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ABSTRACT: Interaction of saltiness and acidity at the threshold level was studied employing 35 to 40 young female panelists. As a 1st step, the detection and recognition thresholds of salt, rice vinegar, and rice black vinegar have been measured for each panelist. To investigate the above interaction, the thresholds have been again measured for each panelist of salt, but this time, vinegar at half the concentration of each panelist's detection threshold was added to the salt solution. Similar measurement has been performed for vinegars with salt at half the concentration of each panelist's detection threshold. The data analysis has been done in 2 ways, namely, (1) by using Student's t-test to detect the significant difference in average between the data with and without the added ingredient and (2) detecting significant deviations from zero in the individual shifts in 2 sensory tests among panelists who participated in the 2 measurements. In doing that, a conversion of the scale was necessary to correct the systematic skewness existing in the original data. As a result, both the detection and recognition thresholds of salt were decreased with the existence of the added vinegar ingredient (P < 0.001). This tendency was more pronounced with rice black vinegar than with rice vinegar. On the contrary, no significant changes in the threshold of both detection and recognition were observed when salt at the half concentration of the detection threshold was added to rice vinegar. The interaction therefore was found to be asymmetric.
Journal of Food Science 05/2009; 74(4):S147-53. · 1.66 Impact Factor
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ABSTRACT: This study investigated whether actin liberation from myofibrils occurs during the heating of various muscles, as well as squid mantle muscle at temperatures, such as 60°C, employed for vacuum cooking of meats. Actin liberation was demonstrated in scallop striated adductor muscle, but not in beef, pork, or chicken, using the detection method previously employed with squid muscle, in which liberated actin was detected with SDS-PAGE, in the supernatant obtained by centrifugation of the homogenate of heated muscle in 0.2M KCl at a neutral pH. However, actin liberation was demonstrated in beef, pork and chicken by a new detection method, in which heated muscle was homogenized in 0.6M KCl or NaCl at a slightly alkaline pH and maintained at 4°C for 16h with stirring, after which the homogenate was diluted three times with water and centrifuged to obtain the supernatant containing the liberated actin. This new method indicated that actin liberation in beef, pork, and chicken was marked by heating at 65°C, but scarcely induced at 80°C. Thus, the liberation of actin from myofibrils may contribute to the greater tenderness of vacuum-cooked meat (meat heated at a low temperature for long time), as compared with meat prepared by cooking at a higher temperature.
Meat Science 03/2009; 81(3):446-50. · 2.28 Impact Factor
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ABSTRACT: Sliced salmon-nose cartilage was cured in 4% acetic acid up to 168h. Using optical microscopy, we observed the reddish-purple color produced by staining with toluisine-blue turned lighter during curing. This meant that the mucopoly-saccharide level of cartilage matrix decreased, causing the structure of the cartilage to become porous. In addition, using scanning electron microscopy, loosenings of collagen fibers was observed after 72 h of curing, thus making the structure of the cartilage fragile. DSC thermograms showed that the denaturation temperature of the native collagen fibers was lowered and an additional peak appeared during curing. These findings lead us to suggest that the collagen in salmon-nose cartilage changes qualitatively during curing.
Journal of Food Biochemistry 02/2007; 16(1):31 - 41. · 0.81 Impact Factor
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ABSTRACT: In order to elucidate the mechanism of the antihypertensive action of dried bonito (katsuobushi), we compared the effects of dried bonito extracts with those of captopril, an angiotensin I-converting enzyme (ACE) inhibitor, on aorta preparations isolated from rats. Dried bonito extracts (3 x 10(-4) to 3 x 10(-3) g/ml) more potently relaxed contractions induced by norepinephrine (10(-7) M) than contractions induced by KCl (55.9 mM). Dried bonito extracts (3 x 10(-3) g/ml) slightly inhibited 10(-7) M angiotensin I-induced contractions. In contrast, captopril (10(-8) to 10(-7) M) did not affect 10(-7) M norepinephrine- or 55.9 mM KCl-induced contractions, but a higher concentration of captopril (10(-6) M) very slightly relaxed it. Captopril (10(-8) to 10(-6) M) markedly inhibited 10(-7) M angiotensin I-induced contractions in a concentration-dependent manner. These results suggest that antihypertensive mechanism of action induced by dried bonito involves direct action on vascular smooth muscle in addition to ACE-inhibitory activity.
