A rapid,automated method for measuring α-amylase in pre-harvest sprouted (sprout damaged) wheat

The quality of wheat for baking is critically dependent on the level of α-amylase (1,4-α-D-glucan glucanohydrolase, EC 3.2.1.1), which can be present as “late maturity α-amylase” (LMA), or due to pre-harvest sprouting due to high rainfall and humidity at the time of harvesting. The most commonly used method to measure α-amylase in wheat grain is the Hagberg Falling Number method, but values are also influenced by rheological properties of starch in the grain. In this study we describe a simple, rapid, automated method (Amylase SD) for measurement of α-amylase in pre-harvest sprouted (sprout damaged) wheat grain. The method (Amylase SD) measures the release of p-nitrophenol from 4,6-O-ethylidene-α-4-nitrophenyl-maltoheptaoside by α-amylase in the presence of α-glucosidase. The absorbance of p-nitrophenolate measured at 405 nm in a ChemWell^®-T auto-analyser is directly related to the level of α-amylase activity present in the milled wheat grain extract. The Amylase SD method generated <6%CV and correlation to the Falling Number method was represented by an inflection point at ∼160 s. The precision, sensitivity and speed of this method provides an ideal alternative to the Falling Number method for measurement of α-amylase (sprout damage) in wheat grain in wheat breeding programmes or at grain receival points.     

三角帆蚌消化酶的分布特性和晶杆的形态结构

三角帆蚌(Hyriopsis cumineii)隶属瓣鳃纲、真瓣鳃目、蚌科,是我国的特有种[1],也是我国生产淡水珍珠的主要贝类[2],产出的珍珠以其品质高而享誉全球.     

贮藏温度对兰州百合生长及鳞茎碳水化合物代谢的影响

以兰州百合为材料,研究了百合种球经不同贮藏温度处理后,植株生长及鳞茎碳水化合物代谢的变化。结果表明:随着贮藏温度的降低,百合各个生育阶段均提前,总生育期缩短,同时百合株高和茎粗的生长加快,叶面积和鳞茎鲜重增加;母鳞茎和新鳞茎淀粉、总可溶性糖含量增加。蔗糖是百合鳞茎内糖分积累和转运的主要形态,其含量变化与总糖变化趋势基本一致。淀粉酶活性变化与淀粉含量变化趋势相反。结合鳞茎鲜重的变化可知,在本试验范围内,2℃贮藏百合种球101d有利于鳞茎发育。     

Studies on amylase inhibitors in some Egyptian legume seeds

Amylase inhibitor activity was determined in four legume seeds which are widely consumed in Egypt. The effect of dehulling, heat treatment, soaking and germination were also assessed. The results showed that faba bean contained the highest activity of amylase inhibitor followed by cowpea, lentils, then chickpea. Dehulling resulted in raising the amylase inhibitor activities in all samples investigated, while heat treatment and cooking lowered it. Soaking for 10 h and germination eliminated completely the inhibitor from all samples.     

植酸和氯离子对稻米品质的影响

 以原丰早为材料进行了在不同时期施用植酸与氯离子的试验。在水稻抽穗至成熟期间叶面喷施植酸，能抑制水解酶类的活性，减弱淀粉酶分解淀粉的反应，提高淀粉合成酶的活性，有利于淀粉合成，改善稻米品质。水稻齐穗期叶面喷施50、100 mg/kg 两种浓度的植酸，碎米率的平均值比对照低2. 8～23. 1个百分点，整精米率上升5～7个百分点；垩白等级、垩白率降低，乳白米粒减少，与对照相比差异显著；对碱消值、直链淀粉含量亦有影响。氯离子作为淀粉酶的激活剂，喷施后能抑制淀粉合成酶的活性，对稻米品质呈逆向效应。     

稻米品质与淀粉酶和蛋白组分的关系研究进展

水稻品质改良已成为当前育种工作的主要趋势,优质米品种选育和米质研究是当前及今后水稻育种的重点。综述了水稻种子α,β-淀粉酶活性的差异与稻米品质之间的关系,以及种子蛋白组分间的差异与稻米米质的相关性。探讨了水稻品种间品质差异与α,β-淀粉酶活性和蛋白组分的关系,并对其在育种中的意义及应用进行了展望。     

Effect of heat treatment and germination on alpha amylase inhibitor activity in chick peas (Cicer arietinum L.)

Chick pea seeds of twenty eight varieties were analysed for alpha amylase inhibitor activity (AIA) using salivary amylase. The effects of heat treatment and germination on the activity of the antinutritional factor was investigated. Heat treatment and germination decreased the activity of amylase inhibitor. Chick pea meal was also subjected to UV irradiation and pressure cooking. These treatments decreased alpha amylase inhibitor activity. The amylase inhibitor activity decreased as the days of germination increased and negligible inhibitor activity was observed on the 6th day of germination.     

Ontogenic development of digestive enzymes in bigfin reef squid (Sepioteuthis lessoniana)

Bigfin reef squid (Sepioteuthis lessoniana) is an economically important exported aquatic animal in Thailand, but little is known about its husbandry, which needs to be clarified. In this study, the ontogenic development of the main digestive enzymes (pepsin, trypsin, chymotrypsin, lipase and amylase) was investigated within 30 days after hatching (DAH). Fertilized eggs of the wild cuttlefish were hatched and then distributed into four replicate aquaria assigned to varying collection times (0, 5, 10, 15, 20, 25 and 30 DAH). The development of pepsin suggests acidic digestion functionality at 5 DAH, and its specific activity was maintained over the studied period. Specific activities of the serine proteases, trypsin and chymotrypsin, fluctuated significantly with similar pattern, and appear to be the key enzymes contributing ontogenic changes in protein catabolism. The specific activity of lipase was relatively high at 0 DAH, dramatically increased by 5 DAH, and then appeared constant until the end of observations, suggesting important role in utilizing the lipid from yolk at hatching, as well as probably in sparing protein utilization. Dramatic increase in amylase specific activity occurred by 10 DAH after which the activity was constant until 30 DAH, suggesting the utilization of carbohydrate as energy evolves comparatively late. Findings from the current study could be used to manage nutritional protocols according to the digestive enzyme patterns, as well as to develop artificial diets for rearing S. lessoniana.     

甘薯微孔淀粉的制备技术及吸附性能的研究

用淀粉糖化酶、α-淀粉酶、普鲁兰酶水解甘薯淀粉制备一种具有吸附功能的微孔淀粉载体。研究表明,淀粉糖化酶对生甘薯淀粉作用力最强;淀粉糖化酶水解制备甘薯微孔淀粉的最佳工艺条件是：温度45℃,pH值4,酶用量为1％,时间24h,水解率为51．52%。微孔淀粉对色素、水溶性维生素、油脂的吸附能力远远高于原淀粉。通过交联反应能明显提高微孔淀粉的结构性能和吸附性能。     

南昌白猪血清转铁蛋白血液结合素及淀粉酶的遗传多态性研究

应用改进的淀粉凝胶电泳法研究了培育品种南昌白猪进贤系、南昌系、安义系及其杂交亲本品种星子黑猪、大约克猪的转铁蛋白（Ｔｆ）、血液结合素（Ｈｐｘ）和淀粉酶（Ａｍ）３种血清蛋白的多态性,测定并分析了各自的基因型及基因频率的特点,结果表明：南昌白猪３个系的遗传结构与大约克猪甚为相似,而与星子黑猪的差异明显。