传统山西老陈醋增香酵母菌的筛选及其特性研究

为选育山西老陈醋用微生物发酵剂,从传统发酵工艺生产的山西老陈醋中分离筛选到5株增香酵母菌。结合形态学和酵母菌26S rDNA Dl/D2区序列分析,初步鉴定Y1为酿酒酵母(Saccharomyces cerevisiae),Y26为毕赤酵母(Pichia scaptomyzae),Y30为假丝酵母(Candida humilis),Y68为红酵母(Rhodotorula sp.),Y70为盔形毕赤酵母(Pichia membranifaciens)。采用固相微萃取和气-质联用技术分析这5株酵母发酵液的主要挥发性成分。结果表明,醇类和酯类挥发性成分种类和组成差异较大;对这5株酵母菌进行耐酸性、乙醇耐受性、高温耐受性发酵试验,结果表明毕赤酵母Y26具有优良的耐酸性、乙醇耐受性。综合其具有高产乙酯类、低产高级醇的特性,毕赤酵母Y26有望开发为山西老陈醋的新型发酵剂。     

耐高糖酵母的筛选及其在黄酒中的应用研究

从蜂蜜、葡萄、面包3种原料中提取天然酵母进行梯度驯化,再通过紫外诱变育种,筛选出具有耐高糖性质的酵母并对其相关特性进行研究,将筛选出的菌株应用于黄酒酿造过程。结果表明,筛选出的酵母可耐受的糖度、pH值、酒精度分别为40%,1.5和10%Vol,将其应用于黄酒发酵中,经过7 d发酵后,菌株降糖能力较传统菌株提高了20 g/L,酒精度提高了0.4%Vol,糖类物质转化率达到11%。采用自然驯化和紫外诱变育种相结合,得到适用于黄酒酿造生产的耐高糖酵母菌株。     

丙酮溶物对天然橡胶臭氧老化性能影响

天然橡胶中的非胶物质种类和含量影响橡胶的质量和应用性能。本文通过硫化性能、交联密度、耐臭氧老化 性能测试和热重分析研究丙酮溶物含量对天然橡胶臭氧老化性能的影响。结果表明，丙酮溶物可以改善天然橡胶的硫 化性能，提高其交联密度。随着丙酮溶物添加量的增加，天然橡胶的热稳定性、臭氧裂纹显现时间、拉伸强度保持率 逐渐提高并达到最大值。采用衰减全反射傅里叶红外光谱分析仪（ATR-FTIR）分析了天然橡胶臭氧老化前后分子结构 变化，可知橡胶在臭氧老化后出现了氧化官能团。     

除虫菊地上部分水浸液对杂草种苗生长的影响

采用室内培养皿法,测试除虫菊地上部分水浸液对田间常见6种杂草种苗生长的影响。结果表明:不同质量浓度水浸液对杂草种苗生长的抑制作用依质量浓度梯度存在差异,除播娘蒿外其他5种总体均表现"低促高抑"趋势,在最高质量浓度0.03g·mL-1处理下,抑制作用最强;杂草种苗所受抑制作用大小依受体杂草种类存在差异,总体抑制作用由大到小依次为播娘蒿泽漆雀麦婆婆纳反枝苋野燕麦;除虫菊地上部分水浸液对试验杂草生理代谢影响测试表明,高质量浓度水浸液处理下,杂草幼苗受氧化胁迫严重。双子叶杂草较单子叶杂草对水浸液更敏感。     

猴头菌子实体提取物对人肺癌细胞SPCA-1的抑制作用

猴头菌(Hericium erinaceus)子实体的醇提物用不同极性有机溶剂分部提取,得到石油醚、氯仿、乙酸乙酯和正丁醇分部,其中仅石油醚分部能抑制SPCA-1细胞增殖和促进其释放ROS(reactive oxygen species),对石油醚分部的进一步研究发现石油醚分部可诱导SPCA-1细胞早期凋亡和降低G_0/G_1期细胞数量。     

Effects of Yeast Culture on Growth Performance,Meat Quality and Intestinal Microflora of Broilers

The experiment was conducted to study the effects of yeast culture on growth performance, meat quality and intestinal microflora of broilers. A total of 432 1-day-old AA commercial broiler chicks with initial body weight of (41.73±0.15)g were randomly divided into 4 groups with 6 replicates per group and 18 broilers per replicate,receiving diets supplemented with 0,0.1%,0.2% and 0.3% yeast culture, respectively. The trial lasted for 42 days which was divided into two periods with 1 to 21 d and 22 to 42 d,respectively.The feed intake,body weight,death and culling rate were recorded in each period. At the end of the experiment,1 chickens in each replicate with the weight close to the average value were slaughtered after fasting for 12 h. The slaughter performance and intestinal microflora counts were determined.The results showed that compared with control group,the supplementation of 0.2% and 0.3% yeast culture significantly increased the body weight at 42 d and the average daily gain (ADG) during the whole trial (P< 0.05).The diet supplemented with 0.2% yeast culture significantly improved the ADG,decreased the F/G of broilers during 22 to 42 d (P< 0.05),and it also significantly increased the average daily feed intake (ADFI) and ADG (P< 0.05),decreased the F/G of the whole period (P< 0.05).Moreover,the supplementation of 0.2% yeast culture significantly decreased the drip loss of meat and the count of Escherichia coli (P< 0.05),and significantly increased the count of Bifidobacterium(P< 0.05). In summary, the supplementation of 0.2% yeast culture could significantly improve the growth performance and the muscle quality of broilers.The intestinal microflora in broiler cecum were effectively optimized after inclusion of yeast culture in the study.     

草菇子实体提取物的抗氧化活性

为考察草菇(Volvariella volvacea)子实体提取物(VBS)的抗氧化活性,测定了对两种自由基的清除率及其总还原力,结果表明:对羟自由基和DPPH自由基的清除率以及总还原力均与VBS的浓度存在正相关的量效关系,IC50值分别为1.40、0.67、0.63mg/mL。以ICR雄性小鼠为研究对象,灌胃给药12d,再用CCl4花生油溶液灌胃,8h后分别测定超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、丙氨酸氨基转移酶(ALT)和谷草转氨酶(AST)的活力及丙二醛(MDA)的含量,各项指标在血清中的结果表明,VBS中剂量组(200 mg/kg)的抗氧化活性较好,而在肝脏中则表明VBS高剂量组(400mg/kg)的抗氧化活性较好。     

酵母浸膏对北柴胡种子萌发的影响及评价

以北柴胡种子为试验材料,分别以0.5％、1.0％、1.5％和2.0％的酵母浸膏液对北柴胡种子进行浸种,在种子萌发过程中测定相关的生理生化指标,探讨酵母浸膏液对北柴胡种子萌发的影响.含水量的测定采用烘干减重法,体积的测定采用排水法,可溶性糖含量的测定采用蒽酮比色法,蛋白质含量的测定采用考马斯亮蓝-G 250染色法,氨基酸含量的测定采用茚三酮显色法;利用隶属函数法对各项指标进行综合评价.结果表明:北柴胡种子在萌发过程中,种子内含水量的变化和其体积的变化呈一定的相关性,都是呈先下降后上升再缓慢增加的趋势;可溶性糖含量的变化呈先下降后上升再下降的趋势;蛋白质含量整体呈先急剧下降后上升再缓慢下降的趋势;氨基酸含量整体呈先上升后下降的趋势.综合各项指标进行综合评价,酵母浸膏液浸种对北柴胡种子的萌发具有明显的促进作用,其中以1.0％酵母浸膏液浸种效果最佳.