Kelulut honey was dehydrated at 40, 55, and 70°C up to 84 h in a dehydrator. The changes of its properties and qualities in terms of moisture content, water activity, hygroscopicity, moisture adsorption isotherm, colour intensity, total phenolic content (TPC), viscosity, glass transition temperature (T g ), surface stickiness, hydroxymethylfurfural (HMF) content, and diastase activity were evaluated. The dehydration process for 18 h between temperatures of 55 and 70°C can safely produce Kelulut honey product with less than 8% moisture content and water activity below 0.6. Similar quality of Kelulut honey dehydrated at lower temperature between 40 and 55°C requires up to 36 h of dehydration. These recommended dehydration conditions were able to increase TPC of honey from 7.86% from its original value for the shorter duration of 18 h and lower dehydration temperature of 40°C and up to 70.9% for the longer duration of 36 h and higher temperature of 70°C. Dehydrated honey was darker, more viscous, and stickier. The increase of HMF content in dehydrated honey at 40 and 55°C up to 36 h was not significant which are at 0 and 5.81 mg/kg honey, respectively, and at 70°C, it was about 80 mg/kg honey. The honey was found to have very low diastase activity ranging from 0 to 0.75 DN, thereby causing its changes to be insignificant during dehydration.

BACKGROUND: The physicochemical characteristics, antioxidant properties, and bacterial profiles of Heterotrigona itama, Apis dorsata, and Apis mellifera honey of Malaysian origin were studied and the results were assessed using Pearson correlation analysis and canonical correspondence analysis (CCA).RESULTS: The analysis showed that the Mellifera honey was characterized by high total sugar content (717.5 g kg −1 ); the Itama honey was characterized by high free acidity (347.5 meq kg −1 ); and the Dorsata honey was characterized by high radical scavenging activity (RSA; 69.3%RSA), total phenolic content (TPC; 1284.5 mg GAE kg −1 ) and hydroxymethylfurfural (HMF; 51.5 mg kg −1 ). Pearson correlation analysis showed that the TPC was positively correlated with HMF as well as RSA. The bacterial profile of Mellifera honey was significantly less diverse than Itama and Dorsata honey. Mellifera and Itama honey seemed to harbour a significant abundance of lactic acid bacteria, with relative abundance of 0.339 and 0.195, which suggests that it possesses probiotic potential. The Dorsata honey, however, contained pathogenic Clostridium genus, constituting 5% of its bacterial profile.CONCLUSION: The characteristic properties of the three investigated honey, Itama, Dorsata, and Mellifera were identified. The distinctive characteristics of the honey varieties informed the development of appropriate processing strategies for retaining the beneficial qualities of raw honey. It is hoped that the results of this study will shine light on Malaysian honey in a highly competitive global market.

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Aims: The kinetics of Kelulut honey quality parameters of hydroxymethylfurfural (HMF), color intensity and total phenolic content (TPC) at dehydration temperatures of 40, 55, and 70 C up to 84 h were studied.Methods: Data were fitted to zero-, first-, and second-order kinetic models and regression analysis were performed to calculate rate constant and activation energy.Result: HMF increased following zero-and first-order kinetics for 40 and 55 C, respectively. However, at 70 C, HMF first increased following zero-order kinetics, peaked at 60 h and then decreased following first-order kinetics. The color intensity of honey increased with dehydration time and was adequately described by zeroorder kinetics. The increase of TPC at lower dehydration temperature of 40 and 55 C followed zero-order kinetics but at higher temperature of 70 C, was better fitted with first-order model. Conclusions:The rate constants for all quality parameters increased with dehydration temperature, indicating that changes were more evident at higher temperature. The increase of TPC was found to be more evident due to its lower activation energy of 54.79 kJ/mol as compared to 104.1 and 63.16 kJ/mol for the increase of HMF and color intensity, respectively.