Fracture properties of heat-induced whey protein gels were evaluated by applying torsional deformation. The torsional deformation method was employed since it generates equivalent magnitudes of the principle normal stress and the principle shear stress within gels. Gels with added NaCl showed a sharp increase in fracture stress values to a maximum at 100mM NaCl and a sharp decrease in fracture strain values to a minimum at 100mM NaCl with increasing NaCl concentration. Further increasing NaCl concentration caused a sharp decrease in fracture stress values and a gradual increase in fracture strain values. These results suggest that fine-stranded networks were formed at low levels of added NaCl (30-50mM) and particulate gels were formed at high NaCl concentrations (300-500mM). At lower pHs than the isoelectric points of whey proteins, brittle gels, with very low fracture stress and fracture strain values, were formed, suggesting that gels formed at low pH should exhibit remarkable differences in texture or sensory attributes, compared with gels formed at neutral pH. However, storage modulus values of gels formed at pH 3 or 4 were larger than those of gels formed at pH 7. It thus appeared difficult to predict textural properties of gels based only on dynamic viscoelastic properties determined in the linear strain region.

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For the purpose of effective utilization of slaughtered animal blood proteins, the gelling properties of the mixture of porcine globin and bovine serum albumin (BSA) were investigated. 1) Gelation of globin required more than 70mg/ml of protein, while the BSA and globin mixture formed a thermal-induced gel at a final protein concentration of 10 and 50mg/ml, respectively. 2) When the globin-BSA mixture (total protein concentration of 90mg/ml, weight ratio of 50/40) was heated, the gelation occurred over a wide pH range (pH 3-9). The gel of the mixture gave the highest breaking intension at pH 7.0, and its water-holding capacity was higher at pH 3 and 9 than at pH 7. 3) The gelation of globin was strongly prevented by the addition of more than 2.0% (w/v) of NaSCN, though the breaking intension of globin gel increased with an addition of 1.0% (w/v) of NaSCN. On the other hand, 2.5% (w/v) of NaSCN could not inhibit the gelation of BSA completely. 4) The breaking intension of the gel of globin-BSA mixture was also influenced by the addition of NaSCN. The breaking intension of the gel of the mixture (pH 7.0) increased by the addition of 1.0% (w/v) of NaSCN.

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Bacterial respiration measurement method with oxygen electrode sensor has been applied to estimate the bacterial cell count in foods. The relationship between respiration of bacteria and its bacterial cell count was examined with the newly developed O₂ uptake detector and the conventional agar-plate. Using 168 food samples, the new method was evaluated. Samples were processed with a stomacher for one minute in saline, and injected into the ninety-six well sensor plate with oxygen electrodes embedded. After nutrient broth was added to each well, dissolved oxygen concentration of each sample was monitored continuously for 24 hours at a temperature of 35°C. Detection time for oxygen electrode method was defined as the elapsed time when the dissolved oxygen is consumed by bacterial respiration to 60% of negative control oxygen concentration. It depended on the number of conventional plate count. As for samples containing 10⁵ [cfu/g] bacteria, detection time was approximately 6 hours, and it decreased linearly with the log number of standard plate count, with a slope of -2.6 [hour/cfu/g]. Correlation coefficient for the estimated cell count with reference curve and conventional plate count was 0.83. This new method detected bacteria more rapidly, in proportion to bacterial concentration in foods.

