By treating hen's eggs with a commercial crude enzyme preparation having both protease and lipase activities, an oligo-peptide was obtained. Its molecular weight was presumed to be 1000 Da or less. The concentration of the oligo-peptide for inhibiting 50% of angiotensin-I converting enzyme (ACE) activity (ICH) was 1.22mg/ml. Some experimental studies have so far been carried out to investigate antihypertensive effect of ACE inhibitory peptides derived from several foods. In most of those studies, however, antihypertensive effect was evaluated after administrating peptides to spontaneously hypertensive rats (SHR) only once. Few studies have been carried out to examine the long-term effect of ACE inhibitory peptides on blood pressure, including the peptide derived from hen's eggs. In this study, the oligo-peptide derived from hen's eggs was orally administered to SHR for 12 weeks and examined for its antihypertensive effect. The blood pressure of the oligo-peptide dosage groups was significantly lower than that of a non-dosage (control) group. In addition, serum ACE activity of the oligo-peptide dosage groups was significantly lowered than that of the control group. These results show that the oligo-peptide derived from hen's eggs can be used as physiologically functional foods and pharmaceutics to control essential hypertension.

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Production process of rice crackers (arare, okaki, senbei) is time consuming and complicating. Therefore, it is difficult to explain the process scientifically. For the explanation of the manufacturing process and the changes of the gelatinized and retrograded rice starch gel produced in its process, we analyzed the products in the manufacturing process and the imitative manufacturing process of glutinous rice crackers by differential scanning calorimetry. As the result, it was proved that the steaming process was to break hydrogen bonds by the gelatinization phenomenon of starch, the refrigeration process was to create the reformation structure by the retrogradation phenomenon of starch; to create new hydrogen bonds, drying process was to create more thermostable reformation structure by the annealing phenomenon of starch and baking process was to break its reformation structure. Furthermore, it was proved that all process was related to each other and affect the glutinous rice crackers (final products). Namely, it was proved that DSC could analyze the manufacturing process of glutinous rice crackers and the changes of the gelatinized and retrograded rice starch gel produced in its process.

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The volatile constituents of fresh peel, fresh vesicles, canned Satsuma Mandarin oranges (vesicles and syrup) and the stored products were investigated. Volatiles were isolated by simultaneous distillation and extraction under reduced pressure, and analyzed by a capillary column GC-MS. Total volatile contents of peel and vesicles were 1.36% and 0.00038%, respectively. A 99.5% of volatiles in peel was terpenoids. The volatiles in fresh vesicles were mainly composed of terpenoids (60.7%), paraffin waxes (28.0%), alcohols (6.5%) and aldehydes (0.9%). The volatiles with relatively large log odor unit in fresh vesicles were limonene (2.2), linalool (0.8) and (Z)-3-hexenal (1.7), and those in the fresh canned oranges were limonene (1.3) and linalool (0.7). Quantitative and qualitative differences in volatiles between fresh vesicles and canned products have been observed. The terpenoids may mainly contribute to the flavor of canned Satsuma Mandarin orange. The some volatiles considerably disappeared by canning, and gradually decreased during the course of storage. The deterioration of flavor quality of the canned Satsuma Mandarin orange during storage is considerably small compared with that of the canned Satsuma Mandarin orange juice. The following two reasons could be proposed. The first, the tin plate can is commonly used for the manufacturing of the canned Satsuma Mandarin orange. Reductive condition inside of the can was rapidly formed after canning by the reaction of plated tin with enclosed oxygen. The second, the terpenoids, of which hydration could produce undesirable flavor compounds, were contained only little amount in the canned Satsuma Mandarin orange.

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In our previous paper, we assessed the antioxidant effect of warm water extract from barley grain on the oxidative deterioration of oil. In the present, antioxidant compositions in hot water extract from barley grain (referred to as barley tea hereafter) were identified, and their antioxidant activity was measured. Polyphenols in barley tea were identified by using high performance liquid chromatography (column, Develosil ODS-HG, mobile phase, distilled water-acetonitrile-0.05 M phosphoric acid 90 : 10 : 0.05 v/v), thin-layer chromatography (the fraction by silicagel G 60) and ultra violet spectrum analysis. Antioxidant activity was assessed by the Rancimat method so as to determine the rancid point (induction time) and the oven test. Polyphenols in barley tea was detected, and the structures of polyphenols were established as catechol, gallic and gentisic acids, gallocatechin (GC) and epigallocatechin gallate (EGCG). The main component of polyphenols was catechol. On the other hand, very small quantities of the GC and EGCG existed in barley tea. Barley tea and ethyl acetate extract obtained from barley tea showed preventive effects on oxidative deterioration of oil. Especially, ethyl acetate extract were markedly higher than that barley tea. Antioxidant activity of gentisic and gallic acids showed a greater preventive effect.

