© All Rights Reserved *Corresponding author. Email: zaizuliana@unisza.edu.my International Food Research Journal 24(Suppl): S475-S480 (December 2017) Journal homepage: http://www.ifrj.upm.edu.my * Nurul Zaizuliana, R. A., Anis Mastura, A. F., Abd Jamil, Z., Norshazila, S., Zarinah, Z. School of Food Industry, Faculty of Bioresources and Food Industry, Universiti Sultan Zainal Abidin, Besut Campus, 22200 Besut, Terengganu Effect of storage conditions on the crystallisation behaviour of selected Malaysian honeys Abstract Honey is a sweet liquid food of high nutritional value and it provides immense health benefts. It is highly concentrated with sugar and contains mostly glucose and fructose, which will crystallize over a period of time. Crystallisation of honey will affect its quality, as well as consumers’ acceptability. Storage condition is one of the factors that infuence the crystallisation of honey. Different types of honey may need different storage conditions to retain the quality. This research was conducted with the aims to study the crystallisation behaviour of the selected Malaysian honeys and to determine the storage conditions that infuence the formation of crystal. The crystallisation of Malaysian honeys (Hutan, Kelulut, Acacia, Gelam) stored at 25, 4 and -20 o C for different storage times of 0, 5, 14, 30, 60 and 180 days was analyzed by a differential scanning calorimeter (DSC), and sugar composition was analyzed using a high performance liquid chromatography (HPLC). The results showed that Hutan honey had the greatest crystal formation at the storage temperature of 4 o C even after 14 days of storage. Glucose compositions in Hutan and Gelam honeys were also high which were 33.49 ± 0.53 % and 33.93 ± 0.15 %, respectively. The enthalpy value for the storage temperature of 25 o C, which represents the amount of heat needed to melt crystals present in honey, was the lowest (0.37 ± 0.1 – 2.56 ± 0.5 J/g) compared to other storage temperatures, which showed only a small amount of crystals was formed at this temperature. Thus, this study suggested that the crystallisation behaviour of Malaysian honeys is infuenced by the storage condition and will be different for each type of honey. Introduction Honey mainly consists of sugar and water (Natalia et al., 2014). It is highly concentrated with glucose and fructose, as well as other complex sugars (Laos et al., 2011). There are more than 25 types of sugar in honey,which make up about 95% of total dry weight of honey (Weston, 1999). Honey also contains minor components such as vitamins, especially B complex and vitamin C, minerals, amino acids, and various phytochemicals (Kaskoniene et al., 2010).The presence of enzymes such as glucose oxidase, diastase, invertase, phosphatase, catalase and peroxidase has also been documented in honey (Crane, 1975). According to Tosi et al. (2004), biochemical composition of honeys varies greatly, depending on the foral, regional, and climatic conditions. In Malaysia, there are varieties of honey produced from honeybee (Apismellifera), which are Tualang, Gelam, Acacia, Hutan and Nenas while Kelulut honey produced from stingless bees. Crystallisation is a mass transfer phenomenon that leads to the creation of a solid-liquid interface and results in a positive contribution to the free energy of nucleation (Marangoni and Wesdorp, 2013). Supersaturation is the driving force of crystallisation (Chen and Chou, 1993). Honey is a glucose supersaturated solution and can granulate or crystallize spontaneously at room temperature (Zamora and Chirife, 2006) during storage (Lupano, 1997). In food products, crystallisation somehow may be important or cause defects to the quality, texture, and shelf life (Hartel, 2001). However, crystallisation is an undesirable process in liquid honey (Assil et al., 1991) and has been misunderstood by most of the customers as they claim it as an adulterated honey. As crystallisation occurs naturally in honey, it can cause major problems during handling and processing (Assil et al., 1991; Venir et al., 2010) and also makes fractionating and pouring diffcult (Tosi et al., 2004). Honey tends to crystallize over a period of time due to the loss of water in glucose and become precipitate. These precipitate is in the form of glucose monohydrate. It will then revert to a more stable saturated state (Zamora and Chirife, 2006; Venir et al., 2010). Crystallisation in honey causes Keywords Malaysian honey Crystallisation Differential scanning calorimeter Article history Received: 21 June 2017 Received in revised form: 9July 2017 Accepted: 21 November 2017