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Pectin (from the Greek pektos, meaning 'jelly') is the stuff that binds fruit together. Specifically, it is the 'mortar' between the cellular 'bricks' in many fruits. Pectinases were some of the first enzyme preparations to be made available commercially. They have been used since the 1930s for clarifying fruit juices (such as blackcurrant) either for drinking directly or before fermentation into wine.

The first section of this booklet provides detailed background information on the use of enzymes in fruit juice manufacture. A second section gives step-by-step instructions for simple practical investigations using pectolytic and other enzymes.

These investigations are suitable for a wide range of ages and abilities and could form starting points for individual or group practical projects.

Specimen enzyme activity graphs are provided in the practical section. It is important to appreciate that these represent the performance of the enzymes under ideal conditions, usually with simple substrates rather than with whole fruits or fruit juice. They therefore show roughly the enzyme performance might be expected in the practical investigations, but do not provide the results that might be obtained.

Safety guidelines for practical work with enzymes in schools
can be found here.

ACKNOWLEDGEMENTS

The production of this booklet was very kindly supported by Unilever plc. The contents are entirely the responsibility of the NCBE however. Unilever's only conditions were that we made this publication freely available via the Internet, and that we consulted Dr Malcolm Thomas, in the Department of Education at the University of Aberystwyth. Malcolm commented on the first draft, for which we are grateful. Marjorie Smith of Dollar Academy provided her usual canny insight into the Scottish education system. Special thanks must also go to Erica Clark at Science and Plants for Schools and to Richard Price, that organisation's former director. Erica was embarrassingly thorough and spotted numerous mistakes and inconsistencies. Our colleague Dr Bob Rastall from the School of Food Biosciences at Reading also gave us the benefit of his wisdom. Any errors that remain are the author's, of course.

SPECIAL ENZYME PACK

The NCBE supplies the individual enzymes required for the practical work described in this booklet. The Centre also sells, at a substantial discount, a pack containing all of the enzymes (five types in total) together with a printed copy of 'In a jam and out of juice'.

For further information, please see the 'MATERIALS' section of the NCBE Web site.

Copyright © National Centre for Biotechnology Education, 2006 | www.ncbe.reading.ac.uk