This study aimed to compare the physical properties of mayonnaise with its perceived texture. Model mayonnaises with the same composition were prepared under different emulsifying conditions. Perceived textural properties of mayonnaise, such as hardness, fracturability, viscosity and adhesiveness, were evaluated by trained panels using the quantitative descriptive analysis method. Rheological properties and particle size distribution were measured instrumentally. Pearson's correlation coefficients between textural attributes and physical properties were calculated. The storage modulus G′ in the linear region showed significant correlations (p<0.001 or p<0.01) with all of the sensory attributes. No significant correlation was observed between sensory attributes and viscosity-related properties, such as apparent viscosities and flow curve parameters. The particle size at 10% cumulative volume had high correlations (p<0.01 or p<0.05) with all of the sensory attributes studied.
The discoloration of L-ascorbyl 6-palmitate, with water contents ranging from 2 to 10% (w/w) during storage at temperatures of 60 to 90°C, was investigated by monitoring the absorbance at 500nm of its solutions dissolved in methanol. The discoloration process of the substrate was expressed by the modified Weibull equation under all conditions, and the kinetic parameters were evaluated. The activation energy and frequency factor were estimated based on the Arrhenius equation for the substrates of various water contents, and the enthalpy-entropy compensation held for the discoloration process. Comparison of the discoloration kinetic parameters for L-ascorbyl 6-palmitate with those for L-ascorbic acid revealed that the discoloration of L-ascorbyl 6-palmitate was weaker than that of L-ascorbic acid.
In the production of soy sauce, the koji making stage during which koji mold is cultivated, is the key process for producing a high quality final product. Koji mold and contaminated bacteria act as antagonists as the koji making stage proceeds. As a result, the usable moisture content was reduced and an antibacterial substance was produced. Both of these effects were observed during our experiments. We confirmed the presence of antibacterial substances in koji. We purified the two main components and identified their chemical structures precisely. Furthermore, we examined the minimum inhibitory concentrations (MIC) of these substrates using selected bacteria, yeasts and molds. Out of these microorganisms, antibacterial substances in koji showed the strongest antibacterial activity toward Legionella erythra.
The effect of the continuous flow of supercritical CO2 microbubbles (the SC-CO2 method) on the inactivation of both Escherichia coli in model water and coliform bacteria in water prior to treatment at a municipal water filtering plant were studied as a way to produce safe drinkable tap water. The number of surviving cells in both samples drastically decreased above a certain concentration of dissolved CO2 (γ=25). When treated for 13.3min, cells were not detected at concentrations over γ=30. The dependences of the number of surviving cells on the concentration of dissolved CO2 were similar in both the treatments for 6.7 and 13.3min. Therefore, it was suggested that effective inactivation could be achieved by minimizing the treatment time. From these results, it was proposed that the SC-CO2 method might be effective in inactivating E. coli and coliform bacteria for the production of public drinking water.
We have been developing and studying an alcoholic fermented beverage produced from a raw purple-fleshed sweet potato cultivar (Ipomoea babatas cv. Ayamurasaki) containing high amounts of anthocyanin. In this study, we investigated the relationship between the anthocyanin content and aroma of the beverage and its manufacturing process. When raw sweet potatoes were allowed to stand for 1h at 5°C or 30°C between grinding and the initiation of fermentation, the anthocyanin content of the resulting beverage was considerably lower than that of an otherwise identical beverage produced from sweet potatoes ground immediately before fermentation. With that in mind, we investigated the effect of pH on maintenance of the anthocyanin content of ground sweet potato and found that decreasing the pH to 3.0 with citric or lactic acid made it possible to allow the ground sweet potatoes to stand for 3h at 30°C before starting fermentation, without any loss of anthocyanin. Moreover, the addition of citric acid led to the production of large amounts of higher alcohols such as isoamyl alcohol and isobutyl alcohol. These findings suggest that citric acid has desirable effects on both the color and the aroma of the alcoholic fermented beverage produced from raw purple-fleshed sweet potato.
Microbial transglutaminase (MTG) was applied to improve the breaking properties and oil absorption of breadcrumbs made from bread prepared with added MTG (0.85-3.34U/gram of protein). The specific volume of the bread and such sensory attributes as softness, moistness, and form stability increased with added MTG except for the highest addition, corresponding to the development of an ε-(γ-Glu)Lys (G-L) bond indicative of an increased G-L content and polymerized proteinaceous components. The fried breadcrumbs containing MTG showed increased breaking strength and distance, corresponding well to the increased crispness and total acceptability from the sensory evaluation. The absorbed oil content of the fried breadcrumbs was significantly decreased with increasing added amount of MTG. The combined use of a low-level addition of MTG and such texture modifiers as wheat gluten, soybean-curd refuse, and alginic acid resulted in a further effective decrease in the absorbed oil content.
