THE INFLUENCE OF PROCESSING BY CRUSHING AND BOILING ON ASCORBIC ACID CONTENT IN SOME PLANT SPECIES

摘要

In this work the influence of processing (crushing and boiling) on ascorbic acid content in four plant specie was searched on. The biological material was represented by: green onion (leaves and bulbs), spinach leaves, pear fruits (from vegetable farms around Suceava town) and kiwi fruits (from supermarket). The ascorbic acid content was determined through a method based on reduction (by the ascorbic acid) of 2.6-Dichlorphenol-indophenol to the corresponding leucoderivate. Through crushing and one hour exposure to air (20-22°C), the largest reduction in ascorbic acid content was registered in pear fruits (50%), and the lowest one in spinach leaves (11.7%). As compared to fresh samples, under thermal processing (boiling) the ascorbic acid content has decreased most in pear fruits (by 52.6%) and least in spinach leaves (by 38.5%). The presence of sugar (10%) in the boiling liquid made ascorbic acid decrease less than in its absence, both in plant tissue and in the boiling fluid.