佛手瓜块根生全粉添加量对小麦粉加工特性的影响

为明确佛手瓜块根生全粉对小麦粉加工特性的影响,在比较佛手瓜块根生全粉和小麦粉基本组成成分差异的基础上,分析了不同添加量(质量分数分别为0、10%、20%、30%)佛手瓜块根生全粉对小麦粉的基本理化性质、糊化特性和流变学特性的影响。结果表明,佛手瓜块根生全粉的总淀粉和总灰分含量均高于小麦粉,而粗蛋白含量、粗脂肪含量和平均粒径均低于小麦粉。X射线衍射分析结果显示,佛手瓜块根生全粉在2θ为5.6°、14.2°、17.2°、19.6°、22.2°、23.9°处存在明显衍射峰,表明其属于B型结构淀粉。加工特性分析结果表明,佛手瓜块根生全粉的添加显著提高了混合粉的吸水性、膨胀度和透光率,降低了其溶解度和冻融稳定性;稳态流变特性研究结果显示,佛手瓜块根生全粉的添加提高了混合粉的表观黏度、稠度系数K、流动特征指数n和屈服应力τ₀;动态流变特性研究结果表明,佛手瓜块根生全粉的添加提高了混合粉的储能模量和损耗模量,降低了损耗角正切值;糊化特性研究结果表明,添加佛手瓜块根生全粉降低了小麦粉的糊化温度和峰值时间,提高了峰值黏度、低谷黏度、最终黏度、崩解值和回生值。佛手瓜块根生全粉显著改变了小麦粉的加工特性,研究结果旨在为佛手瓜块根生全粉的加工应用提供理论依据。     

Changes of polysaccharide content and texture of potato during French fries production

The purpose of the present study was to determine the changes in non-starch polysaccharide and lignin contents of potato during French fries production and also the relationship between the texture of the finished product and half-products, as a result of processing at each stage under investigation. The samples for laboratory studies were taken from potato tubers, strips and French fries collected from nine locations of a technological line. The greatest changes in non-starch polysaccharide content and texture of potatoes resulted from blanching and frying. The texture of French fries was mainly affected by pectin and cellulose. The texture of French fries can be predicted from the measurements of the texture of potato strips after blanching.     

冲压模具实型铸造的铸件结构

着重介绍了冲压模具设计过程中,实型铸造的铸件结构设计要点。     

包装和保鲜剂改善袋装榨菜保鲜效果的研究进展

目的针对方便食用的袋装榨菜相比于坛装榨菜面临着更多的保鲜困境,这里对有潜力改善其贮藏性能的包装和保鲜技术进行总结。方法就榨菜在贮藏中存在的色变、脆性丧失、腐烂、胀袋、营养物质流失等问题和改善袋装榨菜耐贮藏性的有效手段进行探讨,综述包装技术和保鲜剂在袋装榨菜中的应用。结果使用巴氏杀菌结合真空或气调包装能够有效抑制微生物生长,选择合理的包装材料能够控制榨菜的外观变化;这些包装技术和工艺各有特点;多种保鲜剂在袋装榨菜中具有抑菌、改善质构、抑制色变等功效,其中包括工业界广泛接受的苯甲酸钠,前景广阔但鲜有成功案例的天然保鲜剂等。此外,还指出了新型保鲜剂缺乏推广等现状,以及对保鲜技术的发展进行了展望。结论通过改进包装技术和添加保鲜剂来改善袋装榨菜的耐贮藏性,在工业生产中得到了广泛应用,但这些技术需要进一步的研究和改进。     

高盐榨菜废水处理工程实例

采用化学除磷-水解酸化-厌氧接触-CASS工艺处理高盐榨菜废水。工程运行结果表明,进水盐度为0.8%～1.2%(以NaCl计),COD为1 300～2 200 mg/L,氨氮质量浓度90～150 mg/L,总磷质量浓度30～40 mg/L时。处理后出水COD为49～84 mg/L,氨氮质量浓度5～11 mg/L,总磷质量浓度0.3～0.4 mg/L,可达到污水综合排放标准(GB 8978-1996)一级标准。     

