The protective effect of oligosugar alcohols against thermal denaturation of myofibrillar protein from horse mackerel was investigated as a function of the molecular weight and the number of OH group of the sugar alcohols, and its relation to sweetness was discussed. The results obtained were as follows;
1) The protective effect was studied as E or E´=Δ log KD/C (M or %), where the KD is the first order rate constant for thermal inactivation of Ca-ATPase with or without varied concentrations (C) of sugar alcohol. The E(M−1) generally increased and E´(%−1) decreased with the increase in the molecular weight as well as the number of OH groups of the sugar alcohol.
2) The protective effect given with a branched oligosugar alcohol was similar to that of linear oligosugar alcohol having approximately the same molecular weight.
3) There was a good correlation between the E value and the logarithmic value of the molecular weight or the number of OH group of the sugar alcohols.
4) Dependencies of the E´ value or the sweetness level on the logarithmic value of the number of OH group were close to each other.
5) A good correlation between the level of sweetness by sugar alcohols and the E´ value of the same sugar alcohols was therefore demonstrated.
It was thus found that the dependency of the E´ and the sweetness on the logarithmic number of OH group of sugar alcohol was very similar.