Use of sodium bentonite as a pretreatment to the tangential microfiltration of Castilla's blackberry wine Rubus glaucus Benth

Abstract

This research studied the influence of clarification techniques of Castilla's blackberry wine Rubus glaucus Benth on its chromaticity, turbidity and yields of the process. Initially, the tangential microfiltration (TMF) at three different working pressures (1.5, 2.0 and 2.5 bar) and then the treatment of the feed with sodium bentonite prior the filtration. The TMF at 1.5 bar obtained the highest Volume Reduction Factor (VRF) and the best performance, standardizing the pressure conditions for the TMF with pretreatment. According the pH, the optimum quantity of flocculant added to each batch of wine was established at 9 grams, carried to rest at 6 ° C (6, 12 and 24 hours), obtaining 610 ± 38 g for the highest proportion of turbid in the batch of 6 hours of rest, product of a greater unstable catch by the clarifier. The TMF of the pretreated batches indicated representative improvements in the yield, up to 40%. All the analyzed microfiltered wine samples with and without pretreatment achieved a turbidity less than 2 NTU, accomplishing with the quality criterion of "bright red", concluding that the TMF separately and with pretreatment improve the quality of the product, but they can cause color deterioration.