Original scientific paper
https://doi.org/10.17113/ftb.53.01.15.3598
Impact of Pretreatment and Drying Methods on Quality Attributes of Onion Shreds
Nihar R. Sahoo
; Department of Agricultural Processing and Food Engineering, Orissa University of Agriculture and Technology, Bhubaneswar, India
Lalit M. Bal
; Post Harvest Process and Food Engineering, College of Agriculture, Jawaharlal Nehru Agricultural University, Tikamgarh, India
Uma S. Pal
; Department of Agricultural Processing and Food Engineering, Orissa University of Agriculture and Technology, Bhubaneswar, India
Dipika Sahoo
; Department of Horticulture, College of Agriculture, Bhawanipatna, Orissa University of Agriculture and Technology, Bhubaneswar, India
Abstract
Experiments were conducted on dry untreated onion shreds (2 mm thickness) or treated with salt (5 % solution) and potassium metabisulphite (0.5 % solution) in convective drier at 50 °C ((46±4) % relative humidity (RH)), 55 °C ((35±4) % RH), 60 °C ((28±4) % RH) and 65 °C ((20±4) % RH), heat pump-assisted convective drier at 35 °C ((32±2) % RH), 40 °C ((26±2) % RH), 45 °C ((19±2) % RH) and 50 °C ((15±2) % RH) and microwave-assisted convective drier at four microwave power levels, i.e. 120, 240, 360 and 480 W. The quality parameters of the dried onion shreds, namely rehydration ratio, colour diff erence, pyruvic and ascorbic acid contents and sensory scores were evaluated. The quality of dehydrated onion shreds was observed to be comparatively better when treated in heat pump drier at 50 °C, followed by that in microwave-assisted convective drier at 240 W and 50 °C, and last in convective drier at 60 °C. The onion shreds pretreated with potassium metabisulphite retained better colour of the dried product irrespective of drying methods. Therefore, heat pump drying may be recommended as one of the best drying methods for onion shreds, because it maintains the fi nal product quality, which has practical importance for the food industry.
Keywords
pretreatment; hot air drying; heat pump drying; microwave-assisted convective drying; onion
Hrčak ID:
136924
URI
Publication date:
30.3.2015.
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