|Water quality variables and phytoplankton were monitored in five ponds with low-salinity water (2-3 ppt) for culture of Pacific white shrimp (Pennaeus vannamei) at a farm in West Alabama from August to October. Shrimps from these five ponds were sampled weekly from mid August until harvest and subjected to sensory evaluation. Twelve panelists were trained to evaluate the smell and appearance of raw shrimp and the smell, appearance, and taste of cooked shrimp. A testing procedure for assessing sensory characteristics of shrimp was set up with the aid of references and definitions for each of 28 sensory attributes. An intensity scale (0 to 10) was utilized for taste tests. A higher score indicated a greater intensity of each characteristic. At the end of the growing season, shrimps from all ponds on the farm were taken for organoleptic testing. In addition, shrimp samples were obtained from eight ponds at an aquaculture research station located in Gulf Shores, Alabama (average salinity = 12 ppt), three ponds at a farm near Harlingen, Texas (average salinity = 22.4 ppt), and one pond at a farm in Hawaii (full strength seawater). Four samples also were purchased from supermarkets. All samples were subjected to sensory evaluation.
Flavor and appearance of shrimp from the five ponds at the low-salinity shrimp farm in West Alabama changed over time in each individual pond and also varied among ponds. Nevertheless, no relationships were observed among sensory attributes and water variables. Although blue-green algae were abundant in ponds at the farm because of high nutrient concentrations from feed inputs, off-flavor from algal metabolites was not detected in shrimp samples.
Few differences were reported by panelists among shrimp cultured in waters with salinities of 2 to 24 ppt. However, the panelists gave the highest overall approval to shrimp that was reared in full-strength seawater at the farm in Hawaii. Shrimp purchased from supermarkets were scored as less sweet, more bitter, and less firm than shrimp from the other sources.