In-situ and real-time monitoring of enzymatic process of wheat gluten by miniature fiber NIR spectrometer

•An in-situ spectra monitoring system of enzymatic process was created•The optimal intervals for the enzymatic hydrolysis index of wheat gluten were selected.•Spectral quantitative models for the index of enzymatic hydrolysis of wheat gluten were established.

The degree of hydrolysis (DH), peptide content and angiotensin I-converting enzyme (ACE) inhibitory activity of hydrolysates are the three most important indexes for process control in proteins enzymatic hydrolysis and ACE inhibitory peptides preparation. In this study, a miniature fiber optical spectrometer in conjunction with multivariate analysis for in-situ and real-time monitoring of the parameters (DH, peptide content and ACE inhibitory activity) in wheat gluten (WG) hydrolysis process. Synergy interval partial least square (Si-PLS) algorithm was performed to variables selection and the regression model was calibrated. The performance of a model was evaluated by the correlation coefficient (Rp) and the root mean square error (RMSEP) in the prediction set. The results showed that Rp = 0.9270, RMSEP = 1.73% for DH; Rp = 0.9673, RMSEP = 0.79 mg/ml for peptide content; Rp = 0.9507, RMSEP = 5.12% for ACE inhibitory. This work demonstrated that miniature fiber optical spectrometer combined Si-PLS model can be used as an alternative method for in-situ and real-time monitoring the enzymatic process of WG.

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