Cooking of various food materials at lower but acceptable temperatures produces not only tender and tasty food but also nutritionally valuable food relative to food cooked by ordinal methods, i. e. boiling and baking.
Maitake (Grifola frondosa) extract contains proteases which have a high heat resistance as measured by casein hydrolysis assay. The optimal activity was observed at a temperature range between 50-70°C, and 30 to 40 percent of the original activity remained after heating at 70°C for 8 hours. Inside round cuts of beef cooked using low temperature steam cooking with maitake extracts released more protein into the soluble fraction than cooking with ginger extracts or by boiling. However, free gultamic acid, which contributes to umami taste, increased not only in the solubilized fraction but also inside the meat. Histological observation also presents a degradation of protein in the meat treated with maitake extract. Both measurements under the rheoner and sensory evaluation showed a remarkable improvement with respect to hardness and chewiness. All the results that are presented here demonstrate the advantage of combinational cooking at low temperature steam with extract from maitake for tenderizing meats. This suggests a superior method of cooking many other food materials to be served on the table.

View full abstract

This is the first report on the antioxidative effect of katsuo-dashi, the hot water extract from dried bonito, during thermal cooking. The difference in effect is described on sardines boiled in katsuo-dashi and those in plain water.
A sensory evaluation showed that katsuo-dashi suppressed the fishy odor of boiled sardines.
1,1-dipheny1-2-picrylhydrazyl (DPPH) radical scavenging activity increased with increasing concentration.
The thiobarbituric acid reactive substance (TBARS) value of sardines boiled with katsuo-dashi was lower than that with water.
Gas chromatography-mass spectrometry showed that the aldehyde and ketone contents in the volatiles of sardines boiled with katsuo-dashi had been reduced, these compounds being particularly responsible for the fishy odor. The results indicate that katsuo-dashi was effective for suppressing lipid oxidation during thermal cooking.

View full abstract

The freshness of skipjack meat rapidly deteriorates, and skipjack cured in mugi-miso is therefore popularly used in Kyushu in order to preserve the quality and retain the taste. In this study, a chemical analysis of protein was conducted on skipjack meat cured in miso (called misodzuke skipjack) and on miso itself. The degradation of several proteins in the misodzuke skipjack and the elution of some proteins from misodzuke skipjack into miso were observed by SDS-PAGE. Most of the free amino acid contents in misodzuke skipjack increased during the curing period. It was also found that aspartic protease and serine protease were present in miso by measuring the protease activity and the effect of protein inhibitors. Although protease activity was not detected in skipjack meat that had not been cured in miso, protease activity at optimal pH 7 was detected in misodzuke skipjack meat. Misodzuke skipjack cured for 10 days demonstrated a maximum protease activity which was inhibited by the serine protease inhibitor, AEBSF.

View full abstract

The opportunity for practicing deep-fried cooking in schools during homemaking courses at secondary education level was investigated. It was apparent that descriptions of deep-fried food cooking in homemaking texts, have progressively decreased.
Deep-fried food cooking was practiced in about 20% of the junior high schools and in about 20% of the senior high schools investigated (including the cooking practiced in optional courses). Even if the opportunity for cooking deep-fried foods was provided, rarely would the students undertake all the processes for deep-frying food. Although the importance of deep-fried cooking is understood in senior high schools, the potential danger of this cooking method makes it difficult to practise.
The time involved in the preparation and finishing steps, fewer practical cooking classes, and outdated facilities for cooking practice mitigate against offering practical cooking classes.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract