In this work, a protocol for the formulation of an enzyme concentrated product to be applied in fruit juice treatment is described. Downstream processing conditions for the recovery and concentration of pectinases produced by the new strain Aspergillus niger LB-02-SF in solid state cultivation were assessed. The solid-liquid ratio in the extraction step of pectinases recovery from the cultivated media was evaluated and the highest activity was obtained with a solid-liquid ratio of 1:10. The crude extract was concentrated by ultrafiltration and the total pectinase (TP) activity was 73.6-fold concentrated in relation to the crude extract, and a final TP titer of 663 U mL -1 was obtained with 73.7% of recovery yield. KCl and different glycerol concentrations were added to the concentrated extract and the stability of pectinases during the storage at 5°C for 59 weeks was tested. The formulation with 50% w/w glycerol was applied to the treatment of apple and grape juices and the results of these tests were statistically comparable to those obtained with two high-quality commercial preparations.

RESUMO-Pectinases foram produzidas em meio sólido, em biorreator de tambor rotativo, por Aspergillus niger, extraídas em água e concentradas por ultrafiltração. A atividade enzimática em função da temperatura e pH de reação mostraram valores ótimos em pH 4,0 e 60 o C. No ensaio de estabilidade frente à temperatura, as enzimas apresentaram atividades relativas de 76,1 e 19,5% após 1h de incubação a 50 e 60 o C, respectivamente. No tratamento enzimático de suco de uva, o desempenho da preparação experimental foi comparado ao de enzimas comerciais. Todas as preparações testadas mostraram efeito positivo semelhante na redução de sólidos insolúveis, viscosidade, turbidez e aumento do grau de clarificação do suco, com ganho significativo em relação à amostra sem adição de enzimas. O teor de polifenóis totais nos sucos tratados com as enzimas comerciais foi reduzido em torno de 20%, enquanto a preparação experimental não apresentou diferença significativa em relação ao suco controle, revelando seu grande potencial de aplicação no processamento de sucos de frutas.