Characterization of rice cultivars using Raman spectroscopy and multivariate analysis

Rice is a widely consumed cereal known for its high carbohydrate content and the presence of essential nutritional elements such as proteins and lipids. The previous Raman spectroscopy (RS) studies on whole brown rice kernel have only been able to partially reveal nutritional content. This study employs RS to accurately assess the nutritional profiles of forty rice cultivars in powdered form, facilitating their characterization. The combination of RS and advanced chemometric techniques enables the discrimination of rice cultivars based on key biochemical attributes, including amylose and starch content, aromatic properties, protein content, and total antioxidant capacity, resulting in an impressive accuracy rate of 73%. Significant observations in the fingerprint region included specific Raman spectral features associated with glucose ring stretching at similar to 478 cm-1 and indicative stretching vibrations for glycosidic bonds and amylose structures at similar to 409 cm-1, similar to 439 cm-1, similar to 521 cm-1, and similar to 868 cm-1. Furthermore, prominent spectral bands associated with amino acids such as phenylalanine (similar to 1004 cm-1, similar to 1580 cm-1, similar to 1606 cm-1), tryptophan (similar to 872 cm-1, similar to 1360 cm-1, similar to 1543 cm-1, similar to 1620 cm-1), and tyrosine (similar to 853 cm-1, similar to 1176 cm-1, similar to 1556 cm-1) were observed. Additionally, characteristic peaks related to protein content, carotenoids, and amino acids were identified at similar to 1084 cm-1, similar to 1111 cm-1, similar to 1162 cm-1, similar to 1263 cm-1, similar to 1310 cm-1, and similar to 1404 cm-1. These findings underscore the potential of RS as a fully automated, rapid, and accurate tool for evaluating the nutritional content of rice cultivars.