Determination of aquacultured whiteleg shrimp (Litopanaeus vannemei) quality using a sensory method with chemical standard references

Fresh shrimp are highly perishable seafood and a reliable spoilage assessment method is necessary to ensure sufficient quality control. The current quality evaluation method employed by the US Food and Drug Administration (FDA)/National Oceanic and Atmospheric Administration (NOAA) uses subjective terms 'odor of decomposition' to reject shrimp shipments, which lacks reference standards to anchor the concept and can cause ambiguity. The present study aimed to develop chemical reference standards to assist in a more objective and consistent sensory evaluation of shrimp quality.

Chemical references were developed and used by the descriptive panel to demonstrate the aroma quality indicators of shrimp. The most important aroma attributes describing shrimp quality changes were 'salty water-like', 'natto water-like' and 'sour milk-like' based on the results of multiple linear regression analysis. The overall rating consistency of the key quality indicators was confirmed by trained a descriptive panel such that the intensity scores in two separated evaluation sessions (30 days apart) were not significant different (P > 0.05). The sensory ratings also corresponded well with presumed FDA/NOAA grades of shrimp. An untrained panel also confirmed 'salty water-like' as the main indicator of freshness and 'natto water-like' as the main indicator of spoilage, whereas the discriminative capacity was lower compared to the trained panel.

The developed chemical references of key aroma quality indicators allowed the trained and untrained panels to distinguish shrimp of different freshness levels. The results indicate the potential of using chemical references as a new evaluation tool for on-site quality inspection or industrial quality assurance/quality control of shrimp with improved objectivity and consistency. © 2021 Society of Chemical Industry.