小麦纤维对绿豆淀粉理化特性影响

以绿豆淀粉为原料,研究添加不同量小麦纤维对绿豆淀粉溶胀度、可溶指数、糊化特性、凝胶质构、消化性等理化指标影响。结果表明,添加小麦纤维后,绿豆淀粉溶胀度和可溶指数增加;其峰值粘度、谷值粘度、末值粘度、衰减值也增加;绿豆淀粉凝胶硬度随小麦纤维添加量增加而增大;且添加小麦纤维绿豆淀粉,其快速消化淀粉含量和抗性淀粉含量明显低于对照组,但慢速消化淀粉含量高于对照组。     

Effects of germination on nutritional composition of waxy wheat

BACKGROUND: Germination is considered to improve the nutritive value, antioxidant capacity and functional properties of grains. In this study, changes in the chemical composition, nutritive value and antioxidant capacity of waxy wheat during germination were determined. RESULTS: Over a 48 h period of germination the protein and free lipid contents of germinated waxy wheat were not significantly different from those of the control, whereas the bound lipid content decreased significantly. An increase in levels of ash and dietary fibre was clearly observed for the 48 h‐germinated wheat. The total free amino acid content of the 48 h‐germinated wheat was 7881 mg kg^?1 flour (dry basis (d.b.)), significantly higher than that of the ungerminated wheat (2207 mg kg^?1 flour, d.b.). In particular, γ‐aminobutyric acid increased from 84 mg kg^?1 flour (d.b.) in the control to 155 mg kg^?1 flour (d.b.) in the 48 h‐germinated wheat. Germination did not significantly affect the fatty acid composition of both free and bound lipids of waxy wheat, whereas free phenolic compounds increased during germination, resulting in an increase in antioxidant capacity of germinated wheat. CONCLUSION: Germinated waxy wheat had a better nutritional composition, such as higher dietary fibre, free amino acid and total phenolic compound contents, than ungerminated waxy wheat. Therefore germinated waxy wheat should be used to improve the nutritional quality of cereal‐based products. Copyright © 2011 Society of Chemical Industry     

发芽过程对小麦营养成分及抗氧化活性的影响

研究了发芽对小麦化学组成、营养价值及抗氧化活性的影响。试验结果表明,叶酸、可溶性膳食纤维、总蛋白及游离脂质含量随着发芽时间的延长而显著增加(P0.05),而不可溶性膳食纤维及结合脂质的含量并未发生显著变化(P0.05)。小麦发芽36 h后,其叶酸含量与未发芽小麦相比提高了3.3倍,其中5-甲基四氢叶酸为主要的叶酸成分。与未发芽小麦相比,发芽小麦的功能性必需氨基酸包括苯丙氨酸、缬氨酸、亮氨酸、异亮氨酸及γ-氨基丁酸含量增加了2.8~10倍。小麦发芽48 h后,其游离氨基酸总量从1 800 mg/kg上升至7 194 mg/kg;小麦发芽24 h后,其总酚含量及抗氧化活性显著上升(P0.05)。发芽显著改善了小麦营养价值,可用于具有营养强化功能的全谷物食品的生产。     

The nutrition evaluation of kidney beans (Phaseolus vulgaris). The effect of nutritional value of seed germination and changes in trypsin inhibitor content

The total N content of kidney beans (Phaseolus vulgaris) was found to increase on germination. The overall amino acid composition however changed very little. Rats fed on a diet containing raw beans lost more weight than the protein-free controls (negative n.p.u. value). Germination was found to bring about a gradual improvement in nutritive value probably through the elimination of some of the toxic constituents of the seed. The near doubling of the amount of trypsin inhibitors by the 8th day of germination taken together with the substantial improvement in the nutritive value of the bean appeared to rule out trypsin inhibitors as the main toxic components of raw beans.     

Effects of fungal deterioration on grain: nutritional value, toxicity, germination

Moulds or fungi that grow in grains and seeds during storage and transport cause germination decrease, visible mouldiness, discoloration, musty or sour odours, caking, chemical and nutritional changes, reduction in processing quality, and form of mycotoxins. These deteriorative changes affect the grade and price of grain and contribute to customer dissatisfaction when the grain is marketed. The respiration of grain and fungi results in a loss in dry matter as well as the production of heat and moisture which contribute to further spoilage. Net changes in nutritional value and the risk of mycotoxin contamination are difficult to predict because they depend on a complex interaction of factors such as temperature, moisture, storage time, fungal species composition, kind of grain, and previous storage history. Moisture is the most important variable determining the rate of deterioration caused by fungi, with temperature being the second major factor. Problems with deterioration of grain in export shipments are not a recent development. They are related primarily to grain moisture at loading, and also to the extent of previous mould invasion.     

