The effect of some factors on the vitamin C content in vegetables

Abstract

The study into vitamin C content were performed on plants grown in the Department of Horticulture in University of Warmia and Mazury in Olsztyn in 1998–2000. A field experiment was conducted to study the effect of different factors such as species, cultivar, date and site of growing, growing method, foliar nutrition, time of storage on the accumulation of L-ascorbic acid in edible parts of vegetables. Twenty vegetable species grown in fields and in unheated plastic tunnels were studied. The content of the acid was estimated by the Tillmans method [Pijanowski et al. 1964]. The analyses showed a widely varied content of vitamin C in vegetable crops and the levels depended mainly on the species. Paprika berries had the highest content – over 100 mg·100 g -1 . The lowest content of vitamin C was found in scorzonera, salsify, soybeans and cucumber with below 6 mg per 100 mg of fresh mass in 1998. The effect of different cultivation methods on cucumber and lettuce leaves showed no regularities in vitamin C content changes in particular years of the experiment. However, the effect of cabbage cultivar and storage conditions on vitamin C content in cabbage was noted. The L-ascorbic acid content was 33.4 mg·100 g -1 in ‘Kamienna Głowa’ and 48.4 mg·100 g -1 in ‘Litewska’ cabbage. The losses in vitamin C during after 60 days of inadequate storage were from 12.9 to 52.8%. The effect of summer planting date on the content of vitamin C was also shown in two radish cultivars, where ‘Murzynka’ radish was characterised by a higher vitamin C content. The foliar nutrition gave positive results and increased the vitamin C content in redbeet.