a comparison of hot air vs. microwave drying methods in production of banana chips

bananas of long cavendish variety constituted the experimental samples in this research work. following the slicing of bananas, the samples were treated with three pretreatments of: 1% sodium bisulphate (t1), a combination of blanching and 1% sodium bisulphate treatment (t2), combined blanching and treatment with 1% ascorbic plus citric acid (1:1) mixture (t3) as well as an untreated sample, considered as control (t0). all the samples were dried making use of two drying methods: (hot air drying in 60, 70 and 80°c vs. microwave drying of 300, 500 and 700 w power intensity). dried samples were evaluated for some such quality measures as color, sugar content (sucrose), vitamin c content, rehydration as well as drying time and rate. the results showed that drying time in the case of microwave drying was shorter than that in hot air drying. a 90% decrease in drying time was observed in microwave drying method rather than hot air drying. in comparison with untreated samples, pretreatments caused an increase in drying rate while a decrease in the needed drying time. on the whole, (t2) pretreatment acquired a more positive score relative to other treatments from view point of quality parameters.