Chemical analyses were carried out to examine the smell of cooked rice with a particular focus on the odor of old rice. GC-MS measurements indicated that the odor of old rice was clearly related to the formation of aldehyde compounds such as hexanal, heptanal, nonanal, and octanal during storage. These aldehyde compounds were detected in vapor continuously from when the rice started cooking to the end of cooking, and were present in rice after cooking. FT-IR measurements on the surface of new rice before cooking showed a distinct peak of ester groups that were absent in old rice. This peak was the result of a newly formed aldehyde group suggesting the partial conversion of an ester to an aldehyde. Experiments were performed to reduce the odor of cooked old rice using bamboo charcoal for cooking. Bamboo charcoal was found to adsorb the aldehyde compounds during cooking, hence, reducing the odor of cooked old rice and conforming with results from sensory evaluation reports.

We examined the influence of delay in processing time on the quality of brown sugar. A total of 79 brown sugar samples processed in Okinawa Prefecture from March to June in 2015 were used in this study. All brown sugar samples were classified into three clusters according to their quality characteristics by cluster analysis, using data for color (L*, a*-value), pH, conductivity and transmittance. Thirteen samples were selected from each cluster and their components were analyzed. These results showed that brown sugar made at a later date contained more reducing sugar, lactic acid, acetic acid, succinic acid, Ca, Fe, ketones, alcohols than brown sugar made at an earlier date. The score for bitterness according to sensory evaluation and the Taste Sensing System also increased for brown sugar made at a later date. This finding indicates that an increase in reducing sugar, Fe, and Mg may affect caramelization and influence the Maillard reaction; thus, resulting in strong bitterness.

This study was carried out to evaluate the effect of cold stress on matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) cluster analysis of Saccharomyces cerevisiae. Seven pair strains including one bread yeast strain and one or two wild type strains of S. cerevisiae were selected from yeast strain stocks at the Aichi Center for Industry and Science Technology. By using MALDI-TOF MS cluster analysis, those pair strains were shown as being not separated into single strain clusters. When those colonies were re-incubated at low temperatures before MALDI-TOF MS preparation, all pair strains were found to have separated into single strain clusters. These distinctions show that cold stress proteins could be used as biomarkers for MALDI-TOF MS identification of S. cerevisiae strains.

Tabletop type manufacturing equipment for the test production of non-centrifugal brown sugar “Kokuto” was developed which could continuously carry out the finish-heating and cooling-agitation processes while producing kokuto. This equipment comprises a PC-controlled micro heater and a cooling pipe using tap water in a heating and cooling jacket, and an agitating device with a torque meter. In a trial production of Kokuto using this equipment, a rise in syrup temperature was observed at the end point of the cooling-agitation process. The rise in syrup temperature was thought to result from the heat of crystallization of sucrose affected by the temperature rise width and the estimated specific heat of molasses.