Determining chlorophyll and carrotenoid content in Bombyx mori L. excreta by Near Infrared Spectroscopy

S. Atanasova, M. Panayotov, D. Pavlov, M. Duleva
Abstract. For the needs of the experiment excreta age five of silkworms (populations of the monovoltine crossbreds of Bombyx mori L. Super1хХеса2, 19х1014 and 1013х1014) raised in spring have been used. Spectral measurement (NIR spectroscopy) of excreta has been made non-destructively by measuring diffuse reflection of samples within the range 900–1700 nm with the spectrometer NIRQuest 512. Afterwards chlorophyll a, chlorophyll b and carotenoids content in these samples has been determined through acetone extraction and determining the absorption of the resulting solution at 440.5, 644 and 662 nm by spectrophotometer Spekol 11. Partial Least Square Regression (PLS) has been used to obtain equations for determining the amount of chlorophyll and carotenoids in excreta based on near-infrared spectral data. The results obtained show that chlorophyll a, chlorophyll b and carotenoids content in silkworm excreta can be successfully determined by non-destructive spectral analysis within the range 900-1700 nm. The obtained correlation coefficients, revealing the relationship between the parameters tested are higher than 0.96. Extremely high accuracy has been reached in determining the content of chlorophyll a and carotenoids. Lower is the accuracy in determining chlorophyll b, which can be accounted for by the fact that chlorophyll b is more unstable and quickly dissociates after extraction.