Caracterização físico-química e microbiológica de tomate cereja (Lycopersicum esculentum var. cerasiforme) minimamente processado submetido a diferentes tratamentos de sanitização

• Ano de defesa: 2013
• Autor(a) principal: José, Jackline Freitas Brilhante de São
• Orientador(a): Andrade, Nélio José de
• Banca de defesa: Peña, Wilmer Edgard Luera , Bernardes, Patrícia Campos
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Ciência e Tecnologia de Alimentos
• Departamento: Ciência de Alimentos; Tecnologia de Alimentos; Engenharia de Alimentos
• País: BR
• Palavras-chave em Português: Sanitização; Processamento mínimo; Tomate cereja; Ultrassom
• Palavras-chave em Inglês: Sanitizers; Minimal processing; Cherry tomatoes; Ultrasound
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS
• Link de acesso: http://locus.ufv.br/handle/123456789/475

The sanitizing step is essential to contribute to safety and extension of shelf life of fruits and vegetables. This study aimed to evaluate the effect of treatment with ultrasound (US), chlorinated water (DCS), detergent-based surfactants (DET), lactic acid (LA) and silver nanoparticles (NP) on the inactivation of Salmonella enterica Enteritidis cells adhered to the surface of cherry tomato and the effect of these different sanitization treatments on natural microbiota contaminant and physicochemical characteristics of cherry tomatoes stored at 7 °C for 10 days. The evaluation of the natural microbiota of cherry tomato indicated no Salmonella sp., and for mesophilic aerobic, yeasts and molds, lactic acid bacteria, Pseudomonas sp., coliforms at 35 °C and psychrotrophic aerobic equal to 4.06, 4.30, 3.41, 2.78, 4.28, 2,99 log CFU g-1, respectively. The average surface roughness of cherry tomato was equal to 2.66 μm which indicated the presence of surface irregularities that could accommodate micro-organisms. Agreement with assessments of qualitative and quantitative hydrophocity, the surface cherry tomato was considered hydrophobic and S. Enteritidis was considered hydrophilic. The adhesion process of S. Enteritidis was thermodynamically unfavorable in the cherry tomato surface, and yet, after inoculation the number of adherent cells was 6.50 log CFU g-1. No significant difference (p>0.05) was observed between treatments with DCS, AL, US, US and US + NP + DET that presented bacterial removal among 1.54 and 1.60 log CFU g-1, respectively. The best results were observed after treatment with NP and US + AL that reduced 2.29 and 2.37 log CFU g-1 of the pathogen population, respectively. These solutions sanitizers after use, offered no risk of cross contamination. The scanning electron microscopy showed adherence of S. Enteritidis on the surface of cherry tomatoes and removal of cells after sanitization treatments. The transmission electron microscopy revealed that treatment of US + AL, NP and US promoted disruption of bacterial capsule, and on the first treatment was observed breakage of cell membrane. Structure and size of the NP after association with US were modified and this may have influenced the less pronounced effect of cell inactivation. Among the treatments evaluated in this study, there was a greater reduction of count of S. Enteritidis after the use of silver nanoparticles and lactic acid associated with ultrasound. Regarding the assessment of the effect of treatments on natural microbiota of cherry tomato and it was observed that among the treatments, treatments with 1% lactic acid, silver nanoparticles 6 mg L-1 associated or not with US had the largest reduction of micro-organisms evaluated. There was no significant difference in the values of titratable acidity, pH, soluble solids, instrumental color, firmness, lycopene and beta-carotene content among treatments in cherry tomato. The content of ascorbic acid was changed among treatments and during storage. These results indicate that the treatments have the potential for use in sanitizing cherry tomatoes.