USE OF A SPECIFIC‐ION ELECTRODE (AMMONIA) IN DETERMINING THE QUALITY OF SHRIMP

Abstract

ABSTRACTAmmonia and other volatile nitrogen compounds are major components of the off‐flavors and odors associated with spoiled shrimp. Increases in the level of total volatile nitrogen (TVN) have been used as an objective index of shrimp quality. In order to find a simple method for determining shrimp quality the use of an ammonia specific‐ion electrode was investigated. Ammonia produced from both iced and noniced refrigerated shrimp together with direct microscopic bacterial counts, TVN and sensory evaluation were measured as a function of storage time. The results indicated a close correlation between ammonia, as measured by the specific‐ion electrode, and the more traditional spoilage parameters. Frozen shrimp with various pre‐frozen spoilage characteristics were also evaluated using the ammonia specific electrode. Although a correlation was observed between the pre‐frozen spoilage characteristics and ammonia measured in the frozen shrimp, the data fluctuations using the ammonia specific electrode appeared too dramatic to infer spoilage characteristics prior to freezing. The use of the ammonia specific‐ion electrode is a rapid and simple method for determining shrimp quality, especially in iced raw shrimp, and possibly of significant value in the shrimp industry's quality control efforts.