Studying the type of fish, salt concentration and fermentation time on the of Sensory characteristics Iranian fish sauce (Mahyaveh)

Introduction: The fermentation process is one of the oldest methods of food preservation, which in addition to prolonging the shelf life increases the flavor and nutritional value of the product. Proteolysis is one of the most important biochemical reactions that occurs during the fermentation process (Yuen et al., 2009). Fish sauce is a quasi-fermentation liquid product that is obtained by the decomposition of fish proteins in the high concentration of salt and apparently for the first time was observed and discovered by Badham in 1854 (Beddows, 1985). In Iran, also a type of local fish sauce is produced, which is called Mahyaveh, Mahweh or Suragh. Mahyaveh is traditionally produced by the natives in the southern provinces of Iran. According to people in the southern region, eating Mahyaveh contained mustard prevents Pacey's skin disease. Fish sauce is not just a flavoring but contains 0.6 to 1.2 percent nitrogen and has suitable amount of essential amino acids for body. In addition, this sauce contains desirable fatty acids such as docosahexaenoic acid and eicosapentaenoic Acid. Studies have shown that fish sauce yellow color due to non-enzymatic reaction between amino acids and ribose (Saisthi, 1967). The effect of heat process, percentage of salt consumed, fermentation time and use of enzymes and edible microbes can play an important role in the taste, colour and fermentation speed of fish sauce (Mickey and Hardy, 1992). Saisthi et al., examined the aromatic substances in fish sauce and stated this product has a different flavor from the smell of fish, so that it can be said t this smell and taste is specific to fish sauce. In the food industry, the acceptance of a product by consumers guarantees the production of that product and its continued presence in the consumer market, so the evaluation of sensory characteristics plays an essential role in choosing the best formulation and limited information about the characteristics. Also, due to the increasing consumption of seafood, this fermented product is important to study the factors affecting the quality of the product. Therefore, the aim of this study was to investigate the effect of fish type, salt concentration and fermentation time on the sensory properties of Iranian fish sauce (Mahyaveh).
Material and methods: In order to prepare Mahyaveh sauce, tuna, anchovies and sardines were supplied in April 2019 (from Bandar Fish Company in Bandar Abbas, Iran) and frozen at -18 °C and transferred to the Agricultural Laboratory of the University of Tehran. Salt was purchased from Shimiaz Company, Iran. Mustard powder was produced by G.S.Dunn Company, Canada. First, the fish (1: tuna, 2: anchovies, and 3: sardines) were washed with water, along with viscus, and cut to a size of 6 cm. The whole fish (along with viscera) was mixed with water in a ratio of 1 to 1, and the required amount of salt was added to the treatments according to Table 1. Then, fish, water and salt were mixed in a mixer, Model ika, Germany and transferred to wide-mouthed clay pottery with a capacity of 700 ml, and the lids were closed with three-layer plastic films. These utensils were kept in an incubator in time intervals of 30, 75 and 120 days at 37 °C. After passing the fermentation time of each treatment, the samples were passed through a sterile cleaning cloth. Then, the filtered extract was mixed with 10% mustard and the samples were kept at environment temperature for 10 to 15 days, and then physicochemical experiments were then performed on the extracts produced. Sensory test was performed according to the method of Moayedi et al. (2013) and by 5-point hedonic method by 10 trained evaluators. The studied traits were color, odor, taste and general acceptance. The samples were transferred to the evaluation room after being placed in disposable containers and coded. The order of the samples for each evaluator was randomly assigned. In the intervals between each assessment, some water was drunk by the assessor. These individuals consumed 15 available treatments and then judged on color, odor, taste and general acceptance and assigned 1 to 5 points (excellent, very good, good, average and bad) to the samples (Moayedi Et al., 2013).
Results and discussion: The results showed that by passing time (from 30 to 120 days), an increase in salt concentration (from 15 to 35%) And use all three different types of fish (tuna, anchovy and sardine) had a significant effect (P≤0.05) in increasing of sensory characteristics (colour, odour, taste, acceptability). The type of fish and salt concentration did not have a significant effect on the colour of Mahyaveh sauce (P>0.05). The results showed the highest colour amount was observed in the sample of (T15) Mahyaveh sauce containing 35%ww-1 salt, in 120 days of fermentation time and fish type 2 (Anchovy) and the lowest amount of colour in the sample of (T13) Mahyaveh sauce containing 25%ww-1 salt, in 30 days of fermentation time and fish type 3 (Sardine). the highest odour and taste amount were observed in the sample of (T2) Mahyaveh sauce containing 25%ww-1 salt, in 120 days of fermentation time and fish type 1 (Tuna) and the lowest amount of odour and taste in the sample of (T10) Mahyaveh sauce containing 35%ww-1 salt, in 75 days of fermentation time and fish type 3 (Sardine). The highest acceptability amount was observed in the sample of (T8) Mahyaveh sauce containing 25%ww-1 salt, in 120 days of fermentation time and fish type 3 (Sardine) and the lowest amount of acceptability in the sample of (T10) Mahyaveh sauce containing 35%ww-1 salt, in 75 days of fermentation time and fish type 3 (Sardine). Multiple optimization to achieve the maximum colour amount, odour, taste and acceptability in the Mahyaveh sauce was obtained with 99.94% desirability at the time of 120 days of fermentation with the third type of fish (sardine) and at a salt concentration of 28.33 %.
Conclusion: According to the results, by optimizing the conditions of producing Mahyaveh sauce, fish sauce can be produced with the better Sensory characteristics and higher quality.