Peptídeos antimicrobianos produzidos com a hidrólise de proteínas do glúten por proteases vegetais aumentam o tempo de prateleira do pão

Abstract

Bread is one of the most consumed food products in the world and its contamination by fungi can generate economic losses and consumers dissatisfaction. The most common way to extend bread's shelf time is the use of chemical preservatives. Antimicrobial peptides (AMPs) have been reported as a promising alternative to these preservatives. The present study aimed to identify, characterize and synthesize AMPs, generated from the hydrolysis of gluten proteins, with antifungal activity. The gluten proteins were hydrolyzed by the proteolytic fractions of the latex of Calotropis procera, Cryptostegia grandiflora and Carica papaya generating three hydrolysates that exhibited activity against all six fungi tested. Breads were produced with the hydrolysates and analyzed for physical parameters. The averages of specific volume and expansion factor were not affected with the addition of hydrolysates, while the number of alveoli was favored and the hardness was partially affected with the addition of 0.2 and 0.3 g kg-1. The hydrolysates extended the shelf life of the bread by at least three days. From the three hydrolysates, 31 peptides were sequenced and characterized based on criteria attributed to AMPs, and then the four best peptides were synthesized. Antifungal assays against Penicillium sp showed that synthetic peptides were effective in inhibiting fungal growth. Fluorescence and scanning electron microscopy analysis showed that all hydrolysates and synthetic peptides were able to induce damage to the fungal plasma membrane. All results corroborate with the potential of peptides from gluten as natural preservatives to inhibit fungal growth and extend the shelf life of bread.