凯氏定氮法与杜马斯燃烧法检测三氯乙酸沉淀大豆和小麦蛋白中蛋白氮含量研究

目的检验尿素干扰下三氯乙酸沉淀分离大豆和小麦蛋白质的效果。方法本研究以牛奶、大豆蛋白、小麦水溶性组分为参试样品,分别在去离子水、尿素溶液2种溶液体系下分散样品,参考国家标准采用三氯乙酸沉淀蛋白氮,2种蛋白检测方法(凯氏定氮法、杜马斯燃烧法)检测氮含量,并计算氮检测回收率评估三氯乙酸对大豆蛋白、小麦水溶性组分等植物性蛋白的适用性。结果去离子水(无外源氮)分散的上清液经三氯乙酸沉淀,凯氏定氮法和杜马斯燃烧法检测牛奶的回收率分别为114%、101%,大豆的回收率分别为96%、98%,小麦的回收率分别为104%、105%。尿素溶液(有外源氮)分散的上清液经三氯乙酸沉淀,牛奶的回收率分别为99%、94%,大豆的回收率分别为95%、92%,小麦的回收率分别为101%、92%。结论有无尿素干扰时,三氯乙酸均可以沉淀大豆蛋白、小麦水溶性组分中蛋白氮,并可以采用凯氏定氮法、杜马斯燃烧法检测,回收率较好。

施锌方法对小麦籽粒不同脱皮组分中锌与植酸及蛋白质分布的影响

【目的】探讨施Zn方式对小麦籽粒不同脱皮层次中Zn、植酸及蛋白质含量的影响,为通过农艺措施提高小麦全粒尤其是可食部分（胚乳）Zn含量及其生物有效性提供理论依据。【方法】以陕715（Zn高效基因型）和西农889（Zn低效基因型）为供试材料,设置不施锌肥（对照）、土施锌肥（15 kg/hm2）、喷施锌肥（质量浓度为3 g/L,总量为1.5 kg/hm2）、土施＋喷施锌肥4个处理,采用裂区设计进行田间试验,并利用JNMJ3型碾米机对小麦籽粒进行脱皮分层（从外向内依次为P1、P2、P3、P4、P5、P6,其中P1~P5主要为麸皮部分,P6主要为胚乳部分）,分析了小麦籽粒各层中Zn、植酸和蛋白质含量。【结果】在2个喷施Zn肥（土施＋喷施、喷施）处理下,P1-P5和P6层的Zn含量均显著增加,P1-P5中Zn平均分别增加53.4%,43.2%,P6层中分别增加61.1%,52.7%,而单纯土施Zn肥效果不明显。Zn、植酸在小麦籽粒P2层含量最高,蛋白质则在P3层含量最高,3种组分含量随着脱皮进程的增加从外层到内层呈现递减趋势;3种施Zn方式对P1-P5植酸含量影响不显著,但增加了P6层植酸含量;同时降低了籽粒各层蛋白质含量。土施＋喷施和喷施Zn肥处理均能显著降低P1~P5和P6层中植酸与Zn的物质的量（[植酸]/[Zn2＋]）,土施Zn肥处理则不能。【结论】Zn、植酸和蛋白质在小麦籽粒中分布不均匀,在籽粒外层含量均很高,尤其是糊粉层,胚乳中最少,且这种分布规律基本不受施Zn方式和小麦品种的影响。喷施Zn肥是提高潜在性缺Zn土壤上小麦全粒Zn尤其是胚乳部分Zn含量和生物有效性较为经济的方式,对缓减人体Zn缺乏有重要意义。

功率超声对小麦面粉可溶性组分形成溶液过冷度的影响

应用自行设计的超声辅助冷冻循环系统,研究了频率为25kHz、不同电功率的超声对小麦面粉可溶性组分形成溶液过冷度的影响。研究结果表明,功率超声能显著地降低小麦面粉可溶性组分形成溶液中冰结晶的过冷度,促进冰晶晶核的形成。随着超声电功率逐渐增加,小麦面粉可溶性组分形成溶液过冷度逐渐减小,即成核温度随着超声电功率的增加而增加。研究结果有助于揭示超声强化食品冷冻过程中,溶解有多种无机与有机化合物的食品复杂溶液的冰结晶机理。

索氏提取分级分离的小麦组分对菲的吸附

在污染土壤中,多环芳烃(PAHs)是普遍存在的一类疏水性有机污染物(HOCs)[1],可通过植物吸收进入食物链,威胁农产品安全与人类健康[2]。因此,基于植物吸收有机污染物的机理建立植物吸收的预测模型,对于评估有机污染土壤的农作物食品安全及潜在的人类健康风险具有重要作用[3,4]。

发酵面团持气性及品质改良研究进展

面团持气性是面团流变学特性之一,反映了面团在发酵过程中保持酵母产生气体的能力,是影响发酵面制品品质的一项重要指标。影响面团持气性的因素主要有蛋白质含量与组成、破损淀粉含量、麸皮的含量,以及加工工艺中加水量、水温、酵母含量、搅拌时间和醒发时间等。在发酵面制品生产中,面团持气性不足会导致面制品的塌陷和萎缩。为了减少面团持气性不足对发酵面制品品质的影响,常采用添加面团改良剂的方法改善面团品质。该文首先简单介绍了面团持气性的定义、测量方法以及对发酵面制品品质的影响,重点论述了小麦组分和加工工艺条件对面团持气性的影响,并通过比较酶制剂与其他改良剂对发酵面团的影响,总结出酶制剂对面团持气性的改良效果,以期为生产高质量的发酵面制品提供参考。

