Evidence for the complex relationship between free amino acid and sugar concentrations and acrylamide-forming potential in potato.

N Muttucumaru,J.S Elmore,D.S Mottram,S.J Powers,A Briddon,N.G Halford

doi:10.1111/aab.12101

N Muttucumaru, J.S Elmore + Show 4 more

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https://doi.org/10.1111/aab.12101

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Abstract

Free amino acids and reducing sugars participate in the Maillard reaction during high-temperature cooking and processing. This results not only in the formation of colour, aroma and flavour compounds, but also undesirable contaminants, including acrylamide, which forms when the amino acid that participates in the reaction is asparagine. In this study, tubers of 13 varieties of potato (Solanum tuberosum), which had been produced in a field trial in 2010 and sampled immediately after harvest or after storage for 6 months, were analysed to show the relationship between the concentrations of free asparagine, other free amino acids, sugars and acrylamide-forming potential. The varieties comprised five that are normally used for crisping, seven that are used for French fry production and one that is used for boiling. Acrylamide formation was measured in heated flour, and correlated with glucose and fructose concentration. In French fry varieties, which contain higher concentrations of sugars, acrylamide formation also correlated with free asparagine concentration, demonstrating the complex relationship between precursor concentration and acrylamide-forming potential in potato. Storage of the potatoes for 6 months at 9°C had a significant, variety-dependent impact on sugar and amino acid concentrations and acrylamide-forming potential.

Highlights

Reducing sugars, such as glucose and fructose, react with free amino acids during high-temperature cooking and processing in a series of non-enzymatic reactions given the umbrella name of the Maillard reaction (Halford et al, 2011; Mottram, 2007; Nursten, 2005)
The analysis revealed significant differences between the types and varieties nested within types for free asparagine, many other amino acids, total free amino acids and the sugars with the exception of sucrose, which showed an effect of type but not variety
Breeders are more likely to invest in programmes aimed at reducing acrylamide-forming potential in potato if they are confident that the correct target traits have been identified

Summary

Introduction

Reducing sugars, such as glucose and fructose, react with free amino acids during high-temperature cooking and processing (frying, baking and roasting, but not boiling) in a series of non-enzymatic reactions given the umbrella name of the Maillard reaction (Halford et al, 2011; Mottram, 2007; Nursten, 2005). The Maillard reaction results in the formation of a plethora of products, many of which impart colour, aroma and flavour. Acrylamide forms when the amino acid that participates in the reaction is asparagine (Mottram et al, 2002; Stadler et al, 2002; Zyzak et al, 2003). For simplicity we will refer to free asparagine and reducing sugars as precursors of acrylamide, the carbon skeleton of acrylamide is derived entirely from asparagine. It should be noted that other routes for acrylamide formation have been proposed (Claus et al, 2006; Granvogl et al, 2004)

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