Monitoring compositional changes in black soldier fly larvae after processing (drying and blanching) using near infrared spectroscopy

Abstract

Determining which processing technique is better to guarantee the safety and nutritional value of black soldier fly larvae (BSFL) is of critical importance for the food waste industry. This study evaluates the utilization of near infrared reflectance (NIR) spectroscopy as a proxy technique to monitor the effect of two processing treatments commonly used by the food waste industry, namely blanching and the combination of blanching plus drying, on the composition of BSFL. The 5th instar BSFL samples were harvested from a commercial waste processing facility and subjected to drying (2 and 12 hrs at 100 °C) and blanching (4 s and 5 min) treatments. The samples were scanned using a NIR instrument (11,550 to 3950 cm−1) where the data was analysed using principal component analysis (PCA) and linear discriminant analysis (LDA). A correct classification rate above 83 % was obtained for the identification of samples according to the drying treatment, while 56 % of the samples were correctly classified according to the blanching treatment. Overall, NIR spectroscopy has shown great potential as a rapid tool for real-time monitoring of the processing of BSFL (drying and blanching), and thereby assisting in improving the treatment of BSFL samples intended to be used by the animal feed industry.