The production of protein hydrolysate from shrimp cooking water using enzyme Neutrase 0.5L was studied. Variations of enzymatic hydrolysis conditions consisted of enzyme concentration at 0, 0.5, 1.0, 1.5 and 2.0 % V/V; pH 5.5, 6.5 and 7.5; temperature 50, 55 and 60 deg C; and the hydrolysing time; 15, 30, 45, 60, 75 and 90 minute. The optimum condition for production of hydrolysate which gave the maximum amino acid nitrogen at 3.50 mg N/ml were 0.5 % Neutrase, pH 6.5, 50 deg C and 30 minute. The hydrolysate was dried by freeze-drying. The dried product had dark brown color with considerable shrimp flavor and absorbed moisture quite readily. The product contained 3.80 % moisture, 51.89 % protein, 6.57 % fat, 24.76 % ash and 12.99 % carbohydrate. Sensory evaluation on the color and shrimp odor of dried product comparing to the freeze dried unhydrolysed cooking water product showed that the freeze-dried hydrolysate obtained higher scores in color and odor. However, sensory evaluation of the products after dissolving in water revealed that neither the hydrolysated nor unhydrolysed products had the significant differences in color, shrimp odor, sweet taste, bitter taste and overall flavor.

Production of protein hydrolysate from shrimp precooking water using enzyme Nutrase 0.5 L was studied. Variations in the enzymatic hydrolysis were composed of the quantity of enzyme (0, 0.5, 1.0, 1.5 and 2.0 percent v/v), the pH (5.5, 6.5 and 7.5), the hydrolysing temperature (50, 55 and 60 deg C) and the hydrolysing time (15, 30, 45, 60, 75 and 90 min). The optimum condition for production of hydrolysate which gave the maximum amino acid nitrogen at 3.50 mgN/ml was 0.5 percent Nutrase, pH 6.5 50 deg C and 10 min. The chemical composition of the hydrolysate produced was 94.51 percent moisture, 2.52 percent protein, 0.33 percent fat, 1.77 percent ash and 0.88 percent carbohydrate. The hydrolysate was then freeze-dried. The dried product absorbed moisture quite easily and contained 3.80 percent moisture, 51.89 percent protein, 6.57 percent fat, 24.76 percent ash and 12.99 percent carbohydrate. To improve the quality of the dried product, the hydrolysate was mixed with 20 percent maltodextrin solution until the mixture had 10 percent total soluble solid before freeze-drying. It was found that the dried product absorbed moisture less rapidly and was ground easily. The composition of the improved product was 5.23 percent moisture, 36.98 percent protein, 3.71 percent fat, 16.61 percent ash and 41.98 percent carbohydrate. Sensory evaluation on the color and shrimp odor of these two dries products comparing to the freezed-dried unhydrolysed precooking water products showed that the freezed-dried hydrolysate without maltodextrin solution obtained the highest scores in color and odor. However, sensory evaluation the products after dissolving in water revealed that neither the hydrolysed nor unhydrolysed products had the significant differences in color, shrimp for, sweet taste, bitter taste and overall flavor.

This experiment was conducted as a factorial experiment to determine the effects of two factors as well as interaction of these on production of post larvae of the giant freshwater prawn. The first factor was type of food comprising two levels namely Brachionus plicatilis and Artemia salina, respectively, while the other was intervals of exchange of one fifth of the volume of culture media comprising two levels namely two and five days, respectively. Duration of the experiment was 42 days. Results of the experiment indicate that there were no significant difference among the effects of the two factors or interaction of the two on post larvae production of the prawn (P0.05). Average production ranging from 1660 to 2309.5 post larvae were recorded for the four treatment combinations.