Rapid determination of insect lipids and their fatty acid profile in doughs using hand-held and portable infrared spectrometers

Abstract The objective of the study was to evaluate infrared (IR) spectroscopy in combination with pattern recognition analysis as a rapid technique to quantify the percentage of insect lipid added into chickpea-based dough as well as dough’s fatty acid profile. Several chickpea-based doughs were prepared with a variable amount of Tenebrio molitor, Alphitobius diaperinus, and Acheta domesticus lipid fraction (0, 2.9%, 5.8%, 8.7% and 11.6%) replacing the same amount of olive and sunflower oil. The raw doughs were analyzed using portable Fourier transform mid infrared (FT-MIR) and handheld FT-NIR spectrometers. Fatty acid profile was determined by using fatty acid methyl esters (FAME) methods. Partial least squares regression (PLSR) was used to build up a model to predict the percentage of insect lipid added showing a low standard error of cross-validation (SECV≤0.71%), strong correlation (RCV≥0.85) and great predictive ability (RPD: 5.21-5.53). The saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA) fatty acids as well as the content of palmitic, oleic and linoleic were correctly predicted with values of SECV≤5.64% and an RCV≥0.88. Nonetheless, the FT-MIR device tested, showed higher performance to predict SFA, MUFA, PUFA and fatty acids reaching values of 0.97 in coefficient of correlation (RP) and 2.81% in standard error in prediction (SEP).