The significantly decreased availability of the main raw materials for making shrimp paste is a big problem, while most by-products from shrimp processing, especially head, are not yet properly used. Therefore, using shrimp head for shrimp paste production is well motivated. However, traditional shrimp paste is high in salt and can impact health via hypertension, kidney, or cardiovascular disease. This study aimed to produce a reduced sodium shrimp head paste, using 12, 14 or 16-fold amount of shrimp heads relative to salt. The salted shrimp head was fermented for 14-16 hr. Thereafter, it was dried at 60 °C, then ground and fermented further for 30 d. The paste was dried again to 40-45% moisture content and fermented for another 90 d. The total viable count and lactic acid bacteria significantly decreased in all treatments, and no pathogenic microorganisms were detected. After fermentation for 90 d, the a w had decreased in all treatments. The highest shrimp head proportion (16:1) exhibited the highest total volatile basic nitrogen (TVB-N) and trimethylamine (TMA) contents. In conclusion, shrimp head can serve as an alternative raw material in shrimp paste with comparatively low salt content that may reduce the risks of hypertension, cardiovascular disease, and stroke.

Traditional shrimp paste was produced by Litopenaeus vannamei head as a low-priced by-product instead of the tradition raw material. Partial replacement of sodium chloride with potassium chloride at 0%, 30% and 50% was done to reduce risk of hypertension. The reduction of a w and increment of pH, total volatile bases nitrogen (TVB-N), trimethylamine (TMA), thiobarbituric acid reactive substances (TBARS) and degree of hydrolysis (DH) were found in all treatments. After fermentation for 90 d, total viable count (TVC) and lactic acid bacteria (LAB) decreased, with no pathogenic microorganisms found. Angiotensin-converting enzyme (ACE) Inhibition (%) of shrimp head was close to captopril at 2.17 ng/mL but lower than shrimp head paste and captopril at 4.35 ng/mL. Sensory score of all treatments were lower than that of commercial shrimp paste. Partial replacement of sodium chloride with potassium chloride at 50% can be done in shrimp head paste but further study required to improve consumer acceptability.

Head of Litopenaeus vannamei, a low‐priced by‐product, was used to make fermented shrimp paste, Kapi, instead of the traditional raw material. The addition of garlic was hypothesized to prevent oxidation of unsaturated fatty acids, and tested by using garlic at 0%, 3%, and 5%. Decreasing aw was found in all treatments, while pH seemed to not change during fermentation. TVB‐N, TMA, malondialdehyde, and DH significantly increased with fermentation time. The addition of garlic at 3% and 5% seemed to retard lipid oxidation compared to the control case. After fermentation for 90 days, significant indole was noticed but no histamine was detected, while TVC and LAB of all treatments decreased. However, no pathogenic microorganisms were found. Likeness scores of all cases were approximately 6/9. Shrimp head can be used as an alternative raw material for making Kapi, but the texture and taste attributes must be improved in future work to meet consumer preferences. Novelty impact statement Shrimp head can be a substituted raw material to produce shrimp paste. Shrimp head paste with 12:1 ratio of shrimp head to salt and added with garlic at 3% can retard lipid oxidation in the product. Shrimp head waste is brightening for the prevention of authentic Thai dishes collapse due to shortening of shrimp paste.