为了解米粉发酵不同时期的乳酸菌多样性,以5?组0～4?d发酵液样品为研究对象,利用高通量测序技术进行乳酸菌多样性和功能预测分析.结果表明,15?个样品共得到278?个OTU,包括5?个门,27?个属;整个发酵过程中乳杆菌属(Lactobacillus)占绝对优势,相对丰度均在99％以上.随着发酵时间延长,乳酸菌多样性降低,种水平上0?d有32?个种,发酵4?d后仅有12?个种.除乳杆菌属外,样品中还有乳球菌属(Lactococcus)和明串珠菌属(Leuconostoc).PICRUSt功能预测分析表明,不同发酵时期样品均获得氨基酸转运和代谢、碳水化合物转运和代谢、脂质转运和代谢、辅酶转运和代谢、能源产生和转换等与代谢相关的基因.本实验结果为进一步研究乳酸菌对米粉食用品质影响的作用机制,开发米粉专用发酵剂提供理论依据.

该文以米粉发酵液为样品进行发酵米粉优良菌株的分离筛选及鉴定研究.从米粉发酵液样品中分离118株产乳酸细菌,首先通过产酸能力为指标筛选出产酸能力较强的35株菌株,再利用主成分分析方法,通过测定菌株产淀粉酶、蛋白酶、脂肪酶活性,最终得到7株性能优良的菌株.这7株菌株大米发酵液pH为4.21～4.50,淀粉酶活性为97.74～210.43 U/mL,蛋白酶活性为3.97～9.34 U/mL,脂肪酶活性为0～2.15 U/mL.通过形态学特征观察、生理生化试验和16S rDNA序列分子鉴定,确定R133、R02、R1212、R1310、R13为戊糖片球菌(Pediococcus pentosaceus),R29为发酵乳杆菌(Lactobacillus fermentum),R112枯草芽孢杆菌(Bacillus subtilis).这7株菌株具有制备米粉专用发酵剂良好的应用前景.

为了探究米粉生产过程中大米发酵液的菌相变化规律,以不同发酵时间的大米发酵液为研究材料,测定pH值的变化;采用选择培养基进行细菌、乳酸菌、霉菌酵母、球菌及肠杆菌的菌落计数和形态观察,并运用修正的Gompertz模型对菌落总数和乳酸菌进行生长动力学模型的拟合.结果表明,大米发酵液主要含有乳酸菌、霉菌酵母、球菌,其中乳酸菌数量最高,达2.56×108 CFU/mL,采用修正的Gompertz模型能较好地拟合大米发酵液中菌落总数及乳酸菌的生长情况,获得最大比生长速率分别为0.657 d-1、1.418 d-1,延滞期(LPD)分别为0.023 d、0.224 d,稳定期最大菌落数对数值分别为8.40、8.41,且模型的判定系数R2均>0.95.此结果为进一步研究米粉发酵剂、保证米粉发酵质量、维护食品安全提供依据.

发酵米粉比未发酵米粉可以获得更好的口感和品质,发酵过程中微生物对发酵米粉的品质有重要作用.了解发酵米粉中的主要微生物及其对米粉品质的影响,既能为提高传统自然发酵米粉的品质提供参考,又能促进现代生物技术在米粉发酵上的应用.综述了发酵米粉主要微生物的组成及其对米粉的理化性质、微观结构、感官品质、安全性的影响和目前利用纯菌种强化发酵对米粉品质的影响等方面的研究进展,并对目前研究中存在的问题进行了总结,对未来的研究趋势进行了展望.

通过研究影响脱胶的主要因素来确定最适高油酸双低油菜籽油的脱胶工艺,采用响应面法对脱胶工艺进行优化,确定了脱胶的最佳工艺条件:834 mg/kg聚合氯化铝添加量4.0％,在46.6℃,保温静置2.5 h.在此条件下,磷脂残留量为(0.206±0.005)mg/g.

通过梳理影响化学开放实验室安全的几个关键因素,湖南农业大学食品科技学院在结合学校规范管理的基础上,根据自己的专业特色和实验室情况,结合工作经验,从细节入手,在安全管理方面进行了探索与实践,进一步提高了服务与管理水平.

系统阐述了开放化学实验室的特点,从可能引起实验室安全隐患方面入手分析开放化学实验室可能存在的安全隐患,并就开放化学实验室安全管理体系的建设和实践提出了从管理制度建设、安全教育、应急预案与应急演练等方面对开放实验室进行有效的管理的方法.

