Recycling of distillery slops as diluent for second dipping fish sauce (patis) production

Second dipping fish sauce was produced from fish paste using different quantities of ditillery slops as diluent. The water-slop ratios used were 100-0,75-25,50-50,25-75 and 0-100. The various physico-chemical properties of the raw materials and fish paste were investigated. Both water-slop ratio and the length of fermentation affected the volume of fish sauce and the residual weight of the fish paste. The maximum amount of fish sauce produced was 133 milliliters at 25-75 water slops ratio, while the least amount was 117.5 milliliters at 75-25 ratio. The 50-50 and 25-75 ratios did not have the same responses compared to the other ratios because of the nature of the raw materials used. Uneven distribution of fish meat and bones, scale and other components could account for the differences in both the residual weight of the fish paste and the volume of the fish sauce (patis) produced. The crude protein was affected by the length of fermentation and the ratio of the slops in the brine. The 25-75 ratio had the largest amount of crude protein at 7.49 grams, while the 75-25 ratio, had the least amount of crude protein at 6.56 grams. The amount of crude protein recovered could be attributed to the amount of the significant increase in the amount of hydrolysable proteins still present in the fish meat. Lower protein conversion at the 50-50 ratio can be attributed to proteolytic enzyme inhibition in breaking down the peptides of the fish protein at high salt concentration present in the fish paste. The final dissolved solid contents for all concentration of the fish sauce produced, ranging from 33.99 to 36.96 grams per 100 milliliters of sample exceeded the amount specified by the Philippine Standard Association (PSA). The high dissolved solid content of the slops and the presence of salt in the brine contributed to the increased in the solid contents of the fish sauce at different water slop ratio. The length of fermentation significantly increased the amount of dissolved solids. This could be attributed to the decrease in the salt content of the patis which increased the solubility of other solutes. The breakdown of fish flesh resulted to more soluble proteins which increased dissolved solids during fermentation. The pH of the starting materials affected the pH of the fish sauce. As the amount of slops increased in the brine, pH decreased at any given period of fermentation. The pH increased from 5.44 to 6.46 as fermentation progressed. Color was directly proportional to the concentration of slops due to the colorants present in the slops. The color exhibited by the fish sauce at the sixth week was significantly higher than the initial color. Based on the physico-chemical evaluation of the fish sauce at different water-slop volume ratios, distillery slops could be used as diluent in the production of fish sauce. The use of distillery slop resulted to higher protein content and brilliant golden brown color. However, the total solids of fish sauce exceeded the standard except for 0-100 and at 50-50 ratios