Isolation of Saccharomyces cerevisiae strains producing higher levels of flavoring compounds for production of "cachaça" the Brazilian sugarcane spirit

In Brazil, spontaneous fermentation and open vessels are still used to produce cacha?a (the Brazilian sugarcane spirit) and this fermentation is characterized by mixed cultures with continuous succession of yeast species. This work shows the development of a methodology for isolation of yeasts, particularly Saccharomyces cerevisiae, used in the production of cacha?a. According to the proposed strategy, the strains were selected for their ability to adapt to stress conditions encountered during fermentation of the sugarcane juice such as high sucrose concentration; high temperatures and high alcohol concentration; for their capacity to flocculate; and for their higher fermentative ability. For strains with such characteristics, specific procedures were employed to select for 5,5,5-trifluoro-DL-leucine (TFL) and cerulenin-resistant strains, since these characteristics are related to a higher capacity of production of the flavoring compounds isoamyl alcohol and caproic acid, respectively. The effectiveness of such a selection strategy was documented. Taken together, the results obtained present the development of a new strategy to isolate yeast strains with appropriated characteristics to be used in the cacha?a industry. Moreover, the results obtained offer an explanation for the great variability in terms of chemical composition found in products obtained even in a single distillery.     

Effect of free-SH containing compounds on allyl isothiocyanate antimicrobial activity against Escherichia coli O157:H7

ABSTRACT:  Escherichia coli O157:H7 contamination is a significant meat safety issue in many countries. Allyl isothiocyanate (AIT) is a natural compound found to limit the survival of E. coli O157:H7 and other pathogens in meat and meat products. In the present study, it was found that glutathione and cysteine naturally present in meat can interfere with AIT antimicrobial activity. Spectroscopy, HPLC, and LC-MS were used to confirm that glutathione was able to react with AIT and formed a conjugate with no or low bactericidal activity against the tested organisms. The same reaction also occurred at pH values of 4.9 and 5.8 at 25 and 4 °C, respectively, which broadly represent storage conditions in raw beef (pH 5.8) and during fermented sausage (pH 4.9) manufacture. Reactions observed help to explain reduction in antimicrobial potency of AIT in food (meat) systems.     

Effect of high-pressure homogenisation on metabolic potential of Lacticaseibacillus paracasei 90: in vitro and in situ studies in fermented milk and semihard cheese

The influence of high-pressure homogenisation (HPH) at 100 MPa on Lacticaseibacillus paracasei 90 (L90) was studied in vitro and in situ (fermented milk and cheese). Lysis and injury signs were observed in cells treated with HPH, which were linked to the release of intracellular enzymes and changes in the metabolic activity of L90. HPH treatment led to a higher lactic acid content and lower pH and pyruvic acid levels in fermented milk. The microbiological and peptide profiles of cheeses were modified by using cells or cell-free extracts of L90. Finally, this study suggests that L90 could release bioactive peptides.     

Blockchain and smart contract architecture for notaries services under civil law: a Brazilian experience

International Journal of Information Security - This paper proposes a blockchain solution for some activities currently performed by notary offices under the Civil Law judiciary that is technically...     

面向肌电信号的虚拟现实提线木偶动画研究

泉州提线木偶属于首批中国非物质文化遗产，是中华传统文化的实现形式之一.然而，由于木偶体积庞大，携带与操作不便，直接限制了其受众群体.为了实现提线木偶的有效传承与保护，设计了基于手势识别的虚拟现实提线木偶动画方案，构建了基于MYO臂环肌电信号的人体生理信号控制动画原型系统，应用两个用户实验验证了算法的高精确性与易操控性.首先，通过低通滤波与平滑实现多通道肌电信号数据的信号处理.其次，提取八通道时域特征与时频域特征，并通过线性判别器将其降维为六维特征向量，实现特征间关联性消除与算法鲁棒性增强.最后，构造多分类支撑向量机实现特征向量，确定手势识别结果.实验验证算法离线动作平均识别准确率为95.59%，实时动作平均识别准确率达到90.75%，在1.1s左右完成手势识别.面向提线木偶任务，构造了两个用户体验任务，普通用户人群中，木偶动作识别率较高，用户使用意愿、易学性等方面，系统性能亦显著高于真实木偶操控；专业用户在承认系统可用性的同时，具有较高的接受度.用户任务表明该设计满足了手势识别实时性和准确性的要求，具有良好的交互性和趣味性.相关研究可以广泛地应用于计算机动画等类似的系统，对于体验和保护提线木偶具有现实意义.     

Near-infrared spectroscopy: A possible routine analysis to detect the use of frozen curds in the production of Buffalo Mozzarella cheese

Mozzarella di Bufala Campana is a pasta filata cheese with a Protected Designation of Origin whose specifications require the use of fresh milk, forbidding the use of frozen curds. The goal is to develop a routine analysis to identify frozen curd presence. The Buffalo Mozzarella samples were analysed by the near-infrared analytical technique, and the spectral data were processed through an artificial neural network. The results make it possible to identify the use of frozen curd in samples of Buffalo Mozzarella for up to 9 days of storage. The model reported very high accuracy either in training (0.5% of bad prediction) or in tests (6.8% of bad prediction).     

Occurrence and survival of Campylobacter spp. in dairy matrices investigated by viability qPCR

The aim of this study was to investigate the survival of Campylobacter jejuni in dairy matrices by viability qPCR. Survival in UHT milk was examined first and the cheese outbreak strain, C. jejuni 11 218 showed enhanced tendency to become viable but nonculturable (VBNC). It survived for long at different pH values, in raw and fermented milk and cheese. Viability qPCR was also used to examine the occurrence of viable Campylobacter spp. in raw milk, detecting the bacteria in 40.9% of 25 mL samples negative on culture. Results showed that viability qPCR is valuable in estimating Campylobacter risk in dairy products.