It was attempted to find the components responsible for development of off-flavor in freeze-dried Porcine plasma during storage and to find a simple and offective method to remove them. Off-flavor degree (OFD) noticeably developed in freeze-dried plasma after storage at 37°C for 3 weeks and OFD was significantly (p<0.01) correlated to the amount of TBA reactive substances and fluorescence intensity (FI). Off-flavor development was greatly suppressed in freeze-dried plasma processed by ultracentrifugation and charcoal treatment at low pH for diminishing the amount of free fatty acids and phospholipids. The addition of arachidonic acid and phospholipid to the acid-charcoal treated plasma or hemoglobin promoted the increase in FI during storage at 37°C up to 3 weeks, whereas the addition of those compounds to serum albumin caused no change in FI during storage. The addition of hemoglobin to the plasma collected from less hemolyzed blood caused the significant increase in OFD and Fl. It was thus suggested that the responsible components for the off-flavor development were hemoglobin, phospholipids and poly-unsaturated fatty acids, which were effectively removed by charcoal treatment at low pH.

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In Order toinvestigate the gelatinization of pig bone insoluble collagen (IC), pig bone IC was prepared from defatted femur by decalcifying with EDTA and the following extractions of soluble collagens. The yield of IC was about 12% on defatted bone basis. Pig bone IC could be almost all solubilized by pepsin-digestion. It was recognized that pig bone IC was composed of type I collagen similar to pig tendon IC, while the content of total saccharides showed twice as much as that of pig tendon IC. The denaturation temperature of pig bone IC was 3-4°C higher than that of pig tendon IC or pigskin IC, and the solubility of pig bone IC into phosphate buffer solution at 60°C and 80°C was about 1/2-1/3 as compared with that of pig tendon IC or pigskin IC, indicating relatively higher thermal stability. The successive extraction of gelatin from pig bone IC with hot water at 60, 75 and 95°C resulted in the yields of about 7%, 11%and 49% respectively, making a total of about 67%, which was higher than that of 30 days-limed ossein. 60°C-extracted and 75°C-extracted gelatin consisted predominantly of α-chain and showed similar gel strength to that of commercial gelatins. From these results, it is suggested that fresh pig bone can be effectively utilized to collagen and gelatin resources.

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To elucidate the difference of aroma quality among four navel oranges which are very closly related species, the odor quality of volatiles in peel oil was studied by the methods of organoleptic and statistics. The essential oil was prepared by simultaneous distillationextraction from four kinds of navel oranges, such as Washington (Citrus sinensis OSBECK, WASHINGTON), Hukumotobeni (C. sinensis OSBECK cv. HUKUMOTOBENI), Ohmishima (C. sinensis OSBECK cv. OHMISHIMA), Shiroyanagi (C. sinensis OSBECK ev. SHIROYANAGI). Then each oil was separated into two fractions of hydrocarbon and oxygenated compound through a silica gel column. The aroma quality of each component in the fraction of oxygenated compounds having a characteristic aroma was determined by GC-profile, and then by sensory evaluation. Octanal, nonanal, linalool, decanal, neral, geranial, dodecanal, and β-sinensal were selected as the important volatiles for the navel aroma. The odor-unit and odor-contribution of each component in the fraction of oxygenated compounds were estimated on the basis of odor threshold and its concentration. The result did not give enough information for the odor quality, but a mutual relationship of 9 components mentioned above was found by factor analysis. To classify their aroma similarities among these four navel oranges, cluster analyses were performed on the basis of the data regarding to similarity by sensory test. Thus obtained classification (dendrogram) indicated that the similarity of odor quality of peel oil agreed well with that of the mixture of 9 compounds mentioned above. Forthermore, it is suggested that the dendrogram can be separated by the odor-contribution of decanal, dodecanal, terpenes and β-sinensal, respectively.

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hydrochloric acid or citric acid. Growth inhibitory pH value of adipic acid for Clostridium botulinum 62 A and 213 B was 5.5. The minimum growth inhibitory concentrations of adipic acid for theses trains at pH 5.0 and 5.5 were 0.08 and 0.5%, respectively. The concentration of undissociated adipic acid required to inhibit their growth completely was calculated as about 12-15mg/100ml. Adipic acid lowered thermal resistance of Clostridium spores in the solutions of pH 7.0. Thermal resistance of the spores of C. botulinum 62 A, 213 B and C. perfringens was decreased by about 50 and 90% by adding 0.2 and 0.5% adipic acid, respectively. Similarly that of the spores of C. sporogenes was decreased by about 90% by addition of 0.6% adipic acid.

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Soybean protein gels have high water holding capacity and elasticity. We tried to make the protein have other characteristics by limited hydrolysis with a proteolytic enzyme. Native soybean β-conglycinin and glycinin were hydrolyzed limitedly by trypsin. When viscosity change was monitored during heat treatment, viscosities of cleaved glycinin and β-conglycinin were lower than those of the intact globulins and started to rise at around 55°C and 74°C, respectively. These temperatures were lower than that (approx. 90 °C) of native globulins, which indicated that the cleaved globulins became unstable. Lower hardness values were observed on the cleaved globulins than those of intactglob ulins by texture profile analyses. On the other hand, the gels of the cleaved globulins had brittleness which was not observed on the intact globulins. White and rough gels which resem bled tofu or cheese curd were obtained from the cleaved glycinin, whereas transparent and fragile gels were obtained from the cleaved β-conglycinin. These results suggest that gelling properties of these globulins can be modified by limited proteolysis.

