热泵冷风干燥鲢鱼的挥发性盐基氮和脂质氧化品质模型

为深入了解带热泵的冷风干燥机干燥鱼类产品的特点,以鲢鱼为研究对象,确定冷风干燥工艺参数对风干鱼品质劣变的影响,并建立相关模型,通过U10*（103）均匀设计试验,在不同热泵干燥工艺参数（温度、空气旁通率、风速）下,对决定风干鲢鱼品质劣变的挥发性盐基氮（total volatile basic nitrogen,TVB-N）和脂质氧化硫代巴比妥酸（thiobarbituric acid,TBA）值变化情况进行研究,并以TVB-N和TBA值作为风干鲢鱼制品品质判断指标。经统计分析,分别得到冷风干燥鲢鱼样品中TVB-N和TBA的回归方程。结果表明：在试验水平范围内,温度是影响风干鲢鱼制品中TVB-N和TBA的主要因素。由模型方程确定腌制鲢鱼冷风干燥工艺的最优参数分别为温度15.5℃、空气旁通率0.6（考虑能耗）、风速1.65 m/s,此条件下干燥的鲢鱼TVB-N和TBA值最小,品质最好,能耗较低。研究结果为控制热泵冷风干燥过程中鲢鱼的质量品质提供参考。     

Comparison of heritabilities of dairy traits in Australian Holstein‐Friesian cattle from genomic and pedigree data and implications for genomic evaluations

The reliability of genomic evaluations depends on the proportion of genetic variation explained by the DNA markers. In this study, we have estimated the proportion of variance in daughter trait deviations (DTDs) of dairy bulls explained by 45 993 genome wide single‐nucleotide poly‐ morphism (SNP) markers for 29 traits in Australian Holstein‐Friesian dairy cattle. We compare these proportions to the proportion of variance in DTDs explained by the additive relationship matrix derived from the pedigree, as well as the sum of variance explained by both pedigree and marker information when these were fitted simultaneously. The propor‐ tion of genetic variance in DTDs relative to the total genetic variance (the total genetic variance explained by the genomic relationships and pedigree relationships when both were fitted simultaneously) varied from 32% for fertility to approximately 80% for milk yield traits. When fitting genomic and pedigree relationships simultaneously, the variance unexplained (i.e. the residual variance) in DTDs of the total variance for most traits was reduced compared to fitting either individually, suggesting that there is not complete overlap between the effects. The proportion of genetic variance accounted by the genomic relationships can be used to modify the blending equations used to calculate genomic estimated breeding value (GEBV) from direct genomic breeding value (DGV) and parent average. Our results, from a validation population of young dairy bulls with DTD, suggest that this modification can improve the reliability of GEBV by up to 5%.     

食品物理加工技术前沿的教学实践与探讨

食品物理加工技术前沿课程为江苏大学食品科学与工程硕士的核心课程。在本文中对食品科学与工程硕士课程中开设食品物理加工技术前沿课程教学进行总结,分析了食品物理加工技术前沿课程特点、教学内容及教学中的重点及难点,探讨食品+物理型复合型食品科学与工程人才的培养方式。      

新型喜树碱类药性分子的合成与杀螨活性

应用三组分“一锅法”合成了一系列新型喜树碱类药性分子 4a~4n、5a~5n 和 7a~7f ,所有目标化合物均经核磁共振氢谱和质谱确证。室内杀螨活性测定结果表明,所有化合物对朱砂叶螨Tetranychus cinnabarinus均有不同程度的杀螨活性,其中化合物 4l （LC₅₀:25.93 mg/L）和 7d （LC₅₀:28.16 mg/L）的杀螨活性与喜树碱（LC₅₀:24.55 mg/L）的相当。该研究为进一步开展喜树碱作为先导的新农药设计与研究提供了基础。     

