Roasted Rye as a Coffee Substitute: Methods for Reducing Acrylamide.

Johannes Pitsch,Otmar Höglinger,Julian Weghuber

doi:10.3390/foods9070925

Johannes Pitsch, Otmar Höglinger + Show 1 more

Open Access

https://doi.org/10.3390/foods9070925

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Abstract

Acrylamide is assumed to be a potential carcinogen, and reference values have therefore been implemented in EU legislation. Thus, the food industry needs to reduce the acrylamide content in consumer products to the lowest possible value. In this study, roasted rye was evaluated for its suitability as a coffee substitution product with respect to its acrylamide content. The influence of process modifiers, free asparagine content, storage, and rye type on the final content of acrylamide was investigated. Changes in carbohydrate composition and brightness caused by the roasting process were described. Sample analysis was conducted via GC-MS and HPLC-CAD. Existing methods were adapted to roasted rye as the sample matrix. CaCl2 and asparaginase treatment as well as pH adjustments prior to roasting did not prove to reduce the acrylamide content. A significantly (* p < 0.027) lower free asparagine content in the raw material resulted in a lower formation of acrylamide in the final product. The acrylamide content significantly decreased (**** p < 0.0001) after 3 (1100 ± 18 µg kg−1) and 6 (490 ± 7 µg kg−1) months of long-term storage. Only samples stored for 6 months (490 ± 7 µg kg−1) met the EU acrylamide content requirements (<500 µg kg−1) for grain-based coffee substitution products.

Highlights

Acrylamide is an organic compound and belongs to the chemical group of amides [1].This compound has been used for decades in polymerized form in biochemistry, in the paper industry, and in wastewater treatment and is produced on an industrial scale by hydrolysis of acrylonitrile [2]
We focused on the following parameters relevant to the formation of acrylamide: (i) filling volume variations in the drum roaster that might influence the determined concentration of acrylamide; (ii) the asparagine content of rye varieties before and after roasting; (iii) the role of different rye grain types on the formation of acrylamide; (iv) the roasting temperature; (v) modifiers (CaCl2, asparaginase, and pH adjustments), as they potentially impact acrylamide formation; (vi) long-term storage of products at room temperature to validate its influence
We investigated the efficacy of modifiers, substances that were added before or during the roasting process, to inhibit acrylamide formation

Summary

Introduction

Acrylamide is an organic compound and belongs to the chemical group of amides [1]. This compound has been used for decades in polymerized form in biochemistry, in the paper industry, and in wastewater treatment and is produced on an industrial scale by hydrolysis of acrylonitrile [2]. Formed by the Maillard reaction in the presence of reducing sugars and the amino acid asparagine under low-water-content conditions, acrylamide has been of increasing concern for food manufacturers worldwide [5]. Evaluation of carbohydrate and protein contents (especially that of asparagine) prior and after food processing steps seems to be of importance to determine the relation between the raw materials and final acrylamide content.

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