N05051: Comparing fresh and processed fruits and vegetables as sources of bioavailable phytochemicals
Monday 9 February 2004
This project aims to demonstrate the relative nutritional benefit of fresh versus processed sources of fruit and vegetables commonly consumed as part of the diet (apples, tomatoes, broccoli, tomatoes and blackcurrants).
Background
This project will address the problem of limited information concerning the bioavailability of phytochemicals from foods. An established nutrient (vitamin C) and a number of plant secondary metabolites (polyphenols, glucosinolates, monoterpenes) have been selected for study; all of these have been shown to produce responses consistent with the health protective properties of a diet rich in fruits and vegetables. The bioavailability of phytochemicals from apples, broccoli, tomatoes, oranges and blackcurrants will be measured in humans. The aim of the project is to ascertain how factors such as processing of foods and age of the individual impact on the bioavailability of phytochemicals from foods. The results of this study will provide important information of relevance to policy makers including the Agency (e.g. development of the 5-A-Day message, healthy ageing) and food processors (e.g. foods with enhanced phytochemical bioavailability).
Research Approach
This project will:
- Determine baseline composition of fruit and vegetable sources and the effects of processing. Various sources of F&V (apple, broccoli, tomato, orange, blackcurrant) will be purchased and processed (fresh/minimally processed vs more extensively processed), and analysed for baseline composition of phytochemicals.
- Measure the absorption of phytochemicals from fresh apples and apple juice in human volunteers to determine the relative nutritional benefit of a fresh apple versus a portion of apple juice.
- Assess the bioavailability of polyphenols from apple juice in volunteer groups defined by age to demonstrate the effects of stage of life on the bioavailability of phytochemicals from apples.
- Measure the absorption of phytochemicals from fresh oranges and orange juice to determine the effects of juice processing on the bioavailability of orange phytochemicals.
- Determine the relative nutritional value of processed tomato products (fresh tomatoes, tomato sauce and passata) as a source of phytochemicals.
- Measure the absorption of blackcurrant phytochemicals from fruit and juice matrices to determine the relative value of processed sources of blackcurrants as sources of bioavailable phytochemicals.
- Measure the absorption of phytochemicals from fresh and frozen broccoli to determine the effects of freezing and domestic processing on the bioavailability of broccoli phytochemicals.