Processing of Xoconostle fruit (Opuntia joconostle) juice for improving its commercialization using membrane filtration

The aim of this study was to propose a membrane process for processing of a native Mexican fruit with limitations for its commercialization. The clarification of Xoconostle juice was performed using a hollow fiber membrane. The operating conditions were determined (T=25 degrees C, Q(f)=58L/hr, TMP=138kPa); the process presented high productivities in terms of permeate flux (12.0-19.7kg/m(2)/hr). The proposed method achieved high retention of turbidity (87.50%); whereas low retentions of pH (0.98%), total soluble solids (10.17%), carbohydrates (33.17%), polyphenols (2.10%), betalains (5.52%), and antioxidant activity (15.74%) were observed. Finally, a clear juice (3.791.3 NTUs) was obtained with high antioxidant activity (21.40 +/- 1.1 TEAC), high phenolic (27.50 +/- 0.2 mg gallic acid/L) and betalain contents (18.80 +/- 0.6 mg/L). An enhancement on color properties was observed (redness grade, h degrees=10.14 +/- 2.0). Practical applicationsNowadays, the interest of food industry is focusing on the development of functional foods as well as looking for new valuable sources rich in bioactive compounds. Until now, many native Mexican fruits have not been processed in agro-food industry, that is, Xoconostle fruit is one of the natural products not strongly processed. The processing of its derivative products, as fresh juice, can offer benefits to exploit a bit more its well-known functional properties to human health. The enhancement of the quality of this natural juice preserving its nutritional and biological properties can be carried out using pressure-driven membrane processes. Based on (a) the high productivity of the applied methodology for juice processing, (b) the high removal of turbidity, (c) the enhancement of physical characteristics (colorimetric), and (d) the preservation of its natural chemical substances, the membrane filtration seems to be a good alternative to going further in the commercialization of the fruit.