Multi-response kinetic modelling of the formation of five Strecker aldehydes during kilning of barley malt

Abstract

Control of aroma formation during production of barley malt is critical to provide consistent and high-quality products for the brewing industry. Malt quality can be affected by the inherent variability of raw material and processing conditions, leading to inconsistent and/or undesirable profiles. Dried green malts were cured isothermally at 65, 78 and 90 °C for 8.4 h, and characteristic aroma compounds (Strecker aldehydes), precursors and intermediate compounds were analysed over time. By kinetic modelling of Strecker aldehydes, based on fundamental chemical pathways, we showed that degradation of Amadori rearrangement products and short-chain dicarbonyls was more sensitive to temperature change due to their higher activation energies compared to other kinetic steps. This study can help maltsters to manipulate formation of Strecker aldehydes, via raw material screening and process control, and hence optimise the organoleptic quality of malts and their products, such as non-alcoholic beers, where these aldehydes play a key role.

Keywords: 2-methylbutanal (PubChem CID: 7284); 3-methylbutanal (PubChem CID: 11552); Amadori compounds; Kilning; Kinetics; Malting; Methional (PubChem CID: 18635); Modelling; N-fructosyl isoleucine (PubChem CID: 137530247); N-fructosyl leucine (PubChem CID: 129689639); N-fructosyl methionine (PubChem CID: 5487578); N-fructosyl phenylalanine (PubChem CID: 129689862); N-fructosyl valine (PubChem CID: 71777427); Phenylacetaldehyde (PubChem CID: 998); Strecker aldehydes.