Fermentation characteristics and aerobic stability of wet corn distillers grains with solubles ensiled in combination with whole plant corn

BACKGROUND: Wet corn distillers grains with solubles (WDG) are prone to aerobic spoilage when stored for an extended period of time. The objective of this study was to evaluate the fermentation characteristics of ensiling WDG with whole plant corn (WPC) using the following combinations: (1) 100% WPC; (2) 75% WPC + 25% WDG; (3) 50% WPC + 50% WDG; and (4) 100% WDG. RESULTS: The initial pH was greatest for 100% WPC and lowest for 100% WDG (5.7, 4.6, 4.0, and 3.1, respectively). Concentrations of ammonia nitrogen (12.0, 26.8, 40.7, and 50.8 g kg^?1 dry matter (DM)) and Crude protein (CP) (98.7, 155.8, 206.8, and 307.9 g kg^?1 of DM) increased with increasing concentrations of WDG. Lactic acid concentration prior to ensiling was greatest for 100% WDG (9.0 g kg^?1 DM) and decreased with WPC in the silage. Acetic, propionic, and butyric acids were not present prior to ensiling. The pH of the ensiled feeds dropped below 4.0 by day 3, with no further decrease over time. Acetic acid increased from undetected amounts at day 0 to 38.8, 43.9, 43.2, and 2.2 g kg^?1 of DM at day 129 as concentration of WDG increased. Aerobic stability was enhanced with increasing WDG concentration in the silage. CONCLUSION: Fermentation, nutrient profile, and aerobic stability can be improved when ensiling wet distillers grains with whole plant corn. Copyright © 2011 Society of Chemical Industry     

微波消解—流动注射化学发光法测定小麦中铬及其生物吸收比

研究小麦及其土壤中微量铬的相关性,为富铬小麦品种的选育和富铬功能性食品的开发提供科学依据。用微波消解样品,建立流动注射化学发光法测定彩色小麦、普通小麦以其土壤中铬含量的方法。结果表明:在五个地区种植的六个品种小麦,铬含量在0.126 3~0.451 6μg/g之间。不同品种小麦的铬含量有所不同,普通紫麦的铬含量较高;同一品种小麦在不同地区种植,其铬含量也不同,商丘地区小麦铬含量较高。在同一生长环境下,不同品种的小麦铬的生物吸收比不同,普通紫麦的生物吸收比较大,商丘地区种植的普通紫麦的生物吸收比高达27.62%,是补充铬的理想原料,有一定的培育前景。     

功能山杏整仁的酶法制备条件优化及功能评价

本研究对完整形态的山杏整仁进行酶解,使之释放出具有功能活性的短肽,以强化或赋予其保健功能,拟开发出具有降血糖和抗氧化活性的功能山杏仁产品。在单因素试验的基础上,采用响应面试验优化脱苦山杏整仁的酶解条件,得到的最佳酶解参数为：温度50 ℃、pH 7.0、加酶量6.0%、酶解时间8.0 h;同等条件下进行验证实验,得到山杏整仁的水解度为26.43%,与理论模型预测值27.85%基本相符。脱苦山杏整仁水解物表现出了良好的体外抗氧化能力和α-葡萄糖苷酶抑制活性。当质量浓度为10.00 mg/mL时,对1,1-二苯基-2-三硝基苯肼自由基、超氧阴离子自由基（O2－·）和羟自由基（·OH）的清除率分别为50.44%、65.22%、22.78%;当质量浓度为160.00 mg/mL时,其总还原力（吸光度）为1.072;通过超滤分离得到≤5、5～10、10～30、≥30 kD这4 组不同分子质量组分,当质量浓度为10.00 mg/mL时,对α-葡萄糖苷酶的抑制率分别为3.65%、4.43%、7.94%、10.00%;选取抑制效果最好的≤5 kD组分经凝胶层析进一步分离得到3 个洗脱峰,质量浓度为10.00 mg/mL时,3 个洗脱峰的α-葡萄糖苷酶抑制率分别为11.52%、10.65%、9.67%。结果表明：脱苦山杏整仁酶解后产生了具有良好抗氧化活性和抑制α-葡萄糖苷酶活性的多肽,与未经酶解的山杏整仁相比,其保健活性显著提高。     

