Fish meat emulsion was prepared from egg-yolk, very low lipid sardine meat ground or suspended in weak alkaline solution, salad oil, and vinegar. The effect of added water on the flow properties and oil droplet size was investigated. In the ground-meat emulsion at an oil ratio of 1.1 to sardine meat irrespective of water ratio between 0 and 0.3, the hysteresis loop area of the flow curve was small and the small sized oil droplets were uniformly dispersed. When the oil ratio was increased to 1.6, the flow property changed within 1 day of storage. In the suspended-meat emulsion irrespective of the oil ratio of 1.1 or 1.6, the loop area was large with large oil droplets at water ratios of 0 and 0.1, and the area became smaller with smaller oil droplets at water ratios of 0.2 and 0.3. The emulsion with a water ratio of 0.1 was in the intermediate state between the irreversible shear breakdown and the thixotropy. At an oil ratio of 1.1 with this water ratio, both very large and moderately large loop areas were observed. At an oil ratio of 1.6, both the shear thinning flow and the shear thickening ones were observed during irreversible breakdown. The smaller oil droplets were dispersed more uniformly in the sample which showed a moderately large loop area or the shear thickening type breakdown.
An effort was made to elongate the shelf life of strawberries by the application of an alternating current (60 Hz) high electric field (HEF). An internal voltage as high as 174 V was measured in a strawberry by applying a 430 kV/m external electric field. Short treatment periods (0.5-1.5 h) with the HEF (430 kV/m) was found to reduce rotting (%) of the strawberries, but continuous HEF treatment was more effective to control rotting. Because continuous HEF treatment without packaging caused excessive weight loss, the strawberries were packed in polyethylene trays (OPS, P-11) and covered without sealing. The HEF was then continuously applied to the strawberries. Strawberries treated by continuous HEF for 6 days at 20°C and by electric fields of 0, 114, 172, 285 and 430 kV/m resulted in 80, 60, 50, 30 and 0% rotted samples, respectively. No differences were observed in surface color, pH, acidity and sugar contents between treated and non-treated samples.
Different types of polymers were added to ethyl oleate-in-water emulsions and the stability of the emulsions was followed by a turbidimetric technique. Addition of neutral polymers such as pullulan and dextran at 1% (w/v) destabilized the emulsions. The dependence of the stability of the emulsions on pullulan concentration was examined. When the concentrations were lower than 0.5% (w/v) and higher than 8.5%, the stability was almost the same as that at 0%. At the concentrations of 1 to 7%, the emulsions were destabilized. These phenomena are discussed based on a model in which the depletion effect was incorporated into a model derived from a balance of forces working on a coalescing droplet.
An experimental study has been carried out on the permeation of water and various flavors through packaging films used in commercial tobacco products. The permeation coefficients of these films were measured using a flow-type permeation system by means of steady-state transmission. The permeation coefficients of all the tested agents, including L-menthol, through three types of films could be systematically obtained over wide ranges of concentration and temperature. As the concentration of the tested agents in the upstream was increased, the permeation coefficients of water remained constant, while those of ethanol and the flavors increased. The concentration dependence of the permeation coefficients for ethanol and the flavors was caused by a plastic effect, leading to the structural loosening of the molecular chains of the films, and then markedly increased with an increase in the sorbed amounts of ethanol and the flavors on the films and decreased with an increase in temperature. The permeation coefficients of ethanol and the flavors mainly depended on their sorbed amounts by the films and governed by the affinity between the films and the flavors. Finally, a film having a polyvinylidene chloride or an aluminum layer was confirmed to be effective for depressing the permeation of ethanol and the flavors through them during storage.
