2015 Volume 23 Issue 1 Pages 31-37
Hiroshima Prefecture is noted for its shelled oysters. To preserve their freshness as long as possible, a parameter design was carried out on the process conditions from shelling to delivery. The amount of triphenylformazan(TF) produced was used as an index of freshness. TF production mass(PM) was assumed to decrease exponentially from an initial value P0 according to the number of days of storage(M), by the formula PM = P0e(β-γ)M, where β is a coefficient of freshness preservation effect and γ is a freshness degradation constant. The input-output relation y=β×M=γ×M－ln(P0/PM) was used,with days of storage as a signal factor and the shelling quality as a noise factor. There were eight control factors, such as temperature, salt, casing, etc. The factors were assigned to an L18 orthogonal array and an experiment was carried out. The gain of the existing and comparative conditions was reproduced fairly well in the confirmation experiment. There appears, however, to be a need for further study of the setting of the noise factor, the precision of measurement of the TF production mass, and the input-output relation.