小麦胚乳中直链淀粉含量分布及其对面条品质的影响

在同一生产线上对同一品种小麦按加工系统取制面粉样品,测定各粉样的直链淀粉含量;选择部分样品在其中添加整个粉路中最具代表性的系统面粉制成的谷朊粉,使各样品蛋白质含量相等、质量接近,在这种的前提下,研究直链淀粉含量对面条品质的影响。研究结果表明,小麦胚乳中,越接近皮层的部位,直链淀粉含量越低;越接近麦心的部位直链淀粉含量越高。小麦胚乳中的淀粉总量与面条品质无明显的相关性,而直链淀粉及支链淀粉含量对面条品质影响较大。直链淀粉含量与面条感官评价的表观状态、适口性、韧性、黏性、光滑性、食味及总评分都呈极显著负相关;与面条的煮制特性的干物质吸水率、蛋白质损失率和干物质损失率呈极显著正相关;而与面条质构仪TPA测定参数的黏合性、硬度和咀嚼性呈极显著负相关。     

小麦品种对偏高温大曲发酵动态影响的研究

本研究分别以白小麦和花小麦为原料制作偏高温大曲,比较两个品种的小麦曲块在发酵培菌过程中品温变化、水分散失、淀粉消耗和酸度形成等影响曲质指标所存在的差异。研究结果表明:在发酵培菌时,花麦曲块与白麦曲块相比,花麦曲块的温度能满足"前缓、中挺、后提"的工艺要求,曲心水分能及时排出,淀粉消耗适度,形成的酸度适中。因此,在本实验条件下,花麦比白麦更适宜于生产偏高温大曲。     

萌发玉米粉在冷冻面团中的应用研究

本实验研究了影响冷冻面团中酵母发酵活力的因素,确定酵母菌的发酵活力随着冷冻时间的延长而降低,在萌发玉米粉添加量10%以下,酵母菌的发酵活力随着添加量的增加而增加,超过10%后,酵母的发酵活力逐渐下降。以比容为指标,冷冻面团的最佳配方为:萌发玉米粉添加量10%,酵母菌2%,食盐0.4%,水65%,以弹性为指标,冷冻面团的最佳配方为:萌发玉米粉添加量5%,酵母添加量为3%,盐添加量为1.2%,水添加量为60%。与普通冷冻面团相比,萌发玉米粉使冷冻面团面包品质得到改善。     

小麦麸皮微波处理对全麦粉面筋品质和流变学特性的影响

目的 探讨小麦麸皮微波处理灭酶对全麦粉面筋品质特性和流变学特性的影响.方法 以中高筋小麦为原料,对麸皮微波处理后再回添到小麦粉中制得全麦粉,设置麸皮水分含量、微波处理时间和麸皮厚度3个变量因素,固定其中2个变量因素,探讨另1个变量因素对全麦粉中面筋特性和流变学特性的影响.结果 麸皮水分含量对湿面筋含量、面筋吸水率、面团...     

水平气流对小麦进行分级的研究

研究了水平气流速度、分级隔板高度和落料时间等因素对小麦气流分级的性能影响,并在单因素试验的基础上设计了正交试验,得出影响重质小麦水平分级的主次因素为:分级隔板高度、水平气流速度、落料时间;影响轻质小麦水平分级的主次因素为:水平气流速度、分级隔板高度、落料时间.     

Thermal characteristics of ohmically heated rice starch and rice flours

ABSTRACT:  Thermal properties of conventionally and ohmically heated rice starch and rice flours at various frequencies and voltages were studied. There was an increase in gelatinization temperature for conventionally heated rice starches since they were pregelatinized and became more rigid due to starch–chain interactions. In addition, there was a decrease in enthalpy (energy needed) for conventionally and ohmically heated starches during gelatinization; thus, the samples required less energy for gelatinization during DSC analysis. Ohmically heated commercial starch showed the greatest decrease in enthalpy probably because of the greatest extent of pregelatinization through ohmic heating. Brown rice flour showed the greatest gelatinization temperature resulting from the delay of starch granule swelling by lipid and protein. Enthalpy of ohmically heated starches at 20 V/cm was the lowest, which was most likely due to the lower voltage resulting in a more complete pregelatinization from a longer heating time required to reach 100 °C. Ohmic treatment at 70 V/cm decreased onset gelatinization temperature of white flour; therefore, it produced rice flour that swelled faster, whereas the conventionally heated sample showed a better thermal resistance.