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Several approaches for suppressing fishy odor derived from oxidation products of lipids in sardine meat have been attempted. Fishy odor in sardine meat was weakened when its pH was neutralized by an addition of arginine and lysine. Antioxidants such as BHT and α-tocopherol could not suppress fishy odor, although they inhibited oxidation of oil in sardine meat during processing and heating. By sensory test, β- and γ-cyclaodextrins suppressed considerably fishy odor, because they trapped the volatile compounds in sardine meat. In addition, suppressing activity for fishy odor was observed in several phenols (catechol, propyl gallate and pyrogallol) and fiavones (catechin). Judging from headspace gas analysis, alcohol dehydrogenase and aldehyde dehydrogenase reduced aldehydes in a heated sardine meat homogenate, but they did not decrease fishy odor evaluated by sensory test. On the other hand, the extraction of oils with high pressure carbon dioxide which hardly caused protein denaturation, decreased the lipid content to 1/5 in sardine meat and remarkably improved its flavor.

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Rheological properties of spirulinan, a mucilaginous polysaccharide extracted from Spirulina subsalsa Oerst var. crassior, were observed together with other food hydracolloids, λ-carrageenan, locust bean gum, guar gum, xanthan and pullulan. The viscoelastic coefficients of spirulinan did not depend so much on temperature compared with other food hydrocolloids. Spirulinan was found to have gelling ability in the presence of salts, such as KCI, NaCl, CaCl₂, and MgCl₂. Spirulinan gel showed excellent water holding capacity.

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We determined the K values of canned fish meat, using a freshness meter, a kind ofenzyme sensor, the accuracy of which was confirmed to be sufficient. The K values of cannedpink salmon were extremely high, but unusual flavor was not detected. The K values ofcanned mackerel were also high. Any enzyme inhibitors, which might be extracted from fishor can during autoclave-treatment and induce the high K value when the enzyme reagent wasapplied, were not detected. From the results obtained, it was suggested that the unexpectedly high K Values canned fishes reflected the storage conditions of the raw materials. Thefreshness of the raw materials was also discussed on the basis of the values of IMP ratiocalculated fromIMP(%)=100-K(%).

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Four pectin fractions, water soluble, ammonium oxalate soluble, hydrochloric acid soluble and sodium hydroxide soluble fractions, were extracted from water hyacinth (Eichhornia crassipes (Mart.) Solms), and the pectin content in each fraction was determined. The relationship between the pectin content and the growth rate of the plant was discussed. (1) Pectin contents in the plant on a dry weight basis ranged between 10-40% of the leaf and 5-14% of the float, respectively. Sodium hydroxide soluble pectin (SSP) was the most abundant fraction in each part, and SSP decreased in late November. The variation in the level of each soluble pectin fraction was similar at the leaf and float parts during its growth. (2) Total pectin contents of the leaf and the float were closely related tothe growth rate of the plant, and they reached maximal levels in late June.

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Chlorogenic acid (Chl) in coffee samples was analyzed by extracting phenolic substance with 0.01M acetate buffer (pH5) at 100°C. The recovery of Chl in the solution was the same as that in alcohol extract obtained by the usual procedure. The recovery of Chl determined by difference spectral method (DS) and DEAE-Toyopearl^TM column chromatography (DTC) was compared with total polyphenol (expressed as Chl) measured by Falin-Ciocalteau's method. In green coffee beans, Chl estimated by DS or DTC were almost equal, but about 10 % lower than total polyphenol. In instant coffees, Chl obtained by DS was slightly smaller than that of DTC. Total polyphenol was 3 to 4 times of Chl determined by DS.

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This paper described thedetermination of ascorbic acid and erythorbic acid in foods by a reverse phase high performance liquid chromatographic method. The chromatographic system included an Inertsil ODS-2 column and a mobile phase consisting of 0.01M sodium dihydrogenphosphate buffer (pH 4.0) and methanol (95+5v/v) containing5mM tetra-namylammanium bromide and 0.03mM disodium ethylenediaminetetraacetate. The column was cooled at 20°C and an amperometric detector was set at +500mV usAg/AgCl and 320nAFS. Food samples were homogenized with metaphaspharicac acid solution and then treated with a reverse phase C 18 mini column. Recoveries of ascorbic acid and erythorbic acid added to beverage, sausage and pickled radish were94. 2-97. 1% for 100μg/g and 93.7-97.1 for 500μg/g, and there was no interfering substance on examined samples. Their detection limits were5μg/g.

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Polyphenol oxidase (EC. 1.10.3.1, PPO) of defatted soybean has been purified by ammonium sulfate fractionation, DEAE-Toyopearl column, Con A-sepharose column, Phenyl-sepharose CL-4B column and Mono Q column chromatography. The purified enzyme oxidized pyrogallol and phloroglucinol. The enzyme fraction showed maximum absorbance at 403nm and exhibited brown color. The enzyme also has peroxidase (EC 1.11.1.7, POD) activity. Through the purification procedures, PPO and POD activities have been eluted in the same fraction and the ratio of the both specific activities stayed constant. The molecular weight of the purified enzyme is estimated to be 47000 by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The optimum pH of POD and PPO are 5.5 and over 7.5, respectively. Both activities are stable at 80°C for 10min and are inhibited by potassium cyanide and L-ascorbic acid.

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[in Japanese]

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