Different elevation affects the biochemical composition and regulatory patterns of polyphenol compounds in (Coffea arabica)

Abstract

Changes in elevation significantly impact the growth and quality of coffee beans. This study provides valuable insights into the biochemical composition and regulatory patterns of polyphenolic compounds at high (1,600 m-HA1), medium (1,400 m-MA2), and low (1,200 m-LA3) altitudes, along with the effects of natural sun drying processes. Findings indicate that total phenolic acid and total flavonoid content were more abundant at medium altitude (1,400 m-MA2) compared to both high altitude (1,600 m-HA1) and low altitude (1,200 m-LA3). Using UPLC-MS/MS, a total of 326 metabolites were detected. The analysis of differential compounds revealed 70 polyphenolic compounds across the three altitudes, including phenolics, flavonoids, lignans, and coumarins. Specifically, eight phenolic acids were identified in comparing the 1,600 m-HA1 and 1,200 m-LA3 altitudes, while 30 compounds were distinguished between 1,600 m-HA1 and 1,400 m-MA2, as well as between 1,400 m-MA2 and 1,200 m-LA3. The compound 5,7,3',4'-tetrahydroxy-6,8-diprenylisoflavone emerged as a critical and prominently regulated compound between HA1 and LA3, as well as between HA1 and MA2 elevations. The decline in other flavonoid compounds, coupled with the significant increase in total phenolic content, highlights medium altitude (1,400 m-MA2) as the optimal choice for selecting high-quality green coffee beans in the Pu'er region. This research underscores the effects of altitude on green coffee bean quality and highlights the distinct patterns of metabolite accumulation associated with different elevations. Future research could focus on exploring the specific environmental and genetic factors that contribute to the observed variations in polyphenolic composition and overall coffee bean quality across different altitudes.