Quantitative prediction of rice starch digestibility using Raman spectroscopy and multivariate calibration analysis

[Display omitted] •Rice starch digestibility depends on the genetic background the growing environment.•Prediction of digestibility of rice starch by Raman scattering measurement.•The factors that determine the digestibility of rice starch are cultivar specific.•Predictive models should be constructed for each cultivar.•Digestibility determinants fluctuate maintaining a unique balance for each cultivar. Digestibility is an important characteristic of rice starch. It is affected by the growing environment, such as temperature and soil, so that even in the same genetic cultivar the digestibility of each product will be different. Here, we predicted rice starch digestibility by Raman scattering spectroscopy. A partial least squares (PLS) regression analysis was performed between biochemically quantified digestibility index values and Raman scattering spectra of purified starch from rice samples of different cultivars and growing conditions. The prediction model obtained by analyzing the individual cultivars was able to predict digestibility with a high accuracy, with an R2 of 0.95 and RMSEP of 0.43, whereas a mixture of all cultivars resulted in more than two times worse accuracy. Our finding suggests that the molecular structures affecting digestibility fluctuate depending on the growing environment while maintaining a unique balance regulated by cultivar-specific starch synthesis mechanisms.