Water Activity and Temperature Effects on Nonenzymic Browning of Amino Acids in Dried Squid and Simulated Model System


  • Financial support from the National Science Council of R.O.C. under grant number NSC78-0406-E019-01 is greatly appreciated.


At constant temperatures (5 to 45°C) browning rate patterns of 22 amino acids, induced during dehydration in presence of glucose and celite, pH 6.4, Aw 0.60 to 0.85, were classified into three types: 1. (lysine, histidine, and glycine) showed high rates over a broad aw range. 2. (Cysteine and methionine) had intermediate browning rates and a pattern of multiple maxima. 3. Amino acids (glutamine, valine and tryptophan) had low browning rates and showed a single sharp browning maximum. Squid mantle had broad browning maxima over the intermediate a range resembling type 1, which comprised 75% of the total free amino acids in squid. Browning of squid was accelerated at ≥ 23°C, with aw 0.60 to 0.90. Activation energy of the model systems was 10 to 35 kcal/mole, and Q10 were 1 to 8.