Application of nanoemulsions with essential oils as natural coatings for application in post-harvesting strawberry conservation

• Grant number: 18/24612-9
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): March 01, 2019
• Effective date (End): February 28, 2021
• Field of knowledge: Agronomical Sciences - Agricultural Engineering
• Principal Investigator: Marcos David Ferreira
• Grantee: Josemar Gonçalves de Oliveira Filho
• Home Institution: Embrapa Instrumentação Agropecuária. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA). Ministério da Agricultura, Pecuária e Abastecimento (Brasil). São Carlos , SP, Brazil

Abstract

Edible coatings, including active substances, can be used as an alternative to preserve fruits and vegetables during post-harvest. Essential oils (EOs) exhibit antimicrobial activity and by this characteristic have been proposed as natural fungicides.The use of nanoemulsions, as a method to disperse bioactive agents, is emerging as a potential tool for designing new coatings with optimum functionality. In this context, the objective is to evaluate the potential of EOs as natural fungicides and their presence in nanostructured coatings for application in quality maintenance and post-harvest conservation of strawberries, as a proposal to use natural agents of vegetable origin as active materials for coating fruits. The EOs of the species Green Mint (Mentha spicata), Peppermint (Mentha x piperita), Palmarosa (Cymbopogon martinii) and Pau-rosa (Aniba rosaeodora) will be obtained the chemical compositions will be evaluated by CG-SM and CG-FID, and the antifungal activity, in in vitro analyzes for the main post-harvest strawberry fungi. Compound coatings will be produced using hydroxypropylmethylcellulose (HPMC), nanoemulsified carnauba wax and cellulose nanocrystals and will be incorporated with EO which exhibits the highest antifungal activity in the in vitro tests. The coating and EO combinations which exhibit the best barrier properties and antifungal activity will be tested in vivo. Initially, the effect of EO coatings on the control of Rhizopus stolonifer and Botrytis cinerea on infected strawberries will be studied in order to evaluate the effect of coatings on the control of post-harvest diseases. The strawberries were then coated and evaluated during storage (0, 2, 4, 6, 8, 10 and 12 days) for soluble solids content, pH, titratable acidity, maturation index, concentration of anthocyanins, total phenols, antioxidant activity, total fungi count, aerobic mesophilic bacteria, coliform bacteria, visual fungal deterioration, strawberry volatile profile by GC-MS, and sensorial acceptance using a nine-point scale.