Effects of pretreatment-drying method combinations on the drying rates, quality and storage stability of apricots

The effects of pretreatments, i.e. SO2 gas vs. sodium-meta-bisulphite, and operability of a solar drier to replace traditional sun-drying on concrete ground for apricot drying were studied. Increasing initial SO2 concentrations and solar drying increased drying rates. Sodium-meta-bisulphide treated products at an initial SO2 concentration of about 7800 mg/kg dry matter had nearly the same moisture diffusion coefficients as ones treated with SO2 at a concentration of 12,500 mg/kg dry matter. Storage stability of differently treated dried apricots having SO2 concentrations in the range 850 to 3350 mg/kg dry matter was investigated as packaged vs. non-packaged and at 13 degrees C vs 5 degrees C. Both during drying and storage initial SO2 concentrations were seen to decline considerably. Nonpackaged apricots stored at 5 degrees C absorbed moisture to undesirable levels and developed microbial counts were above allowable maximum limits. Microbial counts were below allowable maximum limits in all other treatments.