Author/Authors :
Nordin, M.F.M Faculty of Agro Based Industry - Universiti Malaysia Kelantan, Kelantan - Malaysia , Puspasari, I Department of Chemical and Process Engineering - Faculty of Engineering and Built Environment - Universiti Kebangsaan Malaysia, Selangor, Malaysia , Tasirin, S.M Department of Chemical and Process Engineering - Faculty of Engineering and Built Environment - Universiti Kebangsaan Malaysia, Selangor, Malaysia , Daud, W.R.W Department of Chemical and Process Engineering - Faculty of Engineering and Built Environment - Universiti Kebangsaan Malaysia, Selangor, Malaysia , Gariépy, Y Department of Bioresource Engineering - Faculty of Agricultural and Environmental Sciences - McGill University, Quebec, Canada , Talib, M.Z.M Department of Chemical and Process Engineering - Faculty of Engineering and Built Environment - Universiti Kebangsaan Malaysia - 43600 Bangi, Selangor - Malaysia , Raghavan, G.S.V Department of Bioresource Engineering - Faculty of Agricultural and Environmental Sciences - McGill University - Macdonald Campus, 21,111 Lakeshore, Ste-Anne-de-Bellevue - Quebec - Canada H9X 3V9
Abstract :
Quality changes of red pitaya (Hylocereus undatus) slices dried in hot air, microwave-hot air and
microwave-vacuum dryers were investigated. The quality parameters were colour, water activity, shrinkage,
rehydration ratio, ascorbic acid content and visual market quality. Microwave-vacuum produced pitaya with
the best quality compared to hot air and microwave-hot air. Pitaya dried in microwave-vacuum had the highest
rehydration ratio while the other methods presented similar rehydration ratios. Ascorbic acid in dried pitaya was
also better retained when drying by microwave-vacuum. Apart from that, the drying time of pitaya dried in
microwave-vacuum could be reduced by 83% compared to hot air.
Farsi abstract :
تغييرات كيفيت برش خشك شده پيتايا قرمز (pitaya undatus Hylocereus)در هواي گرم، هوا گرم مايكروويو، خشك كن مايكروويو تحت خلاء مورد بررسي قرار گرفتند. پارامترهاي كيفيت، رنگ، فعاليت آبي، انقباض(آب رفتگي)، نسبت جذب مجدد آب، مقدار اسيد اسكوربيك و كيفيت بصري بازار بودند. مايكروويو خلاء پيتايا (pitaya )با بهترين كيفيت در مقايسه با هواي گرم و مايكروويو هواي گرم توليد نمود. پيتاياي خشك در مايكروويو خلاء بالاترين نسبت جذب مجدد آب را داشت، در حالي كه روش هاي ديگر نسبت جذب مجدد آبي مشابهي نشان دادند. اسيد اسكوربيك در پيتايا خشك نيز بهتر حفظ شده بود هنگامي كه با مايكروويو برقي خشك مي شود. جداي از آن، زمان خشك كردن پيتايا خشك شده در مايكروويو خلاء را مي تواند 83 درصد در مقايسه با هواي گرم كاهش يابد
Keywords :
Dragon fruit , Drying kinetics , Microwave convective drying , Microwave vacuum drying , Product quality
