Exogenous application of allelopathic water extracts helps improving tolerance against terminal heat and drought stresses in bread wheat (Triticum aestivum L. Em. Thell.)

The allelopathic water extracts (AWEs) may help improve the tolerance of crop plants against abiotic stresses owing to the presence of the secondary metabolites (i.e., allelochemicals). We conducted four independent experiments to evaluate the influence of exogenous application of AWEs (applied through seed priming or foliage spray) in improving the terminal heat and drought tolerance in bread wheat. In all the experiments, two wheat cultivars, viz. Mairaj‐2008 (drought and heat tolerant) and Faisalabad‐2008 (drought and heat sensitive), were raised in pots. Both wheat cultivars were raised under ambient conditions in the wire house till leaf boot stage (booting) by maintaining the pots at 75% water‐holding capacity (WHC). Then, managed drought and heat stresses were imposed by maintaining the pots at 35% WHC, or shifting the pots inside the glass canopies (at 75% WHC), at booting, anthesis and the grain filling stages. Drought stress reduced the grain yield of wheat by 39%–49%. Foliar application of AWEs improved the grain yield of wheat by 26%–31%, while seed priming with AWEs improved the grain yield by 18%–26%, respectively, than drought stress. Terminal heat stress reduced the grain yield of wheat by 38%. Seed priming with AWEs improved the grain yield by 21%–27%; while foliar application of AWEs improved the grain yield by 25%–29% than the heat stress treatment. In conclusion, the exogenous application of AWEs improved the stay green, accumulation of proline, soluble phenolics and glycine betaine, which helped to stabilize the biological membranes and improved the tolerance against terminal drought and heat stresses.     

Extensional rheological properties in mixed and fermented/rested dough and relationships with steamed bread quality

In this study, sixteen wheat varieties for cultivation in China were examined for the flour characteristics using the farinograph, extensograph and rheofermentometer, uniaxial extensional rheology employing the extensograph and the Kieffer extensibility rig and biaxial extension by uniaxial compression of mixed dough with and without yeast, rested and fermented dough, and steamed bread quality including specific volume and texture properties. Three statistical analysis methods including Pearson correlation, principle component and stepwise multiple regression analysis were carried out to correlate dough properties with steamed bread quality. Biaxial extension viscosity was positively correlated with texture properties (hardness and chewiness) of steamed bread (r = 0.521–0.685, p < 0.05). Based on the correlation coefficients and the model (r² = 0.852, p = 0.003) obtained using stepwise multiple regression analysis, the best predictors for specific volume of steamed bread were the maximum resistance to extension of rested dough (r = 0.664, p < 0.01) and total work for breakage of fermented dough (r = 0.662, p < 0.01). Principal component analysis of rheological properties of fermented dough and flour characteristics provided more useful information for discriminating wheat flour quality and help breeders to select most convenient wheat flour for the steamed bread making.     

Optimization of Bread Preparation from Wheat Flour and Malted Rice Flour

The feasibility of partially replacing wheat flour with malted rice flour in bread making was evaluated in several formulations, aiming to find a formulation for the production of malted rice-wheat bread with better nutritional quality and consumer acceptance. The whole grains of a local rice variety (Oryza sativa L. subsp. indica var. Mottaikaruppan) were steeped in distilled water (12 h, 30°C) and germinated for 3 days to obtain high content of soluble materials and amylase activity in bread making. The quality of bread was evaluated by considering the physical and sensorial parameters. When the wheat flour was substituted with malted rice flour, 35% substitution level and the malted rice flour from 3 days of germination was the best according to the physical and sensory qualities of bread. The quality of bread was improved by the addition of 20 g of margarine, 20 g of baking powder and 20 g of yeast in 1 kg of flour. Among different ratios of yeast and baking powder, 2:1 was the best. Bread improver containing amylases and oxidizing agents at the concentration of 40 g/kg was selected as the best concentration. When comparing the final formulation made in the bakery with wheat bread, malted rice-wheat bread contains more soluble dietary fiber (0.62%), insoluble dietary fiber (3.95%), total dietary fiber (4.57%) and free amino acid content (0.64 g/kg) than those in wheat bread (0.5%, 2.73%, 3.23% and 0.36 g/kg, respectively).     

