An image analysis was proposed to estimate color changes of broccoli in plastic films. Fresh broccoli was packaged with perforated low density polyethylene (P-PE), non-perforated low density polyethylene (PE: film thickness 18.7μm) and polypropylene (PP: film thickness 30.1μm), and stored at 15°C, 90% RH. Surface color data of the broccoli florets were taken by RGB color system (512×480 pixels, 8bits). Transformation of the color data to Munsell color system using hue, chromaticness and lightness was proved to be effective to eliminate the various interference caused by the packaging film. Estimation of color changes using the image analysis was more closely correlative with sensory score than pigment contents including chlorophyll and carotenoid, and the Hunter Lab value.

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For agar gels with and without sugar, the weight of syneresis and dynamic viscoelasticity were measured. The weight of syneresis increased gradually with the holding time and then reached an equilibrium weight of syneresis over about 40 hours. This behavior was represented by an equation of M=kt/(1+kt) or dM/dt=k(1-M)², (M: a ratio of the weight of syneresis at a holding time t to the equilibrium weight of syneresis, k : a rate constant of syneresis). The equilibrium weight of syneresis decreased with increasing concentration of agar and sugar. The value of k increased with the concentration of agar, but decreased with the concentration of sugar. The storage modulus of agar gel decreased with an increase in density of agar gels and with a decrease in shrinkage. From these results it is considered that the storage modulus is mainly due to the loose network structure of agarose molecules.

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To investigate the heat transfer phenomena in a flat cylindrical model food by microwave heating, temperature distributions were calculated numerically by fundamental equations under certain assumption by a mathematical model considered the angle of microwave incidence. The temperature distributions changed with their radius and as the radius became larger the region of hot-spots moved from a center to surroundings of the cylinder. To check these calculated results, observation of the temperature distributions in the cylindrical modeling samples by a synthetic paste and measurement of the temperature by thermocouples were performed under the same operating conditions as those of the theoretical analysis. The calculated temperature distributions agreed closely with the measured and observed ones.

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The Ohmic heating process equipped with ring electrodes has been applied for variety of liquid foods. The gradient of electric potential formed by ring electrodes was never flat like as made by parallel electrodes. The gradient of potential was estimated by an equation of electric conduction. Assuming the liquid sample flew in the shape of plug through the gradient of potential, the temperature profile in cross-section of sample was estimated by an equation of heat conduction. The flowing sample corresponded to shifting nodes by each step of the Finite Element Method calculation. The result of the temperature profile gave good agreement with the result of the experiment. Other computations with any induced voltage, any velocity of a flowing sample and any space between electrodes were tested. The space between electrodes was the most effective on flat temperature profile of all factors.

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Crude green tea (aracha) is usually refined by heating to dry into 2.5-3% of the moisture content before putting on the market. In this paper, four kinds of aracha was refined by using the following two procedures; hot-air drying at 75-85°C for 30min+gas dram direct heating at 95-102°C for 10-15min (tea I) and microwave heating at 75-80°C for 8min+gas dram direct heating at 95-102°C for 4min (tea II), and the aroma component and the contents of caffeine and catechins were compared between tea I and II. The microwave treatment suppressed remarkably the formation of pyrazines, pyrroles and furan compounds which were well known as the typical thermally generated compounds and were responsible for roasted aroma. In addition, the caffeine content in an infusion of tea II was lower than that of tea I. The infusion ratio of(-)-epigallocatechin, (-)-epigallocatechin gallate or (-)-epicatechin gallate was calculated by dividing each concentration in the infusion by the total content. The infusion ratios of tea II were significantly (p<0.05) lower than those of respective tea I. These results indicated that the microwave treatment to refine tea is very effective to prepare green tea which has refreshing aroma and low astringent. (Received Mar. 29, 1996)

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A composting machine with rotary turning device which processes a large quantity of waste in relatively short time from the processing of Satsuma mandarin has been developed. The most efficient treatment condition for using the machine were developed. Aerobic and thermophilic bacteria including Bacillus stearothermophilus and Thermus sp. isolated from sewage sludge were used as the starting material for the treatment. The starting material was added to a liquid and solid enrichment culture containing the processing waste of Satsuma mandarin and the culture was used as seed compost for the first batch. A part of the first batch was then used to seed further batches of processing waste, achieving an efficient composting process. The initial moisture content of the composting batches were adjusted to 60% and the pH was set to 8.0. The composting was carried out under aerobic condition without heating. Batches were turned once a day by the rotary device and the composting could be completed in approximately two weeks. Thus, the composting under developed conditions was able to convert the substrate into organic fertilizer. The maximum temperature obtained during the three succesive composting process was 60.1-64.2°C, with a reduction in weight and organic materials of 30.6-47.1% and 33.8-46.5%, respectively.

