Noni (Morinda citrifolia L.) fruit as a new source of milk-clotting cysteine proteases

Publication date: Available online 8 October 2019Source: Food Research InternationalAuthor(s): Vilmara Albuquerque de Farias, Amanda Dias da Rocha Lima, Andréa Santos Costa, Cléverson Diniz T. de Freitas, Idila Maria da Silva Araújo, Deborah dos Santos Garruti, Evânia Altina Teixeira de Figueiredo, Hermógenes David de OliveiraAbstractThis work reports the characterisation of caseinolytic and milk-clotting activities of proteases extracted from ripe fruits of Morinda citrifolia L., as a potential of their use in cheese production. Noni puree extract (NPE) was obtained by homogenising the fresh puree in 150 mM NaCl/50 mM sodium phosphate buffer (pH 7.0). The resulting protein concentration was of 0.367 ± 0.006 mg/mL, and an electrophoretic profile of the extract revealed protein bands ranging from 14 to 55 kDa. The proteolytic activity of NPE was higher when the extract had been previously incubated at pH 6.0 (8.859 ± 0.216 U/mg), whereas the optimum caseinolytic activity was observed at 50 °C. Noni puree proteases were strongly (98%) inhibited by iodoacetamide and E-64, suggesting the presence of only cysteine proteases in the crude extract. NPE proteases showed a milk-clotting activity (MCA) of 238.80 ± 5.29 U/mL, a specific milk-clotting activity (SMCA) of 9950.17 ± 220.74 U/mg, and an SMCA/PA ratio of 1124.31 ± 24.94, this last being comparable to those of commercial calf rennet. The cheese manufactured using NPE presented brittle and soft texture, high humi...
Source: Food Research International - Category: Food Science Source Type: research