高温大曲中的微生物研究

通过对茅台高温大曲制曲发酵过程进行跟踪检测,初步分离出地霉属、汉逊酵母属、假丝酵母属、毕赤酵母属、丝孢酵母属、红酵母属6种酵母;枯草杆菌群、地衣芽孢杆菌、凝结芽孢杆菌、蜡状芽孢杆菌、苏云金芽孢杆菌等41种细菌;曲霉属、毛霉属、根霉属、犁头霉属、红曲霉属、青霉属、拟青霉属等51种霉菌,共98种微生物.研究发现,高温大曲发酵过程中的微生物总数以细菌为主,高达2.118x107cfu/g·曲;霉菌次之,为6.446x106cfu/g·曲;酵母最少,仅有6.6×104cfu/g·曲.种类却以霉菌为最多,高达51种;细菌次之,为41种;酵母最少,仅发现6种.随着发酵过程的进行,微生物呈现出不同的消长规律,前期以细菌为主,中后期霉菌大幅度增多,在前期和后期酵母偶有发现.     

酿酒工艺对黄酒中生物胺的影响

采用高效液相色谱技术,针对黄酒酿造工艺,模拟实际生产,分析了微生物、工艺参数和冷热处理等对黄酒中生物胺含量的影响。结果表明,酵母Y可使生物胺总量降低,霉菌M可使生物胺总量增加,细菌除戊糖片球菌L04使生物胺总量降低外,其他细菌均可使生物胺总量增加;在培养温度32 ℃,培养时间3 d,pH值为3.5,酒精体积分数15%的条件下,生物胺总量为60.19 mg/L;煎酒使生物胺含量增加,冷冻过滤技术因有效降低酪胺含量使生物胺总量大幅降低。     

Chemometrics Assess Quality of Breadmaking Starters

Chemometric techniques were used to evaluate 15 wheat doughs containing different starter cultures to establish quality indexes based on objective measures. Correlations were determined among microbial starters, consumer acceptance and anyltical variables, and variables necessary for quality assessment were reduced. In stepwise discriminant analysis six variables were significant (p < 0.95) and used in discriminant functions. Dendograms showed similarities among cases. Strong correlations were found between sensory scores ad some fermentative, biochemical and physical measures. The same variables were significant in formation of clusters by K-means clustering analysis. In factor analysis, the first three factors, accounting for 70% of variability, related to the same variables. Relationships between over-all acceptance and other parameters explained differences in sensory evaluation.     

MICROBES AND GRAIN GERMINATION

The germination of grains that had been steeped in solutions/suspensions of antibiotics was improved relative to water-steeped controls. The effect of the antibiotics was most striking for dormant grain that had been steeped for 90 min rather than 60 min. By incubating decorticated grains under different amounts of water it was shown that restriction of air to decorticated dormant grains reduced germination much more than was the case with decorticated, mature grains. Incubating the dishes of grain in oxygen, rather than air, overcame the inhibitory effect of excess water, confirming that it was the restriction of the oxygen supply by the water that checked germination. It was shown that sprays of dilute sulphuric acid favoured grain germination by acting on the outer layers of the grain. When acid-sprayed and untreated samples were decorticated and incubated their germination rates under different test conditions were essentially identical. In contrast gibberellic acid was shown to exert its germination-stimulating effects and sodium hydroxide its inhibitory effects on the internal tissues. By comparing the respiration rates of ground samples of grain (entire and decorticated; untreated and surface-sterilised) it was shown that microbes in the surface layers have substantial oxygen uptake rates. It seems that the competition of these microbes with the grain tissues for oxygen is a major cause of dormancy.     

