The objective of this study is to determine the effects of high pressure and the addition of glucose, trehalose, or sucrose on the improvement in texture of frozen egg custard gel. Egg custard gel with 5% sugar (glucose, trehalose, or sucrose) was frozen at 0.1-686 MPa and -20°C. The gels with 0% and 5% sugar did not freeze at -20°C during pressurization at 200-400 MPa and 200-500 MPa, respectively. When the pressure was released, the supercooled gel froze quickly by pressure-shift-freezing, and small, granular-shaped ice crystals formed. Thus, a change in texture (rupture stress and strain) of the pressure-shift-frozen gel was slightly prevented. The addition of 5% sugar to the gel was effective in improving the structural and textural quality of the frozen egg custard gel. However, there was no great difference in ice crystal size among the three kinds of sugar.
To investigate the relationship between the texture and protein, the main chemical component of the squid, the muscle and skin of the oval squid (OS), Japanese common squid (JCS), and arrow squid (AS) were stored at 4°C for 5 days, and then the texture, amounts of collagen and DSC characteristics were examined. OS is considered not to be as suitable as the other varieties for eating cooked, because the muscle is toughened by cooking and the outer skin layers are stronger. The amounts of water-soluble collagen at 20°C and 70°C increased in the JCS and AS skins during storage. The DSC thermogram of the JCS skin showed three peaks, and each peak changed during storage. It is considered that the specific thermal characteristics of the JCS skin were responsible for the elastic and tender texture of the cooked JCS skin, which is why the JCS is cooked before eating.
Mieko Kagawa Misuzu Matsumoto Keiko Hatae The changes in the food texture of squid muscle boiled in water (WA), an 18% salt solution (SA), and 100%soy sauce (SO) for 1,5,10, and 30 min were investigated by a sensory evaluation of the texture and measurements of the total weight, moisture content, salt concentration, pH value, mechanical properties, and protein composition. The samples cooked in SO had the highest hardness, followed by the samples in SA and then those in WA. Longer boiling in WA made the meat softer, but had no such effect on the samples boiled in SA and SO. The moisture content of the muscle boiled in SA and SO decreased with increasing boiling time, particularly so in SO. The results from the sensory evaluation of the texture, mechanical properties, and protein composition analysis show different textural properties of the muscle samples boiled in SO from those in SA. Boiling in SO for a short time made the skin tough. It seems that some components in SO other than sodium chloride influenced the physical properties of the muscle and skin of the squid.
Kayoko Nakashima Ritsuko Kishimoto The water absorption and characteristics of Asamurasaki unpolished glutinous purple rice were investigated. The water absorption was affected by the temperature of the distilled water used for washing the rice, being about twice as much when washed at 30° than at 7°. The rice samples were washed under the same conditions for direct comparisons. The amount of water absorbed by the unpolished glutinous purple rice was no different from that by unpolished glutinous whiter ice when the samples were soaked for 4hours in water at 7°. The amount of water absorbed by the unpolished purple rice was 36.8% when it was soaked for 24 hours in water at 30°, and that of unpolished white rice was 33.7%. The soaking time needed to saturate the unpolished glutinous purple rice was 168 hours(34.1% water absorption)in water at 7°, and 72 hours(40.3% water absorption) in water at 30°. Wesuggest in practice that unpolished glutinous purple rice should be soaked for 8 hours at 30°and then heated in a pressure cooker.