The effect of popping,soaking, boiling and roasting processes on antinutritional factors in chickpeas and red kidney beans

This study was conducted to determine the effect that a popping head (like a rice cake machine), a low-shear and low-water processing technology, has on the concentration of antinutritional factors in chickpeas and red kidney beans. Seeds were popped under several parameters (popping time, sample format and equipment type) and analysed against soaking (1:5 w/v in reverse osmosis water for 24 h), roasting (100 g at 180 °C for 20 min) and boiling (1:5 w/v in reverse osmosis water at 100 ± 1 °C for 1 h) processes. Popping and roasting significantly reduced phytic acid content in chickpeas (6%–22%) and red kidney beans (16%–39%). In contrast, phytic acid content after soaking and boiling was not significantly different to raw seeds. Condensed tannins were significantly reduced in red kidney beans after soaking (74%), boiling (100%) and 4 s popping (28%–42%) treatments and increased in both pulses after roasting (137%) and 8 s popping (21%–47%). Further analysis showed that the soluble phenolic content increased with popping, but total and bound phenolic content was reduced. These results demonstrate that the high temperatures and pressures applied during the popping process effectively reduce antinutritional factors in pulses, compared to conventional processing methods.     

New functional legume foods by germination: effect on the nutritive value of beans, lentils and peas

The effect of different conditions of germination at a semi-pilot scale on the content of available soluble sugars, alpha-galactosides, vitamins B₁ and B₂, and inositol phosphates of beans, lentils and peas have been studied. Results obtained indicated that germination modified the nutritional composition of legumes depending on the type of legume and germination conditions. The storage compounds present in dry seeds (alpha-galactosides and higher forms of inositol phosphates) decreased because they were hydrolysed to glucose, fructose, IP₄ and IP₃, compounds that can serve as a source of energy for the new plant. Vitamin B₂ suffered an important increase after germination whereas vitamin B₁ did not change significantly. To achieve legume flours with enhanced nutritive value, 6 days of germination in the presence of light for beans and lentils, and in darkness for peas can be suggested.     

Structural and functional characteristics of dietary fibre in beans,lentils, peas and chickpeas

To better understand the role that dietary fibre plays in the health benefits of pulses, the cell wall polysaccharides of pulses were characterized. To allow comparison between this data and nutritional studies, cooked chickpeas, lentils, beans and peas were used rather than raw seeds. Insoluble fibre, soluble fibre, resistant starch and oligosaccharide fractions were isolated using digestive enzymes at 37 °C. Prebiotic galacto-oligosaccharides, including raffinose, stachyose and verbascose made up between 3.5 and 6.9% of the cooked pulses (dry weight basis). Pulse fibre is pectin rich, with most being found in the soluble fibre fraction. The soluble fibre fraction is a diverse mixture of polysaccharides of varying sizes and solutions of soluble fibre exhibit a range of viscosities depending on the pulse type. The sugars which make up the insoluble fibre fraction suggest a large cellulose component. Microscopic examination of cooked whole pulses showed that a large fraction of the starch was partially gelatinized and contained within intact cell walls whereas boiled flour pastes had few ungelatinized granules. After simulated upper-gut digestion, some starch remained inaccessible to digestive enzymes. Cell walls of pulses modulate starch gelatinization and reduce enzymatic hydrolysis, which may account for the low glycemic response attributed to pulses.     

Protein nutritional value of extrusion-cooked wheat flours

The effect of extrusion cooking on the protein nutritional value of wheat flour and whole-grain wheat flour was studied. Amino acid analysis showed lysine retention between 63 and 100%. The retention was positively affected by an increase in feed rate, and negatively by an increase in screw speed. The prominent lysine damage under severe conditions was probably due to formation of reducing carbohydrates through hydrolysis of starch. The loss of other amino acids was small. The BV of extruded wheat flours was significantly reduced in the products showing the most prominent lysine loss. However, no effect was seen in TD. In contrast, a decrease in BV of extruded whole-grain flour was accompanied by a significant reduction in TD. Extrusion cooking of wheat starch did not affect the nitrogen balance in rats given casein/starch diets containing raw or extruded starch.     