探究以秀珍菇为基础原料,适当添加辅料,制备秀珍菇软罐头的方法.通过采用单因素试验和正交试验,以感官评分为指标对加工过程进行优化,运用模糊数学评价法对感官评分进行计算,得到的最佳柠檬酸护色液为含量为0.100％;最佳汤汁配方为泡椒水与凉开水体积比为1∶4.00、食盐0.10％、食醋1.00％,同时比较了不同杀菌时间对杀菌效果的影响,综合杀菌效果和产品感官影响,采用沸水浴加热20 min的杀菌工艺既可使秀珍菇在30 d内微生物总数在正常值范围类,又可保持秀珍菇正常的色香味.研究结果为开发香气、色泽、汤色和滋味俱佳的秀珍菇软罐头提供参考.

油茶籽壳活性成分,包括总黄酮、高活性膳食纤维、原花青素、多糖、茶皂素单宁及木糖醇等,具有抗菌、抗氧化、抗紫外照射等生理功能.综述油茶籽壳活性物质提取及功能研究进展,为合理有效地综合利用油茶籽壳资源提供参考.

为了系统地揭示储藏期油茶籽霉菌多样性,从广西百色地区采购、在自然条件下储藏15个月霉变的油茶籽(带油茶籽外壳)为检测材料,采用平板菌落计数法进行油茶籽壳、仁可培养霉菌总数测定,Miseq高通量测序方法进行油茶籽壳、仁样品ITS区高通量测序分析.结果表明:油茶籽壳、仁霉菌总数分别为(3.25±0.28) lg CFU/g和(2.70±0.49) lg CFU/g;油茶籽壳、仁真菌有效序列分别为42 332条和34 625条,序列数趋势与可培养霉菌计数结果一致;在97％的相似水平下对所有序列进行操作分类单元(Operational Taxonomic Units,OTU)的划分,油茶籽壳有69个OTU、油茶籽仁有57个OTU;真菌种类覆盖了4个门、26个科、31个属,油茶籽壳、仁的污染霉菌主要是曲霉属(Aspergillus)、节担菌属(Wallemia),其中曲霉属在油茶籽壳中占81.51％,在油茶籽仁中占74.50％,除该属外,节担菌属在油茶籽壳中占10.75％,在油茶籽仁中占18.42％.

依据油茶籽油与菜籽油亲水性不同的特点,通过震荡观察法观察纯油茶籽油、纯菜籽油以及混合标准油(油茶籽油中掺入5％菜籽油)与水混合震荡后所呈现的特征现象,以期鉴别油茶籽油中是否掺有菜籽油,并与电子鼻和醋酸酐-浓硫酸法的测定结果进行比较.试验结果表明:只需使用水、亚甲基蓝及试管等廉价材料即可在16 min内完成对油茶籽油是否掺伪的鉴别,其灵敏度可满足人们日常检测的需要;另外,此法对商品油掺杂鉴定的结果与电子鼻法和醋酸酐-浓硫酸法的检测结果基本一致,证明了此法的可行性和准确性.

以油茶皂素的提取率作为响应值,用响应面法对既能充分发挥壳聚糖凝聚油茶籽工艺水中杂质,又不影响油茶皂素提取的工艺条件进行优化.在考虑壳聚糖浓度及添加量、反应时间及温度、搅拌速度等因素对油茶皂素提取率影响的基础上,筛选出主要影响因素即壳聚糖添加量、反应时间、反应温度进行正交试验,通过响应面分析,得出3种因素的相互作用及最佳提取条件.结果表明,在壳聚糖浓度为0.05％,搅拌速度为10 r/min,壳聚糖添加量为17.8 mL,反应温度为50.1℃,反应时间为16.6 min的优化条件下,油茶皂素提取率为84.97％.