Four varieties of rice were cooked in microwave oven and under pressure and examined for their physical characteristics, cooking quality and sensory attributes. The range of physical characteristics observed for rice varieties were length/width ratio -2.21 to 4.12, 1000kernel weight -16.52 to 17.32g, bulk density (g/ml) -0.781 to 0.860, density (g/ml) -1.327 to 1.427, porosity -35.15 to 45.28%, gel consistency -27 to 29mm, amylose content -20.0 to 23.8g/100g and equilibrium moisture content -27.1 to 29.1%. The time required and water uptake of rice by microwave method was much higher than pressure cooking method. The elongation ratio was higher in pressure cooked samples (1.80 to 1.94) in comparison with microwave cooked samples (1.49 to 1.67). The cooked rice volume (ml/100g) ranged from 430 to 516 with higher values for pressure cooked samples. The sensory data on cooked rice obtained by ranking test and quantitative descriptive analysis indicated that microwave cooked rice varieties were equally preferred and in some attributes proved to be better than pressure cooked ones.
We investigated the use of a high-performance liquid chromatography (HPLC) with o-phthalaldehyde fluorescence detection to simultaneously quantify γ-Aminobutyric acid (GABA), glutamate and alanine. Using this method, the column (COSMOSIL 5C18-MS-II, 4.6mm i.d.×15cm) was eluted using a linear gradient of acetonitrile and 5mM citrate buffer (pH 6.0). The GABA contents of both milled and cooked rice samples were measured, with a gradual decrease observed as the rice was milled in raw rice. However, GABA content was markedly diminished due to washing in rice milled for a longer period. In less milled rice, the GABA and glutamate contents increased when the rice was cooked without washing. As a result, the GABA content of cooked under-milled rice was twice that of cooked well-milled rice available in the market, and three times greater for under-milled cooked rice without washing. These findings revealed that partially milled rice could be utilized as a daily source of GABA.
In this study, we compared the intestinal absorption from different sources with the same amino acid composition (protein, peptide, and amino acid mixture) by measuring changes in serum concentrations of various amino acids. Peptides used in this study were prepared by enzymatic digestion of 11S globulin (a major component of soy protein). Twelve normal male adults were asked to drink beverages containing 12.5g of the test sample, representing 5% suspension of each of the following three different preparations : 11S globulin, 11S peptide, and an amino acid mixture of equivalent composition. Venous blood samples were collected from 0 to 180min to measure free amino acid concentrations. The early slope of serum concentrations and values of area under the curves for each amino acid calculated from changes in serum amino acid concentrations were significantly greater for 11S peptide than for either 11S globulin or the amino acid mixture. This trend was especially remarkable for branched-chain amino acids and aromatic amino acids. Our results suggest that the ingestion of hydrolyzed soy protein results in faster and more efficient absorption than the consumption of protein or amino acid mixtures in healthy adult men.
Eisenia arborea, an edible brown alga, is occasionally used as a folk medicine due to its anti-allergic effect. In the present study to identify the anti-allergic constituents in the alga, the extract of the alga was purified by partition between solvents and by reversed phase chromatography. Separation of the extract was guided by the inhibitory activity upon β-hexosaminidase release from the rat basophilic leukemia-2H3 cells. HPLC purification afforded six active compounds. Spectral analyses clarified their structures as eckol, 6,6′-bieckol, 6,8′-bieckol, 8,8′-bieckol, phlorofucofuroeckol-A, and phlorofucofuroeckol-B. Most of the phlorotannins exhibited activities similar to or greater than the typical inhibitor, epigallocatechin gallate. Phlorofucofuroeckol-B showed the greatest activity among the tested phlorotannins at 2.8 times greater than epigallocatechin gallate.
