Microencapsulation of flavor is an essential technology of enclosing liquid flavor compounds in a carrier matrix to provide protection against the loss of flavors and degradative reactions during food processings. In this review, two encapsulation techniques were discussed; molecular encapsulation in cyclodextrin and microencapsulation by spray drying. Cyclodextrins can include various molecules into their hydrophobic structural cavities to form inclusion complexes. The presence of water is essential for the formation of inclusion complexes between cyclodextrins and guest molecules. There exists a minimum number of water molecules required for inclusion to occur. The release of the encapsulated flavors was markedly dependent on the relative humidity, indicating that water is also an essential factor for release. The retention of flavors during spray drying was dependent on the size of emulsion in the feed liquid. The rate of release and the rate of oxidative reaction were markedly influenced by the relative humidity. This implies that the storage stability of the powders has intimate relations with the changes of matrices structure of the particles, and the glass transition temperature of wall matrices. Confocal laser scanning microscopy (CLSM) was proposed for investigating the cross sectional structure and the release behavior of flavor emulsions in spray dried particles.
When starchy food such as rice grains or noodle strands are boiled for a few minutes, the food body can be interpreted as becoming a multiphase system in terms of water-holding capacity because uneven starch gelatinization takes place in the food body and gelatinization seems to govern water-holding capacity. In order to describe water migration in such a multiphase system, Relative Water Content Model (Water Demand Model) is proposed. For the practical use of this model, information on water-holding capacity is required. In an attempt to measure the effect of temperature and water content on water-holding capacity, pre-heat-treated wheat flour dough packed in a cylindrical frame was immersed in water at 25°C and the time course of water content was observed. Unexpectedly, water content in the sample continued to rise for seven days even though the water content in the sample monitored by NMR imaging showed a flat profile. Since the standard water content to be used in Relative Water Content Model is not necessarily the maximum water content (ceiling water content), we defined first stage water-holding capacity as the water content when the rise of water content changed its rate after NMR imaging profile became flat. The first stage water-holding capacity collected in this way was favorably used to simulate the change of water content profile in a wheat flour dough slab that was temperature-gradient heat-treated.
Generally, it is known that ultrasound application (UA) induces fat mobilization through increasing in norepinephrine secretion from sympathetic nerves in the white adipose tissue. On the other hand, Kurosu, a vinegar made from sweet potatos, has been reported to improve lipid metabolism. In this study, we have examined the effect of combined treatment with UA plus Kurosu administration on fat mobilization, and analysed the changes of serum Triglyceride (TG) and Free Fatty Acids (FFA) . The rats were administered 5 times/week with 4 mg/kg or 400 mg/kg of Kurosu by gastric intubation for a month. At the same time, the rats were subjected to the application of 715kHz ultrasound for 30 min at twice/week. After 14 times and 24 times of Kurosu administration (6 and 10 times of UA, respectively), significant decrease in the non-fasting serum FFA was observed in Kurosu and UA combined treated rats compared with control rats administered distilled water. Moreover, the rates of increase in serum TG and FFA before and 1 hr after the UA were correlated with the dose of Kurosu, and were higher than that of control group. These findings suggest that the lipolytic effect of Kurosu was further promoted by UA.
Naturally brewed soy sauce has been used in flavoring not only Japanese but also international foods. The harmony of aroma, taste and color in the cuisine is important and soy sauce has been playing a big role. Especially the color tone in the processed food is an important standard of quality evaluation. The pigment enrichment method of naturally brewed soy sauce was initially developed by NF membrane filtration system in order to adjust the color tone. Two types of NF membrane elements were selected by considering pressure drop and rejection of color components. The color index was defined to measure the capability to dye foodstuff. Brix concentration was found to be in strong correlation relationship with the color index. Continuous measurement of brix concentration was indispensable in the NF membrane system to adjust the color index of super-dark-color soy sauce. This product was evaluated by ordinary analysis, gas chromatography and sensory evaluation to compare with the dark color soy sauce heated with some sugar and acids. Super dark color soy sauce was admitted to be useful as a pigment to regulate the color of many kinds of foodstuff.
In our previous paper, ultrafiltration (UF) membrane modules were evaluated for clarification of rice washing and soaking drainage from packed rice cake manufacturing plant. And a hollow fiber membrane module of the molecular weight cut off of 150kDa, made by polyethersulfone, was found to be the most suitable. In this paper, suitable operating condition of above membrane module was studied. Drainage were obtained from a rice washing process, composed of five steps of washing and one step of soaking. The drainage from each step was filtrated by the OF membrane, and 80% of each drainage was recovered as permeate for recycling. From the view point of permeation flux and flux restoration rate by membrane washing, the various operating condition was evaluated. As the first and the second step drainage showed extremely low flux and low restoration rate, we concluded that the both drainage are not suitable for recycling after OF treatment and should be treated by active sludge processing as waste water. The third to the fifth step drainage showed higher flux and higher restoration rate than the first and the second steps, and the higher step drainage showed the higher flux and the higher restoration rate. Soaking drainage showed extremely higher flux and higher restoration rate than those of washing drainage. It was concluded the suitable OF operating condition for rice washing drainage treatment for clarification was 0.02 MPa pressure and 0.9m⋅s-1 flow velocity, and that for soaking drainage was 0.1 MPa pressure and 0.9m⋅s-1 flow velocity.
It is very important but so difficult problem for food manufacturing industries to estimate the central temperature of Individual-packed foods accurately during retort sterilization. Not a few numbers of methods by heat transfer equations have been used traditionally to solve these problems, however, these methods are too difficult to apply in the actual fields. Because of these reasons, more practical and convenient methods are under the necessity to be developed. A new practical estimation method named as Ambient Temperature Slide Method (ATS method) was developed. ATS method can simulate changes of central temperatures of packed foods under various ambient temperatures by using only two parameters led from actually measured data. In this method, central temperatures are estimated directly from ambient temperatures without dividing each packed food into many grid points, and as a result, total quantity of efforts for calculation should be largely reduced and commercial spread-sheet software is available. In this study, adaptability of the ATS method was tested using the hot water spray retort. Values from actual measurement and simulation with five kinds of packed foods which have different characteristics from solid to liquid form showed good consistency. These results suggested that the ATS method could be used as a new convenient estimation method.
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