基于温度-伤害度关系分析酿酒葡萄根系及芽抗寒性

采用差热分析系统(DTA)对8个主栽酿酒葡萄品种的芽和根系进行低温放热分析(LTE),建立各品种芽、根系韧皮部及木质部的温度-伤害度(LT-I)回归方程,评估不同品种的根系及芽抗寒性.结果表明： 8个品种的根系韧皮部伤害度50%的温度从高到低为马瑟兰>品丽珠>赤霞珠>小芒森>霞多丽>蛇龙珠>贵人香>熊岳白;不同品种木质部伤害度50%的温度从高到低为马瑟兰>霞多丽>赤霞珠>小芒森>品丽珠>蛇龙珠>贵人香>熊岳白;芽伤害度50%的温度从高到低为赤霞珠>小芒森>蛇龙珠>品丽珠>霞多丽>贵人香>马瑟兰>熊岳白.利用模糊隶属函数值法综合评价根系及芽的抗寒性,马瑟兰根系的抗寒性最差,熊岳白根系的抗寒性最好;赤霞珠、品丽珠、小芒森和蛇龙珠芽的抗寒性最差,贵人香和熊岳白芽的抗寒性最好.     

Evaluation of stereoisomers of 2,3-butanediol and acetoin to differentiate Saccharomyces cerevisiae and Kloeckera apiculata wine strains

The (R)/(S) ratios of acetoin were always higher in wines obtained by Saccharomyces cerevisiae than in those obtained by Kloeckera apiculata. A significantly different behaviour was determined between the two species as regards contents and ratios of 2,3-butanediols: S. cerevisiae produced more (R,R)-2,3-butanediol (about 80%), whereas K. apiculata produced more meso-form (about 90%).     

The selection of yeast strains for the production of premium quality South African brandy base products

One hundred seven yeast strains were screened for their ability to produce a brandy base wine of exceptional sensory quality. Volatile acids, esters and higher alcohols were quantified and the results were interpreted using a multivariate analysis of variance (MANOVA) and an average linkage cluster analysis. Significant differences between yeast strains for higher alcohol, fatty acid ester and acetate concentrations were observed. On the basis of their chemical profiles, 16 strains were selected and re-evaluated in larger-scale fermentations and subsequent double distillations. Results show that the yeast lees can have an important effect on the final concentration of higher alcohols and esters in the distillate. Highly elevated levels of ethyl acetate and iso-amyl acetate were found to be undesirable. Elevated levels of all the esters present contributed positively to the overall potential quality of the brandy base product. Too low higher alcohol concentrations were also not desirable. Sensory evaluations showed that, since the panel was composed of representatives of the three largest brandy-producing companies, each company preferred a different yeast strain most suitable for their style of brandy. For these reasons, three strains, B7, LL2 and 20-2, warranted further evaluation on a semi-commercial scale for each of the respective companies. Journal of Industrial Microbiology & Biotechnology (2000) 24, 431–440. Received 17 November 1999/ Accepted in revised form 07 March 2000     

Geographic variation in plasticity in Eristalis arbustorum

To study the evolution of phenotypic plasticity in the field, six populations of the hoverfly Eristalis arbustorum were sampled along two parallel North-South transects over a maximum daily temperature gradient. Three populations were sampled per transect. Egg batches were collected and the offspring were reared in a split family set up over three different pupal temperature regimes in the laboratory to produce population reaction norms of colour pattern, pupal development time, wing length and thorax length. Wing length and colour pattern were corrected for body size. All four characters showed plasticity in response to rearing temperature and significant differences in height, slope and shape of the reaction norms were found. Only male colour pattern showed variation in reaction norms along the North-South gradient. Most other characters showed variation in reaction norms from West to East. The two populations lying in the middle of the transects were frequendy different from the others. Within the populations, significant genotype-environment interactions were frequently found for wing length and colour pattern, indicating that genetic variation for plasticity was present. The results suggest that the populations may have evolved plastic responses to suit local environmental conditions.     

