Development of chromatographic methods for geographical indication in Thai pineapples

Abstract

Geographical indication (GI), or its equivalent intellectual property tools, is widely used in many countries, including Thailand, to identify specific properties and uniqueness of a product that are related to its production origin. In the case of agricultural products, geographical location, weather, and soil nutrients affect their properties such as flavor and texture. In this study, a chemical method was conducted to attempt to distinguish pineapples based on their origins. This was done by collecting chemical profiles from carotenoids by high-performance liquid chromatography with diode array detector (HPLC-DAD). Thereafter, these chemical data were later processed by chemometric analysis to classify pineapples based on their origins. Importantly, this study was also designed to be a part of a teaching laboratory. Using carotenoid separation as a main goal, column chromatography, thin-layer chromatography (TLC), UV−vis spectroscopy, high-performance liquid chromatography (HPLC), mass spectrometry (MS), and principal component analysis (PCA) can be included in a cohesive laboratory experiment. On the other hand, these activities were also designed to be modular, thus allowing instructors to add, remove, or modify the contents in a highly customizable manner. This makes it highly versatile and amenable to uncertain situations like unexpected university closure due to COVID-19 related lockdown. Overall, this laboratory experiment serves as a practical example of how chemistry can help solve real-world problems while also allowing high flexibility in teaching management. Last but not least, deeper chemometric studies beyond the teaching lab version was also conducted – this can be developed further to become an effective tool to classify origins of Thai pineapple.