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Antioxidative activity of water extract of herbs was investigated. The fresh leaves of herbs were cutted to small pieces and were allowed to stand for 10-15 minutes in hot buffer, then they were filtered off. The antioxidative activity of the water extracts was determined by ferric thiocyanate method and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) method. As the result, the high antioxidative activity of curry plant and sweet lavender against linoleic acid was newly revealed by the ferric thiocyanate method, and nutmeg, sweet lavender, and super aloe showed a quite high radicalscavenging activity by the DPPH method. The antioxidative activity of polyphenols in curry plant, which was extracted with ethyl acetate from water extract of curry plant, was measured by the DPPH method. Resultingly, 25% of the total radical-scavenging activity of curry plant seemed to depend on the polyphenols. The polyphenols in curry plant were identified as gallic acid, pyrocatechol, catechin, dihydroxybenzoic acid, and epigallocatechin gallate (EGCg), and so on by using high performance liquid chromatography using ODS column. The main components of polyphenols were dihydroxybenzoic acid, EGCg, and catechin. EGCg had the greatest DPPH radical-scavenging activity.

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We examined the antioxidative effect of the addition of bamboo charcoal on frying oil. Bamboo (Phyllostachys pubescens) was carbonized at 500, 800, and 1100°C in an electric oven to make bamboo charcoal, referred to hereafter as bc500, bc800 and bc1100, respectively, The higher the oven temperature, the lower was the electric resistance of the charcoal. The surface area of the charcoal was 4.62, 314.21 and 0.79m²/g, for bc500, bc800 and bc1100, respectively. The anisizine value (An V) measured as the indicator of the oxidation of the frying oil to which was added 20% charcoal (w/v) was 151.4±4.5, 54.7±2.9 and 59.1±6.9 for bc500, bc800 and bc1100, respectively, after heating at 180°C for 6h, while that without charcoal was 150.2±1.7. A more detailed examination revealed that antioxidative effect of 1% added oil was not observed, but manifested significantly in both 5 and 10% added oil. The frying oil inside the charcoal was less oxidized than the oil outside the charcoal, the An V value, 83.3±0.6 and 213.6±4.4, respectively, after heating at 180°C for 6h, while that without charcoal was 271.1±3.7. The crashed charcoal (0.5-1.0mm in diameter), in which many small holes were observed by electron micrography, indicated stronger antioxidative activity than smaller or larger diameter samples. From these results, the high antioxidative effect of the addition of bamboo charcoal (bc800) on frying oil was considered to be due to chemical adsorption to the large surface area of the charcoal, and to less oxidation of the oil inside the charcoal.

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With the weak electrolyzed cathode water or a kind of electrolyzed water obtainable by electrolysis of tap water used for cooking of aged rice grains having the quality deteriorated, the effect of improving the eating quality of cooked rice was tested. Further, preservability of rice cooked with the weak electrolyzed cathode water and the mechanism of retarding retrogradation of cooked rice were examined. With the weak electrolyzed cathode water used for cooking of aged rice, the quality of the cooked rice immediately after cooking was improved, as for the texture parameters, the cooked rice with the weak electrolyzed cathode water was significantly lower in hardness and was significantly greater in stickiness than the cooked rice with non-electrolyzed tap water. But the preservability of cooked rice with the weak electrolyzed cathode water deteriorated, as compared with use of non-electrolyzed tap water. Here, it was found that by adding a carbohydrate such as trehalose or a surfactant such as polyoxyethylene polyoxypropylene glycerinether monoglyceride to the soaking water, retrogradation of cooked rice with the weak electrolyzed cathode water could be retarded.

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Experiments on wet and dry curing of porcine muscle (longissimus dorsi) were all carried out in the absence of nitrite. Meat was processed in 3.0% NaCl by dry salting or by soaking in brine for 3 days at 2°C. During the 3-day period of dry curing, total viable microbial counts and counts of various types of microorganisms except lactic acid bacteria were reduced on the meat surface. Compared with those for wet cured meat, there were greater decreases in the total viable counts and the counts of Gram-negative rods and Gram-positive cocci on the dry cured meat. After the meat was dry-cured at 3.0% or 6.0% NaCl for 1 day or 3 days, the cured meat then containing various concentrations of NaCl was further cured in brine, which was adjusted to have a final NaCl concentration of 3.0%. In every case, the brine concentration of curved products ended up at the expected value after wet curing for about 14 days. Lactic acid bacteria predominated among the final flora of the cured meat. Following the wet curing, counts of Gram-negative rods and Gram-positive cocci on the meat dry-cured at 3.0% for 3 days continued to be lower than these counts on the meat that have been only wet cured. In conclusion, we were able to utilize the bacteriostatic action of dry curing to eliminate the use of nitrite in the initial stage of curing and to manufacture meat products with the consumers' favorite salty taste similar to that of wet cured product.s

