1H-NMR BASED METABOLOMICS STUDY OF GREEN BEANS OF GARUT ARABICA COFFEE AND ITS ANTIOXIDANT ACTIVITY

• Main Author: Fadilah, Agil
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/79208
• Institution: Institut Teknologi Bandung

Garut is one of the largest arabica coffee producing regions in West Java. The taste of this coffee is influenced by the chemical contents. The phenolic compounds in the green coffee beans possesses pharmacological benefits, one of which is as an antioxidant. However, the research related to the chemical profile of Garut arabica coffee is still limited in the literature. The aim of this study was to evaluate the metabolite profiles of Garut arabica green coffee beans using 1H-NMR based metabolomics and to investigate their antioxidant activity using DPPH and FRAP methods. The green arabica coffee bean samples used in this study originated from four arabica coffee producing regions in Garut, including Cikuray, Kamojang, Papandayan, and Patrol. Each green coffee bean sample was crushed and then extracted with D2O solvent containing TSP 1 mM in a phosphate buffer with a pH of 6.0. The extracted supernatant was then analyzed with a 1H-NMR spectrometer. The obtained data were processed and then evaluated by multivariate data analysis with Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) as the main model. Overall, 20 metabolites of green beans have been identified including carbohydrates such as sucrose and glucose, chlorogenic acid isomers, caffeine, trigonelline, choline, some aliphatic acids, and some free amino acids. The OPLS-DA Score plot successfully grouped the metabolite profiles of coffee samples based on regional origin. From the visualization of the Score plot, the Papandayan coffee sample has the most different metabolite profile compared to the other three samples. The loading plot showed that the compound signals of quinic acid, GABA, citric acid, asparagine, sucrose, 4-CQA, 5-CQA, caffeine, and trigonelline were the most contributing to the classification. While the S-plot showed that citric acid is a typical compound of Kamojang coffee, sucrose and 5-CQA are distinguishing compounds from Patrol, asparagine and trigonelline are typical compounds of Papandayan coffee samples, while Cikuray coffee samples do not have significant characteristic compounds. The results of the antioxidant activity test of green bean extract of Garut arabica coffee showed that all samples had strong antioxidant activity with Patrol coffee as the most active sample with the average value of IC50 (DPPH) and EC50 (FRAP) respectively was 44.25 ppm and 27.01 ppm. Then, 4- CQA, 5-CQA, citric acid, and quinic acid were positively correlated with FRAP as shown by OPLS-DA loading plot. This study revealed the metabolite profiles of Garut Arabica coffees which can be used as scientific information for confirming the superiority of Garut coffee, and the development of Indonesian Arabica coffee.