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Humans need to eat processed tomato products, such as tomato sauces, to get the most antioxidant benefits from tomatoes, new research has found.
Plant and Food Research, in collaboration with Lincoln University, discovered lycopene, an antioxidant found in high levels in tomatoes, was released only in small amounts when digested by humans.
Scientists used a model of the digestive tract to measure the amount of lycopene and other antioxidants released from tomatoes during typical digestion.
While around 75 percent of the total antioxidants were released, this included only four percent of the lycopene found in the raw tomato.
Nutritional biochemist Carolyn Lister said processing tomatoes increased the amount of lycopene released, "so as well as eating raw tomatoes for their nutritional value, we should eat tomato sauces to get the goodness of the lycopene".
Tomatoes were the richest source of lycopene in the human diet, as well as containing other essential antioxidants, she said.
Plant and Food Research's 'Vital Vegetables' programme would continue to focus on increasing the supply of lycopene to consumers, starting with high-lycopene tomato varieties.