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An extract solution was prepared from brewer's yeast through proteolysis with proteases and the autolyzate of Aspergillus oryzae. This solution was fractionated by simulated moving-bed system chromatography, and powdered by spray-dry. Amino acids and nucleic acids in this extract powder were analyzed by HPLC with columns packed with Shim-pack ISC-07/S 1504 Na type and WAX-1. Magnitude of difference in taste on this extract powder were evaluated by a sensory test, compared with the conventional brewer's yeast extract. The fractionated extract by chromatography contained increased amounts of peptides and nucleic acids, which relate to taste, and was improved in deliciousness.

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To establish a simpler method instead of alcohol extraction for HPLC analysis of sugars in Satsuma mandarins, melons, strawberries, grapes and Japanese pears, a method using squeezed fruit juice was studied. Sugar contents in each fruit juice which was analyzed immediately after squeezing showed high correlation with values achieved by ethanol extraction. Sugar composition of juice in Satsuma mandarin differed slightly from the data by ethanol extraction, but this was due to differences between sugar compositions in juice and residue. Sugar composition of Satsuma mandarin differed slightly with squeezing rate, so the method of squeezing must be consistent between samples to produce accurate results. When squeezed juice or diluted and filtered juices were placed at room temperature for 24 or 48 hours, respectively, sucrose degradation occurred in all samples except Satsuma mandarin. Microwave heating was found to be effective in reducing sucrose degradation in each of the samples except for undiluted grape juice. For these reasons, it has been concluded that the HPLC analysis using squeezed juice with proper microwave heating could give accurate data on sugar contents in many samples of fruits.

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We investigated the fine structure of surface and cross-sections of Japanese noodles in cooking process with a scanning electron microscope. In the surface of noodles after cooking for 3 min, starch granules were no longer recognizable and small plates and network structure were observed. After cooking for 12 min, the plates turned smaller and the network structure developed among these small plates. After cooking for 18 min lace structure (many filaments were observed) was observed. Near the outer surface of the cross-section of noodles, after cooking for 3 min starch granules were not recognized and after cooking for 18 min fine network structure was observed. Near the core of noodles, starch granules and protein matrix were observed clearly after cooking for 3 min. After cooking for 18 min starch granules were swelled having fine pits while they were recognized in their shape, and protein matrix was buried among starch granules.

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In Sunomono (vinegared seaweed and whitebait) and Nanban-tsuke (vinegared fried pond smelt), treatment with vinegar did not affect intakes of calcium, magnesium and phosphorus because theses minerals which were solubilized by vinegar and eluted from food were absorbed by the edible part. In chicken meat with wing bone which was boiled with a solution containing vinegar, and soup of short-necked clams with shell containing vinegar, calcium content in the edible part significantly increased when cooked with vinegar. These results indicate that cooking with vinegar helps to increase the intake of calcium from food effectively.

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Lactoperoxidase was purified from goat milk whey by one-step cation-exchange chromatography. The purified lactoperoxidase yielded a single protein band corresponding to a molecular weight of about 80 kDa by SDS-PAGE analysis. Analysis of heat stability showed that treatments of goat milk at high temperatures completely inactivated goat lactoperoxidase.

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We studied proteolysis of caseins in a Gouda/Cheddar composite cheese manufactured by two different hard cheese methods during ripening. Protease activities by various enzymes in curd were observed in the wide range of pH4.0 to 7.0, and those activities increased with the elapse of time of ripening. Composite cheese was mainly characterized by decomposition of as 1-casein, which is one of the remarkable feature of cheese ripened by lactic acid bacteria. The existence of plural exopeptidases was suggested.

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Antioxidative activity of proanthocyanidins(dimer and trimer) isolated from barley branwere compared with catechins on inhibition of in vitro lipid peroxidation by the erythrocyte membrane ghost, microsomal and low density lipoprotein (LDL) systems. Inhibition to lipid peroxidation induced by t.-butylhydroperoxide on the erythrocyte membrane ghost system of prodelphinidins was found to be higher than that of procyanidins, almost the same as that of (-)-epicatechin gallate ((-)-ECG) and (-)-epigallocatechin gallate ((-)-EGCG). These results had the same tendency as the inhibition to NADPH-dependent microsomal lipid peroxidation of proanthocyanidins. But inhibition of proanthocyanidins and catechins to Cu²⁺-induced LDL oxidation was different from that to lipid peroxidation on the erythrocyte membrane ghost and microsomal systems. Anyway these results suggested that prodelphinidins isolated from barley bran showed the same or more effectiveness to antioxidative activities than catechins.

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