Genome Analysis in Wheat Breeding for Disease Resistance

A brief review on the development of wheat germplasm with introduced powdery mildew and scab resistance from Haynaldia villosa Sch. and Leymus racemosus Lam., Roegneria ciliaris (Trin.) Nevski as well as R. kamoji C. Koch respectively was made. In the course of germplasm development, genome analysis by means of chromosome banding, genomic in situ hybridization (GISH) or fluorescence in situ hybridization (FISH), molecular markers, particularly restriction fragment length polymorphism (RFLP) coupled with aneuploid analysis was employed for the purpose of improving breeding efficiency. Potential use of such germplasm in wheat breeding practice, basic studies and some related problems were also discussed.

Primary Identification of Alien Chromatin in T911289,a Maintainer of Wheat Male Sterile Line with Cytoplasm of Aegilops kotschyi

The genomic composition of 1911289, a wheat ( Tritium aestivum L.) maintainer of K-CMS, was examined by several methods, such as genomic in situ hybridization (GISH), biochemical marking, and DNA molecular marking. The results got by GISH and PCR amplification of dispersed rye-specific repetitive DNA sequence suggested that the alien chromatin in T911289 derived from rye. Specifically PCR amplification of the rye-specific microsatellite primers (SCM9) and seed storage protein analysis indicated that the alien chromatin in T911289 had developed from the short arm of 1R chromosome of rye (1RS). PCR amplification by using microsatellite primers locating on 1BS and seed storage protein analysis also revealed that 1911289 had lost the arm of 1BS or a small distal segment of it. We conclude that T911289 is a heterogeneous population which displays two distinct different types of translocation, i.e. the Robertsonian translocation and small segment translocation. The Robertsonian translocation type observed in our study is different from the 1BL/1RS translocation which is widely used in wheat production; it may be a novel and complex translocation form. Though the linkage between the desirable agronomic traits and the deleterious genes expressed as sticky dough has not got broken in T911289, the recovery of small segment translocation will still benefit the genetic study of wheat and rye.

Localization of Phosphorylated Histone H3 at Mitosis and Meiosis in Wheat

One of the prominent cell cycle related modifications of histone proteins, whose function is correlated with chromosome condensation, is the phosphorylation of histone H3. Wheat (Triticum aestivum L.) mitotic and meiotic cells were analyzed with indirect immunoflurorescence labeling with an antibody recognizing histone H3 phosphorylated at Serine 10 to study the localization of phosphorylated histone H3 at mitosis and meiosis. Our results showed that, during mitotic division, the phosphoryiation of H3 started from early prophase and vanished at telophase, remaining mainly in the pericentromeric regions at metaphase and anaphase. During meiotic division, phosphorylation of H3 initiated at the transition from leptotene to zygotene and remained uniform, along the chromosomes from prophase I until telophase whereas it showed slightly stronger in the pericentromeric regions than along the chromosome arms from metaphase II until Lelophase II The different patterns of H3 phophorylation at mitosis and meiosis in wheat suggested that this evolutionarily conserved post-translational chromatin modification might be involved in more roles besides chromosome condensation.

Research Progress of Special Wheat Nutrition Components and Application

With the increased pace of life and improved consumption level of people, the demand for food developed from natural resources is increasing day by day. Related researches have shown that the nutrition level of special wheat is higher than that of common wheat. Special wheat can improve the nutritional structure and diet quality of people. However, the researches on special wheat are rare at home and abroad. Compared with the common wheat, special wheat still faces many challenges in taste quality, storage stability, processing suitability as main food, etc. This paper summarized the researches on analysis and application of special wheat nutrition components at home and abroad so as to evaluate comprehensively the development prospect of special wheat.

Relationships between high-molecular-weight glutenin subunit （HMW-GS）, pentosan and various component contents in different wheat varieties

The composition of HMW-GS and pentosan and its various component contents in different wheat varieties were analyzed. According to scores of these subunits in several wheat varieties, the correlation relationship between the composition of HMW-GS, subunit combination types and pentosan, various components and component ratio were ascertained. The results showed that HMW-GSs were very diverse which had 11 types. In different varieties, the variation of Ara was obvious while Xyl was not; pentosan and its various component contents were very different, and their coefficient of variability was quite high. The majority of parameters had a significant negative correlation with Glu-1 where Glu-D1 was stronger than other two loci. N, 7, 17＋18 and 2＋12 subunits had influence on pentosan and its various component contents. But some subunits such as 1 and 5＋ 10 which are good for baking quality had little contribution to pentosan and various component contents. The pentosan and various component contents were higher in the varieties which had （N, 7, 2＋12） subunit combinations. Additionally, the 21 varieties were classified into 4 categories according to HMW-GS scores and pentosan content.