AbstractDietary antioxidants (AO) are believed to contribute to the overall health benefits seen from fruit and vegetables. Despite increased public awareness of the health benefits of fruit and vegetables through campaigns such as 5 A DAY, consumption remains low. Freezing is usually regarded as destructive to AO and ascorbic acid (AA) and this has fostered a belief that fresh vegetables are nutritionally superior to frozen. In this study, AO and AA activity in commercially bought fresh and frozen vegetables were investigated and compared after a typical home cooking practice (boiling). Five different vegetables were examined: carrots, broccoli, green beans, peas and spinach. Each vegetable was bought four times from a selection of local supermarkets and green grocers in the Wirral, United Kingdom to account for variation. The oxygen radical absorbance capacity (ORAC) assay and 2, 6-dichlorophenolindophenol (DCPIP) assay were utilised to measure total antioxidant capacity (TAC) and AA content respectively. The results showed both fresh and frozen vegetables to contain AO and AA after cooking. Cooked fresh spinach and peas contained significantly (p<.05) higher levels of total AO than cooked frozen spinach and peas. However the remaining fresh and frozen vegetables (broccoli, carrots and green beans) did not appear to differ in AO content after cooking. Furthermore there was no difference between AA content in fresh and frozen cooked vegetables. The current study provides evidence against the misconception that fresh is always nutritionally superior to frozen at the point of consumption. Frozen vegetable promotion may be the way forward to increase fruit and vegetable consumption as they are generally nutritionally comparable to fresh but, cheaper, result in less waste, are more convenient and, if packaged correctly, taste the same as fresh. Further work, on a larger scale, is needed, to measure AO and AA content of fresh and frozen vegetables bought and cooked by the consumer.
PublisherUniversity of Chester
TypeThesis or dissertation
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