Starch Content and Granule Size Distribution in Grains of Wheat in Relation to Post-Anthesis Water Deficits

Post-anthesis soil moisture condition is closely associated with grain yield and quality in wheat ( Triticum aestivum L.). To investigate the effect of post-anthesis water deficit (WD) on starch content and granule size distribution, pot-experiments were conducted in 2006–2007 and 2007–2008 growing seasons, using five wheat cultivars with different amylose content. The result showed that the grain starch granules had a bimodal curve in the volume and surface area distribution, and a unimodal curve was found in number distribution. Post-anthesis WD reduced the B-granules (<10 μm in diameter) volume % and surface area % in Nuomai50206 and Gaocheng8901, increased the proportion in Weimai10, whereas the effect on those in Jinan17 and Shannong15 was not significant. Post-anthesis WD decreased the number % of <2 μm starch granules, significantly in all cultivars. The amylose content was negatively correlated with the volume of <10 μm and positively correlated to >15 μm starch granules, respectively, suggesting that small starch granules (<10 μm) are low in amylose content, whereas, big starch granules (>15 μm) are high. The results indicate that the grain starch granule size distributions of Jinan17 and Shannong15 with high amylose content were less affected by WD, than those of Nuomai50206 and Gaocheng8901 with low amylose content.     

Combined mutations in five wheat STARCH BRANCHING ENZYME II genes improve resistant starch but affect grain yield and bread-making quality

Increases in the proportion of amylose in the starch of wheat grains result in higher levels of resistant starch, a fermentable dietary fiber associated with human health benefits. The objective of this study was to assess the effect of combined mutations in five STARCH BRANCHING ENZYME II (SBEII) genes on starch composition, grain yield and bread-making quality in two hexaploid wheat varieties. Significantly higher amylose (∼60%) and resistant starch content (10-fold) was detected in the SBEII mutants than in the wild-type controls. Mutant lines showed a significant decrease in total starch (6%), kernel weight (3%) and total grain yield (6%). Effects of the mutations in bread-making quality included increases in grain hardness, starch damage, water absorption and flour protein content; and reductions in flour extraction, farinograph development and stability times, starch viscosity, and loaf volume. Several traits showed significant interactions between genotypes, varieties, and environments, suggesting that some of the negative impacts of the combined SBEII mutations can be ameliorated by adequate selection of genetic background and growing location. The deployment of wheat varieties with increased resistant starch will likely require economic incentives to compensate growers and millers for the significant reductions detected in grain and flour yields.     

可食性液态膜复合保鲜剂对番茄保鲜效果的研究

以番茄为试材,通过壳聚糖、可溶性淀粉、羧甲基纤维素钠配制成不同浓度的复合保鲜液浸泡涂膜处理,研究其对番茄保鲜效果的影响。结果表明,复合保鲜液涂膜可有效地降低番茄果实的失重率、腐烂率、可溶性固形物含量,抑制多酚氧化酶活性,维持番茄VC含量,保持番茄果实较好的感官品质,且以0.5%壳聚糖+0.8%可溶性淀粉+0.3%羧甲基纤维素钠复配的复合保鲜液涂膜对番茄有较好的保鲜效果,15℃环境下其货架期延长到15 d以上。     

紫花地丁开放花与闭锁花的发育及可溶性糖与淀粉含量的研究

紫花地丁(Viola philippica)为典型的两型花自花受精植物,具有开放花和闭锁花混合繁育系统。通过对开放花和闭锁花花芽形态发育的比较发现:开放花与闭锁花在花芽发育早期形态相似,4轮花器官原基均正常发生。出现明显差异的时期为4轮花器官原基形成以后,小孢子发育时期为产孢细胞阶段,开放花的5个花瓣与5枚雄蕊继续发育,每个雄蕊有4个花药室;而闭锁花只有2枚雄蕊继续发育,每个雄蕊有2个花药室,其余雄蕊与所有的花瓣依然为器官原基状态,不再发育。通过对花芽与叶片可溶性糖与淀粉含量的检测发现,花器官原基形成之后,开放花与闭锁花形态出现明显差异阶段开始,随着花芽的发育,可溶性糖与淀粉含量均呈上升趋势,且开放花花芽中的含量均明显高于对应发育阶段闭锁花花芽;而开放花植株的叶片可溶性糖与淀粉含量均低于闭锁花植株叶片,说明开放花所需要的能量高于闭锁花,推测可溶性糖与淀粉含量的差异与两型花发育有一定的关系。     

Low soil temperature reducing the yield of drip irrigated rice in arid area by influencing anther development and pollination

