Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.5/3083
Título: Polpas de maçã estabilizadas pela adição de aditivos. Impacto da componente bioactiva
Autor: Bairinhas, Marisa Alexandra Vitorino
Orientador: Martins, Margarida Moldão
Palavras-chave: apple pulp
bioactive compounds
sensory analysis
physico-chemical stabilization
polpa de maçã
compostos bioactivos
caracterização fisico-quimica
estabilização
Data de Defesa: 2010
Editora: ISA
Resumo: Ever since prehistoric times the man has been diversifying their diet and constantly improving the techniques of food preservation. Nowadays advances are such that the consumer can have a variety of foods, with appealing sensory properties, a high nutritional value and contribute fully preserved to their health and well-being. The act of eating is no longer considered a mere caloric intake needed to maintain the metabolic activity of our body, therefore an alliance as arisen between the intake of nutrients of common foods and the functional foods that besides being healthy are also a source of pleasure. Given this growing health concern and the cult of functional food increasingly sought by consumers, the horticultural industry has suffered a major expansion over recent years. The consumption increase of fruit and vegetables is due, among other things, to the greater availability and better preparation of products in the market and also to the greater awareness by consumers of the important relationship between diet and health. The political and economic scenario that results of globalization makes the development of new products a key factor for business competitiveness by imposing a very fast market dynamic. The modern consumer demands innovative products, with convenience and adequate quality. The objective of this dissertation is to create a product that becomes an answer to the needs of the consumers and the food industry, a Fuji apple pulp stabilized by additives, which will provide a greater nutritional value to the product and a longer shelf life. This pulp will be enriched with antioxidants and dietary fiber and will undergo a study on the effects of de incorporation of additives on the bioactive compounds of the product. For this study the pulps will be under freezing conditions (-18ºC) during 36 days. The experiment was developed in several phases, the first one being the base formulation of the product, its constituents, and based on the results it was decided that the formulation would consist of: 5% pineapple, 5% lemon, 3% blackberry and 2% wheat bran. Two pulps were produced, one with apple, pineapple, blackberry and wheat bran; the other with apple, lemon, blackberry and wheat bran. The stabilization of the pulps was achieved through the use of two food additives: ascorbic acid and citric acid; and completed with a freezing process. This represented a second phase of the experiment, the formulation of the additives concentration. Physical, chemical and sensory analyses were carried out in order to achieve the characterization of the product and the acceptance levels of additives. The parameters evaluated during this phase were: CIE Lab colour, the measurements of dry matter, ash content, pH, total soluble solids, mineral content, water activity, fiber content, total phenols, acidity and ascorbic acid content. All the samples were submitted to sensory analyses. The results were statistically treated using RSM methodology through the statistical program Statistica 8.0. The third phase consisted on the optimization of the pulps formulation. The products were submitted to the same kind of characterization plus the study of the role that the fiber incorporation had on the pulps. The final results showed that the addition of 0,6% ascorbic acid and 0,4% citric acid makes it possible to obtain a pulp with better sensory acceptance and also chemically stable. The phenolic and fiber component of the pulps is very high which indicates that this might be a product with functional properties beyond the nutritional value. The fiber incorporation study showed that it enhances the nutritional value of the pulp. The fourth and final phase was the study of the antioxidant capacity of the final product (pulp with Fuji apple, pineapple (5%), blackberry (3%), wheat bran (2%), ascorbic acid (0,6%) and citric acid (0,4%)), which demonstrated the difference between the final pulp, with all its ingredients and a pulp with only one or two chosen ingredients. This allowed to perceive that this experiment culminated with the development of a product chemically safe, with good quality parameters, and functional properties, rich in fiber, mainly hemicelluloses, a component that promotes the regulation of gastrointestinal transit since they are not digestible by the human body. This product is also rich in minerals such as magnesium and potassium, and antioxidants.
Descrição: Mestrado em Engenharia Alimentar - Qualidade e Segurança Alimentar - Instituto Superior de Agronomia
URI: http://hdl.handle.net/10400.5/3083
Aparece nas colecções:BISA - Dissertações de Mestrado / Master Thesis

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