Whether we are purchasing fresh vegetables from a market stall, ready meals from the supermarket, eating at home or in a five‐star restaurant, we use colour to tell us what to expect in terms of taste, nutrition and safety. This review considers the techniques that have, over the years, been employed to modify the colour of our food, and the interactions of these techniques with issues of safety and nutrition. The demand for brightly coloured food resulted in the incorporation of some questionable inorganic and organic chemistry being used in food products. A limited number of synthetic dyes are still used in food today, but health concerns and the consumer‐driven demand for natural colorants has brought about a change in the way food is coloured. The proliferation of products with labels that state they contain “No artificial colours” on supermarket shelves suggests that the future of azo dyes and their various derivatives is strictly limited. Nature produces an abundance of colours and many of these are extracted and used as natural food colorants; however, they are subject to application limitations and stability problems. Significant research by academia and industry into methods to stabilise and expand the application possibilities for the various approved natural food colorants is ongoing, but most developments that food colour manufacturers proclaim are enhanced vehicles for delivering established natural pigments into food products.

Focuses on teaching and research in the field of food science and technology at South Bank University, featuring the content of courses at both undergraduate and postgraduate level as well as the areas of food science research.

No abstract

The senescence of leaf discs cut from mature B r~~s s e l s s p r o~~t leaves is retarded by a number of kinins. Other plant growth reg~~lators are without effect. When young expanding leaves are treated with Itinins the senescence processes appear to be accelerated. The ef-lect of N-6-benzyladenine on the structure of the cell organelles in young and old leaves has bee11 studied by electron microscopy. I t has been found that ill mature leaves the chloroplast is the organelle which senesces first and the breakdown is retarded by iV-6-benzyladenine. The mitocho~~dria are very stable. 111 young leaves iV-6-benzyladenine appears to over-stin~ulate the chloroplast, causing enlargement and excessive membrane synthesis.

No abstract