Sanitizantes alternativos na qualidade microbiológica, química e física de morangos (Fragaria x ananassa Duch) minimamente processados

• Autor(a) principal: Fernandes, Gislene Regina
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/473
• topic: Ultrassom; Morango; Sanitizantes; Ultrasound; Strawberry; Sanitizers; CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS

Strawberry is a pseudofruit highly consumed worldwide. However, its fragility demands special care from harvesting to marketing. Minimal processing may represent an alternative to extend the product`s shelf life. The sanitization is crutial to assure the microbiological safety and may impact on the sensory and nutritional quality of the final product. The objective of this study was to assess the efficacy of the ultrasound technique (US) coupled with the use of lactic acid in reducing Escherichia coli artificially added on strawberries cv Oso Grande. Additionally, assess the microbiological, physical and chemical properties of minimally processed strawberries were also evaluated. The strawberries were contaminated with E. coli and treated with 1) tap water (control), 2) 40 kHz Ultrasound (US), 3) US + dichloroisocyanurate (DCIS) 100 mg.L-1, 4) US + DCIS 50 mg.L-1, 5 ) US + Lactic Acid (LA) 1% 6) US + LA 2% 7) DCIS 100 mg.L-1, 8) DCIS 50 mg.L-1, 9) LA 1% and 10) LA 2%. The treatments that presented the best efficiency in reducing the microbial count (E. coli) were identified by using the Duncan multiple comparison test (p<0.05) and submitted to minimal processing. These samples were stored at 5 °C for 9 days and were analyzed for microbial counts, physical and chemical properties every 3 days. Samples treated with the combination of LA and US presented a higher reduction of E. coli. The LA treatment was more effective (p <0.05) in reducing the aerobic mesophilic count after the sanitization process, and a lower microbial count after 9 days of storage. The pH of samples sanitized with US + LA was slightly higher, 3.67 (p<0.05). Storage time presented a significant (p <0.05) influence on the counts of psychrotrophic bacteria and filamentous fungi and yeast, and the microbial counting was about 104 CFU after 9 days of storage. Storage time also presented a significant (p <0.05) effect on pH and weight loss, and for the instrumental color of strawberries, with increased the brightness and decreased °Hue and chromaticity. The mean content of soluble solids was 7.3 oBrix, titratable acidity 0.95 % of citric acid and firmness of 1.96 N did not present any significant changes in response to the sanitization procedure, storage period or due to the interaction between storage period and sanitization. Once a low microbial count, absence of Salmonella and non-significant changes on the physical and chemical properties of strawberries were attained, it is possible to assume that the minimal processing conditions used in this study were adequate for maintaining the quality and safety of strawberries. Further studies should assess the effect of this type of minimal processing on the sensory and nutritional properties of strawberries.