Author(s):
Dias, Rita Alvarenga Vieira 
Date: 2011
Persistent ID: http://hdl.handle.net/10400.5/4202
Origin: Repositório da UTL
Subject(s): fruit juices; heat treatment; storage; quality; shelf life
Document details
Sumos de fruta naturais: características físico-químicas e sensoriais
Description
Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia Considering the market’s potential growth of the natural fruit juices, this paper focuses on the study of four of these products. Since the microbiological quality of these juices is guaranteed, this work concentrates on the study of the physical, chemical and sensory characteristics of the juices. It was intended to assess the impact of the thermal shock and the cooling time of storage on the quality of the juice. For this study we analyzed four C-Optima juices (Mild Orange, Tropical Orange, Strawberry Banana and Red Berries). The samples were analyzed before and after the pasteurization and after 7, 14, 21, 28 and 35 days of refrigerated storage for the following parameters: pH, acidity, soluble solids, CIELab color and viscosity. The analysis of the results shows that the most significant change concerning physical and chemical characteristics of the analyzed juices is due to thermal shock. The pasteurization treatment causes some changes in the CIELab color parameters. There are no significant change color in general samples of Mild Tropical Orange and Orange; however the samples of Red Berries Strawberry Banana become discolored. In general, the physical and chemical changes occurring during storage are not perceived sensorily, which reinforces the idea that the shelf life proposed by the industry is designed with a large margin of time.
Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia Considering the market’s potential growth of the natural fruit juices, this paper focuses on the study of four of these products. Since the microbiological quality of these juices is guaranteed, this work concentrates on the study of the physical, chemical and sensory characteristics of the juices. It was intended to assess the impact of the thermal shock and the cooling time of storage on the quality of the juice. For this study we analyzed four C-Optima juices (Mild Orange, Tropical Orange, Strawberry Banana and Red Berries). The samples were analyzed before and after the pasteurization and after 7, 14, 21, 28 and 35 days of refrigerated storage for the following parameters: pH, acidity, soluble solids, CIELab color and viscosity. The analysis of the results shows that the most significant change concerning physical and chemical characteristics of the analyzed juices is due to thermal shock. The pasteurization treatment causes some changes in the CIELab color parameters. There are no significant change color in general samples of Mild Tropical Orange and Orange; however the samples of Red Berries Strawberry Banana become discolored. In general, the physical and chemical changes occurring during storage are not perceived sensorily, which reinforces the idea that the shelf life proposed by the industry is designed with a large margin of time.
Document Type
Master Thesis
Language Portuguese
Advisor(s) Martins, Margarida Moldão; Oliveira, Sara
Language Portuguese
Advisor(s) Martins, Margarida Moldão; Oliveira, Sara
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