Post-harvest Coffee Processing Research Articles

Effect of different post-harvest processing on the sensory profile of Java Arabica coffee

Coffee consumption in the world is continuously growing and demanding high quality. Coffee cup quality is a complex matters involving several factors that includes post-harvest processing factor. The objective of this research is to investigate the impact of different coffee post-harvest processing methods i.e. fermentation methods (natural/dry, semi-washed and fully-washed processing), and drying methods (mechanical and sun drying) on the sensory quality of Java Arabica medium-roasted coffee beans. The sensory quality was evaluated through cupping test employing five expert judges. The result revealed that different post-harvest processing factors has a significant influence on coffee sensory quality, particularly on four cupping attributes, namely fragrance/aroma, flavour, defects and final scores. Fermentation using more water and controlled mechanical drying were found to yield a better coffee sensory profile due to less identified defective characters in the cup. Nevertheless, different processing created specific coffee character that would have its own market provided the quality is properly controlled.

Qualitative carbonyl profile in coffee beans through GDME-HPLC-DAD-MS/MS for coffee preliminary characterization

In this work, an analytical methodology for volatile carbonyl compounds characterization in green and roasted coffee beans was developed. The methodology relied on a recent and simple sample preparation technique, gas diffusion microextraction for extraction of the samples' volatiles, followed HPLC-DAD-MS/MS analysis. The experimental conditions in terms of extraction temperature and extraction time were studied. A profile for carbonyl compounds was obtained for both arabica and robusta coffee species (green and roasted samples). Twenty-seven carbonyl compounds were identified and further discussed, in light of reported literature, with different coffee characteristics: coffee ageing, organoleptic impact, presence of defective beans, authenticity, human's health implication, post-harvest coffee processing and roasting. The applied methodology showed to be a powerful analytical tool to be used for coffee characterization as it measures marker compounds of different coffee characteristics.

Discrimination of post-harvest coffee processing methods by microbial ecology analyses

Two main types of processing are applied to coffee: the dry and wet processes. The aim of this study was to measure the impact of post-harvest processing on coffee microbial ecology and search for microbial markers of process discrimination. Coffee samples were collected in three farms in two locations of West Cameroon (Bafoussam and Dschang). Samples of Coffea arabica were collected along wet and dry methods and Coffea canephora samples were collected only during treatment using the dry method. Bacterial and fungal communities present on coffee beans were determined by using a molecular method PCR-DGGE (Denaturing Gradient Gel Electrophoresis) generating 16S rDNA and 26S rDNA profiles for bacteria and fungi. Results showed that microbial ecology structures were different depending on three main parameters: i) the method applied, ii) the coffee species and iii) their geographical origin. Statistical analysis applied allowed to measure the impact of all parameters and showed that the method was the major parameter influencing microbial communities' structure. Microbial DNA markers that appear specific of coffee origin, species or treatment were identified, such as lactic acid bacteria (LAB) which were detected only during wet process. They are specific of the fermentation step. DNA from Wallemia sp. was only detected in Robusta coffee beans (Coffea canephora). The study of microbial communities at the molecular level appears as a promising approach to discriminate between coffee processing types.

A decision support system to aid the calculation of the cost of the post-harvest processing of coffee

Various computer programs were developed to calculate the cost of the coffee harvest. However, few address the costs of coffee in its post-harvest stage. This study was aimed to develop a system for calculating the cost of the coffee postharvest to facilitate decision making regarding the most cost-effective post-harvest processes. Thirty-four farmers in southern Minas Gerais state answered a questionnaire designed to validate this system. The use of a decision support system showed that the simulated costs in the post-harvest stage were not statistically different from the costs informed by the representatives of the selected farms.