The sterilization rate for Saccharomyces cerevisiae and the spores of Bacillus subtilis in a process using high pressure CO2 was analyzed. The microorganisms were placed in a reservoir, and the pressure was increased to a selected value. The sample was kept at constant pressure and temperature for a certain period. Thereafter, the pressure was decreased and the number of the living cells were determined from the colony count. The time course of the survival ratio for the microbial cells were described as a first order reaction, with the sterilization rate constant k being evaluated. This result indicates that the microbial cells are killed mainly at the constant pressure stage. At constant temperature, the values of k for the microorganisms increased with the increase in pressure and definitely increased near the critical pressure of CO2. From the Arrhenius plots of k, the values of the activation energy E and the frequency factor A were evaluated, decreasing with the increase in pressure. The orders of the values for E were 104 to 105 J/mol.
The percent suppression of the methanol extracts from rice-koji miso (RM), barley-koji miso (BM) and soybean-koji miso (SM) on the SOS response of Salmonella typhimurium TA1535/pSK1002 induced by MNNG was determined. The suppression in commercial mature misos and miso preparations decreased in the order SM, RM, BM. The daidzein and genistein contents of the extract from the commercial mature SM were highest, followed in order by BM and RM. The percent suppression and aglycon content of the miso preparation increased with the degree of fermentation. However, there was no direct relationship between the suppression and aglycon content.
Persimmon (Diospyros) contains polyphenol compounds (proanthocyanidin polymers). The content of polyphenol compounds in persimmon extract was estimated to be 27% by the acidified vanillin method. The effect of persimmon extract on a two-stage model of carcinogenesis which consisted of initiation by 7,12-dimethylbenz [a]-anthracene (DMBA) and promotion by 12-O-tetradecanoyl-phorbol-13-acetate (TPA) was investigated. Formation of mouse skin papillomas was remarkably inhibited by persimmon extract. In in vitro experiments, it was found that the [3H]TPA binding to mouse skin particulates and the activity of ornithine decarboxylase (ODC), a marker enzyme of tumor promotion, were inhibited dose-dependently by the persimmon extract, and that DPPH radicals and active oxygens (OH, O2-) were scavenged by persimmon extract. These findings suggest that the suppression of the skin carcinogenesis results from the inhibition of [3H]TPA binding to mouse skin particulate and ODC activity and the scavenging of active oxygens by the persimmon extract.
The relationship between loaf volume and the proportion of SDS-insoluble gluten in wheat flour was studied using N-ethylmaleimide (NEMI) as a modifying reagent of gluten. The loaf volume responded to NEMI and was maximum at 10 ppm NEMI, but was minimum in the absence of yeast food. SDS-insoluble gluten had the same response to NEMI. Therefore, it was concluded that the loaf volume was positively related to the proportion of SDS-insoluble gluten. With excess NEMI (100 ppm), a substantial decrease in SDS-insoluble gluten was observed in the doughs. This was accompanied by a decrease in the relative viscosity of the ethanol-insoluble fraction (glutenin). This result suggested that excess NEMI caused a decrease in the molecular size of glutenin, probably by a thiol radical mechanism, leading to the decrease in SDS-insoluble gluten and then to deterioration of the baking quality of wheat flour. On the other hand, a lower amount of NEMI may determine the proportion of SDS-insoluble gluten and loaf volume.
The Masai, a nomad living in East Africa, consume a large quantity of fermented milk as the main staple. Angiotensin I-converting enzyme inhibitory activity of their fermented milk was compared with those of commercial ones. Relatively strong activity was detected in their fermented milk. The inhibitory activity in the milk increased during fermentation with Lactobacillus confusus and Lactococcus lactis subsp. lactis which were isolated from the Masai fermented milk as the dominant strains. Two inhibitory peptides were purified by ethanol fractionation and four HPLC steps. Their amino acid sequence were identified as Ser-Leu-Val-Tyr-Pro-Phe-Pro-Gly-Pro-Ile-His-Asn and Lys-Thr-Thr-Met-Pro-Leu-Trp. Their IC50 values were 38.5 μM and 28.7 μM, respectively.
