Contribution to the quality evaluation and the water activity prediction of La Palma Island honey

Abstract

The quality of 13 home-produced samples of honey from La Palma Island (Canary Islands, Spain) was evaluated. The samples exhibited adequate maturity as shown by the moisture mean content (174%). The mean pH was 3.89. The mean total ash content was 0.17% (0.06-0.46%) and the mean electrical conductivity was 4.88 10(4)s/cm, ranging from 2.86 10(4)s/cm to 7.32 10(4)s/cm. Both are typical values for floral honeys. Since the hydroxymethylfurfural content was low and the diastase activity value was high, a good freshness grade was evident. All samples displayed a water activity (aw) within a narrow range of values (0.570-0.622). Finally, we have obtained an equation for predicting the water activity, which takes the form Awc = 0.35732 + 0.01349 moisture/100 g of honey with a R-2 coefficient of 0.6541. This model allows the prediction of the water activity for La Palma Island honey in a reasonable, direct and simple way.