Coffee has refreshing, diuretic, strong heart, anti-oxidation, anti-aging and other effects, is one of the favorite drinks. The primary processing of coffee mainly adopts two ways, medium seed coffee is mainly processed by dry method, and small seed coffee is mainly processed by wet method. Drying is a very important processing link of coffee from fresh fruits to commercial beans, the traditional drying method is sun drying, its drying time is long, affected by the external environment, easy to produce mold beans, smelly beans, smelly beans, resulting in uneven quality of green coffee beans, affecting its commodity value.
Vacuum freeze-drying technology is an emerging food drying technology developed in recent years, with no addition, clean and pollution-free characteristics, its coffee freeze-drying principle will freeze fresh food into a solid state at a lower temperature, and then in the vacuum state, heating the water in it directly sublimed into a gas without liquid, and finally make dehydration dry.
The processing method of vacuum freeze-dried green coffee beans includes: Step 1: clean the fresh coffee fruit, drain the water and then pre-freeze; Step 2: Vacuum freeze-drying of the pre-frozen fresh coffee fruit is carried out in three stages. In the first stage, gradient heating takes 30min to 50-60
℃ and constant temperature drying for 12.5-14.5h; in the second stage, gradient cooling takes 15min to constant temperature drying at 45-55℃ for 7-9h. In the third stage, it takes 15min for gradient cooling to 40-50℃ for constant temperature drying for 2-4h; Step 3. The vacuum freeze-dried fresh coffee fruit is shelled and vacuum-packed to obtain the vacuum freeze-dried green coffee beans.
The advantages of freeze-dried coffee The coffee fruit itself has a unique multi-layer structure and physiological characteristics, and the vacuum freeze-drying technology is used for processing, which avoids excessive loss of nutrients and active substances, improves the appearance of green coffee beans, and effectively retains the flavor components and nutrients of fresh coffee fruit. The water content of vacuum freeze-dried green coffee beans obtained by freeze-drying is about 12%, and the content of nutrients and flavor active substances is higher. Vacuum freeze-drying of green coffee beans can avoid excessive loss of nutrients and active substances such as coffee fruit caffeine, trigonelline, fat and protein during processing, retain their content well, and shorten the processing time.