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To determine the effect of homogenizing pressure on the physicochemical properties and sensory characteristics of UHT milk, which was milk, pasteurized at 130°C for 2 seconds using an indirect heating method, was studied. A panel of experts evaluated the sensory characteristics and a panel of housewives evaluated palatability. As homogenizing pressure increased, fractionation of fat globules occurred, causing average dispersed fat globule size to decrease. It resulted in an increase in viscosity, degree of whiteness, and the refractive index of UHT milk. Further, rennetability tended to decrease as homogenizing pressure increased. Evaluation of the sensory attributes and principal components analysis revealed that the lower the homogenizing pressure is, the greater the fattiness, body, milk taste, sweetness, and thickness of milk become. According to the panel of housewives, palatability was better when milk was homogenized at low pressure.

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A protease was purified from commercial natto. The protease extracted from commercial natto was purified sequentially by column chromatographies on DEAE-Toyopearl, Butyl-Toyopearl, and Mono Q. The enzyme was most active at pH 10, and its optimum temperature was 50°C. The molecular weight was 29kDa by SDS-PAGE and 28077.4 by mass spectrometry. N-terminal 21 amino acid residues exhibited a high homology with those of subtilisins and nattokinase. The activity was inhibited by PMSF (Phenylmethylsulfonyl fluoride). Hydrolysis of the oxidized insulin B-chain with this natto protease was observed primarily at Leu¹⁵-Tyr¹⁶, and as the secondary cleavage site at Ala¹⁴-Leu¹⁵, which was not yet observed in the already-known subtilisins. The isoelectric point (pI) of 9.6 is different from that of the serine protease (pI of 8.6) purified from natto. These results indicate that this protease is a subtilisinlike serine protease different from subtilisins and natto protease which have been reported.

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A convenient method to measure physical properties of dough by using 10g dough was established. The relationship between dough's physical properties (breaking force, breaking deformation, physical property ratio and breaking energy) thus obtained and specific loaf volume was examined. There was a clearly positive correlation between breaking force, physical property ratio and specific loaf volume and was a clearly negative correlation between breaking deformation and specific loaf volume, however there was hardly correlation between breaking energy and specific loaf volume. These results largely correspond to general results between physical properties measured by conventional methods and specific loaf volume. Because of its capability to measure the physical properties of dough in a small flour sample, our new method will be useful to evaluated the breadmaking quality of flours at early stage.

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The mixture of cinnamon and basil (Mixture 1) and that of rosemary and caraway (Mixture 2) were prepared and fed for Holstein cows in two period. Cinnamic aldehyde (0.6ppb) and dcalbone (0.5ppb) were found in the milk from the cows fed Mixture 1 and Mixture 2 in the period 1. In the period 2 both essential oil contents were under the limitation of the analysis. Milk from the cow fed Mixture 1 had less milk smell than that from the cows fed the basal diet in the period 1. These results showed the possibility that herb essential oil could be passed to milk and milk flavor could be controlled by feeding dried herb to dairy cows.

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We examined an estrogen-like activity in the pomegranate (Punica granatum) juice. The juice or its methanol eluate from C18 cartridge competed with 17β-estradiol for estrogen receptor (ER) binding and also stimulated proliferation of human ER-positive cell (MCF-7) in vitro. Furthermore, they effectively increased uterine weight in the ovariectomized rat. On the basis of these data, we concluded that the pomegranate juice contained estrogen-like compounds.

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