ASIAN JOURNAL OF CHEMISTRY ASIAN JOURNAL OF CHEMISTRY http://dx.doi.org/10.14233/ajchem.2016.19422 INTRODUCTION Fermented fish, prepared by adding salt and by fermen- tation, can be largely classified into fermented fish with its flesh remaining intact and liquefied fish sauce. Fermented fish retaining the flesh include those for which the body of fish such as salted shrimp, salted manila clam and salted oysters is used as well as those for which the intestines and other byproducts such as salted guts of hairtail, sauced intestines and salted Pollock gills are used. Fish sauces, in which proteins from the flesh are completely degraded during fermentation and have been liquefied, include anchovy sauce and sand lance extract. Fermentation of fish with salt is one of the hallmarks of the Asian food culture whose staple food is rice. Fish sauce is used not only as a main condiment to flavour kimchi, but also as a cooking condiment used as a substitute for soybean sauce. In Southeast Asian countries such as Thailand, Vietnam and Philippines, fish sauce has established itself as an important food item that is used as a condiment in most of the cooking. Although known as a product unique to the Asian food culture, fish sauce has also been widely used in Ancient Rome. It has a long history and has become the major marine fermented food that has been used throughout the world in the east as Physico-Chemical Properties of Salt-Fermented Commercial Fish Sauces in Thailand BYOUNG-MOK KIM 1 , SUJINDA SRIWATTANA 2 and IN-HAK JEONG 3,* 1 Division of Strategic Food Industry Research, Korea Food Research Institute, Seongnam 463-763, Republic of Korea 2 Division of Biotechnology, Faculty of Agro Industry, Chiangmai University, Chiangmai 50100, Thailand 3 Department of Marine Food Science & Technology, Gangneung National University, Gangneung 210-702, Republic of Korea *Corresponding author: Fax: +82 33 6402340; Tel: +82 33 6402341; E-mail: ihjeong@gwnu.ac.kr Received: 20 June 2015; Accepted: 19 August 2015; Published online: 5 December 2015; AJC-17657 In this study, the characteristic components of commercially available fish sauces from Thailand were investigated. Moisture, ash, crude protein and crude fat content was 51.8-59.5 %, 20.8-28.3 %, 11.4-20.6 % and 0.1-0.6 %, respectively. Salinity was 19.1-28.0 % and the volatile base nitrogen content was the highest in TF10 (298.8 mg %) and the lowest in TF3 (19.1 mg %). pH was in the range of 5.1-5.8. The total nitrogen content was 1.8-3.5 g % and was the highest in TF5. Amino nitrogen content was 406.0-1,750.0 mg % and was the highest in TF6. Lightness, redness and yellowness were 34.7-53.3, 10.68-28.79 and 4.74-36.06, respectively. Major organic acids were acetic acid, lactic acid, propionic acid and butyric acid and the total amount of organic acid was 1.11-7.06 mg/L. The total amount of free amino acids was 1,103.7-9,581.8 mg % and the major free amino acids were aspartic acid, glutamic acid, glycine, alanine, methionine, isoleucine and phenylalanine. Umami amino acid was the highest in TF11, while sweet amino acid (SA) and bitter amino acid (BA) were the highest in TF1 and TF11, respectively. The ratio of SA/BA was the highest in TF8; essential and non-essential amino acid were the highest in TF11 and TF1, respectively. The aroma pattern measured using an electronic nose differed depending on each product. Keywords: Fish sauce, Sweet amino acid, Bitter amino acid, Thailand. Asian Journal of Chemistry; Vol. 28, No. 3 (2016), 589-595 well as in the West [1,2]. In rice culture, high-quality liquefied fermented products have also been developed as products that carry equal or more significance as condiments [3,4]. Korea primarily uses soybean sauce, which has been fermented from soybeans, as a cooking condiment, similar to that in the Japanese and Chinese cultures. In Southeast Asian countries such as Vietnam, Thailand and Philippines, on the other hand, fish sauce is still mostly used in cooking. Varieties of fish fermented products are used in Thailand and liquefied fish sauce (Nam pla) is used not only as a condiment to flavour most dishes, but also as a substitute for table salt. Therefore, there have been various types and qualities of commercially available fish sauces, with large differences in their price. In Korea, fermented fish has been accepted as the typical high- sodium product with a high salt content and therefore, there has been a sharp decline in its consumption in recent years. Although it has been largely consumed as an additive, while making kimchi, it is predicted that the decreased consumption of kimchi in the current young generation will further dampen the future consumption of fermented fish. According to the recently expanding FTA flow, if, in the future, Korea is introduced to fish sauce produced in Southeast Asia such as in Thailand where there is massive production and circulation,