A freezing theory of agricultural products has been presented for design and application of a fluidized bed freezer. Freezing time can be easily calculated from the analytical results of the applied method. Using this method the freezing time of green peas was estimated in detail. The calculated values were in good agreement with the observed data. It is expected that this method would be useful for operating fluidized bed freezer of frozen food.

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Low-amylose rice will be supposed to increase in quantity as food materials. So, physicochemical properties of milled rices were investigated in consideration of amylose content using 19 varieties of non-glutinous rice, 11 of low-amylose rice and 10 of glutinous rice. The amounts of acid hydrolysis residue from rice starches showed high correlation with amylose content (r=0.917^**). The amount of the residue of glutinous rice starches, low-amylose rice starches and non-glutinous rice starches was 30-81, 183-252 and 305-516 mg/100g, respectively. Water absorption of milled rices showed high correlation with either amylose content (r=-0.955^**) or the water absorption of rice starches (r=0.953^**). The water absorption of rice starches from glutinous rice, low-amylose rice and non-glutinous rice was 49.3-50.8, 47.0-48.3 and 44.5-47.8%, respectively. From this result, water absorption of milled rices would depend on that of rice starches. Peak viscosity of amylograph characteristics showed high correlation with amylose content (r=-0.923^**). Tanδ(=G"/G') of cooked rice showed high correlation with amylose content (r=-0.944^**), and the tanδ of glutinous rice, low-amylose rice and non-glutinous rice was 0.426-0.529, 0.360-0.415 and 0.196-0.349, respectively. Acid-solubility showed high correlation with either amylose content (r=-0.973^**) or tanδ of cooked rice (r=0.951^**). The acid-solubility of glutinous rice, low-amylose rice and non-glutinous rice was 92.2-99.4, 79.6-84.3 and 52.5-77.5%, respectively. However, these components showed no correlation to protein content of milled rices. From these results, it was concluded that low-amylose rice whose amylose content was less than 14.0% were intermediate properties between glutinous rice and non-glutinous rice for all the components related to amylose content.

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In order to remove oxygen from food packaging, disodium ascorbic acid/polyvinyl chloride (AsN/PVC) was coated onto its cap. When a container with a AsN/PVC cap containing 100mg of AsN was used for a storage experiment, the oxygen in it was effectively removed more than 50% from the headspace during 30 days' storage at 35°C. The consumption behavior of oxygen was found to depend on the headspace volume of the container; for the container with 31ml of headspace volume the O₂ consumption ratio per volume was 1.4-fold higher than that for the container with 77.5ml of the volume. Also, the O₂ consumption lowered with lower storage temperature. By using the AsN/PVC cap, flavors in the container were successfully preserved from the oxidative deterioration; the residual ratios for n-hexanal, n-heptanal, d-limonene, and α-pinene with the AsN/PVC cap were 65.0%, 48.9%, 39.1% and 41.0%, respectively after 42 days' storage. In addition, when the cap was used for a liquid food container with 46.5ml of headspace volume, more than 85% of dissolved oxygen was found to be removed from 0.1% arabic gum solution within 25 days' storage.

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Wash-free rice (WF rice) had the following characteristics; high moisture content, high degree of brightness (high L-value) and also, low contents of protein, crude lipid and total free fatty acid. However, there were slight differences in the total free fatty acid contents among WF rice samples. For the residues of processed WF rice, the contents of protein and crude lipid were high. These characteristics suggest that the removal of the aleurone layer was more efficiently conducted by the treatment for wash-freeing than by the ordinary polishing treatment. WF rice packed in air underwent the following changes in a storage test. The high degree of brightness initially observed for WF rice were apt to be kept during the storage. The beginning temperature of gelatinization was lower in WF rice compared to the ordinary milled rice for the same raw material. Further, the time-course increases in the maximum viscosity and the final viscosity tended to be low. The increase in the total free fatty acid content in WF rice compared to the ordinary milled rice tended to be small. These tendency was marked for the stored rice under ambient temperature package in polyethylene film and slight for PVDC coated-nylon film package. Storage at a low temperature (at 15°C) resulted in small changes in rice qualities and so, the differences between WF rice and the ordinary milled rice were also small. Determined values by using ADAM and fat acidity determined by the conventional method were in close correlations. The relation between these two values could be expressed in the following equation: y=2.4x-0.15. The correlation coefficient was 0.995 and thus, a significant correlation was found between the two (P<0.01). An eating taste test was carried out after storage for 1 year, and significant differences between WF rice and the ordinary milled one were found in respect of flavour (P<0.05) and of stickiness (P<0.01). These significances were assumed to be mostly due to the low content of free fatty acid content.

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Conformational behavior of curdlan, a (1→3)-β-D-glucan, in its trisodium phosphate (Na₃PO₄) aqueous solution which was utilized as a food additive was examined. In the concentration range of 0.05 to 0.4 M where curdlan could be dissolved, it was found that the viscosity of curdlan solution was decreased a little with the increase of the alkaline concentration, that the absorption maximum (λ_max) of visible absorption spectra of a congo red solution showed a red shift from 485-490 to 518-520 nm by the addition of curdlan, and that a circular dichroism (CD) band was observed. When 1 M NaOH solution of curdlan was added to the curdlan 0.4 M Na₃PO₄ solution a drastic decreasing of viscosity, blue shift of curdlan-congo red solution, and no CD band were observed. These results suggested that curdlan took up an ordered conformation in the Na₃PO₄ solution, but, by the addition of the NaOH solution a conformational transition occurred to a random coil which is similar transformation having been observed in the NaOH solution.

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Eutectic points (EPs) of polyols (sorbitol, xylitol, maltitol and lactitol) and the corresponding reducing sugars (CRS) (glucose, xylose, maltose and lactose) were determined from intercept between curve of freezing point (FP) which was obtained by differential scanning calorimetry (DSC) and plot of solubility. Glass transition temperature (Tg'), solute concentration (Cg') and unfrozen water (Wg') of maximally freeze-concentrated solutions were also obtained from the DSC measurement. In monosaccharides FPs of polyol were slightly higher than those of CRS and in disaccharides they were nearly equal to those of CRS. Solubilities of polyol were fairly higher than those of CRS. As a result, the EPs of polyol were at fairly lower temperature and higher concentration than those of CRS. Tg' values of polyol solutions tended to be lower than those of CRS, and in monosaccharides Tg' between two groups were nearly the same but in disaccharides considerably larger differences on Tg' between two groups were found. Cg' values of all used samples were made ranging in concentration from 73% to 87% and were nearly equal to those in literature (Roos).

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[in Japanese]

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