A beneficial decoloration effect resulted for horse mackerel mince washed with ozonized water within 10-20 min, but a longer washing time was required to improve the color properties when cold water or alkaline solution was used. Increase in pH as well as improvements in gel-forming ability occurred for mince washed with alkaline solution. The maximal gel strength of surimi was found when washed for 90 min. A marked decrease in pH and an undesirable gel strength of mince, as well as oxidation of the fish oil occurred during ozone treatment. Since the salt-soluble protein concentration increased for all minces washed with the three methods, improvement in gel-forming ability of washed mince was attributed to the increase in pH rather than to oil removal.

No abstract

Heterocyclic compounds are primarily formed through non -enzymatic browning reactions.Recent studies of deep -fat fried food flavors led to the identification of pyrazines, pyridines, thiazole, oxazoles and cyclic polysulfides which had long-chain alkyl substitutions on the heterocyclic ring. The involvement of lipid or lipid decomposition products in the formation of these compounds could account for the long-chain alkyl sub stitutions. Model systems were used to study the par ticipation of lipids in the formation of pyrazines, pyridines, thiophenes and cyclic polysulfides.More than 10,000 compounds have been identified as volatiles of foods. Of these, heterocyclic compounds are an important class, be cause of their exceptional sensory properties (1). Heterocyclic compounds contain one or more heteroatoms (0, S and/or N) in rings or fused ring systems.The majority of heterocyclic compounds are formed through thermal interactions of reducing sugars and amino acids, known as Maillard reactions. Other thermal reactions such as hydrolytic and pyrolytic degradation of food components (e.g. sugars, amino acids and vitamins) and the oxidation of lipids also contribute to the formation of heterocyclic compounds responsible for the complex flavor of many foodstuffs.Recent studies in our laboratory show that lipids may be di rectly associated with the Maillard reaction in the formation of some heterocyclic compounds. The effect of lipids on the formation of heterocyclic compounds in a model Maillard reaction has also been reported by Mottram and Whitfield (2). This paper discusses model studies which indicate that lipid decomposition products such as 2,4-decadienal and hexanal may react with Maillard reaction intermediates to form heterocyclic compounds.