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Please use this identifier to cite or link to this item: http://hdl.handle.net/10400.5/1608

Title: Desenvolvimento de pasta de azeitona Negrinha de Freixo
Authors: Freire, Soraia Alexandra da Silva
Advisor: Martins, Margarida Gomes Moldão
Keywords: olive paste
new products
Negrinha de Freixo olives
pasta de azeitona
novos produtos
azeitona Negrinha de Freixo
Issue Date: 2009
Abstract: The Portuguese olive industry often faces difficulties in finding added value produces for the surplus production and for low size or physically damaged raw materials. Olive pastes may be an interesting alternative to use this kind of raw material, helping companies to minimize losses and reduce the economic and environmental impact. Simultaneously to answer to this challenge and to the modern consumer demand of innovative products, the present study intended to develop an olive paste using as raw material fruits from a regional variety, Negrinha de Freixo (PDO). In order to develop a new olive paste with higher sensorial and nutritional value, several commercial olive pastes bought in Portuguese market were studied. Five green pastes and four black pastes were purchased: PV – Casa da Prisca (green); PP – Casa da Prisca (black) ; M – Maçarico; GV- Gallo(green); D – Despensa; S- Sacla; SO – Santa Olaia; T – Tojeira; GP- Gallo (black). To be noted that a great part of this samples were collected in the gourmet market. Physical, chemical and sensory properties were assessed. Physical parameters evaluated were: color, texture and syneresis. CIELab parameters were evaluated by using a colorimeter and results were expressed as the calculated c* and h*. Texture was determined by performing a TPA test using a TAXT2 texture analyser. Texture measurements were taken as firmness (maximum force attained), cohesiveness and adhesiveness. Chemical parameters analysed were: pH, moisture content, total and volatile acidities, total phenols, fat content and ash. Descriptive and preference sensory tests were performed in the sensory laboratory of the Department of Food Science and Technology, ISA/UTL. The sensory evaluation was performed by a total of ten semi-trained judges (food engineering students and staff). All of them were non-smokers and their age ranged from 21 to 68 years old. The room, at 20 °C, was equipped with six isolated sensory booths. Panellists performed a descriptive test and were asked to analyse the samples for: olive taste, off taste, spreadability, homogeneity, particle size and general appearance. Sensory test results were subjected to the Friedman test. Physical, chemical and sensory results were submitted to the multivariate analysis, Principal Component (PCA) and Cluster analysis (CA) using “Statistica” v. 6.1 software from Statsoft,Inc. As the variability of the results was too high It was not possible to establish a characteristic profile for this kind of products. The principal factors of differentiation between samples are the texture parameters. The two samples with higher score in descriptivesensorial analysis are the Tojeira and Casa da Prisca (black). Those pastes are characterized by medium (c.a 1mm) to big particle size and marked olive taste. Aiming to improve the antioxidant value of the olive paste, fruits without elimination of oleuropein were used. However, the result is a product excessively bitter. So, sweetened olive fruits Negrinha de Freixo were used as raw material to produce the new paste, having as guide lines, the characteristics of the commercial preferred pastes. The formulation of the new product includes the same ingredients of Tojeira paste (olives, garlic and oregano) however the Tojeira paste, and all of others commercial samples studied include the addition of olive oil that was not necessary in the new paste, because Negrinha de Freixo used as raw material has a fat content high enough. The developed paste was characterized for the all the parameters analyzed for the commercial ones and microbial count for molds, yeasts, mesophiles and psychrophiles. All the sample of developed paste showed no microbial count, indicating that it is a stable product. This paste presents a lower salt content than the commercial pastes with higher sensorial score and was chosen by 80% of the tasters.
Description: Mestrado em Engenharia Alimentar - Qualidade e Segurança Alimentar - Instituto Superior de Agronomia
URI: http://hdl.handle.net/10400.5/1608
Appears in Collections:BISA - Dissertações de Mestrado / Master Thesis

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