Effects of drying temperature on quality parameters of Thai fermented fish dip (Jaew Bong)

Abstract

Fermented fish dip is a popular condiment in Thailand and the Lao People’s Democratic Republic. Thai fermented fish dip (TFFD), can be dried to increase its shelf life and ease of transportation. Dried TFFD can be rehydrated to return the powder to its original, paste-like form. Pre-cooked TFFD paste was dried at three different temperatures (40, 60, and 80 ºC). Total plate count, yeast and mold count, CIE colour values (L*, a*, and b*),non-enzymatic browning, and sensory scores of the resulting powders were determined. The CIE colour values and sensory scores were alsoanalysed for rehydrated TFFD. Increasing the drying temperature did not affect the total plate count or yeast and mold count. When dried at 80 ºC, the L* value of TFFD powder was reduced, although the a* and b* values were unaffected compared with lower temperatures. All CIE colour values of rehydrated TFFD decreased as drying temperature increased. Drying temperature did not affect the sensory scores of dried TFFD powder. However, rehydrated samples that had been dried at 80 ºC had significantly lower sensory colour scores than those dried at 40 or 60 ºC. Overall preference rankings of dried and rehydrated TFFD dried at 40 and 60 °C were better than for those dried at 80 °C. Due to an undesirable colour change in the rehydrated product, 80 ºC was deemed to be an unsuitable temperature for drying TFFD paste. In conclusion, both 40 and 60 ºC are appropriate temperatures for drying the product.