Bioscience Biotechnology and Biochemistry 06/2005; 69(5):911-5. · 1.28 Impact Factor
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ABSTRACT: Chicken bouillon is well accepted all over the world, but dried bonito stock is only preferred by the Japanese, and only the Japanese use dried bonito as material for soup stock. To learn the reason, we compared the sensory responses to the taste of dried bonito stock and the chicken bouillon by employing Japanese and Chinese as panelists for sensory evaluation. The descriptive terms were 1st designed and used for sensory analysis of food action rate scaling and paired comparison. The Japanese panel evaluated dried bonito stock as less greasy, no odd taste, weaker in fishy flavor, more well-balanced taste, and preferable to chicken bouillon. The Chinese panel evaluated dried bonito stock as less greasy, stronger in odd taste, stronger in fishy flavor, less well-balanced taste, and less preferable to chicken bouillon.
Journal of Food Science 03/2005; 70(3):S193 - S198. · 1.66 Impact Factor
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ABSTRACT: The high molecular weight protein connectin (also called titin) in Japanese common squid (Todarodes pacificus) mantle muscle was identified by western blotting analysis with 3B9, the mouse anti-chicken skeletal muscle connectin monoclonal antibody. Similarly to vertebrate samples, there exists connectin in invertebrate squid mantle muscle, and the amino acid sequences are assumed to resemble those present in the A band of vertebrate connectin, judging by the specificity of 3B9. Moreover, the connectin in squid muscle migrated in this study as a closely spaced doublet of alpha and beta (titins 1 and 2). Between 5 and 7 h post-mortem, the SDS PAGE patterns of the squid sample indicated a change of the doublet bands into a single beta-connectin band. Simultaneously, the rheological properties of the squid muscle changed substantially. This degradation of alpha-connectin into beta-connectin in the muscle can explain the critical change that occurs during the post-mortem tenderization of squid muscle.
Bioscience Biotechnology and Biochemistry 06/2004; 68(5):1119-24. · 1.28 Impact Factor
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ABSTRACT: Dried sea cucumber must first be soaked in water, then heated and finally left at 20°C for 24 h, this procedure being repeated several times in preparation for cooking. In the case of dried sea cucumber soaked in distilled water, it gradually increased in weight. After full-scale soaking twice, its weight increased to 7.6-fold the original weight, which softened it thoroughly. The water content after this soaking process was 94.5%, which is almost the same as that of raw sea cucumber. During the soaking process, not only was water absorbed, but components of the ingredients of sea cucumber were eluted into the soaking water. Among these components, ash was eluted fastest, next was glycosaminoglycan and last was collagen. In addition to distilled water, rice-washing water, a coarse-tea-infused solution and a potassium carbonate solution were used as the soaking solutions. Sea cucumber absorbed water and swelled in the potassium carbonate solution faster than in the other three solutions. Textural measurements and a sensory evaluation clarified that the softest sea cucumber resulted from the rice-washing water, and the hardest sea cucumber from the coarse tea.
