Geographical Classification of Okra (Abelmoschus esculentus) by Chemometric Analysis of Polyphenolic Profiles...

Okra is a widely consumed vegetable known for its medicinal properties due to its abundance of flavonoids. This has fueled the demand for okra and made it an economically important vegetable in the global market. However, despite the increasing demand for okra, its market value remains low. To overcome this problem, geographical indication (GI)an intellectual property linking a product's unique characteristics to its geographical origincan be an effective tool to sustainably increase the value of okra. Therefore, this study aimed to classify okra based on its geographical origin by means of chemometric analysis on flavonoid profiles. First, sample preparation was optimized with greenness in mind, yielding a total flavonoid content of 9.25 mg QE/g, compared to 6.21 mg QE/g obtained using the conventional method, while also providing a better greenness character as evaluated by the AGREE tool. Thereafter, the extracts from various okra samples were analyzed on high-performance liquid chromatography with a diode array detector (HPLC-DAD) and liquid chromatography-mass spectrometry (LC-MS) for their flavonoid profiles, including quercetin and catechin derivatives. The resulting data were then subjected to principal component analysis (PCA) and linear discriminant analysis (LDA), where PCA clearly revealed variations and features in the data, and a high overall classification and prediction accuracy was observed in LDA (80-100%) in all substudies (countries of origin, geographical origins within Thailand, and one-versus-all classification). Overall, this study highlights the utility of the developed tool as a stepping stone for the sustainable promotion of local agricultural products.