This review provides an overview of the data mining on fluorescence fingerprint (FF) and the application of data mining to flow cytometry (FCM). Canonical discriminant analysis, which is one of data mining method, on FF of taros revealed that their geographic origins (Japan or China) could be predicted as accurate as the standard methods such as inorganic elements composition and isotopic ratio analyses. In addition, the histogram of the fluorescence signal obtained by FCM for the prediction of Escherichia coli (E. coli) concentrations in green tea beverage were analyzed with partial least squares regression (PLSR) method, and it was clarified that E. coli concentration could be predicted by PLSR with higher accuracy than conventional FCM with reduced false positives and false negatives. Data mining can be applied to both FF and metabolomics for sample quality estimation or exploration of important compounds. Therefore, using data mining as a clue, it would be expected that the development of research that integrates or compares FF and metabolomics data for the understanding of overall food quality in more detail.
Egg yolk powder is industrially produced by spray-drying fresh raw egg yolk separated from shell eggs. Stress due to heat and dehydration causes denaturation of egg yolk proteins, so it largely affects the quality level of the resultant dried powders. In this study, denaturation kinetics of dried egg yolk powder were measured under isothermal and iso-humidity conditions. The denaturation level was evaluated by using color index, viscosity values of the slurry (made from the dried powder dispersed in water) and the agglomerated particle sizes. Fresh egg yolk was spray-dried and the resultant quality levels of the dried powders were evaluated in the same manner. Some of these quality factors would not simply relate with the temperature and RH. It was suggeted from the kinetic parameters and the spray-drying experiments that the residence times of products in the specific parts of a drying system (e.g. atomizer, chamber, pipe for transport, collector etc.) would have critical impacts on the product qualities. The kinetic parameters predicted that even under a relatively low RH conditions, a rate of a quality change would significantly increase when products are subjected to higher temperature above threshold.
We investigated the factors affecting preparation of water-in-oil (W/O) emulsions using olive oil as the continuous phase, based on direct observation of microchannel (MC) emulsification.
Monodisperse droplets were produced using polyglycerin polycondensed ricinoleic acid ester (PGPR) as an emulsifier. The mean droplet diameter and the time required for droplet formation (droplet detachment time) increased with increased viscosity of the continuous phase. Emulsifier concentration affects droplet formation, and stable emulsification was observed at PGPR concentrations exceeding 1wt％. Adsorption of PGPR was analyzed based on interfacial tension measurement with different measurement time scales. Monodisperse droplets with mean droplet diameters of 24 µm to 90 µm and coefficients of variation below 7％ could be produced using MC plates having different MC geometries. Furthermore, we demonstrated that droplet formation behavior differed with the addition of milk components (skimmed milk powder and whey powder) to the dispersed phase, based on high-speed observation of individual droplet formation.
A mathematical model that could simulate multi-dimensional freeze-drying operated by radiative heat was developed and applied to a freeze-drying process of instant soup. A model product (precooked soybean paste soup) set in a cuboidal plastic cup was freeze-dried where drying progressed multi-dimensionally, that is, the surface area of the sublimation interface changed as a progress of drying. In order to simplify model equations, the relationship between the sublimation surface area and degree of drying was empirically estimated and applied to the model calculation. The simulation results of the present mathematical model were in good accordance with the experimental results. Based on the mathematical model, a method was shown to calculate the design space where rational choice in better drying conditions can be selected.