Quantitative measurements of binary amino acids mixtures in yellow foxtail millet by terahertz time domain spectroscopy. (15th November 2016)

• Record Type: Journal Article
• Authors: Lu, Shaohua; Zhang, Xin; Zhang, Zhuoyong; Yang, Yuping; Xiang, Yuhong
• Is Part Of: Food chemistry. Volume 211(2016)
• Page Start: 494
• Page End: 501
• Publication Date: 2016-11-15
• Subjects: Partial least-squares (PLS) -- Multivariate curve resolution alternating least squares (MCR-ALS) -- Terahertz time domain spectroscopy (THz-TDS) -- Amino acid; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2016.05.079
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: THz-TDS was proved to be a good method for quantitative analysis of amino acids. Chemometrics methods can be applied for analyzing THz-TDS data of complex system. PLS gave accurate prediction for binary amino acids analyzed by THz spectroscopy. MCR can resolve pure spectra and concentration profiles of components in THz data. Abstract: Terahertz time domain spectroscopy (THz-TDS) combined with chemometrics has been utilized for the qualitative and quantitative analysis of binary mixtures ofl -glutamic acid andl -glutamine which have similar chemical structures and properties. The binary mixtures of amino acids were prepared with yellow foxtail millet matrix, substituted for polyethylene (PE) as previously reported. After proper pretreatment of absorption spectra, quantitative analysis was achieved by partial least squares (PLS) and interval partial least squares (iPLS) regressions. The performance of models was evaluated based on the root mean square error of prediction (RMSEP) and correlation coefficient (R 2 ) of cross-validations with bootstrapped Latin partitions as criterion. The iPLS yielded better results with low RMSEP (0.39 ± 0.02%, 0.39 ± 0.02%), and higher R 2 values (0.9904, 0.9906) for glutamine and glutamic acid comparing to the conventional PLS models. Multivariate curve resolution alternating least squares (MCR-ALS) was successfully applied for resolution of pure THz spectra and concentration profiles of two amino acids components from mixtures.