Characterisation of viscosity, colour, 5-hydroxymethylfurfural content and diastase activity in raw rape honey (Brassica napus) at different temperatures

Abstract

The effect of heating at various temperatures (30, 40, 50, 60, 70 and 80 °C) on dynamic viscosity, colour, 5-hydroxymethylfurfural (5-HMF) concentration and diastase activity of raw rape honey were assessed. In fresh honey, moisture, ash, free acidity, pH and electrical conductivity averaged 185.3 g kg(-1), 1.2 g kg(-1), 18.71 mEq kg(-1), 4.2 and 0.25 mS cm(-1), respectively. Heating significantly (p ≤ 0.05) increased lightness (L*), yellowness (b*), chroma (C*), hue (h°) values, but decreased redness (a*). The viscosity at 20 °C (33.6 Pa s) differed significantly (p ≤ 0.01) with those at 30, 40 and 50 °C (8.2, 2.5, and 1.6 Pa s, respectively). Diastase activity decreased concomitant with heating at higher temperatures. Honey heated at 80 °C for 15 min showed the maximum increase of 5-HMF content, with an average of 1.9 mg kg(-1) (62 %), compared to unheated samples. Heating for 15 min between 50 °C and 80 °C did not significantly degrade the quality of the honey, but, slightly enhanced formation of 5-HMF and reduced the diastase activity.

Effect of freezing and room temperatures storage for 18 months on quality of raw rapeseed honey (Brassica napus)

“…The granulation of honey consists of two processes: the formation of crystals and their gradual growth (in shape and size), which depend on composition of honey and temperature of storage (Lupano 1997). Despite the fact that the crystallisation is natural process and does not reduce the quality of honey, Polish consumers consistently prefer fresh liquid honey ('patoka') (Kędzierska-Matysek et al 2016).…”

Dielectric properties of honey: the potential usability for quality assessment

“…Since customers often prefer fresh liquid honey and a lot of honey types crystallize rapidly, many beekeepers and factories heat honey at high temperatures for melting. This may result in unfavorable chemical processes [reduction of α-amylase activity and increase of 5-hydroxymethyl furfural (HMF) content] [7]. Therefore, honey quality assessment is crucial at every stage of the production process.…”

The synthesis of two long-chain N-hydroxy amino coumarin compounds and their applications in the analysis of aldehydes

“…[1][2][3][4][5] The existence of certain aldehydes can serve as indicators of quality deterioration, microbacterial fermentation and so on. 2,5,6 This makes the determination of aldehydes in foodstuffs critical for consumer protection and quality control.…”

“…[1][2][3][4][5] The existence of certain aldehydes can serve as indicators of quality deterioration, microbacterial fermentation and so on. 2,5,6 This makes the determination of aldehydes in foodstuffs critical for consumer protection and quality control. Besides the points mentioned above, certain aliphatic aldehydes are key biomarkers for lipid peroxidation in biological organisms, which has a major effect on a variety of diseases including heart disease, diabetes mellitus, et al [22][23][24] The analysis of aldehydes is thus very helpful for the evaluation of these diseases.…”

“…2,5,10,12 The existences and concentrations of these furfuraldehydes are relevant to food safety and avor, which makes the detection and analysis of them quite important. In this study, we focused on the analysis of them via derivatization reaction with 1a and 1b.…”