Potencial de peptidases cisteínicas do purê de noni (Morinda citrifolia L.) na hidrólise de proteínas do glúten de trigo e avaliação de sua segurança alimentar

Abstract

Proteases are among the most important groups in the enzyme market, with applications in various industrial processes. Several reasons influence the use of proteases in the food industry. They can change chemical, physical, and biological properties, including reducing the toxic potential of some food proteins, such as gluten, whose intake is associated with activation of the immune response in intolerant individuals. Currently, enzymatic hydrolysis represents a more advantageous method for gluten detoxification in foods than chemical hydrolysis. However, plant proteases have not been extensively explored for this purpose. Previous studies have reported the presence of cysteine proteases in the aqueous extract of noni puree (Morinda citrifolia L.), named NPE, with milk-clotting activity and potential to be used in cheese production. The present work aimed to expand the investigation of its applications analyzing the potential of NPE in the hydrolysis of wheat gluten. Acute toxicity, repeated dose administration toxicity analysis (subchronic), and genotoxic effects were also evaluated regarding its use as a novel food ingredient. NPE was able to hydrolyze both gliadins and glutenins, and after 4 h of reaction, it reached a degree of hydrolysis (DH) of 24.40% (± 0.09) and 31.78% (± 1.28), respectively. NPE reduced in 96.80% (± 0.10) the intact gliadins content detectable by the R5 ELISA with DH of 24.4% (± 0.09) after 4 h. Fractionation of NPE by ionexchange chromatography (Source 30S) resulted in one unretained peak (P1) and only one retained peak (P2). Both peaks showed proteolytic activity, with P2 showing higher specific activity (5.96 ± 0.34 U/mg) than P1 (3.75 ± 0.16 U/mg). P1 and P2 displayed similar DH (p<0.05) in gliadins (9.31 ± 0.80% and 9.25 ± 0.37%, respectively). P1 showed better performance (p<0.05) in glutenin hydrolysis (10.68 ± 0.04%) compared to P2 (8.55 ± 0.39%). After the simulated digestibility test, it was verified that NPE proteins were susceptible to the action of gastrointestinal enzymes, pepsin, and trypsin. NPE did not show cytotoxicity by MTT assay and could not induce DNA breaks and micronucleus formation in murine fibroblasts. Animals orally treated with NPE once (80 or 160 mg/kg) or for 28 days (5, 10 or 20 mg/kg) did not show changes in body mass, hematological and biochemical parameters, relative weight, and histopathology of the organs analyzed, compared to control. These findings suggest that NPE is a promising candidate for use as a new safe food ingredient for the production of glutenfree foods.