The determination of the best heat pump drying mode for manufacturing green peppercorn

Green peppercorn is a special product from pepper cherries. Green peppercorn has a very specific flavor and different with other pepper products (black pepper, white pepper): fresh and light flavour of green peppercorn, excellent aftertaste and good hot. In the world, there are some products of green peppercorn, such as: dried green pepper, green pepper in vinegar and freeze-dried green peppercorn.  These products usually have high economic value and they are widely used in Asian countries and some European countries. There is limited research as well as application in producing green peppercorn products in Vietnam. The method of drying heat pump (freeze drying) is one of the advanced drying methods which have been being researched for application on processing many high-quality food and agricultural products. This method is able to maintain the color, heat sensitive nutrients and vitamine. Green pepper fruits are easily changed its color during processing, so it is very difficult to remain its natural color in final product. The chlorophyll in the pepper fruits is easily turned from green to oliu or yellow or black when exposed to high temperatures, sunlight and air. Therefore, using heat pump drying method (freeze drying) is able to keep the color of the pepper fruit during processing. This is also the research goal of the research project “Research design, manufacture equipment for processing green pepper corn, red peppercorn and white pepper using enzyme technology” implemented in 2 years 2017-2018. Results for the determination of the best heat pump drying mode for manufacturing green peppercorn was that: drying temperature is 300C, air humidity is 40%, wind speed is 3m/s, drying time is about 40 hours. This drying mode produced the highest percentage of Green peppercorn and oliu peppercorn, but the lowest percentage of black pepper. Taste and quality of dried green peppercorn products were the best and very clean.

Key words: pepper processing, green pepper corn, heat pump drying, pepper drying