Shade and Altitude Implications on the Physical and Chemical Attributes of Green Coffee Beans from Gorongosa Mountain, Mozambique

Abstract

Coffea arabica L. is as a tropical crop that can be grown under monocrop or agroforestry (AFS) systems, usually at altitudes greater than 600 m, with suitable environmental conditions to bean quality. This study aimed to assess the effect of altitude (650, 825, and 935 m) and light conditions (deep shade—DS, and moderate shade—MS provided by native trees, and full Sun—FS) on the physical and chemical attributes of green coffee beans produced in the Gorongosa Mountain. Regardless of altitude, light conditions (mainly MS and FS) scarcely affected most of the studied physical and chemical attributes. Among the few exceptions in physical attributes, bean mass tended to lower values under FS in all three altitudes, whereas bean density increased under FS at 650 m. As regards the chemical compound contents, sporadic changes were found. The rises in trigonelline (MS and FS at 935 m), soluble sugars (FS at 935 m), and the decline in p-coumaric acid (MS and FS at 825 m), may indicate an improved sensory profile, but the rise in FQAs (FS at 825 m) could have a negative impact. These results highlight a relevant uncertainty of the quality changes of the obtained bean. Altitude (from 650 to 935 m) extended the fruit maturation period by four weeks, and altered a larger number of bean attributes. Among physical traits, the average sieve (consistent tendency), bean commercial homogeneity, mass, and density increased at 935 m, whereas the bean became less yellowish and brighter at 825 and 935 m (b*, C* colour attributes), pointing to good bean trade quality, usually as compared with beans from 650 m. Furthermore, at 935 m trigonelline and 5-CQA (MS and FS) increased, whereas FQAs and diCQAs isomers declined (in all light conditions). Altogether, these changes likely contributed to improve the sensory cup quality. Caffeine and p-coumaric acid showed mostly inconsistent variations. Overall, light conditions (FS, MS, or DS) did not greatly and consistently altered bean physical and chemical attributes, whereas altitude (likely associated with lower temperature, greater water availability (rainfall/fog), and extended maturation period) was a major driver for bean changes and improved quality.

Drought responses in Coffea arabica as affected by genotype and phenophase. I – leaf distribution and branching

“…Among about 130 species of genus Coffea (Davis and Rakotonasolo, 2021), only two dominate the entire coffee trade, Coffea arabica -Arabica coffee and C. canephora -Robusta coffee (Cassamo et al, 2022), both originated from African continent (Davis et al, 2006). In its natural evolution, C. arabica became allotetraploid as a result of a natural cross of two parental diploid species: C. canephora and C. eugenioides (Bardil et al, 2011).…”

“…Among about 130 species of genus Coffea (Davis and Rakotonasolo, 2021), only two dominate the entire coffee trade, Coffea arabica – Arabica coffee and C. canephora – Robusta coffee (Cassamo et al. , 2022), both originated from African continent (Davis et al. , 2006).…”

Overexpression of Water-Responsive Genes Promoted by Elevated CO2 Reduces ROS and Enhances Drought Tolerance in Coffea Species

“…Coffee is one of the most important agricultural commodities worldwide, generating about USD 200.0000 million [ 16 ], and constituting a crucial source of income for 20–25 million smallholder farmers, which are mostly based in the tropical region [ 17 , 18 ]. Despite the recognized resilience and metabolic flexibility of some coffee genotypes to environmentally stressful conditions, adverse temperatures and limited water availability are the major causes of crop failure, affecting the yield and quality of coffee beans, promoting livelihood insecurity, and constraining the value chain of coffee [ 19 , 20 ].…”

“…Currently, the optimum mean annual temperature range for arabica coffee is considered to be between 18 and 21 °C, although elite cultivars under intensive management allow the spread of arabica coffee to regions with average temperatures as high as 24–25 °C. Coffea canephora can grow under higher temperatures with optimum annual mean temperatures ranging from 22 to 30 °C, depending on authors [ 18 ]. Despite drought is a concern for the crop, some genotypes can maintain high photosynthetic rates, especially under eCO 2 conditions [ 12 , 21 ], reducing physiological constraints imposed by drought (e.g., overcoming diffusional CO 2 limitations due to stomatal closure), and reinforcing some defense mechanisms, contributing to maintaining photosynthetic performance and, likely, crop yield, at least under moderate levels of drought [ 12 , 17 , 22 , 23 , 24 ].…”

Genomic Evaluation of Coffea arabica and Its Wild Relative Coffea racemosa in Mozambique: Settling Resilience Keys for the Coffee Crop in the Context of Climate Change

“…Another recommended approach to mitigate climate change impacts on the coffee crop is the shift from intensive production under the full sun (and monocrop systems) to agroforestry systems (AFS) using native or other economic-important trees for shade, constituting refuges for biodiversity and providing multiple ecosystem services (e.g., timber, food, carbon sequestration, or nutrient cycling) [ 10 , 24 , 25 , 26 ]. The effectiveness of this strategy, which provides a better micro-environment for coffee plants, is however dependent on several factors, such as the agroecological conditions, shade density, crop management, and the cultivars used [ 27 , 28 ].…”