Yasushi Ogasawara

Phenolic compounds responsible for the superoxide dismutase-like activity in high-Brix apple vinegar.

High-Brix apple vinegar (HBAV) with palatable drinking qualities has been developed using a greater amount of apple ingredients. In HBAV and in regular apple vinegar (RAV), constituents of 4 kinds of organic acids, 20 kinds of amino acids, 3 kinds of sugars, 4 kinds of minerals, and phenols were determined. These constituents, except for acetic acid, in HBAV are of higher abundance than in RAV. HBAV had a 7.1 times greater superoxide dismutase (SOD)-like activity compared with RAV. Those constituents, except for phenols, had very low SOD-like activity, and total phenol levels in HBAV were comparable to 181 mg of gallic acid equivalents/100 mL, which was 6.0 times more abundant than in RAV. Nine kinds of phenols including two kinds of hydroxycinnamates, two kinds of hydroxybenzoates, and five kinds of hydroxycinnamoyl quinates, originating from raw material were determined, but there were no ascorbic acid and flavonoids in HBAV. Chlorogenic acid, 4-p-coumaroylquinic acid, and caffeic acid were the three major phenols, and their content levels were 19.6, 13.5, and 0.76 mg in 100 mL of HBAV, respectively. Sum of contents of chlorogenic acid and the isomers was 24.0 mg/100 mL, and the percentage was 56.9% in the total identified phenols in HBAV. In RAV, only chlorogenic acid was determined as phenols, and the content was 3.1 mg/100 mL. SOD-like activities of the constituents of HBAV were obtained through high-accuracy assays using vinegar reconstitutions, and each contribution to the total SOD-like activity was found. As a result, 77.2% for all SOD-like activity of HBAV was reconstituted using the determined nine phenols and other constituents. Chlorogenic acids were the most effective, and the contribution to the total activity was 41.7%. The most abundant phenols, chlorogenic acids, were the most important contributors to the SOD-like activity. These SOD-active phenols originated from raw material and remained through the acetic acid fermentation processes. In the fermentation process of HBAV, the active constituents were well maintained, providing an advantage in the production of a phenol-rich product.

Saltiness and Acidity: Detection and Recognition Thresholds and Their Interaction Near the Threshold

Interaction of saltiness and acidity at the threshold level was studied employing 35 to 40 young female panelists. As a 1st step, the detection and recognition thresholds of salt, rice vinegar, and rice black vinegar have been measured for each panelist. To investigate the above interaction, the thresholds have been again measured for each panelist of salt, but this time, vinegar at half the concentration of each panelists detection threshold was added to the salt solution. Similar measurement has been performed for vinegars with salt at half the concentration of each panelists detection threshold. The data analysis has been done in 2 ways, namely, (1) by using Students t-test to detect the significant difference in average between the data with and without the added ingredient and (2) detecting significant deviations from zero in the individual shifts in 2 sensory tests among panelists who participated in the 2 measurements. In doing that, a conversion of the scale was necessary to correct the systematic skewness existing in the original data. As a result, both the detection and recognition thresholds of salt were decreased with the existence of the added vinegar ingredient (P < 0.001). This tendency was more pronounced with rice black vinegar than with rice vinegar. On the contrary, no significant changes in the threshold of both detection and recognition were observed when salt at the half concentration of the detection threshold was added to rice vinegar. The interaction therefore was found to be asymmetric.

Fermentation-induced changes in the concentrations of organic acids, amino acids, sugars, and minerals and superoxide dismutase-like activity in tomato vinegar

ABSTRACT Various raw materials are used to produce vinegars that contain functional compounds associated with disease prevention. We evaluated changes in functional compounds during tomato vinegar production and superoxide dismutase-like activity of tomato vinegar. Tomato vinegar contained abundant anti-hypertensive compounds, e.g., γ-aminobutyric acid and potassium derived from tomatoes and acetic acid and pyroglutamic acid produced during fermentation. It had stronger superoxide dismutase-like activity than commercial vinegars because of tomato-derived superoxide dismutase-like compounds, including phenolic acids, flavonoids, and glutathione. These data indicate that tomato vinegar is a candidate dietary supplement with potential preventive effects against cardiovascular diseases due to its anti-hypertensive and superoxide dismutase-like compounds.

Preparation of an Aroma Fraction from Dried Bonito by Steam Distillation and Its Effect on Modification of Salty and Umami Taste Qualities

To study the effects of dried bonito aroma on taste perception, dried bonito aroma fraction (DBAF) as a steam distillate in liquid was added to the salt solutions containing 5 different salt concentrations (0.68% to 1.5% [w/v]) before sensory evaluations. Perception of the taste qualities of salt solutions with added DBAF varied depending on the salt concentration. At low salt concentrations (0.68% to 0.83%), after-taste intensity of saltiness and overall taste intensity were significantly enhanced by the addition of DBAF. This suggests that DBAF can be applied to a low-salt seasoning at these salt concentrations. Umami taste intensity was significantly enhanced by the addition of DBAF at all salt concentrations (0.68% to 1.5%). The addition of heat-treated DBAF, which no longer had the dried bonito odor, exerted no significant influences on any taste descriptors. As the result of gas chromatography-mass spectrometry analysis, sulfur-containing compounds, pyrazines, alcohols, and phenols were contained in DBAF and not detected in heat-treated DBAF. Because these compounds contributed to the dried bonito odor, the taste modifications were thought to be induced by these compounds. The effects of the DBAF on Japanese noodle soup (mentsuyu) were also examined. The saltiness intensity of 1.2% salt concentration of mentsuyu containing both DBAF and DBS (dried bonito stock) as a hot water extract of dried bonito was not significantly differ from that of 1.5% salt concentration of mentsuyu not containing any of them. It will thus be possible to develop a reduced salt seasoning by combining DBAF and DBS.