Detection of l-Cysteine in wheat flour by Raman microspectroscopy combined chemometrics of HCA and PCA

•Addition of l-Cysteine to the wheat flour isn't allowed in Turkey.•Demand exists for effective methods for detection of l-Cysteine in wheat flour.•For the first time, l-Cysteine was detected in ten different types of wheat flour.•Raman findings were successfully confirmed using HCA and PCA analysis.•Developed method has a great potential for detection of l-Cysteine in wheat flour.

l-Cysteine is deliberately added to various flour types since l-Cysteine has enabled favorable baking conditions such as low viscosity, increased elasticity and rise during baking. In Turkey, usage of l-Cysteine as a food additive isn't allowed in wheat flour according to the Turkish Food Codex Regulation on food additives. There is an urgent need for effective methods to detect l-Cysteine in wheat flour. In this study, for the first time, a new, rapid, effective, non-destructive and cost-effective method was developed for detection of l-Cysteine in wheat flour using Raman microscopy. Detection of l-Cysteine in wheat flour was accomplished successfully using Raman microscopy combined chemometrics of PCA (Principal Component Analysis) and HCA (Hierarchical Cluster Analysis). In this work, 500-2000 cm−1 spectral range (fingerprint region) was determined to perform PCA and HCA analysis. l-Cysteine and l-Cystine were determined with detection limit of 0.125% (w/w) in different wheat flour samples.

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