电生功能水对绿豆芽生长促进效果的研究

为了降低豆芽表面的微生物数量,延长其货架期,使用电生功能水代替普通自来水进行豆芽的生产,研究发现,电生功能水在降低豆芽表面微生物数量的同时,对豆芽的生长也具有一定的促进作用。实验证明,经微酸性电解水生产出的豆芽胚轴长和胚根长可分别高出自来水对照20.51%和8.80%。因而将电生功能水应用于豆芽的生产具有广阔的市场前景。     

菱角淀粉与绿豆淀粉的糊化及老化性质共性与区别

通过快速黏度测定仪、差示扫描量热仪等仪器,对菱角淀粉和绿豆淀粉的糊化以及老化性质进行一系列的研究比较并分析其对粉丝品质的影响;主要通过测定淀粉直链淀粉含量、溶解度和膨润力、淀粉糊黏度性质、存放过程中的淀粉糊浊度和凝沉性变化以及热力学特性,综合分析得知,菱角淀粉直链淀粉含量以及回生能力大于绿豆淀粉,菱角淀粉糊的冷热稳定性较差,糊的黏度远小于绿豆淀粉。     

A research note: the potential for transfer of Salmonella from irrigation water to tomatoes

The transmission of Salmonella Enteritidis from soil to fruit by contaminated irrigated water was studied using 20 patio tomato plants. In order to track the presence of Salmonella in the soil and plants a luminescent strain transformed with the full luxCDABE gene cassette from Photorhabdus luminescens was used. The tomato plants were irrigated every other day by direct application of water containing Salmonella Enteritidis (10⁵ CFU ml^?1) to the soil. Samples of soil, stem, leaf and fruit were taken weekly and assayed for Salmonella by plating onto Luria Bertani agar containing 50 µg ml^?1 ampicillin. There was a significant difference (P < 0.05) in Salmonella counts from soils sampled during the course of the study. No Salmonella were recovered from the leaf, stem, and fruit samples taken from the tomato plants. This indicates that, under these test conditions, watering with contaminated water directly into the soil does not result in the transmission of Salmonella, and possibly other pathogens, to tomatoes. Copyright © 2004 Society of Chemical Industry     

Optimization of acidified warm water treatment to improve the microbiological status and sensory quality of iceberg lettuce

The optimal conditions of washing iceberg lettuce with acidified warm water to improve the hygienic and sensory product quality were determined with the aid of a central composite design. To determine the criteria of product quality, in the course of storage for 13 days at 4 °C lettuce was subjected every 2 days to sensory evaluation. The sensory values were found to correlate with the physical measurements of color (a* value) (R²=0.83) and texture (specific energy of deformation) (R²=0.77), respectively. Color, texture and overall visual quality correlated with product acceptability (R²=0.96, 0.97, 0.96, respectively). In the experiments of series I, the effect of temperature at washing (45–50 °C), pH (4–5) and treatment time (5–10 min) were investigated and the results were used for the construction of a model to describe the effects on color and texture and to define an area of sensory product acceptance. In series II the parameters were changed to ranges of temperature (45–50 °C), pH (4.6–6) and treatment time (2–5 min), and the effect on the reduction of bacterial counts within the area of product acceptance was defined. In that area reduction rates of total counts by 0.9–2.9 log cfu/g and Enterobacteriaceae by 0.8–3.0 log cfu/g were achieved. The initial germ- reducing effect was sustained until the end of storage for 7 days at 4 °C. At 50 °C, washing for 5 min at pH 4.93, the total bacteria and Enterobacteriaceae were reduced by 2.9 and 3.7 log cfu/g, respectively. The removal of the two groups of bacteria exhibited characteristic differences. Two independent experiments confirmed the reliability of the models.