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Following the ripening of bananas
23 February 2006
A technique developed to study the sugar conversion process during fruit ripening could inform the design of polysaccharide processing methods.
Guillermo Moyna and colleagues at the University of Alabama, US, have used 13C NMR and an ionic liquid to follow the sugar conversion processes that occur during fruit ripening.
Bananas are a staple food in many developing countries and are the fourth most valuable food crop worldwide. As bananas ripen, their carbohydrate compositions change. Unripe bananas contain mostly starch polysaccharides and ripe fruit contains a mixture of mono- and disaccharides: mainly sucrose, glucose and fructose.
Measuring the changes in carbohydrate composition during ripening is difficult using traditional analytical techniques because carbohydrates are only sparingly soluble in common organic solvents and long work up processes are needed to prepare each sample.
Moyna and colleagues used the ionic liquid 1-n-butyl-3-methylimidazolium chloride to study the ripening process. Banana pulp samples were used with very little preparation and the sugar conversion process was followed by comparing high-resolution 13C NMR spectra. The method could easily be extended to analysing carbohydrate mixtures from other fruits and grains and more complex lignocellulose structures such as woods and grasses, said Moyna.
The most important challenge will be in using this method for 'the development of environmentally-friendly alternatives for the extraction, processing, and recycling or polysaccarides particularly starch and cellulose,' said Moyna. Work in this area is already underway.
D A Fort, R P Swatloski, P Moyna, R D Rogers and G Moyna, Chem. Commun., 2006, 714 (DOI: 10.1039/b515177p)