Studies on frozen pourable custard apple (Annona squamosa L) pulp using cryoprotectants

Custard apple pulp treated with 100 ppm ascorbic acid as antibrowning agent and packed in 200 gauge polyethylene was frozen at -25 degrees C in an alc ohol bath and stored at -18 degrees C in a deep-freeze. The effect of three cryoprotectants (w/w), namely 0.5% propylene glycol (I), 0.5% glycerol (II ) and 2% glycerol + 1% propylene glycol + 10% glucose syrup + 10% maltodext rin (III), on the thawing time of this pulp was studied for a period of 3 m onths. A control sample without any cryoprotectant was included for compari son. The half-life for ascorbic acid degradation was monitored in the contr ol pulp and that containing the cryoprotectants. It was found that formulat ion (III) gave a product that was pourable even on frozen storage and also had the highest half-life of 75.33 days for ascorbic acid degradation as co mpared to 34.82 days for the control. (C) 2000 Society of Chemical Industry .