红薯叶、紫薯块根及不同时期紫薯叶中主要活性成分含量比较

研究紫薯叶中主要活性成分含量的动态变化规律,确定紫薯叶的最佳采样时期;比较紫薯叶、红薯叶、紫薯块根中主要活性成分的含量。总多酚、总黄酮、花色苷的含量采用紫外分光光度计测定,绿原酸、芦丁含量采用高效液相色谱测定。结果表明:不同品种紫薯叶中活性成分含量的动态变化特征大体一致,但不同采收期的含量变化并不完全一致,且不同品种间活性成分含量差异显著。紫薯叶中活性成分的含量较红薯叶、紫薯块根更高,因此更具营养价值。紫薯叶中几种活性成分的累积含量均在采收期150d时达到最大,此时薯叶资源丰富,采收紫薯块根的同时采收紫薯叶进行开发和研究,有利于紫薯资源的综合利用。     

Effects of mucilage on the thermal and pasting properties of yam, taro, and sweet potato starches

This study investigates the effects of water-soluble mucilages (0, 2.5, and 5 g/100 g; w/w, dry basis) on the thermal and pasting properties of isolated starches from three root and tuber crops. The results show that yam tuber presents the greatest level of mucilage and also possess the largest amylose content of the three isolated starches. The addition of mucilage caused a remarkable increase in the temperature of gelatinization for the three tested starches due to the competition for water during starch gelatinization. Furthermore, adding mucilage increased the phase transition temperature range (Tc-To) of starches but decreased enthalpy (ΔH). However, although the pasting temperature increased with the addition of mucilage into tuber starches, it did not change that of taro starch. The peak viscosity of taro and sweet potato starches decreased significantly as their mucilages were added into each starch suspension system (p < 0.05). However, the addition of mucilage slightly increased the viscosity of yam starch. Furthermore, the addition of mucilage slightly increased the swelling power of yam and taro starches, but did not change that of sweet potato starch.     

A Method for Intercultivar Comparison of Potato Tuber Nutrient Content Using Specific Tissue Weight Proportions

ABSTRACT:  Potato tubers are a staple food item in the North American diet. Each potato cultivar has unique tuber appearance and nutritional composition. A method was developed to facilitate better cultivar selection for dietary purposes and obtain a better understanding of the nutrient distribution within specific tissues of potato tubers. This involved a procedure for estimating the percent weight contribution of the 3 major tissue components, including periderm or "skin," cortex, and pith for 20 potato cultivars. Weight determination was based on the volume (calculated through an ellipsoid formula) and density of each component tissue. Calculated percent weight and dry matter data for each tuber tissue provided conversion factor values that were tabulated for all cultivars. An example is provided to illustrate the application of this procedure in facilitating identification of cultivars with significantly greater or lesser protein content.     

离子电极法快速测定榨菜中硝酸盐含量

建立一种采用离子电极快速测定榨菜中硝酸盐含量的方法。首先组建由硝酸根离子选择电极、参比电极、离子计和计算机构成的测试仪器,然后分析温度、离子强度调节剂及干扰离子对测试的影响,并建立标准曲线和校准方程,最后采用离子电极法测定榨菜成品液和榨菜脱盐液中的硝酸盐含量,并与紫外分光光度法进行比较。结果表明：温度、离子强度调节剂及干扰离子对榨菜中硝酸盐含量的测试影响较小;离子电极法测定结果与紫外分光光度法测定结果的总体平均相对误差为4.247%,相对标准偏差小于2.0%,且t检验的显著性水平大于0.05,2 种方法测试结果无明显差异,并且离子电极法测试时间小于15 s。本方法可代替紫外分光光度法作为榨菜中硝酸盐含量的快速测定方法。     

方便榨菜肉沫关键工艺参数的研究

以涪陵榨菜、肉沫为主要原料,采用单因素试验与正交试验的方法,通过感官评价研究了不同肥瘦肉比、菜肉比及各辅料配比对榨菜肉沫品质的影响。研究结果表明:肥瘦肉比1:2,肉菜比例1:1,榨菜100g,猪肉100g(其中瘦肉67g、肥肉33g),辣椒粉9g,白砂糖4g,五香粉3g,食盐0.6g,真空包装后在85℃水浴灭菌20min,在此条件下炒制的榨菜肉沫感官评价最高,且符合国家卫生标准。