Natural antioxidant extract from galangal (Alpinia galanga) for minced beef

Raw and cooked minced beef samples containing commercial antioxidants or galangal (Alpinia galanga) extract were evaluated for storage stability at 4 ± 1 °C. Thiobarbituric acid (TBA) values of raw and cooked samples containing galangal extract at 5 and 10% (w/w) were significantly (p < 0.05) lower than those of the controls. In raw beef, galangal extract at 10% (w/w) was as effective as α‐tocopherol at 0.10% (w/w) and butylated hydroxytoluene (BHT) at 0.02% (w/w) in inhibiting/minimising lipid oxidation. Galangal extract also delayed the induction period of lipid oxidation in cooked beef but was again observed to be effective at a higher concentration than the commercial antioxidants studied. No difference in total plate count was observed in raw beef, but samples with galangal extract had higher Hunter a (redness) and chroma (colourfulness relative to the brightness of the surroundings) values. However, cooked beef treated with galangal extract or antioxidants had lower Hunter a values and total microbial counts than the control. Thus galangal extract may be a possible natural antioxidant source for meat and meat products. © 2000 Society of Chemical Industry     

印染废水水解酸化作用及其调控研究进展

阐述了水解酸化工艺的机理,介绍了其以独立的工艺或与其他工艺相结合在印染废水处理中的应用,并分析了水解酸化过程中微生物及其产生的胞外酶的作用。另外,本文还总结了水解酸化阶段的优化调控方法,包括直接投加菌剂或共代谢基质类物质和投加激活剂,并概括了水解酸化调控效果的评价指标,包括pH值、色度、挥发性脂肪酸VFA、BOD5/COD、有机物组成的变化、酶活、微生物种群结构变化。目前,虽然水解酸化工艺在印染废水处理中应用广泛且有所成效,但是对其中微生物的作用机制尚不十分了解,无法有针对性地对功能菌群进行优化调控。本文提出在深入探讨微生物作用机理的基础上,针对功能菌群进行优化调控,是提高水解酸化速率的一个有效途径,从而最大限度地发挥水解酸化工艺在印染废水处理中的作用。     

竹叶对食品致病菌的抑菌作用

竹叶的乙醇醋酸提取液Ａ和乙醇提取液Ｂ对食品致病菌伤寒沙门氏菌，痢疾志贺氏菌、小肠结炎耶尔森氏菌、金黄色葡萄球菌，蜡样芽孢杆菌，魏氏梭菌，肉毒梭菌均有不同程度的抑制作用。在相同时间内，竹叶提取液浓度越高，抑菌率就越高。同一浓度的提取液，作用时间越长，抑菌率也就越高。     

衡阳酒药中微生物的初步分离

通过平板稀释分离法,对衡阳酒药的微生物组成、菌落形态以及主要酶活力进行初步分离和分析.结果表明,自然制曲成熟的衡阳酒药中主要的微生物为酵母菌、霉菌和细菌,放线菌数量不多,霉菌中根霉的淀粉酶和蛋白酶活力旺盛.     

空间诱变优良上面啤酒酵母发酵性能研究

以中德啤酒技术中心303上面啤酒酵母为出发菌株,将经过"神舟九号"宇宙飞船搭载进行航天诱变的303上面啤酒酵母菌进行分离得到若干菌株,对其中3株酵母的酵母凝聚性、发酵度、双乙酰还原能力、外观糖度变化、高级醇和酯类物质进行检测,从而选出1株优良的上面啤酒酵母菌。     

Microbial conversion of food wastes for biofertilizer production with thermophilic lipolytic microbes

Food waste is approximately one quarter of the total garbage in Taiwan. To investigate the feasibility of microbial conversion of food waste to multiple functional biofertilizer, food waste was mixed with bulking materials, inoculated with thermophilic and lipolytic microbes and incubated at 50 °C in a mechanical composter. Microbial inoculation enhanced the degradation of food wastes, increased the total nitrogen and the germination rate of alfalfa seed, shortened the maturity period and improved the quality of biofertilizer. In food waste inoculated with thermophilic and lipolytic Brevibacillus borstelensis SH168 for 28 days, total nitrogen increased from 2.01% to 2.10%, ash increased from 24.94% to 29.21%, crude fat decreased from 4.88% to 1.34% and the C/N ratio decreased from 18.02 to 17.65. Each gram of final product had a higher population of thermophilic microbes than mesophilic microbes. Microbial conversion of food waste to biofertilizer is a feasible and potential technology in the future to maintain the natural resources and to reduce the impact on environmental quality.