Non-destructive and in-situ detection of shrimp freshness using mid-infrared fiber-optic evanescent wave spectroscopy

There is strong interest in non-destructive and rapid determination of food freshness in food research. In this study, mid-infrared (MIR) fiber-optic evanescent wave (FOEW) spectroscopy was applied to monitor shrimp freshness through the evaluation of protein, chitin, and calcite contents in conjunction with a Partial Least Squares Discriminant Analysis (PLS-DA) model. Shrimp shells were wiped with a micro fiber-optic probe to obtain a FOEW spectrum which quickly and nondestructively allowed evaluation of the shrimp freshness. Peaks for proteins, chitin, and calcite, which are closely related to shrimp freshness, were detected and quantified. Compared with the standard indicator for evaluating shrimp freshness (total volatile basic nitrogen), the PLS-DA model gave recognition rates for shrimp freshness using calibration and validation sets of the FOEW data of 87.27%, 90.28%, respectively. Our results show that FOEW spectroscopy is a feasible method for non-destructive and in-site detection of shrimp freshness.

Automated summary

There is a growing interest in non-destructive and rapid determination of food freshness. This study applied mid-infrared fiber-optic evanescent wave spectroscopy to monitor shrimp freshness. By evaluating protein, chitin, and calcite contents and using a Partial Least Squares Discriminant Analysis model, the freshness of shrimp could be quickly and nondestructively assessed. The results showed that the spectroscopy method achieved high recognition rates for shrimp freshness compared to the standard indicator, making it a feasible method for non-destructive and in-site detection of shrimp freshness.