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subsequent frozen storage that losses of more labile vitamins occur
(Czarnowska and Gujska 2012). Scott and Eldridge (2004) indicate that
freezing step generally has no significant effect on the vitamins con-
tent of vegetables. Research done by Ninfali and Bacchiocca (2003)
on freezing using a Lewis individual quick freezing (IQF) tunnel
and blast freezer also did not show differences in ascorbic acid con-
tent of vegetables. Lisiewska and Kmiecik (1991) also reported no
effect of freezing on the content of thiamin and riboflavin of veg-
etables, and this concept could also be extended to other components
of vegetables. According to Thane and Reddy (1997), the amount of
carotenoids is also not affected by freezing, particularly rapid freez-
ing. Deteriorative process occurs, although at a very low rate, during
storage. This is desirable, of course, because of the high value placed
on carotenoids as nutrients.

MATERIALS AND METHODS

Samples preparation

The fresh vegetables samples were collected from local
market and the fresh samples were washed under running tap
water and kept on 4 °C until needed of analysis. Also, another
vegetables samples were collected after blanching and freezing
and kept on -18 °C until needed for the different investigations.
Moreover, all the chemicals used in this study were of analytical
grade.

Chemical composition

Moisture, protein, fat, fiber and ash were determined according
to AOAC (2010). The carbohydrate content was determined by dif-
ference. Ascorbic acid was determined according to Ruck method
(1963) in the manner described by El-obeid (2003), and minerals
were extracted according to Pearson’s method (1981), potassium and

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