Kokuto, a traditional cane sugar of Okinawa, has been reported to have antioxidative and lipid-lowering properties. In this experiment, we investigated the effect of three different kinds of Kokuto (KA, KB, and KC) on atherosclerosis in two different animal models : Japanese quail and apolipoprotein E deficient (apoE-/-) mice. Ingestion of Kokuto had no significant effect on the serum and liver lipid levels of Japanese quail. Dietary intake of atherogenic diet (AD) with KA and KB decreased the liver triglyceride level and body weight in apoE-/- mice. Quail fed on AD with KA developed less extent of lipid-containing aortic intimal thickening lesions than those fed on AD with sucrose. Dietary intake of AD with Kokuto or sucrose induced aortic atheromatous lesions in mice, but the extent of atheromatous lesions was roughly comparable between these dietary groups of apoE-/- mice. The present study suggests that Kokuto prevents lipid-containing aortic intimal thickening lesions in Japanese quail.
Antioxidant activity and flavonoid content of Welsh onion (Allium fistulosum) (green-leafy and white-sheath varieties) and the effect of thermal treatment on them were studied by comparing with those of onion (Allium cepa) (yellow and red varieties). Antioxidant activity was measured by Trolox equivalent antioxidant capacity (TEAC) and ferric reducing antioxidant power (FRAP) assays. The order of these indices of antioxidant activity was red onion>yellow onion=green Welsh onion>>white Welsh onion. The order of the total flavonoid content was red onion>yellow onion>green Welsh onion>>white Welsh onion. Major flavonoid of yellow and red onions was quercetin, and that of green Welsh onion was kaempferol. Antioxidant activity of green Welsh onion was increased, but that of the other three vegetables was decreased during boiling for more than 15 minutes. Flavonoids in green Welsh onion were less stable than those in the other three vegetables during the boiling procedure. These results suggested that green Welsh onion, but not the white one, is a potent antioxidant food comparable to yellow onion, and is a good source of kaempferol. Increased antioxidant activity and decreased flavonoid content during boiling were characteristics of green Welsh onion.
The structural properties of starches isolated from five quinoa lines were characterized. All quinoa starches used in the study exhibited the A-type of diffraction pattern. The starches were waxy, with low amylose contents (5.2 to 10.9%) and high degrees of relative crystallinity (39.0 to 43.0%). Quinoa amylose molecules had a large number of branched chains, and the λ max (maximum absorption wavelength) and BV (blue value at 680nm) of quinoa amylose molecules were low compared to barley amylose molecules. On the other hand, quinoa amylopectin molecules had a large proportion of LC (longest chain) with a high λ max and BV. These structural characteristics of quinoa starches suggested that quinoa could be used as a novel food source.
We investigated the carotenoid composition of thirteen types of Capsicum annuum fruit at full maturity and discussed the ratio of β-carotene to capsanthin. Among the thirteen types examined, “Cherry sweet” and “Raruku” had the fruit with the highest values of total carotenoid content and capsanthin content. “Raruku” and “Sarara”had high capsanthin content (”Raruku” 63%, “Sarara” 59%). Although ten C. annuum varieties were included in the 13 fruit types sampled, a high correlation (r=0.960) was observed between β-carotene and capsanthin. In addition, the 1 : 10 carotene capsanthin ratio was used as an index for the capsanthin content of ripe C. annuum.
In the present study, the relationship between the addition ratio of palatinose in feed and body fat accumulation was investigated in mice. Thirty eight-week-old male mice (C57BL/6CrSlc) were divided into three groups : a 0% palatinose group (control group), a 18% palatinose group, and an 40% palatinose group. The 3 groups were then fed their respective diets for 8 weeks. Following the conclusion of the feeding period, fat tissues in the perirenal, periepididymal, and perimesenteric regions were removed to determine their wet weight. The weight of the visceral fat was clearly lower in mice of groups fed with feed containing palatinose than in the mice of the control group. In particular, the weight of perirenal fat was significantly lower in the 40% palatinose group than in the control group (p<0.05).
The formation of zinc protoporphyrin IX (ZnPP) and protoporphyrin IX (PP) in porcine heart mitochondria was investigated by fluorescent spectral analysis. The time-course study at 37°C and pH 5.5 with 100μM ZnCl2 showed a linear formation of ZnPP from oxymyoglobin after a lag-period (9h) at the formation rate of 0.46nmol/h. The formed amount of ZnPP is dependent upon the ZnCl2 concentration. In the incubation without ZnCl2, the new peak derived from PP appeared at 633nm after 12h, and then its intensity gradually increased. The formation of PP is believed to be due to the release of Fe2+ in porphyrin ring of oxymyoglobin during the incubation. This suggests that the mitochondria have the ability to form PP from oxymyoglobin, and therefore, are directly related to the release of Fe2+ from porphyrin ring in myoglobin.