脱脂和重组对面粉理化特性和烘焙品质的影响

选用3个筋力不同的小麦品种（系），通过比较其采用脱脂面粉、重组面粉和原面粉，研究了小麦脂类对面团揉混特性和面包加工品质的影响。结果表明，（1）3个品种（系）面粉脱脂前后蛋白质含量、沉淀值和灰分含量无显著性差异，但脱脂后面粉白度显著提高。（2）脱脂后3个品种（系）揉混仪峰高和峰宽增大，衰落角变小。（3）面粉脱脂后面包加工品质有所改善，其作用大小与蛋白质的质量和蛋白质间的互作有关。脱脂面粉加入起酥油对面包品质无明显改善作用，起酥油是通过面粉脂类对面包品质产生作用的。

Effects of Defatting and Reconstitution on Dough Mixogram and Processing Quality of Bread

Wheat flour lipids,although only constituting about 2% of flour in weight,makes important contributions to dough properties,baking behavior,and bread staling.Function of lipid is expressed through interactions with other components of dough.Especially,lipid-protein interactions have attracted attention of the cereal scientists since the time more than 40 years ago.Zawistowska and co-workers reported that 56% of the gluten lipids were associated with gliadin proteins and 44% were associated with glutenin proteins.Different models associating gliadins-glutenins and lipids or gliadin-glutenin and starch have been proposed to explain the role of lipid-protein interactions in the dough and gluten viscoelasticity.Lipids and lipid-protein complexes influence the formation and stability of air-water (foam) and oil-water (emulsion) interfaces during dough mixing,proofing and baking.Lipid-carbohydrate interactions are also of importance for the quality of all cereal products.The presence of lipids,resulting in a decreased amylose leaching,less amylose will be available for the formation of a network,and a softer product could be expected.Amylopectin-lipid complexes can decrease the retrogradation and keep the bread soft for a longer period of time.In this study,three wheat cultivars(lines)with different gluten strength were used to study the effect of wheat flour lipids on mixogram characteristics of dough and processing quality of bread.The result showed that: (1) There was no significant difference between control flour and defatted flour in sedimitation value,protein and ash content.But flour whiteness was increased by defatting significantly.(2) Mixing time,peak value and peak width of mixogram were increased,and right of peak slope were decreased by defatting.(3) The improvement of processing quality of bread by defatting depended on the quality and interaction of protein.The processing quality of bread made of defatted flour was not improved after adding shortening,which and an effect on the processing quality of bread by wheat flour lipids.