Abstract
Clarification is an important step in the fruit juices processing, because it has as result a noble product that assists to the consumer's new lifestyle. The objective of this work was to evaluate the best condition for the acerola pulp clarification through the processing with membranes, as well as the juice quality, being used a ultrafiltration module - Labscale TFF System of Millipore. The acerola pulp was centrifuged using a centrifuge FANEN, baby model 206 II - R, rotation of 50 rpm for 10 minutes, resulting in a normalized juice, due to limitations of the ultrafiltration equipment. Polissulfone membranes with cut-off 300, 100 and 5 kDa, with transmembrane pressures among 5 and 20 psi, and room temperature. The centrifugation did not cause significant variations in parameters such as soluble solids, total carbohydrates, reducing sugar, glucuronic acid, protein and vitamin C. However, it removes 100% cellulose and 60% suspension turbidity, which results in substantially improved color and clarity in comparison with the original juice, and did not affect the taste of the acerola juice. The ultrafiltration processes efficiency was evaluated using as parameters the permeated flux, the fouling and the rejection coefficient (R) of the compounds responsible to juice’s turbidity and nutritional value. The process of clarification by ultrafiltration was efficient in the removal of substances causing turbidity, which results in a particle free clear juice or pulp suspension. This can be proved, therefore, that in the best condition, the highest coefficient of rejection of reducing sugars (22.5%), the third highest rate of rejection of glucuronic acid (12.5%) and the sixth largest coefficient was observed rejection for total sugar (19.9%), this are some of the main substances responsible for turbidity in juices. The clarification in the best condition also resulted in a juice with excellent nutritional quality, as it showed the lowest coefficient of protein rejection (4.8%), the second coefficient lower rejection vitamin C (8.4%) and showed no rejection to total phenolic compounds.The best ultrafiltration condition, obtained using membrane of 300 kDa at 15 psi of transmembrane pressure, resulted in the biggest permeate flux, with the lesser fouling and excellent nutritional quality of the permeate.
