. Effect of location and residence time of honey in the hive on humidity, color and HMF

Abstract

Sugary foods are very sensitive to heat and can deteriorate during storage. Hydroxymethylfurfural (HMF) is a compound formed by the dehydration of fructose; its presence in honey is related to color alterations, development of flavors and strange odors. The objective of the work was to evaluate the effect of sun exposure and the time spent in the hive on the color, the percentage of humidity and the concentration of HMF in freshly harvested honey. The work was carried out at the Agricultural Experimental Station (EEA) Rafaela from the National Institute of Agricultural Technology (INTA), province of Santa Fe, Argentine Republic, during the 2017-2018 campaign. Five hives were in the sun (S), five hives under partial shade (SP) and five hives under total shade (ST). Samples of the half supers of the 15 hives were taken 4 times during 3 months, identifying the half supers by time spent in the hive. The average humidity of honey obtained from treatment S (17.6%) was higher (P<0.001) than honey from hives exposed to SP (16.6%) and ST (16.8%). The mean color value of the ST group (16.8 mm Pfund) was lower (P<0.001) than that of the S and SP groups (22.35 and 20.99 mm Pfund, respectively). No differences were observed (P=0.777) in the average concentration of HMF in the honeys of the different treatments (6.47, 7.06 and 6.74 mg/kg for ST, SP and S, respectively). The honey accumulated in the hive for the three groups evaluated with different stay times in the hive presented average HMF (mg/kg) of 4.9; 7.02; 6.79 and 9.9, for the initial sampling, 30, 60 and 90 days of residence, respectively, detecting significant differences (P<0.05) between the initial sampling, the 30 and 60 days and the final sampling. This trend did not change depending on the location of the hives. No differences were observed (P=0.269) in humidity according to the length of time the average rise remained (17.2%, 17.0%, 16.8% and 17.4% for the initial sampling, 30, 60 and 90 days of storage, respectively). The color of the honey increased over time (P<0.05), reaching values of 16.1; 20.07; 22.26 and 25.5 mm Pfund, for the initial sampling, 30, 60 and 90 days of storage, respectively, being independent of the location of the hives. The location of the hives modified humidity and color, but not HMF levels. As the storage time of the honey in the half-stores progressed, regardless of its location, the color and HMF values increased.