Prediction of amino acid content in live black soldier fly larvae using near infrared spectroscopy

Black soldier fly (Hermetia illucens) larvae are emerging as a sustainable protein source for animal feed and human nutrition. Ensuring consistent amino acid composition is crucial for quality control, necessitating rapid, non-destructive assessment methods, particularly for selective breeding. This study validates near-infrared (NIR) spectroscopy with partial least squares (PLS) regression as a reliable tool for predicting free amino acid (FAA) profiles in live larvae. Using a FOSS DS2500 spectrometer (400-2500 nm), 204 live larval samples reared on 17 diets with varying protein (2.3-89.8 percent) and sugar (8.5-96.0 percent) levels were scanned, followed by FAA extraction. Alanine (6.50 +/- 3.52 mg/g) and proline (5.61 +/- 4.45 mg/g) were the most abundant FAAs, with key NIR absorption bands at 1670-1786 nm and 2300-2366 nm enabling accurate predictions. PLS models showed strong predictive power for individual FAAs (e.g., glutamate: R^2 = 0.88; asparagine: R^2 = 0.78; alanine: R^2 = 0.65) and total FAAs (R^2 = 0.64). These results highlight NIR's potential for real-time quality control and phenotyping in BSF production and breeding.