Date of Publication

7-2025

Document Type

Bachelor's Thesis

Degree Name

Bachelor of Science in Biology

Subject Categories

Biology

College

College of Science

Department/Unit

Biology

Thesis Advisor

Ma. Carmen Ablan-Lagman

Defense Panel Chair

Mark Angelo O. Balendres

Defense Panel Member

John Paul S. Domingo
Emmanuel V. Garcia

Abstract (English)

Coffea liberica is in the process of being reconsidered as a climate-resilient alternative to C. arabica and C. canephora due to its ability to tolerate heat and resist coffee leaf rust. Two infra-species were recognized, C. liberica var. liberica and C. liberica var. dewevrei (marketed as excelsa), which are frequently mislabeled due to the fact that both have overlapping traits and limited studies on post-roast beans. This study aimed to evaluate the two varieties based on morphology, chlorogenic acid (CGA) concentration, and caffeine concentration of roasted coffee beans sold in Luzon, Philippines. Random selection of samples from ten commercial retailers were used; about 75 beans per bag were measured in centimeters for morphology and was analyzed via standardized length- and width-to-height ratios, while 15 beans per bag were used for UV-Vis spectrophotometry after the ethanol-based extraction for the CGA and caffeine concentrations. The statistical analyses include PERMANOVA for morphology, ANOVA for chemical concentrations, and Principal Component Analysis (PCA) for multivariate patterns. Morphological analysis revealed no significant difference between the two varieties (p = 0.722), given the substantial overlap and variability within the species, which may be influenced by postharvest processes and roasting levels. CGA and caffeine concentrations also showed that there is no significant difference within-species (p = 0.568 and p = 0.105, respectively); notably, there is an intra-group variability, particularly among the “excelsa” labeled samples. PCA indicated that the biochemical variables explained a greater proportion of the overall variance than morphology, with a partial overlap; this suggested that there are inconsistencies in the classification and labeling. These findings are consistent with previous studies that CGA degradation occurs in roasting while caffeine maintains stability; furthermore, the findings supported the need for a combined morphological and chemical profiling to distinguish the two infra-species. Overall, the study emphasized the high variability and labeling inconsistencies in the commercially sold C. liberica beans and calls for improved authentication labeling methods to ensure transparency, species conservation, and accurate identification to support the specialty coffee chains.

Abstract Format

html

Abstract (Filipino)

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Abstract Format

html

Language

English

Format

Electronic

Keywords

Coffee; Chlorogenic acid; Caffeine

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Embargo Period

8-10-2026

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Available for download on Monday, August 10, 2026

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