Effect of puff drying on seedless grape fruits quality criteria compared to convective air drying [electronic resource]

Includes references.

The goal of the present study is to investigate the effect of explosion puffing and convection air drying on the physical,
chemical and sensory properties of dried seedless grape, and cost of operation. The obtained results showed that, the drying
rate of puff drying method (PD) was faster than that of convection air drying method at the corresponding drying condition
of (60°C and 1.5 m/s air velocity). The seedless grape samples dried by PD were the best for the most of physico-chemical
quality properties such as color index, texture, rehydration ratio, and shrinkage rate compared to similar samples dried
by AD that required a longer time. The seedless grape dried by PD method had the highest amount of total phenolic compounds
(276.73 mg/100g DM) than that in convection air drying. The highest value of total carotenoids (84.44 mg/100g DM) was found
in seedless grape dried by PD method. The PD drying process led to retention of total flavonoids in dried seedless grape
samples at a wide rate depending on the drying time compared to the AD drying methods. The PD technique exhibited the ability
to obviously quench the DPPH radical compared to the AD method. In conclusion, the seedless grape samples dried by PD exhibited
good sensory properties and better acceptability. PD can meet the four major requirements in drying foods: short time of operation,
energy efficiency, cost of operation, and quality of dried products which indicates that puff drying is a good choice for grape processing.
Keywords: Explosion puff drying; air drying; color index; texture; sensory quality.

Summary in Arabic.