Total anthocyanin content determination in intact açaí (Euterpe oleracea Mart.) and palmitero-juçara (Euterpe edulis Mart.) fruit using near infrared spectroscopy (NIR) and multivariate calibration

• Published in: Food chemistry 2013-02, Vol.136 (3-4), p.1160-1164
• Main Authors: Inácio, Maria Raquel Cavalcanti, de Lima, Kássio Michell Gomes, Lopes, Valquiria Garcia, Pessoa, José Dalton Cruz, de Almeida Teixeira, Gustavo Henrique
• Format: Article
• Language: English
• Subjects: algorithms; Anthocyanins - analysis; Arecaceae - chemistry; Biological and medical sciences; Calibration; detection limit; Euterpe edulis; Euterpe oleracea; Food industries; Fruit - chemistry; Fruit and vegetable industries; fruits; Fundamental and applied biological sciences. Psychology; least squares; Multivariate Analysis; Multivariate calibration; near-infrared reflectance spectroscopy; near-infrared spectroscopy; Net analyte signal; NIRS; Non-destructive method; Plant Extracts - analysis; PLS; prediction; rapid methods; Spectroscopy, Near-Infrared - methods; Spectroscopy, Near-Infrared - standards; Variables selection
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2012.09.046

► This study is the first attempt to use NIR spectroscopy to determine anthocyanin (TAC) in açaí and juçara. ► Optimal combination of informative regions from iPLS, GA, SPA models improved the predicted TAC. ► The model developed by NIRS for TAC can be used as an alternative to UV–Vis measurement. ► NIRS can be used as a non-destructive method to determine TAC with promising use in grading lines. The aim of this study was to evaluate near-infrared reflectance spectroscopy (NIR), and multivariate calibration potential as a rapid method to determinate anthocyanin content in intact fruit (açaí and palmitero-juçara). Several multivariate calibration techniques, including partial least squares (PLS), interval partial least squares, genetic algorithm, successive projections algorithm, and net analyte signal were compared and validated by establishing figures of merit. Suitable results were obtained with the PLS model (four latent variables and 5-point smoothing) with a detection limit of 6.2gkg−1, limit of quantification of 20.7gkg−1, accuracy estimated as root mean square error of prediction of 4.8gkg−1, mean selectivity of 0.79gkg−1, sensitivity of 5.04×10−3gkg−1, precision of 27.8gkg−1, and signal-to-noise ratio of 1.04×10−3gkg−1. These results suggest NIR spectroscopy and multivariate calibration can be effectively used to determine anthocyanin content in intact açaí and palmitero-juçara fruit.