No abstract

Coffee berry borer (CBB, Hypothenemus hampei Ferrari) is a common insect pest in coffee plantations and is a suspected vector of various mycotoxin-producing molds. In the present study, field trials were undertaken consecutively for 3 years to evaluate the impact of CBB on the microbial contamination of Arabica and Robusta coffee bean varieties, with emphasis laid toward ochratoxin A (OTA)-producing fungi. Results revealed higher microbial contamination in CBB-infested beans in both the varieties of coffee with the presence of toxigenic molds (such as Aspergillus niger, Aspergillus ochraceus). The "timely harvested" coffee, which was infested with CBB, was found to possess comparatively lesser OTA levels than those berries left in soil or on coffee plants. Studies carried out on coffee beans collected from nine curing factories indicated the presence of OTA in almost all the CBB-infested coffee beans, irrespective of the variety. Results of the present study provide sufficient baseline information and evidence to understand and correlate the role of CBB with various OTA-producing molds in coffee beans. Understanding the role of CBB might be useful and applicable in the coffee-growing regions of the world, especially in plantations for production of quality coffee.

The objective of the work was to study the effect of drying temperature on cup quality of the robusta coffee subjected to mechanical drying in comparison with conventional sun drying. The robusta coffee processed by wet (parchment coffee) and dry (cherry coffee) methods were subjected to drying at different temperature regimes (40 oC, 50 oC and 60 oC) in a rotary mechanical dryer. The results of the study indicated that as the drying temperature increased, the time of drying reduced. Sun drying of parchment coffee took 48 hours (approximately seven days) to attain the desired moisture content of 11-12 per cent, while mechanical drying reduced the drying time to 16 to 24 hours. Similarly, cherry coffee subjected to sun drying took 88 hours (approximately 15 days), while mechanical drying reduced the drying time to 32 to 48 hours. The cup quality rating of coffee dried by different drying methods revealed that sun-dried robusta parchment coffee scored the highest cup rating. As the drying temperature increased, the cup quality ratings decreased. A similar cup quality rating was also observed with cherry coffee. These results indicate a considerable reduction of drying time when coffee beans are dried in a mechanical dryer. However, there is a need to regulate the drying temperature, which otherwise would negatively impact the quality of coffee. The drying temperature should not exceed 40oC for preserving the innate quality of robusta coffee because the high drying rates provoked by high temperatures can cause damage to the coffee quality due to the damage caused to the cell membranes. Overall, mechanical drying is more advantageous to sun drying in-terms of drying hours (indirectly reduces dependency on manpower) and preservation of innate quality of the coffee.

No abstract

The aim of this study was to evaluate the impact and contribution of various drying surfaces (soil, cement, and tarpaulin) and raking frequencies (1 and 4/day) on the incidence of toxigenic molds, ochratoxin A (OTA) production, and on the overall cup quality during preparation of arabica and robusta coffee cherry in India. Two individual experimental batches (run 1 at the begin of harvest and run 2 at the end of harvest) were set up for the study. Results showed high incidence of molds in coffee dried on soil surface compared with that on cement and tarpaulin surfaces. In both arabica and robusta, OTA could be detected in Aspergillus ochraceus contaminated samples at the end of harvest. Raking of the cherries 4 times/day showed lower fungal incidence with no OTA levels detected. Overall, coffee cherry prepared by drying on tarpaulin surface with 4 rakings/day showed lower OTA and fungal incidence with good and acceptable cup quality, and this is recommended to be practiced at the farm level.