Development and evaluation of a low erosive blackcurrant juice drink 2. Comparison with a conventional blackcurrant juice drink and orange juice

Objective: A previous study demonstrated that an experimental low pH blackcurrant juice drink with calcium was markedly less erosive to enamel both in situ and in vitro than orange juice. Further development of the experimental blackcurrant juice drink formula has occurred and the aims of the present studies were two fold. Firstly, to confirm the low erosivity of the modified formulation and secondly, to provide more comparative data with other acidic fruit drink products. Method: The study was a single centre, single blind, randomised placebo controlled 4 cell crossover design involving 12 healthy volunteers. The test drinks were orange juice, water, experimental blackcurrant juice drink with calcium and a proprietary blackcurrant juice drink. Enamel samples were retained in situ at the mid palatal regions using intraoral appliances and exposed to 250 ml volumes of the drinks 4 times per day during 15 working days. Measurements of enamel loss were made by profilometry. The same method was modelled in vitro. Results: By day 15 the mean losses of enamel in situ for orange juice, water, experimental blackcurrant juice drink with calcium and blackcurrant juice drink were 1.70, 0.05, 0.44 and 2.75 μm respectively. At all bar one measurement, the loss of enamel was significantly greater for all fruit drinks compared to water. Losses caused by the blackcurrant juice drink with calcium were significantly less than the other two fruit drinks at all time points. Losses of enamel by day 15 in the study in vitro were 13.02, 0.00, 1.78 and 39.02 μm respectively. The blackcurrant juice drink with calcium was not significantly different from water at days 3 and 6, otherwise all pairwise comparisons for differences between the 4 drinks at each time period were significant. Conclusions: The methodologies in situ and in vitro again appear to correlate in ranking the order of erosivity of drinks. The data particularly from the study in situ allude to the very low comparative erosivity of the further modified experimental blackcurrant juice drink with calcium and support the further development of such drinks for public consumption.