A review on fish sauce processing, free amino acids and peptides with sensory properties

Fish sauce is a well-known condiment for its delicious flavour developed through a fermentation process. It is generally used as an additive for flavour enhancement in cooking. The fish sauce comes in several appearances, ranging from a clear liquid with light colour and texture to a dark and cloudy liquid. This product is produced by a longduration of fermentation process by the combination of fish and salt. This high salt fermentation began with the action of enzymes from fish muscle and its digestive tracts, then continued with halophilic bacteria activity to further break down fish proteins in producing a liquid product with a mixture of soluble proteins, peptides and amino acids. This review is comprised of two sections, the first section covers various processing methods of fish sauces, mainly in the Asia region, namely Nam-pla, Nuoc-mam, Yu-lu, Ishiru, Shottsuru, Bakasang and Budu. These fish sauces roughly involve applying salt for fermentation, with different fish species, salt concentration, fermentation duration and processing techniques. The later section covers taste-contributing components of fish sauces in the scope of amino acids and peptides. Five of the major amino acids found to taste in the fish sauce, glutamic acid, threonine, alanine, methionine and histidine, are also reviewed in this paper. Sensory peptides in fish sauces shown in this paper are peptides with salt taste enhancement properties and peptides exhibiting sweet, sour, bitter, umami and kokumi tastes.