Optimization of iron speciation (soluble,ferrous and ferric) in beans,chickpeas and lentils

A spectrophotometric method with bathophenanthroline for iron determination that makes it possible to differentiate between iron (II) and iron (III) in total soluble iron in legumes (beans, chickpeas and lentils) was optimized. Sample size, volumes of reducing agent and bathophenanthroline were selected. Matrix interferences made it necessary to apply the addition’s method. To check the quality of the method, linearity and precision (RSD%) were determined. A linear response between 0.1 and 1.8 μg Fe/ml in the assay and precision values ranging from 2.1 to 6 for instrumental precision, and from 1.6 to 1.7 and 2.7 to 9.1, for intra- and inter-day assays, respectively were obtained. The application of the method to legumes indicated: total soluble iron ranging from 0.52 (microwave cooked legumes) to 5.01 mg/100 g dry matter in raw beans. The percentage of soluble iron (II) with respect to total and soluble iron ranged from non detectable to 14.8% and from non detectable to 50%, respectively.     

Comparative analyses of total phenols,flavonoids, saponins and antioxidant activity in yellow soy beans and mung beans

Total phenol, flavonoid and saponin content of soy bean and mung bean were systemically compared in order to evaluate their contribution to overall antioxidant activity. Mung bean extract possessed significantly higher total phenol (2.03 GAE g^?1 vs. 1.13 GAE g^?1) and flavonoid contents (1.49 GAE g^?1 vs. 0.41 CAE g^?1) than soy bean extract, while the saponin content of the soy beans was 4.5 times greater than that of the mung beans. In several antioxidant assays including DPPH and ABTS radical scavenging, FRAP, SOD‐like activity, and a β‐carotene bleaching assay, mung bean extract consistently showed significantly greater antioxidant activity than soy bean extract. The specific antioxidant activity, which was evaluated at the same phenolic content suggested that the phenolic compounds present in the mung bean extract were not only of greater quantity but also had better quality to eliminate radicals. The radical scavenging activities of saponins were only marginal.     

常压室温等离子体诱变对螺旋藻中氨基酸成分的影响

旨在了解常压室温等离子体诱变处理对螺旋藻氨基酸含量及营养价值的影响。以TJF1为出发藻株,多功能等离子体诱变仪对藻株进行诱变处理,日立L-8900氨基酸自动分析仪测定其氨基酸组成和含量,利用模糊识别法和氨基酸比值系数法对突变体与出发藻株的氨基酸营养价值进行评价。结果表明:与出发藻株相比,15个突变株中的17种氨基酸含量均高于出发藻株,总氨基酸含量差异显著;突变株的氨基酸含量分布与出发藻株保持一致;总必需氨基酸与总氨基酸含量比值(E/T)维持在0.43~0.45,没有明显变化;2种营养价值评价结果表明,等离子体诱变没有降低氨基酸营养价值;突变株10的总氨基酸含量最高,比出发藻株高出53.52%,可以作为高产蛋白优势藻株。     

发芽对小麦品质的影响

本试验以普通小麦为原料,研究了未发芽的小麦和发芽6、12、18、24、30、36、42、48 h不同时段小麦的品质(籽粒品质、营养品质、磨粉品质)的变化情况。结果表明,小麦发芽前后诸多成分都有明显变化:总淀粉、灰分及粗脂肪、千粒重、容重呈下降趋势,与未发芽小麦相比显著性下降;还原糖和部分矿物质、维生素类则有不同程度的升高,其中还原糖含量比未发芽小麦升高1.34%;粗蛋白的含量先增后减,到发芽24 h含量最高,发芽后总氨基酸明显上升。另外,抗营养因子植酸显著下降,功能因子γ-氨基酸含量显著升高。随着发芽时间的变化面团流变学特性发生明显变化:面团形成时间、稳定时间与粉质指数呈下降趋势,延伸度升高,拉伸阻力和拉伸比降低。发芽对小麦品质的影响明显。     

A preliminary study on the effect of germination on saponin content and composition of lentils and chickpeas

Two cultivars of chickpeas (Cicer arietinum) and one cultivar of lentils (Lens culinaris) were subjected to germination in the dark for 6 days at 20°C. Soyasaponin VI, also known as soyasaponinβg, a DDMP- (2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one-) conjugated form of soyasaponin I, was the only saponin detected in both the unprocessed and germinated seed. No significant changes in saponin content were observed for chickpeas or lentils after a 6-day germination.