The purpose of this study is to elucidate the relationship between food histological structures and structural components in cooked chicken meat of Cochin (Nagoya-Cochin; Nagoya Breed). The results obtained were summarized as follows; 1) Significant differences could be admitted in breaking strength between two different kinds of cooked dark meat: Cochin and broiler after 24hrs post-mortem storage at 4°C.2) There were no differences in water holding capacity by pressure in raw dark meat between Cochin and broiler. On the other hand, there were significant differences in cooking loss and water holding capacity by heating and then pressure.3) There were no differences in 5'-inosinic acid (IMP) content and glutamic acid content in dark meat and also soup prepared from dark meat between Cochin and broiler on both after 24hrs post-mortem storage at 4°C.4) In the light microsccpy, the structures of raw dark meat in the both species that had undergone frozen storage showed wide gap of the muscle fiber. Especially, the cross section of the muscle fiber of 8 weeks old broiler occasionally showed round shaped contour and amorphous cytoplasm. These observations had not recognized in the fresh broiler that had not undergone frozen storage by the same fixation. The cooked dark meat in the both species had been characterized by small red granules in the inter-fiber-space in the Masson's trichrome stain section, and had not shown reticular fibers network. These phenomena were more marked in the specimens of frozen and then cooked broiler. The cooked dark meat of 8 weeks old broiler clearly indicated above observations than in Cochin. In the electron microscopy, the cleft was observed under the cell membrane of the muscle cell in the frozen tissue in both species. It was suggested that the cleft was made by growing ice-crystal under the cell membrane. It was an interesting finding that the I-band of the muscle-fiber in the cooked dark meat was composed of triad band showing light-dark-light electron density.
For the purposes of speedup, rationalization and commercialization of extraction methods of kombu soup stock, we studied on a heating extraction method in which ultrasonication was used jointly in the heating process as a new processing method of food. Moreover, the relationship between the extractable components of kombu soup stock and the tastes and the optimum preparation conditions were examined. 1) Slightly larger amounts of the constituents were extracted from kombu and a better soup stock were produced by using the heating method introducing a step of applying ultrasonication than in the control without ultrasonication. 2) Soup stock was obtained in a shorter time. Under the most appropriate condition for preparation of kombu soup stock, the optimum heating times were 8 minutes for the ultrasonication method and 15 minutes for the method without ultrasonication. There were no significant differences in the soup color between the two methods. The contents of total extracted components, total nitrogen,5'-nucleotides and minerals in the soup were nearly the same for the two methods, whereas the contents of free amino acids were higher in the soup obtained by 8 minutes ultrasonication, producing a more satisfactory soup, and leading to decrease in the consumption of electric power, compared with the control without ultrasonication. Therefore, the cooking method involving a step of ultrasonication is considered useful when the soup-stock is used together with the traditional heat applying method or the water extracting method.
Effects of the components of wheat flour for cream puff paste, such as prime-starch, tailing-starch and gluten were examined on the dispersibility and viscoelasticity of the paste and on the expanded volume of baked cream puff. 1) The paste became homogeneous easily or hardly depending on the flour ingredients. The dispersion of paste was accelerated with tailing-starch and gluten, but inhibited with prime-starch. 2) The more homogeneously the paste dispersed, the smaller the viscosity of paste became. And the smaller the viscosity of paste was, the larger the volume of baked cream puff became. 3) The stress relaxation curves, observed on gels prepared by cooked cream puff paste at 90°C for 30 min., could be explained well by three Maxwell models. The more homogeneously the paste dispersed, the smaller the relaxation time τ 1 of the first Maxwell models was. And the elastic modulus E 1 had the optimum level for the large volume of baked cream puff.
We investigated the influence of various types of salt containing different ingredients on the characteristics of cooked rice and its taste. Both the swelling value and solubility of rice starch were highest in cooked rice without added salt and the cooked rice without added salt showed the highest water absorption on heating and coloring by iodine, and there was a tendency for these characteristcs to decrease when salt was added to the rice to be cooked. The creep characteristics of cooked rice were analyzed with the six-factor Voigt model. Both the instantaneous elasticity and stable viscosity were higher for cooked rices with salt added, the highest value being recorded for cooked rice with NaCl added. The strain recovery rate was larger and permanent strain was smaller in the salt-added cooked rice than in the cooked rice without added salt. The samples cooked with table salt and natural salt were preferred in sensory characteristics to those without salt. An X-ray microanalysis of the inorganic elements revealed that they were initially localized on the outer surface of the uncooked rice, and that they migrated inside the rice when it was cooked.
In Shiitake mushroom (Lentinus edodes),5′-nucleotides, especially 5′-GMP, are major umami components.5′-Nucleotides are degraded products by ribonuclease (RNase) from RNA and moreover they degrade into nucleosides by phosphomonoesterase (PMase). In this process, RNase is more stable on heating than PMase and consequently 5′-nucleotides accumulates. Taking this property into account, we studied on the effect of various heat processing and damaging of tissues on 5′-nucleotide contents of Shiitake mushroom. The following results were obtained. 1. In various heat processing tests, the heating from water to boiling or by a 100W electronic oven accumulated the more amount of 5′-nucleotide than that by putting in boiling water or a 500W electronic oven. 2. Heating from water to boiling after damaging the tissues of Shiitake mushroom, especially damaging by freezing led to the increase of 5′-nucleotides. 3. According to the defrosting methods, the amounts of 5′-nucleotides in frozen Shiitake mushroom, when heated from water to boiling, increased in the order of defrosting in a refrigerator, without defrosting and defrosting in an electronic oven. 4. Though the amounts of 5′-AMP,5′-UMP and 5′-CMP in frozen Shiitake mushroom seemed to decrease slightly when heated after defrosting in a refrigerator or an electronic oven after storage at -40°C, RNA and 5′-GMP were constant in any way.
Effects of wrapping with the contact-dehydrating sheets on sensory scores of cooked frozen meats were assessed. The contact-dehydrating sheets retarded the drip formation during thawing, and the loss of flavoring substances such as free amino acids in drip. The sensory test of cooked meats showed a singnificant preference for the dehydrating sheettreated ones over the control.
From the viewpoint of food hygiene, public nutrition and food chemistry, were studied the bacterial contamination, the amounts of sodium, potassium and salt, and the free amino acids composition of “kapit” in Thailand. The results were as follows: 1. Bacterial counts isolated from “kapit” were 106-107/g. The detected ratio of Coliform organisms, E coli and Staphylococcus were 40.0%,40.0% and 0%, respectively. 2. The genus of Family Enterobacteriaceae (14 strains) isolated from “kapit” consisted of Enteraerogenes (4 strains), Proteus mirabilis (5 strains) and Escherichia coli (1 strain) and others. 3. The averages of contents of sodium, potassium and salt and water activity of “kapit” were 4318.4mg/100g,179.8mg/100g,11.0% and 0.872, respectively. 4. The total amounts of free amino acids of “kapit” were 721.3mg/100g-4565.1mg/100g. The major free amino acids of “kapit” were glutamic acid, leucine, alanine and lysine. The content of glutamic acid was 26.4-77.4% of total free amino acids.