Change in contact temperature of finger touching on cold surfaces

This study deals with human fingers touching cold surfaces of four materials (aluminium, steel, nylon and wood) at different surface temperatures (−20°C, −15°C, −10°C, −4°C, 0°C and 2°C). Contact finger skin-surface interface temperature and subjective responses on thermal and pain sensations were determined during touching. Type of material and their surface temperature clearly affected the contact cooling of the finger. Individual variation in finger contact cooling was significant. Contact temperature limits for human fingers touching cold surfaces are suggested according to the experimental results. In addition, time to reach a critical temperature (7°C, 5°C or 0°C) when contacting a cold metallic surface is discussed.

Relevance to industry

The outcome of this experimental study supplies as a basis for the development of an ergonomics database to determine temperature limit values for cold touchable surfaces. The critical temperatures are relevant to all industries where cold surfaces cause a risk of finger contact cooling for the manual protection in the cold operations.     

Emulsifiers affect the texture of pastes made from fermented and non-fermented cassava flours†

The effects of glycerol monostearate (GMS) and sodium steroyl lactylate (SSL) on the rheological properties of native, naturally fermented (NF) and mixed culture fermented (MCF) cassava flour pastes were measured using instrumental texture profile analysis (TPA) and by finger cohesiveness (difficulty in separation). Fermentation reduced the TPA parameters, hardness, cohesiveness and gumminess, but not springiness/elasticity. These were reduced further when either GMS or SSL were incorporated into the pastes. Pastes made from native and naturally fermented flours were scored by a Cameroonian sensory panel as difficult to separate, whereas scores for native and fermented flour pastes treated with 1% or more of GMS or SSL were easy to separate. Increased internal stability of the cassava flour starch granules was suggested as the cause of the effects.     

豆渣小米蛋糕研制

用豆渣粉、小米粉取代部分面粉制成一种新型蛋糕。通过正交实验得出新型蛋糕的最佳配方,该蛋糕纤维含量高、蛋白质营养价值高、有特殊的米香味。     

Nitrophosphates and DAP are equally effective as P fertilizers for various crop species grown in rotation on a Typic Haplustept

In two long-term field experiments using wheat-maize and potato-sunflower-pearl millet (fodder) cropping systems on Typic Haplustept loamy sand, three different water-soluble P fertilizers [diammonium phosphate (DAP, water-soluble phosphorus content (WSPC) of 89.1%), ammonium nitrophosphate (ANP, WSPC 59%) and suphala (ammonium nitrophosphate, WSPC 26.7%)] were compared. Five amounts of P (0, 8.75, 17.5, 26 and 35 kg P/ha) were applied to wheat and (0, 13, 26, 39 and 52 kg P/ha) to potato. The succeeding crops under both the rotations used residual P from the P applied to wheat and potato crops. Grain yield and P content of wheat increased significantly up to an applied P level of 26 kg P/ha while the residual effect on maize crop was significant up to 17.5 kg P/ha. Tuber yield and P content of potato increased significantly up to an applied P level of 39 kg P/ha while the residual effect on sunflower and pearl millet (fodder) crops was significant up to 26 kg P/ha. Total profits in a year from wheat-maize and potato-sunflower-pearl millet (fodder) cropping systems increased significantly up to an applied P level of 26 and 39 kg P/ha, respectively. However, at all the levels of applied P and under both the cropping systems, the three P fertilizers used were found to be equally effective for plant yields, P contents, relative agronomic efficiencies and total profits in a year. Hence, it was concluded that the two nitrophosphates can be used instead of DAP as P fertilizers for the soil, plant species and crop rotations studied.     