The effects of soybean pectic polysaccharide on cholesterol metabolism in rats were examined. The polysaccharide gradually repressed the increase in the serum cholesterol level; whereas, citrus pectin rapidly repressed the increase and cholesterol accumulation in the liver was not observed. Significanct differences in cecal short-chain fatty acid concentrations were not observed; therefore, further experiments are necessary to clarify the mechanism.
An antimicrobial fraction was fractionated from the water-extract of paprika seeds by salting out with ammonium sulfate and successive column chromatographies on DEAE Sepharose FF and Sephadex G-200. The fraction strongly inhibited the growth of yeasts, especially Saccharomyces cerevisiae, and its MIC value was 15.6 μg/ml. The main components of the antimicrobial fraction were proteins (52%) and neutral carbohydrates (24%). Viable cells completely disappeared within 24 h after the addition of the antimicrobial fraction to a growing culture of S. cerevisiae. The activity of the antimicrobial fraction was constant over a wide pH range from 4.0 to 7.0 and was not influenced by heat treatment (50 to 100°C). These outstanding characteristics indicate that the antimicrobial fraction may be a good food preservative for yeasts.
The microbiological quality of chicken meat samples produced in several different areas in Japan was investigated. The total aerobic bacteria were between 8×104 to 6×106 per gram. Coliforms were 9×101 to 2×104 per gram for Escherichia, Proteus and Klebsiella. The dominant putrefactive bacteria under chilled conditions were determined to be lactic acid bacteria, Pseudomonas and Flavobacterium. Low dose γ-irradiation at 1 kGy resulted in disappearance of the dominant putrefactive bacteria, coliforms and Staphylococcus on plate agars. The shelf life of irradiated chicken meat at 1 kGy was prolonged 3 times compared with non-irradiated chicken meat and could be stored for 6 days at 10°C storage. Irradiation of chicken meat at 3 kGy reduced the aforementioned dominant flora to the yeasts and Psychrobacter. Salmonella was detected slightly in some samples and was reduced to a 10-4 survival by a 1 kGy irradiation dose.
Lactic acid bacteria were evaluated for suitability in producing a fermented carrot juice. All nine strains of lactic acid bacteria studied grew well in the juice. Sensory evaluation indicated that L. delbrueckii subsp. bulgaricus IAM-1120 and L. helveticus JCM-1120 produced the most favorable juice. These strains produced less diacetyl, suggesting that the lack of diacetyl production is an important factor for acceptable fermented juice. Moreover, decreased aldehyde and increased ketone components of fermented carrot juice by these selected strains was observed by gas chromatography/mass spectrometry, and this was suggested to contribute to taste improvement. Although the color of the fermented juice changed in fresh orange color, there was no significant difference in carotenoid composition and their contents.
γ-Irradiated onions (0.2, 1, 2 and 5 kGy) were stored for 1, 3, 7 and 11 weeks. Cooked onion aroma concentrates were prepared by a simultaneous distillation and extraction (SDE) method and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) at all stages of storage. A total of 27 compounds was identified. The similarities among the GC patterns obtained from all the onion samples were calculated using the ratios of 148 peak areas. The qualitative and quantitative characteristics of the cooked aroma constituents of 0.2 kGy-irradiated onions were very similar to those of non-irradiated onions. The similarities between non- and 0.2 or 1 kGy-irradiated onions were great during all stages of the 11 weeks storage. However, similarities between non-and 2 or 5 kGy-irradiated onions were low during storage. The radiation dose of 0.2 kGy for preventing sprouting does not change the cooked flavor characteristics. A dose of 1 kGy is the irradiation limit before the cooked onion flavor is affected.
