槟榔预处理及热风干燥工艺条件优化

为了探索槟榔的优良加工工艺，研究采用不同水煮时间（10、20、30 min）和水煮温度（80、90、100 ℃）预处理工艺后槟榔的干燥特性和干燥后长径比变化情况；并研究不同干燥温度（50、55、60、65 ℃）和装载质量（16、24、32、40 kg/m2）条件下的干燥特性。结果表明：不同水煮时间对槟榔干燥后水分比的变化影响不显著；不同水煮温度对槟榔干燥后水分比的变化影响较显著。不同水煮时间和水煮温度条件下槟榔干燥后的长径比变化差异显著，长径比随着水煮时间的延长而降低，随着水煮温度的升高而升高。较优的水煮预处理工艺为：水煮时间10 min、水煮温度100 ℃。干燥温度和装载质量对槟榔干燥的含水率变化有显著影响，且干燥速率随着干燥温度的升高而增大，随着装载质量的增加而减少。槟榔的热风干燥没有恒速干燥阶段，只有降速干燥阶段。较优的热风干燥工艺为：干燥温度60 ℃、装载质量24 kg/m2。

Pretreatment and Hot Air Drying of Betel Nuts

This study explored the effects of different boiling periods (10, 20 and 30 min) and temperatures (80, 90 and 100 ℃)
for pretreatment as well as different drying temperatures (50, 55, 60 and 65 ℃) and loading weights (16, 24, 32 and 40 kg/m2)
on drying characteristics and length/diameter ratio of betel nuts. The results showed that different boiling periods had no
significant effect on water content, but different boiling temperatures had an obvious effect. The length/diameter ratio of
betel nuts was significantly changed with different boiling periods and boiling temperatures, revealing a decrease with
extended boiling time but an increase with increasing boiling temperature. The optimum pretreatment parameters were
cooking for 10 min at 100 ℃. Both drying time and loading weight had remarkable effects on the moisture content of betel
nuts. The drying rate of betel nuts became higher at elevated drying temperature, but declined with increasing loading
weight. The whole drying process was a falling-rate period. The optimum drying parameters were 60 ℃ and 24 kg/m2 for
drying temperature and loading weight, respectively.