Banca de DEFESA: SILVIA VALERIA DE MEDEIROS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : SILVIA VALERIA DE MEDEIROS
DATE: 25/03/2020
TIME: 14:00
LOCAL: Sala de aula 07 do Departamento de Nutrição
TITLE:

Effect of chitosan and bentonite films on postharvest conservation of prata bananas (Musa spp.)

KEY WORDS:

Polysaccharides; edible coatings; post-harvest quality; fruits; clay.

PAGES: 126
BIG AREA: Ciências da Saúde
AREA: Nutrição
SUMMARY:

Banana culture in Brazil plays an important economic role and bananas are the most consumed fruit in Brazil and in the world. However, about 40% of production is lost due to rapid ripening. Studies with edible coatings based on biodegradable polymers, such as chitosan, are important to prolong the shelf life of fruits. This work aimed to evaluate the postharvest conservation of prata bananas coated with biopolymeric and clay-biopolymeric films. The first stage characterized the films and the second evaluated the post-harvest conservation of bananas coated with films with better physical characteristics. Six films were prepared and characterized: three biopolymeric, with concentrations of chitosan at 0,5, 1,0 and 1,5% and fixed concentration of glycerol (15%), and three clay-biopolymeric ones, prepared with the addition of bentonite ( 0,2%) to the formulations of biopolymeric films - FBP1, FBP2 and FBP3; FABP1, FABP2 and FABP3, respectively. The films were analyzed for morphology, chemical composition, microstructure of the surface, disposition of bentonite in the polymeric matrix, thermal decomposition and permeability to water vapor. The evaluation of post-harvest conservation of coated fruits was carried out with physical-chemical, physical, microbiological and sensory analysis, in addition to photographic and disease incidence records, during 12 days of storage at room temperature. The characterization of the films showed greater surface uniformity in the biopolymeric films and the presence of roughness on the surface of the biopolymeric clay, attested to the presence of bentonite in the biopolymeric clay films and evidenced predominantly amorphous material without noticeable changes with the insertion of the bentonite. Vibrational bands characteristic of bonds and groups existing in chitosan were observed in biopolymeric films, in addition to those characteristics of bonds and groups existing in the structure of bentonite, in clay-biopolymeric films. The addition of clay resulted in greater residue formation after thermal decomposition of the material and enhanced the barrier property against water vapor permeability. The clay-biopolymeric film with the highest concentration of chitosan showed greater thickness, less permeability to water vapor and less loss of mass related to the thermal decomposition of the polymer. The bananas were coated with chitosan films at 1,0%, without (BP1,0%) and with clay (ABP1,0%) and 1,5%, without (BP1,5%) and with clay (ABP1,5%) and compared to the control group. Bananas in the BP1,5% group had significantly lower total soluble solids and acidity content (p < 0,05) than the control. The BP1,5% and ABP1,5% groups had significantly lower pulp/peel ratio (p < 0,05) than the control, and higher firmness values after the third day of storage. The results showed that the ABP1,5% and BP1,5% groups not only delayed ripening, but increased the postharvest life of bananas by 2 and 4 days, respectively; results that corroborate with the photographic records. It was found that BP1.5% kept bananas with mold and yeast count within microbiological standards, throughout storage. The films did not alter the sensory characteristics of the banana. Therefore, 1,5% chitosan films, with and without bentonite, were more efficient in delaying ripening and prolonging the shelf life of bananas.

BANKING MEMBERS:
Externa à Instituição - JAILANE DE SOUZA AQUINO - UFPB
Presidente - 3211846 - KARLA SUZANNE FLORENTINO DA SILVA CHAVES DAMASCENO
Externo à Instituição - ROBERTO RODRIGUES CUNHA LIMA
Externo ao Programa - 1149328 - VALTER JOSE FERNANDES JUNIOR