Antimicrobial activity of dogwood fruits (Cornus drummondii) from winter food caches of eastern woodrats (Neotoma floridana)

Post-harvest loss of resources to microbial competitors affects a number of species of animals, and many of them have evolved behaviors that reduce the likelihood of such loss. We previously described the inhibition ofBacillus psychrophilus by dogwood fruits (Cornus drummondii), which can comprise a significant portion of the winter food cache of the eastern woodrat (Neotoma floridana). The present study is a further investigation of the ability of dogwood fruits to inhibit growth ofB. psychrophilus. Additionally, we tested the antimicrobial activity of dogwood fruits onEscherichia coli andStaphlococcus aureus. Results of our study indicate that fresh fruits inhibit the growth ofB. psychrophilus andS. aureus but notE. coli. However, fruits taken from woodrat dens after four and six months storage inhibited growth of all three species of bacteria. Further, the strength of inhibition increased over the test period. We suggest the presence of an inhibitor allows woodrats to compete effectively for a valuable and limited food resource.     

山茱萸果酒澄清工艺的优化及其抗氧化活性

采用果胶酶对山茱萸果酒进行澄清处理,通过单因素试验和正交试验确定了果胶酶的最佳澄清工艺参数;并利用DPPH自由基（DPPH·）、ABTS自由基（ABTS+·）及羟基自由基（OH·）清除能力测定了山茱萸果酒的抗氧化活性。结果表明,对山茱萸果酒澄清度影响的次序为酶解温度＞酶解时间＞酶添加量;果胶酶用量0.04%、酶解温度40 ℃、酶解时间120 min为最佳澄清工艺条件,在该优化条件下,果酒的澄清度为92.3%,澄清效果较好,果酒感官评分为96分。山茱萸果酒对DPPH·、ABTS+·及OH·的清除率分别为80.62%、82.22%和85.07%,表明其具有一定的抗氧化活性。     

超临界CO2流体萃取山茱萸有效成分的工艺研究(Ⅰ)

应用超临界CO2流体萃取技术进行了萃取山茱萸有效成分的研究，考察了萃取压力、温度、CO2流量、时间等因素对萃取率的影响，得出了超临界CO2萃取山茱萸有效成分的最佳工艺参数：萃取压力为30MPa，萃取温度为45℃，CO2流量为14kg／h，时间为3h。     

Identification of Host Fruit Volatiles from Flowering Dogwood (Cornus florida) Attractive to Dogwood-Origin Rhagoletis pomonella Flies

Solid-phase microextraction and gas chromatography coupled with electroantennographic detection were used to identify volatiles from fruit of flowering dogwood, Cornus florida, as key attractants for Rhagoletis pomonella flies originating from dogwood fruit. A six-component blend containing ethyl acetate (54.9%), 3-methylbutan-1-ol (27.5%), isoamyl acetate (0.9%), dimethyl trisulfide (1.9%), 1-octen-3-ol (9.1%), and -caryophyllene (5.8%) was identified from flowering dogwood fruit that gave consistent EAD activity. In a flight tunnel assay there was no significant difference in the response of individual dogwood flies exhibiting upwind anemotactic flight to volatile extracts from dogwood fruit and the six-component synthetic mixture. Dogwood flies also displayed significantly greater levels of upwind flight to sources with the dogwood volatile blend than with previously identified volatile blends from domestic apple or hawthorn fruit. Selected subtraction assays showed that the three-component mixture of 3-methylbutan-1-ol, 1-octen-3-ol, and -caryophyllene elicited levels of upwind flight to the source equivalent to the six-component mixture. Our study adds to previous ones showing that populations of Rhagoletis pomonella flies infesting apple, hawthorn, and flowering dogwood fruit are attracted to unique mixtures of fruit volatiles, supporting the hypothesis that host fruit odors could be key traits in sympatric host shifts and establishing host fidelity within members of the Rhagoletis pomonella species complex.     

刺葡萄酒香气成分的研究

利用液-液萃取法提取刺葡萄酒中的挥发性香气成分,用气相色谱-质谱（GC—MS）技术进行分析。通过计算机图谱鉴定出47个峰,46种香气物质,并利用面积归一法,计算出一些香气成分的相对含量,其中醇类为主要成分。     

一种复合保健饮料的研究

以山茱萸、羊栖菜为原料,探求山茱萸羊栖菜保健饮料研制的最佳工艺。通过对浸提时间、温度、pH值和风味调配试验配比的单因素和正交试验研究,得出最佳工艺条件为：山茱萸浸提温度为80℃,时间为1h,pH为3.3;混合浓缩液在3500r／min下离心20min。确定最佳风味配方为：山茱萸提取液加入量40ml／100mL、羊栖菜提...     

菠萝果酒酿造工艺的研究

菠萝的营养丰富且具有一定的保健功能。以新鲜的菠萝果实为原料，清洗去皮果肉破碎加果胶酶取汁后，调整糖度至18％、接入12％活性干酵母，20℃发酵9d，可得营养丰富、典型性突出的低度菠萝酒。