Articles
VARIATION IN CHEMICAL COMPOSITION OF POTATO TUBERS AND DISCOLOURATION OF CRISPS BETWEEN AND WITHIN YEARS
Article number
684_15
Pages
109 – 118
Language
English
Abstract
Potatoes (Solanum tuberosum) for processing of crisps and French fries have special quality demands compared with ware potatoes.
A low amount of reducing sugars in the tubers is necessary to prevent the non-enzymatic Maillard reaction between sugars and free amino acids during frying.
The Maillard reaction is responsible for the development of undesirable dark coloured compounds with bitter taste.
Moreover, it was recently discovered that intermediates in the Maillard reaction were responsible for the formation of the potentially carcinogenic compound acrylamide.
Variation in suitability of potato tubers for processing is not influenced only by cultivar and storage conditions, but also by differences in normal cultural practices and growing conditions.
A three-year study with the potato crisp cultivar Saturna was conducted to evaluate the effect of different vine killing dates on development in crisp colour during storage in relation to the variation normally observed between commercial fields.
In addition to measurements of fry colour, the tubers were analysed for concentrations of fructose, glucose, sucrose, asparagine, and glutamine.
During storage seasons the course of sugar accumulation in the tubers was unique for each of the three experimental years.
Smaller changes in the concentration of free amides were seen during storage in general, but larger differences were seen between commercial potato fields compared with the results obtained for reducing sugars.
Variation in fry colour between years exceeded variation due to growth location, cultural practices and distinct vine killing dates.
A low amount of reducing sugars in the tubers is necessary to prevent the non-enzymatic Maillard reaction between sugars and free amino acids during frying.
The Maillard reaction is responsible for the development of undesirable dark coloured compounds with bitter taste.
Moreover, it was recently discovered that intermediates in the Maillard reaction were responsible for the formation of the potentially carcinogenic compound acrylamide.
Variation in suitability of potato tubers for processing is not influenced only by cultivar and storage conditions, but also by differences in normal cultural practices and growing conditions.
A three-year study with the potato crisp cultivar Saturna was conducted to evaluate the effect of different vine killing dates on development in crisp colour during storage in relation to the variation normally observed between commercial fields.
In addition to measurements of fry colour, the tubers were analysed for concentrations of fructose, glucose, sucrose, asparagine, and glutamine.
During storage seasons the course of sugar accumulation in the tubers was unique for each of the three experimental years.
Smaller changes in the concentration of free amides were seen during storage in general, but larger differences were seen between commercial potato fields compared with the results obtained for reducing sugars.
Variation in fry colour between years exceeded variation due to growth location, cultural practices and distinct vine killing dates.
Authors
P.E. Lœrke, J. Christiansen
Keywords
processing quality, glucose, fructose, sucrose, asparagine, glutamine
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