含量较低,淀粉含量较高等问题,提高烟叶含钾量,降低淀粉含量,已成为河南烟叶生产中亟待解决的突出问题.2)不同产区相比较,豫南烤烟总植物碱含量较高;豫西烤烟钾含量偏低,还原糖含量略高,钾氯比偏低;豫中烤烟淀粉含量偏高;豫东烤烟钾氯比偏低,可用性较差.     

A comparative study of the physico‐chemical properties affecting the organoleptic quality of fresh and thermally treated yellow tomato ecotype fruit

In recent years, yellow commercial tomatoes have attracted great interest from consumers. The goal of this work was to characterise the parameters of three yellow genotypes that affect the fruit quality, in comparison with those of a red fruit genotype. Compared to the other genotypes, the GiaGiù ecotype was characterised as having the highest titratable acidity, organic acids content and pectin content before and after a thermal treatment simulating industrial pasteurisation. Most of the analysed parameters influence the taste and aroma of fresh fruit and processed products, particularly the high glutamic acid content measured in the GiaGiù ecotype. This genotype was also distinctive for its higher pectin content, which influences the texture. These features might allow the development of new food products that require a specific viscosity, such as sauces and ketchup. Interestingly, the beneficial properties of GiaGiù were preserved after thermal processing.     

The effects of soil management systems on the chemical composition and quality of golden delicious and cox's orange pippin apples—a follow-up study

Tests on Golden Delicious and Cox's Orange Pippin apples, evaluated in five and three seasons, respectively, between 1972 and 1980, indicated that method of soil management was still influencing fruit quality 15 years after commencement of the experiment, although to a lesser extent than in the earlier years. In 1973, the soluble solids content, skin colour and yield values of Golden Delicious differed between treatments but no differences were observed for fruit firmness in any of the five seasons when fruit were tested. Acidity values differed in 1972, 1973 and 1980. Overall herbicides gave the highest yields in 1973 and 1975 and the lowest levels of soluble solids. The yield of Cox's Orange Pippin fruit varied considerably between seasons; yields between treatments within seasons were only different in 1975. Correlation coefficients between yield and soluble solids were negative and ranged from -0.51 to -0.68.     

Edible coating materials—their properties and use in the fortification of rice with folic acid

This study investigated the technical feasibility of adding folic acid on to rice and coating with edible polymers. The coating solutions were cast into film and their properties were investigated. A concentrated premix of rice was prepared in a rotating coating pan by spraying first with folic acid solution, and then with polymer solutions and drying. The fortified rice premixes were evaluated for washing and cooking losses. The loss of folic acid in washing was lowest in rice premixes coated with ethyl cellulose followed by pectin, composite mixtures of locust bean and other coating materials with highest loss in gum arabic coated rice. No edible polymer could satisfactorily retain folic acid during boiling in excess water. Edible polymers failed to mask the yellow color of folic acid and additional masking agent was needed. The premixes had a higher water uptake ratio than raw milled rice had. Triangle tests did not show any significant difference (=0.05) between the sensory qualities of cooked fortified rice and raw milled rice.     

白酒微量成分与酒体风格特征关系的探讨

列举了部分名优白酒的微量成分含量，并探讨了由这些微量成分构成的风味特征。指出主体香味成分的含量比例构成了各种香型白酒的不同风格。     

Monomeric and dimeric phenolic constituents of plant cell walls—possible factors influencing wall biodegradability

A range of plant cell walls fiom graminaceous and leguminous plants were examined qualitatively and quantitatively for monomeric and dimeric phenolic constituents that were released by treatment with sodium hydroxide. The total amounts of phenolics released fiom the walls of the graminaceous plants varied fiom 8 to 28 mg g^?1 walls compared with less than 3 mg g^?1 walls jiom the legumes. p-Coumaric and ferulic acids were the major components of the monomeric fraction. The cell walls also contained substituted cyclobutanes having molecular weights equal to two p-coumaric acid molecules, two ferulic acid molecules or one p-coumaric plus one ferulic acid molecule, All the walls contained dehydrodiferulic acid. If it is assumed that the substituted cyclobutanes and dehydrodiferulic acid arise from dimerisation of feruloyl and p-coumaroyl groups linked to cell wall polysaccharides, then, for the graminaceous walls, it is calculated that between 5 and 14% of these groups had converted to dimers. This dimerisation process may limit the biodegradability of the wall polysaccharides.     

