草酸铵法提取冬瓜皮果胶及其理化性质研究

以冬瓜皮为原料,采用草酸铵法提取冬瓜皮果胶。通过单因素试验和正交试验确定提取冬瓜皮果胶的最优工艺条件,并对提取的果胶成品进行理化指标测定。结果表明:在试验范围内,草酸铵质量浓度、提取温度、提取时间和料液比对冬瓜皮果胶的提取得率均有一定的影响,其最佳工艺条件为草酸铵质量浓度1.5%、温度为80℃、提取时间2.0 h、料液比为1∶30(g/m L);在该工艺条件下果胶提取率达8.91%。该方法提取的果胶各项指标均达到了国家标准GB 25533-2010《食品添加剂果胶》和行业标准QB 2484-2000《食品添加剂果胶》要求。     

肉粉替代鱼粉对肉鸡生产性能、血清生化指标和抗氧化性能的影响

用不同水平肉粉等蛋白替代基础日粮中的鱼粉,研究其对AA肉鸡生长、血清生化指标及抗氧化功能的影响.结果表明:肉粉替代鱼粉对肉鸡前、后期平均体重、平均日增重、料重比及死淘率影响差异均不显著(P＞0.05);与对照组相比,1％、2％肉粉替代组肉鸡后期胸腺指数分别提高了26.09％ (P＞0.05)和52.17％ (P＜0.05),前期血清甘油三酯均极显著降低了18.75％ (P＜0.01),后期有降低趋势(P＞0.05).1％、2％肉粉替代组血清总蛋白、球蛋白含量与对照组比有降低趋势(P＞0.05);1％、2％肉粉替代组肉鸡前期血清过氧化氢酶活性均显著提高(P＜0.05),后期肝脏总抗氧化能力分别提高了24.32％(P＞0.05)和41.44％ (P＜0.05).     

分子蒸馏对高酸值花椒籽油脱酸的初步探讨

利用分子蒸馏装置对高酸值花椒籽油进行脱酸来表明脱酸效果显著,重馏份（油脂）的得率高,对酸值在10mgKOH/g-40mgKOH/g花椒籽油进行脱酸,得到的油脂酸值均小于4mgKOH/g,同时所得到轻馏份（脂肪酸）酸值均在192mgKOH/g-198.5mgKOH/g之间。     

气相色谱-质谱法测定奶粉中香兰素的不确定度评估

目的采用气相色谱-质谱法对奶粉中香兰素含量的不确定度评估。方法建立不确定度评估的数学模型,通过对不确定度的各主要分量进行分析计算,得出合成不确定度以及扩展不确定度。结果当香兰素的测定结果为57.1 mg/kg时,其扩展不确定度为4.4 mg/kg,k=2。结论采用气相色谱-质谱法测定奶粉中香兰素含量,其不确定度的主要来源为样品的回收率和最小二乘法拟合的标准曲线,该评估模型为检测奶粉中香兰素的不确定度评估提供了参考依据。     

Effects of chitosan coating enriched with cinnamon oil on qualitative properties of sweet pepper (Capsicum annuum L.)

Effect of chitosan–oil coating on qualitative properties of sweet pepper (Capsicum annuum L.) stored at 8 °C for 35 days was investigated. The chitosan–oil coating treatment exhibited the best control effect on decay (below 5%). At the end of storage, samples treated with chitosan-oil coatings maintained good sensory acceptability, whereas the sensory quality of control samples became unacceptable. The higher activities of scavenger antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), in treated peppers at the 35th day should be contributed to the chitosan–oil coating. Malondialdehyde (MDA) and electrolyte leakage contents in chitosan–oil-coated peppers were increased but were still lower than in control samples. Atomic force microscopy images showed that the surface of sweet pepper without coating treatment was rougher than that of peppers treated with chitosan–oil coating. Our study suggests that chitosan–oil coating might be a promising candidate for enhancing the keeping quality of sweet peppers.     

河南烟区烤烟叶片含钾量低的原因初探

温室盆栽和大田试验结果揭示．烟叶评吸质量与烟叶含钾量呈正相关。尽管河南植烟土壤含钾量高于南方红壤，但其所产烟叶含钾量却远低于红壤。造成这种现象的主要原因包括土壤水分不足钾素迁移速度低，补充速度赶不上吸收速度的需要；土壤固相对钾的固定，河南烟区上镶中过量的钙对钾吸收的拮抗等。盆栽试验表明烤烟缺钾临界值为烤烟收获后土壤速效钾含量小于150mg／kg。通过调节土壤水分状况，选用吸钾能力高的烤烟品种和调节烤烟的生理活性可以有效地提高烟叶含钾量。     

Effect of Co γ-irradiation on postharvest quality and selected enzyme activities of Pleurotus nebrodensis

Freshly harvested Pleurotus nebrodensis fruit bodies were exposed to four different doses (0.8-2.0 kGy) of ⁶⁰Co γ-irradiation and various physiological changes associated with postharvest deterioration, as well as the activities of selected enzymes (proteinase, polyphenoloxidase, superoxide dismutase, catalase) thought to play a role in the process of deterioration, were monitored during 22 days of subsequent storage at 4 °C and 65-70% relative humidity. An irradiation dose of 1.2 kGy significantly delayed (by 6-9 days) the onset of fruit body softening, splitting and browning compared with non-irradiated controls and test samples subjected to lower or higher irradiation doses. Irradiation with 1.2 and 1.6 kGy also had a positive effect on other indicators of mushroom tissue senescence, resulting in smaller decreases in soluble protein levels and more protracted increases in proteinase activity. Peak levels of polyphenoloxidase activity, widely recognized as causing postharvest browning of mushroom tissue, were also significantly lower (P < 0.05) in fruit bodies exposed to 1.2 kGy compared with non-irradiated controls. Our data increase our understanding of the effects of γ-irradiation on the biochemical changes associated with postharvest deterioration in P. nebrodensis, and improve the prospects of more targeted strategies for extending the shelf life of both this and other mushrooms.     

应用于脑出血探测的宽带定向天线研究

设计了一款尺寸为70 mm×30 mm×30 mm的加载三圆式引向器宽带定向天线。该天线采用三维偶极子结构并加载三圆式引向器来改善天线在整个频段内的辐射特性,以满足微波探测脑出血穿透力的需求。天线在S₁₁<-10 dB的工作频带为1.1～3.57 GHz,相对带宽为104.3%,最大增益达到7.24 dBi,相对于未加载引向器的情况,频带内增益最大提高了3 dB。对该天线进行加工测试,实测结果与仿真结果吻合良好。将该天线导入Sim4Life中并进行脑出血仿真研究,结果表明,加载引向器的天线能获得大脑内部更强的散射信号,可应用于脑出血探测等领域。     

nBn型InAsSb探测器的材料及器件研究

nBn型红外探测器可有效抑制产生-复合电流,进而提高探测器的工作温度。由于制备工艺可移植于III/V族成熟工艺以及存在晶格完全匹配的衬底等优势,InAsSb/AlAsSb材料是nBn型红外探测器的首选。简单介绍了InAsSb/AlAsSb nBn型红外探测器的研究现状、工作原理以及近期的研究成果。通过生长试验实现了良好的材料表面质量、晶体质量和光学性能。相关结果表明,在制备器件时,nBn结构中势垒层的掺杂浓度不应低于8×1016cm-3,否则就不利于减小nBn型器件的暗电流。