Non-intrusive prediction of fruit spoilage and storage time via detecting volatiles in sealed packaging using laser spectroscopy

Monitoring fruit spoilage can effectively avoid waste and reduce economic losses. Recent studies have proved that the measurement of food volatile compounds is effective to detect food spoilage at its early stage. Indeed, some fast analytical methods have been developed to measure the volatiles released from food, such as proton transfer reaction mass spectrometry, gas-phase infrared spectroscopy, and E-nose. However, these methods can only be applied to measure volatiles in unsealed packages of food and are unable to detect volatiles that are sealed in containers or packages, which are the common situations in food storage and sales. Herein, we investigated a non-intrusive method for detecting food volatiles and monitoring fruit spoilage during storage. A laser directed incident radiation into the food package where it diffused through the box, and absorption spectra were generated. The fingerprint spectra of the molecules in food volatiles were used to determine the concentrations of the volatiles inside the food package. In the experiment, grape spoilage was monitored by measuring changes in oxygen concentration and we successfully predicted the beginning of grape spoilage on the seventh day. The root-mean-square errors of prediction for the storage times of grapes and strawberries were 0.4426 and 0.3079 days, respectively.