Liberica Coffee (Coffea liberica): A Bibliometric Analysis and Targeted Review of Physical, Bioactive, and Sensory Characteristics

Liberica coffee (Coffea liberica), including its varieties C. liberica var. liberica and C. liberica var. dewevrei (Excelsa), is the third most commercially important coffee species; however, scientific knowledge on its physicochemical, bioactive, and sensory characteristics remains limited compared with Arabica and Robusta. This study evaluates the development of Liberica coffee research and synthesizes current evidence on its key quality attributes. A bibliometric analysis of publications indexed in Scopus, PubMed, and Semantic Scholar was conducted to identify trends, themes, and knowledge gaps, followed by a targeted review of physical properties, bioactive compounds, antioxidant and antibacterial activities, and sensory characteristics. Results show a gradual increase in Liberica research over the past decade, with a shift toward quality attributes and functional properties. Liberica coffee exhibits distinctive physical traits, moderate caffeine levels, and a bioactive profile characterized by chlorogenic acids that vary with processing and roasting, alongside relatively stable alkaloids such as trigonelline and theobromine. The diterpene composition, particularly the kahweol-to-cafestol ratio, distinguishes Liberica varieties. Sensory studies report fruity, jackfruit-like aromas, moderate acidity, and a relatively full body. Despite its potential, standardized data remain limited, highlighting the need for integrated research to support quality differentiation and value addition.