副干酪乳杆菌发酵制备牛乳抗氧化肽饮料工艺优化

将副干酪乳杆菌用于牛乳发酵,制备含抗氧化肽的新型乳酸菌功能性饮料。通过测定发酵终产品的活菌数、酸度、多肽含量、多肽转化率和1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除率,探讨最优的发酵培养方式和培养基配方。结果表明:确定出的最佳培养方式为摇床培养,摇床转速180 r/min、发酵时间24 h、脱脂乳粉添加量12 g、葡萄糖添加量6 g、接种量5％,在此条件下,产品的多肽产量最高达0.98 mg/mL,活菌数最高达8.5×108 CFU/mL,DPPH自由基清除率最高可达62.38％。     

南瓜片真空脉动干燥特性及含水率预测

为探索南瓜片真空脉动干燥特性,并实现干燥过程中南瓜的含水率预测,该文研究了不同常压保持时间、真空保持时间、干燥温度和切片厚度对南瓜干燥时间和速率的影响;利用温度传感器实时采集南瓜在干燥过程中的中心温度,阐述压力脉动过程对物料传热传质的影响;建立了输入层个数为5,隐藏层个数为11,输出层为南瓜含水率,结构为"5-11-1"的BP神经网络模型,实现对南瓜含水率实时预测.结果表明:真空保持时间和常压保持时间均对南瓜干燥时间有显著影响,干燥温度60℃,切片厚度7mm条件下,常压保持时间10min和真空保持时间9min所用干燥时间最短,约为352min;干燥温度和切片厚度均对干燥时间有显著影响,提高干燥温度、减少切片厚度能够有效缩短干燥时间.采用Levenberg-Marquardt算法为训练函数,经过有限次训练得到的BP神经网络模型,其预测值与实测值之间的决定系数R2为0.9968,均方根误差RMSE为0.0173,能够很好预测南瓜在真空脉动干燥过程中的含水率.研究结果为南瓜真空脉动应用以及含水率在线预测提供理论依据.     

超声预处理大米蛋白制备抗氧化肽

为优化中性蛋白酶酶解大米蛋白制备抗氧化肽的工艺条件,采用超声波预处理大米蛋白.以1,1-二苯基-2-苦基苯肼(DPPH)清除率为响应值,用响应面分析法研究超声功率、超声处理时间和超声处理初始温度对制备抗氧化肽工艺的影响.同时研究了其抗氧化肽清除超氧自由基、DPPH、羟自由基能力及螯合Fe2 和还原能力.结果表明:最佳超声预处理大米蛋白的工艺为:超声功率1500 W、超声处理时间20 min、超声处理初始温度40℃,该条件下的抗氧化肽(2.2057 g/L)清除DPPH可达到74.8%,抗氧化肽得率为33.2%.与未经超声预处理比较,抗氧化肽得率提高了43.7%,DPPH的半抑制率(IC50)降低了17.7%.抗氧化试验表明,大米蛋白抗氧化肽清除超氧自由基、DPPH和羟自由基的IC50值分别为0.0678、0.9315和0.1173 g/L,分别是维生素C的IC50值的1.8、175.8和1.4倍;其螯合Fe2 的IC50值是乙二胺四乙酸的42.2倍,还原能力是维生素C的0.7倍.     

Mass movement mapping for geomorphological understanding and sustainable development: Tigray,Ethiopia

Mass movement topography characterises the escarpments and piedmont zones of the tabular ridges in the western part of the Mekelle outlier, Tigray, Ethiopia. Several types of mass movements can be distinguished. The first type is rockfall produced by 357 km rocky escarpments and cliffs during the rainy season. In the study area, every current kilometer of Amba Aradam sandstone cliff annually produces 3.7 m³ of rock fragments. However, this is an under-estimation of the actual cliff and escarpment evolution, which is also characterised by debris slides and small rock slides.     

优质食品原料生产技术的现状与展望

优质食品原料对优质食品的生产有着重要的意义。为了得到优质的食品原料,农业生产在提高产量的同时,应强调食物营养的增强和安全性的改善。文章还回顾了生物技术在食品原料生产中的应用,强调优质、天然、无害、健康的主题