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

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=0.79mg/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.