Effects of alcoholic beverage treatment on spatial learning and fear memory in mice

Although chronic ethanol treatment is known to impair learning and memory, humans commonly consume a range of alcoholic beverages. However, the specific effects of some alcoholic beverages on behavioral performance are largely unknown. The present study compared the effects of a range of alcoholic beverages (plain ethanol solution, red wine, sake and whiskey; with a matched alcohol concentration of 10%) on learning and memory. 6-week-old C57BL6J mice were orally administered alcohol for 7 weeks. The results revealed that red wine treatment exhibited a trend toward improvement of spatial memory and advanced extinction of fear memory. Additionally, red wine treatment significantly increased mRNA levels of brain-derived neurotrophic factor (BDNF) and N-methyl-D-aspartate (NMDA) receptors in mice hippocampus. These results support previous reports that red wine has beneficial effects.     

Derepressed utilization of L-malic acid and succinic acid by mutants of Pachysolen tannophilus

Utilization of the tricarboxylic acid (TCA) cycle intermediates, L-malic acid and succinic acid, by the yeast Pachysolen tannophilus is repressed in the presence of glucose. Strains of P. tannophilus containing mutations in two hexokinases and a glucokinase were characterized for growth on glucose plus L-malic acid or succinic acid. Increased specific utilization rates of malic acid and succinic acid in the presence of glucose were observed in mutants containing a lesion in hexokinase A, an enzyme associated with catabolite repression. Such derepressed mutants may have application in winemaking in which utilization of a major grape acid, L-malic acid, is often desirable for acidity reduction. Received 04 October 1996/ Accepted in revised form 13 March 1997     

Stereoselective Behavior of the Fungicide Benalaxyl During Grape Growth and the Wine‐Making Process

Benalaxyl is widely applied as a fungicide during grape planting processing. In this experiment, the stereoselective behavior of benalaxyl was studied during the grape growth and wine‐making process. A simple method based on high‐performance liquid chromatography (HPLC) equipped with a chiral column and UV detector was established to separate and determine the enantiomers of benalaxyl. Stereoselective degradation of the two enantiomers of benalaxyl was found in grapes. The degradation of both enantiomers followed pseudofirst‐order kinetics, and the degradation rate of R‐(?)‐benalaxyl was faster than S‐(+)‐benalaxyl. The half‐life of R‐(?)‐benalaxyl was 27 h, while the half‐life of S‐(+)‐benalaxyl was 31 h. The enantiomer fraction value decreased from 0.50 to 0.34 and finally only S‐(+)‐benalaxyl could be detected. In the fermentation process, both enantiomers of benalaxyl were hardly degraded, and no configuration interconversion was observed. Meanwhile, both enantiomers of benalaxyl showed little influence on the growth of the yeast, consumption of carbon sources, or production of alcohol. The result of this study might provide more sufficient data for the evaluation of food safety and potential risk. Chirality 28:394–398, 2016. © 2016 Wiley Periodicals, Inc.     

Red wine activates plasma membrane redox system in human erythrocytes

In the present study, we report that polyphenols present in red wine obtained by a controlled microvinification process are able to protect human erythrocytes from oxidative stress and to activate Plasma Membrane Redox System (PMRS). Human plasma obtained from healthy subjects was incubated in the presence of whole red wine at a concentration corresponding to 9.13–73?μg/ml gallic acid equivalents to verify the capacity to protect against hypochlorous acid (HOCl)-induced plasma oxidation and to minimize chloramine formation. Red wine reduced hemolysis and chloramine formation induced by HOCl of 40 and 35%, respectively. PMRS present on human erythrocytes transfers electrons from intracellular molecules to extracellular electron acceptors. We demonstrated that whole red wine activated PMRS activity in human erythrocytes isolated from donors in a dose-dependent manner with a maximum at about 70–100?μg/ml gallic acid equivalents. We also showed that red wine increased glutathione (GSH) levels and erythrocytic antioxidant capacity, measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) quenching assay. Furthermore, we reported that GSH played a crucial role in regulating PMRS activity in erythrocytes. In fact, the effect of iodoacetamide, an alkylating agent that induces depletion of intracellular GSH, was completely counteracted by red wine. Bioactive compounds present in red wine, such as gallic acid, resveratrol, catechin, and quercetin were unable to activate PMRS when tested at the concentrations normally present in aged red wines. On the contrary, the increase of PMRS activity was associated with the anthocyanin fraction, suggesting the capacity of this class of compounds to positively modulate PMRS enzymatic activity.