Effect of Six Month Storage on Physicochemical Analysis and Antioxidant Activity of Several Types of Honey

Abstract

Honey composition could change during storage, which might affect the quality of honey. Subsequently, it could reduce the honey commercial value. However, data on the effect of the storage on several types of local honey is still lacking. Thus, in this study, moisture content, pH and antioxidant level of honey stored at 4°C were analysed after six-month of the storage. Initially, physicochemical properties (moisture, electrical conductivity, ash content, pH, free acidity and hydroxymethylfurfural (HMF) level) and antioxidant levels of five local honey samples (Tualang, Gelam, Pineapple, Acacia and Kelulut honey) and Manuka honey as a control were determined. Afterwards, honey samples were stored at 4°C for six months and their moisture content, pH and antioxidant levels were monitored monthly. Physicochemical properties were measured based on the standard method set by the International Honey Commission (IHC). Antioxidant activity was determined based on previous studies. Most of the honey samples exhibited physicochemical properties within the range set by the Codex Standard for Honey but displayed lower antioxidant level compared to other studies. On average, honey moisture content increased by 0.1 to 0.4% while their antioxidant level increased by 2.6 mg GAE/kg to 6.3 mg GAE/kg monthly. In contrast, pH level of honey decreased by 0.03 to 0.09 monthly. Storage of honey at low temperature increases its moisture and antioxidant level while decreases its pH level. However, further study needs to be carried out to observe whether the pattern will continue even after a lengthy storage period exceeding six months.