Terminalia chebula seed oil—a minor source of 12-hydroxyoctadec-cis-9-enoic acid: Natural products as a source for the food and agricultural industries

Terminalia chebula, Retz seed oil belonging to the Combretaceae plant family, was found to contain 12-hydroxyoctadec-cis-9-enoic acid (20.5% of the total silylated methyl esters) previously hitherto unknown in the Terminalia genera. The identification and characterisation was based on thin-layer chromatography, ga:-liquid chromatography, and ultraviolet, infrared, nuclear magnetic resonance and mass spectral analysis, and chemical degradations.     

Extraction and Isolation of β‐Glucan from Grain Sources—A Review

A collective report on the extraction and isolation of β‐glucan from grain sources, namely, oat, barley, and wheat is presented. An analysis on the effect of medium, pH, and temperature on the purity and yield of the β‐glucan derived under acidic/alkaline/aqueous/enzymatic conditions is also made. Water extraction and alkali extraction processes are preferred as the yield and recovery of extracted β‐glucan were good. Cost‐effective development of the process for deriving high molecular weight β‐glucan is the current requirement for its wide applications in food and pharmaceutical industries.     

Oxidation process of oils with high content of linoleic acyl groups and formation of toxic hydroperoxy‐ and hydroxyalkenals. A study by 1H nuclear magnetic resonance

The oxidation process of sunflower and corn oils at 70 °C with circulating air has been studied by means of ¹H nuclear magnetic resonance (NMR). The changes produced in the two oils are compared not only in relation to the rate of degradation of acyl groups but also with reference to both the rate of formation and degradation of primary oxidation products as well as the rate of formation of secondary oxidation products such as aldehydes. Special attention is paid to the evolution of the different kinds of aldehydes formed throughout the process. The great ability of these oils to produce geno‐ and cytotoxic aldehydes under the above conditions is proved. Moreover, peroxide and anisidine values of corn oil throughout its oxidation process have also been determined and the results obtained have been compared with those provided by the ¹H NMR spectra, showing good agreement. Copyright © 2005 Society of Chemical Industry     

A comparative study of chemical attributes and levels of amines in defective green and roasted coffee beans

Differences in chemical attributes (proximate composition, water activity, sucrose, acidity and pH levels) and amine levels between defective and healthy coffee beans were studied. Before roasting, significant differences (p < 0.05) were observed for the ash contents of the coffee samples, with the highest values found for black beans. Moisture content was higher for non-defective beans in comparison to defective beans. Non-defective coffee beans had higher lipids contents than both sour and black beans. There were no significant differences (p > 0.05) for protein levels between defective and non-defective beans. After roasting, protein levels remained constant, there was a small decrease in ash contents and a slight increase in oil contents of black and sour beans. Both black and sour beans had higher acidity levels than immature and non-defective beans. Acidity levels decreased after roasting. Water activity levels also decreased with roasting, with slightly higher levels for defective beans in comparison to non-defective ones. Sucrose levels were much higher in non-defective beans, and the lowest values were in black beans, prior to roasting. After roasting, only traces of sucrose were found. Total amine levels were much lower for black beans, in comparison to the other coffee samples. Putrescine was the prevailing amine in all samples. Histamine was only detected in the defective coffee samples. Small amounts of serotonin, cadaverine and tryptamine were found in some of the samples. After roasting to a light degree, only traces of serotonin were detected and no amines were detected after roasting to medium and dark degrees.