Green coffee beans are stored for a certain period and under certain conditions until they are finally utilized. The storage period may depend on customer demand while the storage conditions depend on where the coffee beans are stored. Thus, this research emphasizes the physicochemical changes that occur in Liberica coffee beans during storage under the Malaysian
climate (average temperature and relative humidity of 29.33ºC and 71.75% respectively). The changes in the physico-chemical (coffee size, mass, densities, colour, proximate analysis, sucrose, chlorogenic acid content) and microbiological (yeast and mould count) properties were evaluated during eight months of storage. After the storage, the physical properties of the coffee changed as the coffee beans expanded in size, reduced in mass and density and became brighter in colour. Changes in the chemical properties were also detected where the moisture decreased and the ash content increased. In addition, the sucrose level was found to decrease with a corresponding increase in chlorogenic acid. During storage, the counts of yeast and mould were reduced. Model equations describing the changes in the properties were developed. The overall conclusion was that the coffee beans reduced in quality during storage.
This study was conducted to determine the influence of raw material variation, equipment
process variables and device stability on the drying process of rambutan seed using oven and
microwave drying equipments. The raw material variations studied were skin colour (yellow
and fully red), storage period (fresh and stored) and seed mass (5 and 10 g). The important
equipment process variables studied were oven temperature (40 and 60°C) and microwave
power (250 and 1000 W).The output power and drying distribution in the drying chamber were
studied to examine the device stability. Results indicated that the seed mass, oven temperature
and microwave power influenced the drying time. The skin colour and storage period were
negatively correlated with drying time due to drying time speculate to relay on time required for
moisture removal that associated to initial moisture content and seed mass. It is also observed
that the drying time will be shorten if the sample was located at the central of the microwave
drying chamber. In contrast, the oven exhibited higher stability compared to microwave due
to its ability to provide similar level of heating at each location in the drying chamber. This
information will aid researchers and industrial operators to design an effective drying process
using microwave and oven thus reducing cost and time.