Características físico-químicas do tomate submetido a esforço controlado de compressão

• Autor(a) principal: Oliveira, Gabriel Henrique Horta de
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3557
• topic: Danificação mecânica; Licopeno; Propriedades físicas; Mechanical damage; Lycopene; Physical properties; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA::ENGENHARIA DE PROCESSAMENTO DE PRODUTOS AGRICOLAS

The aim of this work was to evaluate the physical and chemical alterations due to the effect of a controlled force over tomato fruits stored at 15 and 25 ºC during 18 days, as well to study and model the fruits behavior during the relaxation test. Tomato fruits cv. Pizzadoro were used, obtained from a commercial plantation of Coimbra (MG) city area. A mass of 5 kg was used upon fifteen fruits inside of a wooden box of 23x20x20 cm, resulting in a weight per unit area of 12.5 g cm-2, simulating the real process that occurs in a commercial wooden box type "k". Textural analyses were made from compression, relaxation and puncture tests on the tomato fruits every two days of storage. Analysis of pH, total soluble solids and lycopene were also accomplished every two days. Weight loss and color evaluation of the tomatoes were made daily. To model the relaxation process, the Maxwell generalized model was used. Using the information gathered from the texture results, the following mechanical properties were obtained: force to obtain a specific deformation of 0.005 m, proportional deformity modulus and the required energy to deform the product through evaluation of force-deformation curve; penetration force of the tomato skin and the energy required to do so. According to the obtained results, it was concluded that: (a) The structural alterations caused by the induced compression on the tomato fruits significantly altered solely the penetration force of the tomato skin; (b) the Maxwell generalized model fitted to the observed data in all conditions utilized; (c) the mechanical properties studied significantly decreased during storage. The values obtained for firmness of fruits stored under the temperature of 15 ºC varied between 34.68 and 21.24 N; proportional deformity modulus between 40.62 and 24.99 MPa; energy, 79.86 to 50.92 mJ; periderm penetration force between 21.33 to 11.04 N and the energy to break it between 73.12 and 44.13 mJ. On the other hand, for fruits stored at 25 ºC, the firmness values obtained were between 32.96 and 19.79 N; proportional deformity modulus between 38.61 and 22.90 MPa; energy between 74.78 and 46.99 mJ; periderm penetration force between 22.76 and 11.18 N, and the values encountered for energy to break the periderm varied between 78.37 and 39.00 MPa; (d) weight loss varied significantly among control and treatment fruits and x during storage, being that stored fruits at 25 ºC obtained higher values of this parameter; (e) significant differences between control and treatment fruits were obtained for color total difference and colorimetric indices chroma and hue angle, at both temperatures; (f) lycopene content increased during the storage time, being that solely the fruits stored at 25 ºC presented differences among control and treated fruits. The values encountered varied between 2.25 and 145.17 μg g-1 and 3.30 and 95.01 μg g-1 for tomatoes stored at 15 e 25 ºC, respectively; and (g) the total soluble solid and pH values presented differences among control fruits and treated fruits stored under 25 ºC.