Drip irrigation can produce high rice yields with significant water savings; therefore, it is widely used in arid area water-scarce northern China. However, high-frequency irrigation of drip irrigation with low temperature well water leads to low root zone temperature and significantly reduce the rice yield compared to normal temperature water irrigated rice, for example, reservoir water. The main purpose of this paper is to investigate the effects of low soil temperature on the yield reduction of drip irrigated rice in the spike differentiation stage. The experiment set the soil temperatures at 18°C, 24°C and 30°C under two irrigation methods(flood and drip irrigation), respectively. The results showed that, at the 30°C soil temperature, drip irrigation increased total root length by 53% but reduced root water conductivity by 9% compared with flood irrigation. Drip irrigation also increased leaf abscisic acid and proline concentrations by 13% and 5%, respectively. These results indicated that drip irrigated rice was under mild water stress. In the 18°C soil temperature, drip irrigation reduced hydraulic conductivity by 58%, leaf water potential by 40% and leaf net photosynthesis by 25% compared with flood irrigation. The starch concentration in male gametes was also 30% less in the drip irrigation treatment than in the flood irrigation treatment at soil temperature 18°C. Therefore, the main reason for the yield reduction of drip irrigated rice was that the low temperature aggravates the physiological drought of rice and leads to the decrease of starch content in male gametes and low pollination fertilization rate. Low temperature aggravates physiological water deficit in drip irrigated rice and leads to lower starch content in male gametes and low pollination fertilization rate, which is the main reason for the reduced yield of drip irrigated rice. Overall, the results indicated that the low soil temperatures aggravated the water stress that rice was under in the drip irrigated environment, causing declines both in the starch content of male gametes and in pollination rate. Low temperature will ultimately affect the rice yield under drip irrigation.     

用绵羊小肠液冻干粉测定饲料过瘤胃淀粉小肠消化率方法的研究

本试验旨在以玉米为样本筛选用绵羊小肠液冻干粉测定精饲料瘤胃非降解残渣淀粉小肠消化率的最佳培养条件。分别研究了小肠液冻干粉用量(0.2、0.3、0.4、0.5和0.6g)对16h玉米瘤胃非降解残渣干物质和淀粉小肠消化率的影响;离体培养时间(4、8、12、16、20和24h)对16h玉米瘤胃非降解残渣干物质和淀粉小肠消化率的影响。结果表明,在本试验条件下,绵羊小肠液冻干粉测定玉米瘤胃非降解残渣淀粉小肠消化率的最佳用量为0.45g小肠液冻干粉/0.56g玉米瘤胃非降解残渣,最佳培养时间为12h。利用绵羊小肠液冻干粉测定常用饲料过瘤胃残渣淀粉小肠消化率的方法是可行的。     

酶—湿热处理对锥栗淀粉理化特性的影响

采用酶-湿热处理锥栗淀粉,研究酶用量与脱支时间对复合变性锥栗淀粉理化特性的影响。结果表明:酶-湿热处理锥栗淀粉的晶型均为A型,且预期血糖指数(p GI值)大多低于55%,属于低p GI值食品。由体外消化动力学分析、扫描电子显微镜、X-射线衍射、差示扫描量热、高效阴离子色谱-脉冲安培检测等实验分析得出,酶-湿热处理锥栗淀粉的抗性淀粉含量、分子链平均聚合度(DP值)、相对结晶度和熔融焓等随酶用量和脱支时间的变化表现为3个阶段,尤其在第2阶段,即当酶用量在50~60 U/g且反应时间在12~16 h范围内时,因分子链DP值适合重新聚合形成稳定的结晶结构,抗性淀粉含量、相对结晶度和熔融焓均达到最大。     

基于近红外与中红外光谱技术的淀粉回生度检测

淀粉食品在加工、运输及储藏过程中会逐渐出现回生,其回生程度是影响淀粉食品品质的重要因素。利用近红外和中红外光谱技术快速、无损检测淀粉回生度。首先采集了储存不同时间淀粉的近红外和中红外光谱,分别利用近红外、中红外以及两者融合的光谱数据结合化学计量学方法(偏最小二乘法(PLS、iPLS、biPLS、siPLS))建立淀粉回生度检测模型。结果显示,近红外和中红外融合光谱技术的biPLS检测模型最佳,校正集和预测集相关系数分别为0.965 5和0.931 3。研究结果表明,红外光谱技术可以快速、无损检测玉米淀粉回生度,保障了富含淀粉食品的质量与安全。     

甘薯淀粉接枝共聚高吸水树脂的合成及在种子包衣上的应用研究

以甘薯淀粉为原料,高锰酸钾为引发剂合成高吸水树脂,并研究高吸水树脂作为种子包衣剂对种子发芽率的影响.通过正交试验,探讨了引发剂浓度、催化剂浓度等因素及皂化条件对高吸水树脂吸水率的影响.研究结果表明,接枝共聚的最佳条件是:淀粉1 g,丙烯酰胺7.5 g,糊化水100 mL,催化剂1.54×10-2 mol/L,引发剂1.5×10-3 mol/L.最佳皂化条件为:氢氧化钠用量26 mL/(g单体),100℃水浴,皂化3 h.用制备的高吸水树脂做玉米种子包衣剂,初步试验结果表明可有效提高种子发芽率.     

锥栗贮藏温度对淀粉降解速率的影响

研究了3个不同锥栗品种在1，5，10℃等不同温度下贮藏120 d，并研究了贮藏过程淀粉含量的变化和淀粉降解速率，将降解速率与贮藏温度、品质变化和贮藏时间相关联，建立了锥栗贮藏方程。根据该方程，淀粉的含量随贮藏时间和贮藏温度的提高而降低，在试验范围内，低温度效果比高温度效果好。锥栗的品质与贮藏时间、贮藏温度和品种有关。