Fisheries Science 03/2004; 70(2):319 - 325. · 0.94 Impact Factor
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ABSTRACT: Dried squid were prepared at 4 or 40 °C and softened first in water and then in alkaline solution. The physicochemical and structural changes in the dried squid during the softening treatment were examined. A significantly higher wet weight was observed for the 4 °C-dried squid during the softening treatment compared with the 40 °C-dried squid. The rupture stress and rupture energy of the 40 °C-dried squid were significantly higher than those of the 4 °C-dried squid during the softening treatment. The sodium dodecyl sulphate polyacrylamide slab gel electrophoresis (SDS-PAGE) pattern of the 4 °C-dried squid was almost the same as that of raw squid. The SDS-PAGE pattern of the 40 °C-dried squid showed many fragments of lower molecular weight. After soaking in distilled water the SDS-PAGE pattern of the 40 °C-dried squid did not change significantly; however, the SDS-PAGE pattern of the 4 °C-dried squid became the same as that of the 40 °C-dried squid. Histological analysis by light microscopy showed the formation of muscle fibre bundles in the 40 °C-dried squid. A higher water permeation was observed among the muscle fibres of the alkali-softened 4 °C-dried squid when compared with the alkali-softened 40 °C-dried squid. Copyright © 2003 Society of Chemical Industry
Journal of the Science of Food and Agriculture 11/2003; 83(15):1565 - 1570. · 1.44 Impact Factor
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ABSTRACT: The effect of acetic acid on the dissolution of proteins in rice was studied to elucidate the mechanism for the textural change induced by the acid by chemical and SDS-PAGE analyses of the rice proteins in the soaking solution. More proteins were extracted with 0.2 M acetic acid (pH 2.7) than with water (pH 6.8). The effect of acetic acid on the protein dissolution increased with increasing temperature. Immunoblotting confirmed that, when rice was soaked in acetic acid, glutelin was dissolved into the soaking solution and degraded by aspartic proteinase. Aspartic proteinase degraded glutelin much more than it did albumin and globulin. It was found that the combined amount of albumin and globulin dissolved into the acetic acid solution was much larger than that of glutelin, despite the smaller amounts present of albumin and globulin than of glutelin. Metal ions were extracted more with acetic acid than with water. In addition, carboxypeptidase was activated under the acidic condition and resulted in an increase in the amount of free amino acids. The main effect of acetic acid on the dissolution of rice proteins was enhancement of the solubility of albumin, globulin, and glutelin, the effect of proteases being minor.
Journal of Agricultural and Food Chemistry 08/2003; 51(14):4054-9. · 2.82 Impact Factor
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ABSTRACT: An improved method was investigated for sodium dodecyl sulfate polyacrylamide slab gel electrophoresis (SDS-PAGE) to facilitate the analysis of the giant myofibrillar proteins, connectin and nebulin, in fish meat by using jack mackerel (Trachurus japonicus) as the sample fish. It was established that separation of the alpha-connectin band from the beta-connectin band by SDS-PAGE could be achieved by using 3-5% gradient gels with glycerol to facilitate the formation of a gradient with polymerization at 35 degrees C. SDS-PAGE samples of white dorsal muscle from the jack mackerel were homogenized with a 2% SDS solution containing an inhibitor mixture (1 microg/mL of phenylmethanesulfonyl fluoride, 1 microg/mL of leupeptin, and 1 microg/mL of E-64) and heated at 50 degrees C for 20 min. Heating these samples at 100 degrees C for 2 min resulted in the disintegration of connectin but did not affect nebulin. A purified myofibril sample and a whole muscle sample showed similar changes in the overall rate of degradation of whole connectin and nebulin during the postmortem storage period, but it was clear that beta-connectin was cleaved from alpha-connectin during the preparation of myofibrils at the early stage postmortem. Storage of the SDS-PAGE samples at -85 degrees C was preferable to storage at -18 degrees C for a long period.
Journal of Agricultural and Food Chemistry 01/2003; 50(26):7499-503. · 2.82 Impact Factor
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ABSTRACT: Physicochemical changes of Japanese cockle foot parts occurring during cooking and cold storage at 4°C for 10 days were examined. Raw samples decreased in weight by 27% during cooking at 85°C for 15 s. Both raw and cooked samples decreased in weight to the same extent of 22–23% during the 10-day cold storage. The levels of ATP and related compounds, as well as those of free amino acids, were higher in raw than in cooked samples, although the former were found by sensory evaluation to have a stronger fishy odor. Raw samples started to decrease in ATP content after 5 days of cold storage, showing K′ values of 18 and 42% after 5 and 7 days, respectively. The L* value in the Hunter scale color evaluation increased during the cold storage of raw samples, revealing a gradual disappearance of its original purple–gray color. Meanwhile, the L* value of cooked samples remained constant during the cold storage. The tensile strength of cooked samples was significantly higher than those of both raw samples before and after the cold storage, indicating increased toughness by cooking.
