Investigation of water state during induced crystallization of honey

Silvia Tappi; Luca Laghi; Amanda Dettori; Lucia Piana; Luigi Ragni; Pietro Rocculi

doi:10.1016/j.foodchem.2019.05.047

Investigation of water state during induced crystallization of honey

Food Chem. 2019 Oct 1:294:260-266. doi: 10.1016/j.foodchem.2019.05.047. Epub 2019 May 9.

Authors

Silvia Tappi¹, Luca Laghi², Amanda Dettori³, Lucia Piana⁴, Luigi Ragni⁵, Pietro Rocculi⁵

Affiliations

¹ Interdepartmental Centre for Agri-Food Industrial Research, Alma Mater Studiorum, University of Bologna, Piazza Goidanich 60, 47521 Cesena, FC, Italy.
² Interdepartmental Centre for Agri-Food Industrial Research, Alma Mater Studiorum, University of Bologna, Piazza Goidanich 60, 47521 Cesena, FC, Italy; Department of Agricultural and Food Science, Alma Mater Studiorum, University of Bologna, Campus of Food Science, Piazza Goidanich 60, Cesena, FC, Italy. Electronic address: l.laghi@unibo.it.
³ Department of Agricultural and Food Science, Alma Mater Studiorum, University of Bologna, Campus of Food Science, Piazza Goidanich 60, Cesena, FC, Italy.
⁴ Piana Ricerca e Consulenza, Castel San Pietro Terme, Bologna, Italy.
⁵ Interdepartmental Centre for Agri-Food Industrial Research, Alma Mater Studiorum, University of Bologna, Piazza Goidanich 60, 47521 Cesena, FC, Italy; Department of Agricultural and Food Science, Alma Mater Studiorum, University of Bologna, Campus of Food Science, Piazza Goidanich 60, Cesena, FC, Italy.

PMID: 31126461
DOI: 10.1016/j.foodchem.2019.05.047

Abstract

This work studied water state of honey during crystallization, obtained statically and dynamically, by differential scanning calorimetry (DSC), water activity (a_w) assessment and time domain nuclear magnetic resonance (TD-NMR). Crystallization was induced by adding 5% of crystallized honey to three honey samples with different fructose/glucose ratio, the key characteristic for honey crystallization. Samples were stored at 14 °C. Dynamic crystallization was obtained by using an impeller. DSC showed that the dynamic crystallization was faster than the static one, the latter characterized by two phases, showing different rates. The crystallization rate did not affect a_w, that remained below 0.600. TD-NMR allowed to separately observe two kinds of protons, both pertaining to liquid sugars, one chemically exchanging with water and one not exchanging with it. The combination of techniques allowed speculating that the two crystallization methods led to crystals of different size and shape.

Keywords: Differential scanning calorimetry; Dynamic crystallization; Honey; Static crystallization; Time-domain nuclear magnetic resonance; Water activity; Water state.

MeSH terms

Calorimetry, Differential Scanning
Crystallization
Honey / analysis*
Magnetic Resonance Spectroscopy
Water / chemistry*

Substances

Water