Abstract:

Low-sugar preserved yacon fruit was processed from fresh yacon fruit through the following procedures: bleaching, color fixing, hardening, sugaring and drying. These procedures were optimized by comparative experiments or orthogonal array design. The optimal processing technology of low-sugar preserved yacon fruit was determined as follows: fresh yacon fruits were cut into slices of 0.5 cm thickness, and the slices were then bleached in boiling water for 4 min and immediately cooled; following color fixing and hardening by soaking for 2 h in a solution containing salt 1.0%, citric acid 0.5%, and calcium chloride 1.5%, sugaring with a 15% fructose syrup containing sucrose 30%, CMC-Na 0.8% and citric acid 0.4% was done at 80 ℃ in an ultrasonic field, followed by sugar-dipping for 2 h at room temperature; finally, variable low temperuture airblast drying was done in the following program of 50 ℃ for 5 h → 65 ℃ for 3 h→ 50 ℃ for 5 h. The finished product was good in color, flavor, taste and appearance.

Key words: yacon, low-sugar preserved fruit, color fixing, ultrasonic-assisted sugar-permeating, technological conditions