Microbiological screening and biochemical analysis of the conservation rate of strawberries treated with the antimicrobial peptide Ctx(Ile21)-Ha and its analogues

• Grant number: 19/07438-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): July 01, 2019
• Effective date (End): June 30, 2020
• Field of knowledge: Agronomical Sciences - Food Science and Technology - Food Science
• Principal Investigator: Eduardo Festozo Vicente
• Grantee: Rafael Shoiti Souza Yokoo
• Host Institution: Faculdade de Ciências e Engenharia. Universidade Estadual Paulista (UNESP). Campus de Tupã. Tupã , SP, Brazil
• Associated research grant: 16/00446-7 - Application of antimicrobial peptides as new additives in animal nutrition, AP.JP

Abstract

The antimicrobial peptide Ctx(Ile21)-Ha, isolated from the skin secretion of the Hypsiboas albopunctatus frog, demonstrated, according to previous studies, biological activity against bacteria and fungi. The mechanism of action, unlike classic antibiotics, promotes a disturbance of the membrane of the attacked microorganisms, thus changing its permeability. Such a mechanism hinders the antibiotic resistance capacity of these pathogens. This fact makes this molecule a promising candidate in the fight against these microorganisms and also in the use in food preservation. Thus, the present project aims to synthesize, purify and characterize the antimicrobial peptide Ctx(Ile21)-Ha and its analogues, which will contain modifications in their primary sequence, in order to make it more selective to bacteria or fungi. Antifungal and antimicrobial tests will be carried out in parallel to the project to choose the peptide that presents the best biological activity. The object of studies of this project will be the strawberry, being its choice due to the fact of being a highly perishable fruit, non climacteric and also due to its great economic and social importance. For the conduction of the studies and verification of the application of the peptide will increase the shelf life of the strawberry, will be carried out analyzes of the effectiveness of the peptides by physicochemical and biochemical parameters such as pH, titratable acidity, loss of mass, brix, texture , respiratory rate, ratio (brix/acidity), visual and pigment analysis, as well as the enzymatic analysis of the enzymes pectinamethylesterase (PME) and polygalacturonase (PG) and chromatographic analyzes of sugars and vitamin C content in fruit samples, seeking differences in rates of deterioration or conservation of food. It is expected that, with the application of the peptide Ctx(Ile21)-Ha and its analogues, there will be a decrease or even inhibition of the microbial growth when compared to the strawberries without the treatment. The expected results should bring an increase in the quality and conservation of the product, increasing its shelf life.