南方馒头加工中的辅料配比优化研究

为给改进实验室馒头制作和评价方法提供参考依据,以3种弱筋面粉(市售美玫牌面粉;磨自弱筋小麦品种宁麦9号和生选6号的面粉)为基础粉,采用响应面法中心组合试验设计,研究了酵母、糖、起酥油和泡打粉含量对南方馒头加工品质的影响,并建立了南方馒头感官得分与因素变量的二次回归模型方程,该模型回归显著。响应面分析结果表明,南方馒头加工中的最佳辅料配比条件为:酵母含量1.0%、糖含量15.0%、起酥油含量1.8%、泡打粉含量1.0%。在此配比条件下,3种弱筋粉制作南方馒头的感官得分预测值分别为86.5、88.3和84.5分,验证值分别为86.1、87.8和83.7分,与预测值的相对误差分别只有0.46%、0.57%和0.95%。     

燕麦混粉馒头加工品质特性评价

在传统的馒头加工过程中,添加一定比例的燕麦粉,研究其对馒头感官品质和质构的影响。结果表明,在小麦粉中添加适量的燕麦粉,加工出的馒头在结构、色泽、韧性等感官特性方面都有改善,馒头的硬度、咀嚼性、黏聚性等物性参数得到改变。当燕麦粉添加量为25%时,不仅馒头感官评价得分最高,而且营养价值也得到极大提高。因此,建议在馒头加工中添加25%的燕麦粉为宜。     

面包及蛋糕的质构与感官评价的相关性研究

为了系统的量化不同厂家生产的、不同添加物、不同产品类型的面包和蛋糕的感官品质,采用物性测试仪和感官评价法,研究面包和蛋糕的质构与感官品质的相关性。结果表明：硬度和弹性指标可系统的量化同一厂家生产的不同添加物的面包和不同厂家生产的全麦面包的感官品质;弹性可系统的量化不同厂家生产的白面包的感官品质;回复性可系统的量化不同产品类型的海绵蛋糕的感官品质;硬度、黏聚性、咀嚼性、回复性可系统的量化不同添加物的戚风蛋糕的感官品质;硬度、弹性、黏聚性可系统的量化不同种类的蛋糕的感官品质。     

微晶化豆渣膳食纤维在面包中的应用研究

试验选择微晶化的豆渣膳食纤维为原料,通过焙烤试验,对添加豆渣膳食纤维的面包品质进行比较分析,并通过添加适量的面筋粉改善豆渣膳食纤维面包品质。以感官评价为指标,通过正交试验,得出最佳的工艺条件和参数为:豆渣膳食纤维的添加比例6%,面筋粉比例5%,发酵时间45min,可以得到品质较好的高纤维面包。     

小麦主要品质性状影响面包烘烤的回归分析

以47个小麦品种为材料,测定其主要面粉理化指标、面团流变学指标和面包烘烤指标,通过相关性分析确定各品质指标间的相互关系,并进一步进行逐步回归分析确定对面包烘烤起主要作用的品质性状,以期为小麦品质育种、面包小麦品种品质指标的制定及加工原料的筛选提供参考依据。     

节水处理对新春9号面包小麦产量和品质的影响

研究了省去最后一水对新春9号产量和面包烘焙品质的影响,结果表明,省去最后一水使新春9号的产量和容重有所下降,但有利于抗倒伏、节水和基肥施硫酸钾有改善面包烘焙品质的趋势.     

小麦A型淀粉粒大小对淀粉特性及面包品质的影响

利用扫描电镜对10份小麦种质材料的淀粉粒大小和形态进行了观察,测定了供试样本的直链淀粉含量、面粉膨胀势和Zeleny沉淀值,分析了淀粉粒大小、形状与直链淀粉含量、面粉膨胀势、Zeleny沉淀值的关系。结果表明,不同小麦样本A型淀粉粒的大小有明显差别,淀粉粒的形状有圆形、椭圆型和长圆形。圆形和椭圆型淀粉粒比长圆形淀粉粒要大一些;直链淀粉含量低的小麦样本,A型淀粉粒的直径相对较大,膨胀势较高,Zeleny沉淀值也较高;淀粉粒直径与面粉膨胀势之间的正相关不显著,与直链淀粉含量的负相关达到极显著水平,与Zeleny沉淀值之间的正相关达到极显著水平。研究结果为小麦品质育种以及食品加工提供了理论依据和技术指导。