Recipient Organization
TUFTS UNIVERSITY
28 SAWYER AVE
MEDFORD,MA 02155-5811
Performing Department
Biology
Non Technical Summary
Coffee is a globally important crop with a complex supply chain supporting over 20 million families worldwide. In 2018, global coffee production was estimated at 160 million bags of green coffee, but the global average coffee market price has recently dropped to its lowest level since 2005. In addition, coffee is identified as a climate sensitive species and research suggests that by 2050 the land currently utilized for coffee growing will shrink an estimated 38% to 90%. Given these economic and climatic pressures coffee producers are facing a severe challenge leaving them vulnerable and at risk of being forced out of the sector. One way for coffee producers to insulate themselves from these challenges is to differentiate in the market and produce specialty, high quality, and environmentally friendly coffees. However, the links between the environment, agronomical practices, and the chemical and sensory quality of coffee is not fully understood. Firm linkages between agronomical practices and quality would allow farmers to inform their strategy in the future and contribute to a more sustainable coffee value chain.This project aims advance our fundamental understanding of coffee plant health, production, and sustainability within the context of examining the agriculture system from seed to cup. A further understanding of the relationship between farming management, green coffee metabolites, and the sensory characteristics will allow for production of a diversified coffee product. The result will establish how desirable sensory characteristics are related to these farm-level adaptations. This will be completed by using mass spectrometry to profile the chemical fingerprint of shade-grown and monoculture sun-grown coffee, each farmed in an optimal and suboptimal coffee-growing region of Costa Rica. Descriptive analysis will capture the quantitative sensory profile and hedonic measures will be used to evaluate the purchase intent of coffee roasters. Research conclusions can be applied to multiple levels of the coffee supply chain, with emphasis towards providing feedback to coffee farmers.
Animal Health Component
15%
Research Effort Categories
Basic
75%
Applied
15%
Developmental
10%
Goals / Objectives
Goals:This project aims to evaluate how farming practices (fertilization, crop load, sun/shade exposure) interact with growing region to modify the chemistry and sensory of coffee grown in Costa Rica. This will be approached by exploring the metabolites from four phenotypes of coffee seeds: shade-grown and monoculture sun-grown coffee, each grown in optimal and suboptimal coffee-growing region of Costa Rica. The chemical traits induced by the applied farming treatments and growing region will be followed through to roasting and to the coffee beverage.Objectives:1) Profile the volatile and non-volatile metabolites of the green coffee seeds2) Effects of roasting on the metabolite profile3) Sensory evaluation of roasted coffee
Project Methods
Coffee production -The experimental coffee will be grown in Costa Rica, which will rely on pre-established partnerships. Methodology will focus on capturing the effect of the applied field treatments on the occurrence and abundance of volatile and non-volatile plant metabolites. Coffee will be grown in three monoculture sun-grown coffee farms in optimal (Santa Maria de Dota, Tarrazú) and sub-optimal (Moravia, Central Valley) coffee-growing regions. The region of Tarrazú is at a higher elevation (1200 - 1900 m) with cooler, more stable weather versus the hotter lower elevation (<1200 m) Central Valley growing region. Within each farm, additional experimental treatments of fertilizer and crop load will be applied.Physical and growth measurements of the plants, flowers, and seeds will be collected. A Garmin handheld GPS will be used to record location and altitude at each plant. Four branches on each selected plant, one in each cardinal direction, will be flagged for repeated measurements of branch length, number of nodes, number of fruits, and pest and disease incidence; additionally, plant height, percent shade cover, and planting density will be recorded. From the data, fruits/node will be used to calculate the yield effort (fruits/node in June), and actual yield (fruits/node in December). The difference between the latter two provides an estimate of fruit loss. Physical attributes of berry weight and seed size will be determined for each treatment. Fresh berry weight (g) will be measured at harvest. Harvested ripe coffee cherries will then undergo a standard "wet processing"- depulping, fermenting, and drying the samples to 10-12% humidity. The dry seeds will be passed through a series of sieves (6.7, 6.4, and 6.0 mm) to evaluate seed size distribution. After processing, the green beans will be packaged and sent to the Tufts University for storage (-80oC) and analysis.Chromatographic analysis -The green coffee and its roasted counterpart will be analyzed for its volatile and non-volatile metabolites. The volatile profile will be collected using a GC-GC/MS workflow. The GC-GC/MS is first used to analyze a sub sample of the experimental coffee which provides increased resolution and thus clearer spectral data due to reduced analyte coelution. The collected spectrums are then querying against established mass spectral libraries (e.g. NIST, Wiley, METLIN) with the results added to an experimental database. Using this tailored database of collected spectra, the complete experimental sample set is then analyzed using GC/MS and spectral deconvolution. Peak area from confirmed compounds will be collected. The non-volatile metabolites will be analyzed using LC-MS with a specific focus on quantifying multiple chlorogenic acids.Sensory analysis -Descriptive analysis will be applied to assess the sensory properties of each treatment. This methodology uses trained panelists to evaluate objective sensory characteristics (e.g. flavor, aroma, texture, appearance) of a product set. Prior informed consent will be obtained from all panelists in order to participate, as per IRB guidelines. Evaluation terms are consensus generated by the panel, with each described by a clearly defined reference standard. Each coffee is then evaluated in blind triplicate with a randomized service order with each panelist providing an intensity for each attribute for each replicate. Coffee will be ground and brewed to meet the SCA "Golden Cup Standard" of total dissolved solids ranging between 1.15 to 1.35 % and solubles extraction yield of 18 to 22 %. The brewed coffee samples will be presented to the descriptive sensory panel in pre-heated china cups using a blind and random design. Each sensory panel will consist of at least 8-12 trained descriptive panelists.Acceptance testing will be aimed at evaluating how importers and roasters of green coffee view coffee produced under various management regimes. This segment of the coffee value chain is vital to evaluate, as they determine which coffees will be purchased and thus hold tremendous influence over which practices a coffee grower will utilize. These surveys will specifically measure how the chemical fingerprint and sensory descriptive drivers relate to the perceived quality and purchase intent of roasters and importers. The evaluation will utilize hedonic scaling, "check-all-that-apply" (CATA), and "just-about-right" (JAR) scales to evaluate the experimental coffees. Participants will be screened to include only those who are directly responsible for roasting and/or purchasing green coffee with greater than one-year experience. Roasted coffee will be served in as described in the SCA cupping protocol.Data Analysis - Relationships will be evaluated using Partial Least Squares Regression (PLS-R) and Multifactor Analysis (MFA). Penalty analysis will be applied to evaluate the relationship between JAR results and 9-point acceptance. CATA lift will also be applied in a similar manner to capture the sensory attributes associated with acceptance. These results can be compared between the panelist groups (having cupping scores vs no knowledge of cupping score).Efforts -Results will be presented to the coffee growing community in Costa Rica through outreach and workshops. Additionally, results will be presented to coffee community at the annual Speciality Coffee Association Coffee Expo, which hosts the largest gathering of coffee industry professional worldwide.Evaluation -Project outputs will be evaluated through publication of research results.