Abstract
Objective judgements of the freshness of raw oyster using fuzzy reasoning were carried out based on the three biochemical indicators such as gill respiratory(succinate dehydrogenase(SDH))activity, body fluid pH and body fluid ammonia concentration. After tuning treatment of fuzzy inference rules, more excellent correlation(correlation coefficient r=0.947)could be obtained between the sensory judgements of the experts of oyster farm and fuzzy estimations of the freshness compared with that obtained in our previous work(r=0.936). Moreover, availability of this fuzzy reasoning were examined using several types of membership functions and rules. As a result, estimated freshness were almost constant irrespective of membership functions used. In addition, estimations by fuzzy reasoning showed always better correlations between the expert sensory judgements and calculated judgements compared with the conventional mean-squre methods indicating that the availability of fuzzy reasoning could be confirmed.