黍子醇溶蛋白提取工艺的研究

以雁黍为原料,对黍子醇溶蛋白的提取工艺进行研究,以凯氏定氮法测定蛋白质含量和提取率,得到黍子醇溶蛋白的最佳提取条件为:料液比1∶6,乙醇浓度65%,温度75℃,提取时间1h。在该条件下,黍子醇溶蛋白质的提取率为78.65%,蛋白质的含量为87.90%。      

不同品种黍子营养成分及功能活性成分差异化分析

目的:研究黍子营养及功能活性成分的品种差异化。方法:选取8个品种的黍子,对水分和灰分等基本组分和淀粉、蛋白质、脂肪等营养组分及多酚、黄酮、低聚糖等功能活性成分的含量进行了检测分析。结果表明:不同品种黍子样品中,基本组分水分的变异系数为8.43%,变幅为9.38%~12.39%;灰分的变异系数为23.48%,变幅为0.94%~1.79%。营养组分粗淀粉的变异系数为2.77%,品种间含量较为稳定,但冀张黍1号和安塞黄糜子所含慢消化淀粉和抗性淀粉含量比例相对较高;粗蛋白的变异系数为8.04%,品种之间差异显著(p<0.05),其中龙黍18总氨基酸最高,约为149.06 mg/g,且必需氨基酸可达总氨基酸含量的44.54%;此外,粗脂肪的变异系数为23.23%,品种之间差异显著(p<0.05),其中宁糜9号不饱和脂肪酸占总脂肪酸比例最高,为87.06%。功能活性成分中,总黄酮的含量差异最为显著,变异系数为73.07%,变幅为0.89~10.17 mg/g;总多酚含量变异系数为67.78%,变幅为0.74~3.44 mg/g;同时,低聚糖含量的品种间差异也较大。本研究结果对于保留和选育黍子优良品种及黍子食品和保健品的开发具有指导意义。      

基于主成分分析的不同品种小米品质评价

目的:分析不同小米的品质差异,为小米品种品质改良、加工利用提供理论依据。方法:从陕西和贵州分别选取7种和8种主栽小米品种,基于主要营养、功能成分及理化特性,进行主成分分析评价其品质。结果:供试小米中蛋白质、淀粉和脂肪等含量差异显著(p<0.05),蛋白质中必需氨基酸占氨基酸总量的40%以上,符合WHO/FAO规定模式,淀粉中贵州小米直链淀粉含量(3.46%~4.18%)均低于陕西小米(19.07%~23.58%)。不同小米功能成分差异显著(p<0.05),其中施秉小米的多酚含量最高,晋谷29的黄酮和黄色素含量最高。在小米理化特性中,糊化度、水溶性和吸水性指数最高的分别为盘州、新氿谷及黄平小米。经主成分分析,提取出5个主成分,累积方差贡献率达86.368%,通过水溶性指数、水分、氨基酸、多酚、黄酮及黄色素等主要因素解释了原有15个指标的信息,经评价模型计算综合得分,排名前 5的品种依次为晋谷29号、镇宁、新氿谷、施秉以及琉璃谷。结论:基于主要品质特性及主成分分析对比15种小米的营养、功能及理化品质的差异性,可为小米特色化加工利用,品质改良提供理论依据。     

挤压加工对小米多酚及抗氧化活性的影响研究

研究了挤压加工温度、螺杆转数、物料含水量变化对小米中多酚类物质含量、存在形式和抗氧化功能性质的影响,并分析了总酚、黄酮含量与抗氧化能力之间的相关性以及挤压前后的变化。结果表明,挤压温度、螺杆转数、物料含水量变化对小米中多酚类物质含量、存在形式以及抗氧化功能存在显著性影响,其中游离黄酮含量受温度影响较小,螺杆转数的变化对结合酚含量的影响不显著;小米中总酚、黄酮含量与抗氧化能力之间具有显著的相关性(p<0.01)。总体而言,挤压加工有利于保留小米中的多酚类物质,是一种有效的加工方式。      

小米豇豆营养挂面的研制

为丰富小米食品的种类,开拓小米消费的新途径,以小米粉为主要原料,通过添加谷朊粉、豇豆粉、食盐、食碱制作了小米豇豆营养挂面。以落杆率、蒸煮损失率、熟断条率、感官评价为考核指标,研究了谷朊粉、豇豆粉、食盐、食碱的添加量对面条品质的影响,通过单因素和正交实验,得到最佳的工艺配方:小米粉79%、谷朊粉14%、豇豆粉7%、食盐为混合粉质量的2%、食碱为混合粉质量的0.3%。所得挂面的落杆率为5.4%,熟断条率为2%,蒸煮损失率为8.6%,感官评分为90.4,综合得分为92.86。