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An efficient method of hydrolyzing hesperidin to prepare hesperetin 7-glucoside (Hesperetin monoglucoside; HMG) was established. Hesperidin was first converted from its fiavanone form to the chalcone form under alkaline conditions, and then hydrolyzed with HCl in the presence of a water-soluble solvent such as isopropyl alcohol (IPA), n-propyl alcohol, ethyl alcohol (EtOH) and methyl alcohol. When the reaction mixture containing optimal concentrations of 6% hesperidin, 20% IPA and 1.5N HCl was heated for 15min in a boiling water bath, the maximum amount of HMG were accumulated. HMG can be precipitated and efficiently recovered by dilution and evaporation to lower the IPA concentration. The solubility of crude HMG against distilled water, hot water and EtOH was 42.5, 12.5 and 40.7 times higher than that of reagent grade hesperidin, respectively.

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n-3 Polyunsaturated fatty acids (PUFAs) enriched with fish oil were supplied to pigs and the effects of PUF As on fatty acid composition, cholesterol level and tasty compounds (pH, total peptides, total free amino acids and inosinic acid) in the pork loin were investigated. Thirty-six LWD pigs were divided into 6 groups (6 animals each). In experiment 1, 2.5% purified fish oil was added to the basic diet from 85kg body weight for group A and from 75kg body weight for group B, and group C was fed with the basic diet only (control). In experiment 2, from 85kg body weight 0.8% vitamin E was supplied with the basic diet for group D, and 0.8% vitamin E plus 2.5% sardine oil for group E, and group F was same to the group C in experiment 1. After slaughtering these pigs, loins were cut from the 12th dorsal vertebrae. Among each groups in either experiment 1 or 2, there is no difference in the lipid levels of the loins. The cholesterol levels of loins from pigs fed with fish oil supplements (groups A, B and E) were significantly (p<0.05) lower than those from pigs that fed without fish oil (groups C, D and F). The fatty acid composition and proportion of unsaturated fatty acids in neutral lipid did not differ from each groups in either experiment 1 or 2. The n-3 PUFAs compositions in polar lipids in groups A, B and E were significantly (p<0.05) higher than those in groups C, D and F. The n-3 PUF As in dietary fish oil transferred to the meat and the n-6/n-3 ratio became significantly (p<0.05) higher, but the levels of pH, total peptides, total free amino acids and inosinic acid were unchanged. The addition of fish oil or vitamin E to the diet did not affect on the flavor of the pork.

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A byproduct of Tofu or Okara was experimentally treated by simultaneous saccharification and fermentation process (SSF) to find some operational conditions for its utilization. Baker yeast could produce ethanol from glucose under the conditions for enzymatic saccharification by cellulase. Lower production yield of ethanol from reducing sugars showed that the saccharification of Okara produced some reducing sugars which could not be utilized by baker yeast. In SSF of Okara, higher initial concentration of reducing sugar resulted in higher production of ethanol.

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Bradykinin was converted rapidly into the fragment 1-8 by kininase I when incubated with human plasma. Kininase II inactivated bradykinin by splitting the Pro⁷-Phe⁸ and the Phe⁵-Ser⁶ bonds in it. ACE inhibitory peptide Val-Tyr and captopril did not inhibit the conversion of bradykinin in human plasma into the fragments 1-8, 1-7 and 1-5. Bradykinin was converted into the fragments 1-7 and 1-5 by dipeptidyl peptidase activity of ACE. Captopril inhibited degradation of bradykinin by dipeptidyl peptidase activity of ACE, but Val-Tyr did not inhibit.

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