THE EFFECT OF AN INDIVIDUAL QUICK BLANCHING METHOD ON ASCORBIC ACID RETENTION IN SELECTED VEGETABLES

Method of blanching (including cooling) was found to have a significant effect on residual ascorbic acid level in peas (P 0.05). The separate parts of the procedure (heating and cooling) had an additive effect but acted independently of one another. In each case where a difference was observed the experimental procedure (individual quick blanch/evaporative or “air” cool) was found to yield a product higher in ascorbic acid than the conventionally processed product (water blanch/water cool). The practical implication is that adoption of specialized steam blanch procedures or evaporative cooling will result in improved nutrient levels in sensitive vegetables (e.g. peas and broccoli) as compared to conventional product. The experiments also indicated that any contact of heat and water with susceptible vegetable materials will cause a marked reduction in ascorbic acid levels. For the vegetables studied, the K-1 individual quick blanch system yielded fully blanched product which retained mean ascorbic acid levels between 82 and 91 % of raw values, depending on the specific vegetable.