Effects of extraction conditions on proteins' profiles of Tenebrio molitor

Abstract

Edible insects are recommended as a future food because of many reasons. The nutritional value of edible insects is one of criteria for the selection of seven most promising species among which is Tenebrio molitor. The objective of this study was to examine the effects of different flour Tenebrio molitor. Twelve different extraction conditions were set up in which three parameters were combined: pH extraction solutions (6, 8 and 12.5), temperature (30 °C and 60 °C), and ultrasound (US). Shotgun proteomics of trypsin digests profiled protein isolates. The highest protein yield was in extractions at pH 12.5. The temperature elevation and US application significantly increased the yield of isolated proteins at pH 12.5 but their solubility at the pH 7.4 was lower compared to isolates at pH 6 and 8. 1D-SDS-PAGE showed marked differences in protein profiles on various extraction conditions, with highest number of the distinctive bands at pH 8 at 30 °C. Shotgun proteomics showed that extraction condition at pH 12.5, on 30 °C has the highest numbers of different proteins, however, among the top 20 abundant proteins are chitin-associated proteins, allergens and proteinases, while at pH 8 these proteins are not enriched. Highly basic extraction significantly contributes to protein hydrolysis while application of US contributes to the protein cross-linking and this effect is more prominent at high temperatures.