用筒仓干燥方法对带壳澳洲坚果质量的研究

Research on Quality of the Macadamia Nut-in-shell by Silo Drying Method

采用二步干燥过程,即风机强制风干(<38℃)和热风干燥(50℃～60℃)为一体的筒仓来研究新鲜带壳澳洲坚果的干燥规律。根据含水量、颜色褐变、还原糖含量和过氧化值,评估被干燥的带壳澳洲坚果的质量。结果表明:筒仓干燥带壳澳洲坚果适合的条件是先采用30℃风机强制风干72h,含水量降到8%～10%,然后采用50℃热风干燥72h,含水量降低到干燥标准要求的1.5%以下;干燥后的带壳澳洲坚果的褐变率为2.3%,还原糖含量为0.04%,过氧化值为1.1300meq/kg;与传统网筛干燥方法相比,风机强制风干和热风组合的筒仓干燥,显著地缩短了带壳澳洲坚果的干燥时间,提高了品质。

Drying process, namely, the use of heat pump drying （38 ℃） followed by hot air drying （50 ℃~60 ℃） was chosen to investigate its feasibility to dry fresh macadamia nut-in-shell.The quality of dried macadamia nut-in-shell was assessed in terms of the moisture content, color, reducing sugar content and peroxide value. The results showed that the suitable drying conditions for macadamia nut-in-shell are the use of heat pump drying at 30 ℃（72 h）to decrease the moisture content to 8%～10%; this should be followed by hot air drying at 50 ℃（72 h）until the moisture content was reduced down to 1.5%. After dried macadamia nut-in-shell, the browning rate was 2.3%, reducing sugar content was 0.04%, peroxide value was 1.1300 meq/kg. Based on the comparison between conventional net screen drying and combined heat pump and hot air drying,it significantly save the drying time and improve quality of macadamia nut.