Changes in physico-chemical properties, hydroxymethylfurfural and volatile compounds during concentration of honey and sugars in Alicante and Jijona turrón

Turrón has being elaborated in a traditional way; however, manufacturers are trying to (a) change production systems from discontinuous to continuous and (b) improve quality/homogeneity of products. To get these objectives, detailed scientific information regarding each of the unit operations involved is needed. Thus, the objective of this study was to gain as much information as possible about the initial operation of " honey+sugars" concentration. During this stage, humidity was reduced from a 29 to 0.5% and water activity from 0.86 to 0.18. At the same time, the soluble solid content increased from 51 to 81 Brix. 5-Hydroxymethylfurfural increased during the heating stages and was constant during the cooling stage; however, contents were always below 40 mg kg. Finally during this heating step, characteristic honey volatile compounds decreased their concentration, for instance acetoin, benzaldehyde, phenylacetaldehyde, and linalool oxide, while compounds arising from amino acids and sugars through Maillard and Strecker degradation reactions significantly increased, for instance furfuryl alcohol, furfural and 5-methyl furfural. © 2006 Springer-Verlag.