Chemical and microbial changes of stingray fish (Trygon sephen) during soaking in salt solution before smoking process

Abstract

The salting process at a fisherman's level is still traditional and does not yet have a standard for salt concentration and soaking time, thus affecting the freshness and quality of fish for further processing. For this reason, it is necessary to conduct research that can maintain the quality of fish before the smoking process to ensure results can be recommended for fellow fishermen. This research aimed to find the best quality of lowsalted stingray fish (Trygon sephen) treated with different salt solution concentrations and soaking time durations before the smoking process. This study used three levels of salt solution concentration (10%, 20%, and 30% w/v, respectively) as the first factor and soaking time duration (1 hr, 2 hrs, and 3 hrs) as the second factor. Chemical and microbial analyses of samples were performed during treatment to investigate their quality. The results showed that stingray fish soaked in 10% salt solution for 1 hr was the best treatment. In this treatment, the pH, total plate count (TPC), total volatile base nitrogen (TVB-N), and trimethylamine nitrogen (TMA-N) values were 6.92, 4.98×105 CFU/g, 6.12 mg N/100 g, and 5.56 mg N/100 g, respectively. Meanwhile, protein loss in this treatment was 2.66. In conclusion, treatment with 10% salt solution for 1 hr could be used in stingray fish considering that this treatment resulted in good quality with the lowest protein loss. Furthermore, this treatment is used as a reference for the smoking process because the concentration of the salt solution is low and the soaking time duration is short.