Quantitative determination of vanillin and its detection threshold in sake.

Vanillin is naturally occurring in various food products, including alcoholic beverages; however, its contribution to the aroma of sake is unclear. In this study, an HPLC-MS/MS quantification method was developed and validated by linearity, precision, and recovery, and it was applied to 115 bottles of highly diversified sake. Furthermore, the odor detection threshold of vanillin in sake was determined.

Effect of water deficit stress during fruit cultivation on the carbon stable isotopes of organic acids in Japanese apricots and liqueur prepared from these fruits.

The objective of this study was to assess the impact of water deficit stress during fruit cultivation on the C values of citric acid and malic acid in Japanese apricots at different ripeness stages and their resulting liqueurs. Our experiments show that water deficit stress increases the C values of citric acid and malic acid in tree-ripened fruits, counteracting the typical decrease during ripening. However, water deficit treatment has a minimal effect on the C values of organic acids in green fruits.

Presence of Disulfide-Bonded Thiols in Malt and Hops as the Precursors of Thiols in Beer.

Disulfide-bonded thiols in malt and hops were first identified as possible precursors of thiols in beer. The presence of disulfide-bonded 3-mercaptohexan-1-ol (3MH) was confirmed in malt and hops by observing an 8.9-9.

Carbon stable isotopic compositions of citric acid and malic acid in Japanese apricot liqueur decrease as the fruit ripens.

The carbon stable isotopic composition (δC) is often analyzed to quantify the addition of acidulants to Japanese apricot liqueur, but little is known about the variation in the δC values of the main organic acids arising from differences in the ripeness of Japanese apricots. We show that in Japanese apricot liqueur prepared using fruits at different stages of ripeness, the δC values of citric acid and malic acid ranged from -25.1‰ to -23.

Application of carbon and hydrogen stable isotope analyses to detect exogenous citric acid in Japanese apricot liqueur.

Japanese apricot liqueur manufacturers are required to control the quality and authenticity of their liqueur products. Citric acid made from corn is the main acidulant used in commercial liqueurs. In this study, we conducted spiking experiments and carbon and hydrogen stable isotope analyses to detect exogenous citric acid used as an acidulant in Japanese apricot liqueurs.

Detection of gastroenteritis viruses among pediatric patients in Hiroshima Prefecture, Japan, between 2006 and 2013 using multiplex reverse transcription PCR-based assays involving fluorescent dye-labeled primers.

Multiplex reverse transcription (RT)-polymerase chain reaction (PCR)-based assays involving fluorescent dye-labeled primers were modified to detect 10 types of gastroenteritis viruses by adding two further assays to a previously developed assay. Then, these assays were applied to clinical samples, which were collected between January 2006 and December 2013. All 10 types of viruses were effectively detected in the multiplex RT-PCR-based assays.

Method for the isolation of citric acid and malic acid in Japanese apricot liqueur for carbon stable isotope analysis.

A method for detecting the undeclared addition of acidic ingredients is required to control the authenticity of Japanese apricot liqueur. We developed an analytical procedure that minimizes carbon isotope discrimination for measurement of the δ(13)C values of citric and malic acid isolated from Japanese apricot liqueur. Our results demonstrated that freeze-drying is preferable to nitrogen spray-drying, because it does not significantly affect the δ(13)C values of citric acid and results in smaller isotope discrimination for malic acid.