谷蠹不同虫态蛀蚀对小麦成分及食用品质的影响

摘要

In order to investigate the physicochemical and application quality changes of wheat damaged by Rhizopertha dominica in different growth stages, the nutritional properties, dough rheological properties, food processing properties and other relevant quality indices of wheat were determined after infestation by Rhizopertha dominica in the egg stage, larval stage, pupa stage and adult stage under the optimal growth conditions such as the temperature of (32±1)℃ and relative humidity of 75%±1%. And all data were processed by the differential analysis method. The results showed that the ash content of the wheat firstly decreased and then increased after infected by Rhizopertha dominica from the egg to the adult stage, and the ash content between the infested wheat sample in the pupal and adult stage and the control sample showed a significant difference (P<0.05). The albumin and reducing sugar content had a tendency of increasing firstly and then decreasing, and the albumin content between the infested wheat sample in all development stages and the control sample showed significant difference (P<0.05), while the reducing sugar content had not significant difference. The crude fat content and glutenin content decreased gradually, and the crude fat content between the infested wheat sample in all different development stages and the control sample showed significant difference (P<0.05), while the glutenin content between the infested wheat sample in the larval, pupa and adult stage and the control sample had significant difference (P<0.05). The globulin and gliadin content irregularly changed, and the globulin and gliadin content between the infested wheat sample in the larval, pupal and adult stage and the control sample had significant difference (P<0.05) respectively. In addition, with Rhizopertha dominica eggs growing and developing in the wheat grain kernel, the microstructure of the wheat endosperm showed the interface damaged by Rhizopertha dominica became to have hard texture and rough surface, the structure was softening, the matrix proteins had severe fracture, and the damaged starch gradually increased. The rheological properties of whole wheat flour dough changed obviously, the peak time gradually decreased, and the peak time between the infested wheat sample respectively in the pupal and adult stage and the control sample showed significant difference (P<0.05); the peak height and peak area first decreased and then increased, the peak width had an overall upward trend, and the peak height, front width and peak area between the infested wheat sample in all different development stages and the control sample showed significant difference (P<0.05). The slope of the right side of the midline peak had a tendency of first rising and then decreasing, and the slope of the right side of the midline peak between the infested wheat sample in all different development stages and the control sample had significant difference (P<0.05). The sensory evaluation scores of the steamed bread made with whole wheat flour decreased gradually, and the elasticity, adhesiveness and restorative parameters in texture analysis of the steamed bread decreased, while the hardness, chewiness, gumminess changed irregularly. The differential analysis results indicated that the infestation by Rhizopertha dominica in different growth stages had significant effects on the physicochemical and application quality of wheat (P<0.05). The physicochemical properties and application quality of wheat infested by Rhyzopertha dominica in the larval and adult stages changed more obviously, and the differences with the control sample were more significant (P<0.05). The research results show that the wheat damaged by Rhizopertha dominica in different growth stages can not only cause the change of physical and chemical properties of wheat, but also directly affect their eating quality, and therefore it should pay much attention to the prevention and control of Rhyzopertha dominica in the different growth stages during the wheat storage.%为研究谷蠹不同生长发育阶段侵害小麦后其成分及食用品质的变化，设定谷蠹在最适生长发育条件下（温度(32±1)℃、相对湿度75%±1%）对小麦进行侵害，测定受谷蠹卵期、幼虫期、蛹期和成虫期侵害后小麦的营养品质、流变学特性、食用品质等相关指标。结果表明：谷蠹感染小麦后，随着谷蠹在小麦籽粒内从卵生长发育到成虫阶段：灰分呈先降低后上升趋势，蛹期和成虫期与原始样间差异显著（P<0.05）；清蛋白和还原糖含量等营养指标呈现先升高后降低，清蛋白各虫期均与原始样间差异显著（P<0.05），还原糖各虫期与原始样间无显著差异（P<0.05）；粗脂肪、谷蛋白含量逐渐降低，粗脂肪各虫期均与原始样间差异显著（P<0.05），谷蛋白幼虫期、蛹期和成虫期与原始样间差异显著（P<0.05）；球蛋白、醇溶蛋白含量呈波动变化，球蛋白和醇溶蛋白均在幼虫期、蛹期和成虫期与原始样间差异显著（P<0.05）；另外，其微观结构显示随着谷蠹卵在小麦籽粒内生长发育，谷蠹侵害界面的质地变硬、表面粗糙、结构疏散、基质蛋白质断裂严重，且破损淀粉逐渐增多；流变学特性变化明显：出峰时间呈逐渐降低趋势，在蛹期和成虫期与原始样间差异显著（P<0.05），峰高和峰面积先降低后升高，峰宽整体呈上升趋势，峰高、锋宽和峰值面积在各虫期间均与原始样间差异显著（P<0.05），中线峰值右侧斜率呈先升高后降低，各虫期与原始样间差异显著（P<0.05）；馒头感官评价总分逐渐降低；全麦粉馒头质构参数中弹性、黏聚性和恢复性逐渐减小，硬度、咀嚼度、胶着性呈波动性变化。从谷蠹不同虫期感染小麦与其理化及应用品质指标间差异性分析可看出，不同虫期之间受谷蠹感染的小麦理化及应用品质指标变化显著（P<0.05）。谷蠹在幼虫期和成虫期侵害小麦后各项理化及应用品质指标变化更明显。结果表明不同虫期谷蠹对小麦蛀蚀不仅可造成理化指标的变化还可直接影响其食用品质，因此在储藏期间应注重防治不同生长期的谷蠹。