Fisheries Science 10/2002; 68(5):1138 - 1144. · 0.94 Impact Factor
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ABSTRACT: The present study examined the changes in texture and protein components during cold storage of different squid varieties. Raw oval squid, Japanese common squid and arrow squid were sliced fresh and the muscles were stored at 4°C for 0, 4, 8, 12, 18, 24, 48 and 120 h. The rheological measurements, protein components and amounts of collagen were examined. The adhesiveness of each squid increased significantly in the early stage of cold storage. In all varieties, penetration decreased at 4 h, which is considered to be rigor mortis, then increased. The amounts of total collagen, 20°C water-soluble collagen and 70°C water-soluble collagen did not change significantly in each variety during cold storage. Sodium dodecylsulfate–polyacrylamide gel electrophoresis (SDS-PAGE) pattern showed that the 580 kDa component gradually disappeared up to 48 h. The correlations between the amounts of 580 kDa component and adhesiveness or firmness were high. Models of fit based on chemical kinetics accurately expressed the behavior of adhesiveness, firmness and penetration showing that 63.2% of adhesiveness changes occurred in 13–19 h and that 63.2% of firmness changes occurred in 18–24 h.
Fisheries Science 08/2002; 68(4):783 - 792. · 0.94 Impact Factor
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ABSTRACT: We investigated the effect of calcium and magnesium ions on the hardening of Japanese radish by the pressure treatment at 400 MPa. The pectins were separated into the three components. Water-soluble pectin (WP) and hydrochloric acid-soluble pectin (HP) were decreased by the pressure treatment, whereas hexametaphosphate-soluble pectin (PP), which is a metal binding type pectin, was increased. The degree of esterification of WP was decreased by pressurization. Variations with time after pressure release of all pectin fractions and the concentrations of calcium and magnesium ions contained in pectin fractions were small. We studied the hardness of the pressure treated samples by soaking them with or without EGTA and EDTA and the effect of the order reversal of the soaking and the standing. It was found that the magnesium ions had a great influence on the hardness of both non-treated and pressure-treated uncooked samples and that calcium ions affected the hardness of pressure-treated cooked samples. The suppressing effect of the calcium ions on the softening during cooking suggested that the interactions between such components as proteins and hemicellulose were promoted by the calcium ions. The mass transfer processes followed by the collapse of the cell membranes by the pressure treatment are considered to strengthen these interactions. Keywords: Pressure treatment; pectin; calcium ion; magnesium ion; hardening
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ABSTRACT: A high hydrostatic pressure of 100-400 MPa was applied to fresh egg yolks. The rheological properties of the resulting egg yolks were evaluated by measuring viscosity at a high shear rate(10^<-1>-10^3s^<-1>)in steady-state and at a very low shear rate(10^<-1>-10^<-3>s^<-1>)in spring relaxation. The flow curves for the egg yolks showed non-thixotropic behavior after the application of 200-300 MPa, but thixotropic behavior after 400 MPa. The thixotropic property and yield values were then evaluated. The thixotropic parameter T_h of the egg yolk pressurized at 400 MPa(12.8×10^3Pa・s^<-1>)was larger than that of egg yolk pressurized at 100 MPa(0.09×10^3Pa・s^<-1>). The viscosity of all pressurized egg yolks obeyed the power law. While the consistency index K was increased, the flow behavior index n was decreased with increasing pressure and time applied. Casson's yield value in the spring relaxation was 140 MPa for the egg yolk which had been pressurized at 400 MPa for 10 min. This value is less than the 340 MPa which was evaluated for the steady state. This result indicates that a spring relaxation study would be useful for evaluating the yield value.
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ABSTRACT: NMR imaging was used to follow changes in the water content and distribution during the cooking of Nipponbare (Japonica), Khao Dawk Mali (Indica) and High Amylose (Indica) rice. Samples were cooked in closed glass vials for various times, quenched to stop cooking and then investigated using two-dimensional multi-echo 1H imaging experiments at 20 °C. Images calculated from the first-echo revealed changes in the water content of the rice grains. T2 images calculated using the first 16 echoes were converted into quantitatively reliable contour maps of the water concentration using an empirical T2 vs. water content calibration determined from a series of water/rice starch mixtures. Considerable differences in the rate of water uptake and diffusion, the average water contents and the proportions of under-, optimally- and over-cooked rice were observed for the three rice types studied
