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    Rights: The University of Waikato
    Published 1 February 2007 Referencing Hub media

    Using vegetable materials to make new foods like healthy snack bars can lead to unwanted colours, tastes or smells. How are scientists at Plant & Food Research tackling these problems?


    Kevin Sutton (Plant & Food Research) There are several areas about the vegetable materials we would like to manipulate. The first of those is colour, and then there’s odour and taste. And then there are other effects such as flatulence, which are caused by those materials.

    With colour, in reality a lot of vegetable materials have got greens or browns or other types of colours, and other compounds in them. This can give rise to grey colours once those materials are integrated into other foods. So a lot of the work we’ve been looking at is to how to either remove that effect…to remove the colour, or to get rid of the compounds in the vegetable material which cause those colours to develop.

    Because people do not want to eat grey food. They don’t tend to like eating greeny or blue coloured foods because they are associated with problems such as mould growth.

    The colour problem is caused by groups of compounds called phenolic compounds which are very small molecules. When they’re heated, in the presence of moisture, they tend to join together. The poly phenolic material that’s produced is black in colour, so when this is at a very low concentration in food it appears to be grey.

    In order to remove them - basically, they’re soluble in water. So we’ve developed a process where we can wash them out of the material, while leaving all the healthy components that we require for our low glycaemic foods.

    One of the other issues with vegetable materials is taste and odour. We’ve been developing some processes where we can take the vegetable material and use very simple, quite natural processes to remove the odours which people would find objectionable.