Proteins are very often used as emulsifying agents and stabilizers for real food emulsion systems. Such situation increases the importance of research works about the structure and functions of proteins at oil droplet surfaces, because adsorbed proteins at the surfaces affect the overall properties and qualities of emulsions. In this review, I described our recent results about the interactions of proteins with other components, particularly lipid components. The effects of such interactions on physical properties of emulsions were also shown. In the former part, the interaction between fat crystals and β-casein at oil droplet surfaces in creams was investigated using various techniques such as NMR, ESR, oscillation rheometry, etc. I have shown the mechanism whereby fat crystals in oil droplets affect the adsorption and conformation of the protein at oil droplet surfaces thereby causing the changes of physical properties of emulsions. In the second part, I described the results on the displacement of milk whey proteins by egg yolk lipoproteins at oil droplet surfaces, particularly emphasizing the effects of temperature on the displacement behavior.

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Thermal processing is one of the most common methods used for extending the shelf life of processed foods. In commercial heat sterilization of foods in cans or retortable pouches, the food container has been heated in a pressurized steam or hot-water retort at certain conditions of temperature and time. Although this process will certainly make microorganisms and spores inactive, it may also cause the destruction of essential quality factors such as nutrients, colour, texture or flavour. Consequently, much attention has been paid to maximizing quality retention for a specified reduction in the number of undesirable microorganisms during the heat sterilization. Mathematical methods available to optimize the heat sterilization of foods in cans and retortable pouches are critically reviewed.

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Ozone is attracting more and more attention in wide areas of applications, especially in food and food processing. For decades, huge amounts of chlorine compounds like sodium hypochlorite have been used for disinfection in food processing. However, its long term use has caused the new problem of the appearance of drug-resistant microbes. Also, consumers want to have natural foods, without additives, free from pollution and disinfectant odor. Ozone is, in contrast to chlorine compounds, one of the oldest chemicals on the earth. It kills viruses and bacteria the same as chlorine and reverts back to oxygen leaving no chemicals behind. Furthermore, it produces no drug-resistant microbes. In this report, the use of highly concentrated ozonated water is introduced with an explanation of its marvelous effects and advanced technology.

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Recently, we reported that the ball milling for starch, converts the semi-crystal state to an amorphous state, and the prolonged procedure promotes the enthalpy relaxation, substantially accompanied with the structural relaxation such as a decrease of free volume [1] . From such a result, it is predictable that the prolong ball milling might cause a decrease of water sorption ability by decreasing the free volume. In this study, to confirm the above presumption, the change of water sorption properties by milling for amorphous starch was investigated. Ball milling for potato starch was carried out at room temperature for lhr, 2hr, 4hr, 17hr, 45hr, and 140hr. The water sorption isotherms for each milled samples were measured by a conventional desiccators method, and analyzed by a dual mode sorption model to obtain a so called sorption capacity parameter that relates to the free volume in an amorphous polymer. The result surely showed a decrease of the water sorption capacity with milling time, which supported our presumption. Further analysis, as for the rate process, elucidates that a decreasing rate process on water sorption ability of starch during milling obeys the so-called KWW equation that has been applied for relaxation processes of amorphous polymers. From these results, it was suggested that long ball milling for starch would cause the structural relaxation, and result in the decrease of water sorption ability.

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