Effect of different technological and culinary treatments on iron retention, nutritional density and recommended dietary intake in fourteen vegetable species


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The present work determined iron content in fourteen species of vegetable prepared for consumption. The experimental material consisted of raw and boiled raw vegetables and two types of frozen product: one traditionally produced (blanching before freezing); the other obtained using the modified method (boiling before freezing), having the characteristics of a ready-to-eat convenience product. Nutrient density (ND) and recommended dietary intake (RDI) were established on the basis of iron content. The highest iron content was found in pea seeds (2.03 mg per 100 g fresh weight) and the lowest in root vegetables (0.38–0.60 mg). Iron retention was similar in all pea, broad bean, New Zealand spinach, kale, white cauliflower, celery and red beet products. In the remaining products, the significantly lowest retention was found in the traditionally frozen product (Sample C) and the highest in the ‘convenience’ frozen product (Sample D). The above-mentioned order also applied to ND and RDI values. Only in the ND of parsnip calculated for women did any value fall below 100%.