This experiment was conducted to study the effect of "water enzyme method" tea seed meal on growing and finishing pigs, the possibility that tea seed mea used as feed ingredient was dis?cussed. Through single factor experiment design, the ratio of tea seed meal replace wheat bran in feed formula were 3%(group 1), 4%(group 2), 5%(group 3), the control group was nomarl feed without tea seed meal. This experiment was conducted to choose 72 barrows(Duroc × Landrace × Yorkshire), which were allotted to 4 treatments with 3 replicates per treatment and 6 barrows per replicate.Growth perfor?mance, and related blood biochemical indexes were determined. The results in growing process showed as follows: ①The ADG among control group, group 1 and group 2 were no significantly different(P>0.05), control group was significantly higher than group 3(P<0.05); F/G showed no significantly differ?ent among four groups(P>0.05). ②serum aspar?tate aminotransferase(AST), alanine aminotrans?ferase(ALT), blood urea nitrogen(UREA) and al?kaline phosphatase (ALP) showed no significant difference among four groups(P>0.05). The diar?rhea was in the normal range.The results in finishing process showed as follows:①The daily intake among control group, group 1 and group 2 were no significantly different(P>0.05), control group was significantly higher than group 3(P<0.05); The ADG of control group was sig?nificantly higher than others(P<0.05), The ADG of group 1 was significantly higher than group 3(P<0.05). The F/G of control group was significantly lower than others(P<0.05), the F/G among group 1, group 2 and group 3 had no significant difference (P>0.05). ②The content of glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) in control group were not significantly higher than others(P>0.05), the content of serum superoxide dismutase (SOD) in control group were significantly lower than others(P<0.05). ③Organs were normal after slaughtered. This experiment showed that: water enzyme method tea seed meal has certain value in the feed, with low adding(less than 4%);The active ingredi?ent such as polysaccharide and polyphenol which was left from oil extraction was help to protect the health of pigs.

采用水酶法、水代法、压榨法及有机溶剂浸提法制取油茶籽油,并对这4种油茶籽油的理化指标、角鲨烯及苯并芘含量、脂肪酸组成、抑菌效果进行了对比分析.结果表明:制取工艺对油茶籽毛油的理化性质、角鲨烯及苯并芘的含量影响显著;水酶法和水代法制得的毛油的理化指标、角鲨烯及苯并芘含量都相近;浸出法制得的毛油酸价、过氧化值均最低,角鲨烯含量最高;压榨法制得的毛油品质较差.这4种制油工艺得到的油茶籽油的脂肪酸组成与含量较为相近.5％的油茶籽油即能较好地抑制大肠杆菌、金黄色葡萄球菌、沙门氏菌3种致病菌的生长,但以浸出法毛油的抑菌效果最佳.

以油茶籽仁浆液为原料,以油脂提取率为指标,利用单因素试验及响应面中心组合试验研究了酶制剂的配方、料水比、复合酶添加量、酶作用时间等因素对水酶法提取油茶籽油的影响.得出优化的提油条件为:先加入高温淀粉酶再加入酸性蛋白酶,二者比例为1:1,复合酶添加量0.13％、料水比1:3.9、酶作用时间4h,在此条件下油茶籽油的提油率为92.45％.

In order to enhance the comprehensive use value of protein in double-low rapeseed dregs after oil extraction with aqueous-enzymatic method, the technology of brewing soy with double-low rapeseed dregs was studied. The results showed that the optimal fermentation conditions were as followed: mixed inoculation of Aspergillus oryzae No.1, Aspergillus niger No.1 and Trichoderma viride with 3:2:1; making yeast at 28℃ with humidity of 95%; adding 15% salt water to the yeast, and then fermenting at 42℃ for 20 d. The soy fermented with the optimal conditions, its quality can meet the standards of second level soy stated in GB 18186-2000.

T he application of phytosterols nutrition enhancer in rapesee d oil w as investigated in this study, the results show ed that the phytosterol could be dissolved in rapeseed oil at a high ratio w hen tem perature reaches its m elting point, and recrystallized w hen the oil becom es cool. T he final am ount of added phytosterols in rapeseed oil depends on the types and proportion of phytosterols. A nd appropriate stirring can preventfoam ing and bum ping in the process ofadding phytosterols.

Penicillium was screened for the degradation of camellia saponin.The optimal condition for Penicillium culture and camellia saponin degradation was determined through single factor test and L9(34)orthogonal test.The best culture conditions were: culture temperature 28 ℃,inoculation dose 12%,pH 4.5,and Penicillium cultivating time 5 days.Under these condition degradation rate of camellia saponin could reached 83.11%.

The main chemical composition of Iron Dioscorea opposita Thunb,was determined and compared with common Dioscorea opposita Thunb.Results showed that the solids content of fresh Iron Dioscorea opposita T.was 28.67%,far higher than the content of 13.86% of common Dioscorea opposita T.The content of total nitrogen,total ash,starch and glycosaminoglycan was 0.616%,2.03%,15.29% and 1.59% respectively,which were higher than that of common Dioscorea opposita T.,which was 0.154%,1.36%,6.57% and 1.47% respectively.The nutrient value of iron Dioscorea opposita T.is much higher than common Dioscorea opposita T.,which is worth of further reseach and developement.