After treatment with about 200 ppm hypochlorite solution, ume fruit (Japanese apricot, Prunus mume Sieb. et Zucc.) was soaked in water, 5% NaCl or 10% NaCl with Ca lactate or ashed kelp as a hardener. The fruit was stored at a pressure of 1.2×103 Pa. After 6 months, we analyzed the organic acids, free sugars (sugars), free amino acids (amino acids), inorganic cations and pectic substances in the ume fruit. We also measured the hardness, and the yeasts and lactic acid bacteria were examined. The following results were obtained: (1) Yeasts and lactic acid bacteria were not detected. (2) Ume fruit without a hardener obviously softened. Though ume fruit with a hardener generally maintained hardness, the fruit stored in water decreased slightly more than that stored in 5% and 10% NaCl. (3) Ume fruit with Ca lactate contained lactic acid produced by dissociation of the lactate to Ca ion and lactic acid. However, organic acids in ume fruit were not decomposed during storage. (4) Though sucrose was resolved to glucose and fructose, no sugars in ume fruit decomposed to any compound except the sugars. (5) The major amino acid in fresh ume fruit was asparagine which represented 93.3% of the total amino acids. The ratio of asparagine in stored ume fruit was almost the same as that in the fresh fruit. In addition, amino acids in ume fruit were considered not to decompose during storage. (6) Because the Ca content in the alcohol-insoluble substances prepared from ume fruit with Ca lactate or ashed kelp increased, Ca in both hardeners was thought to bind to some components such as pectic substances. (7) With storage, ume fruit decreased in the ratio of 0.05 N hydrochloric acid-soluble pectin (HSP) to total pectin and increased in the water soluble-pectin (WSP) ratio. Though the HSP in ume fruit with Ca lactate also decreased, the degree of decrease was less than that of the fruit without a hardener. In addition, the WSP ratio did not increase. Furthermore, ume fruit with ashed kelp was remarkably larger in HSP ratio than the fruit with Ca lactate, and the WSP was less than that in the fresh fruit. From these results, it was found that under low pressure storage, though sucrose was resolved to glucose and fructose, the taste components in ume fruit were maintained. Furthermore, it was found that ashed kelp has an ability about equal to that of Ca lactate to maintain the hardness of ume fruit during storage. However, it was considered that the mechanism for maintaining hardness might differ each case.
The effects of a non-dialyzable extract of amaranth seeds on the biological functions of the cultured human leukemia cell lines such as monocytic U-937, promyelocytic HL-60 and macrophage-like U-M cells were examined. The extract stimulated the nitroblue tetrazolium (NBT)-reducing activity of HL-60 and U-937 cells. It was also found that the extract enhanced their α-naphthyl butyrate esterase activity. On the other hand, the NBT-reducing activity of U-M cells was not affected by the extract, but it slightly enhanced their tumor necrosis factor producing activity. These results suggest that the non-dialyzable extract of amaranth seeds contains some leukemia differentiation-inducing and macrophage-activating factors.
The functions of the 350 kDa glycoprotein in royal jelly (RJ) on the primary monolayer culture of rat hepatocytes were examined. In the serum-free L-15 medium supplemented with the RJ protein, the monolayer culture of hepatocytes was maintained for 20 days. In contrast, without the RJ glycoprotein, the number of the hepatocytes which adhered to the dish decreased to less than one-half the number of inoculated cells during 20 days of culture. The amount of albumin secreted in the medium was monitored as an expression of liver-specific function. In the medium with the RJ glycoprotein, the hepatocytes maintained the secretion of albumin at a similar high level for 2 days compared to that in the starting culture, followed by diminishment to a low level. In contrast, the secretion of albumin by the hepatocytes cultured without RJ glycoprotein was decreased rapidly with time. As a control experiment, bovine serum albumin added to the medium did not show any effect both on the maintenance or albumin synthesis of rat hepatocytes.
Acetic acid, N-butylacetamide, N-butyl-2-formyl-5-(hydroxymethyl)pyrrole, and N-butylformamide were formed as major compounds in a butylamine and 3-deoxyglucosone (3DG) reaction system under physiological conditions of 50°C at pH 7.4. N-Butylformamide is postulated to be formed by the cleavage of the C-C bond in α-dicarbonyl groups with the addition of amino compounds. Carbon at the 6 position in 3DG is speculated to be principally converted into methyl carbons of N-butylacetamide and acetic acid during the Maillard reaction.