Produção de sucedâneos de cereais de pequeno almoço ricos em compostos bioativos a partir de subprodutos da indústria agroalimentar

• Author(s): Sales, Bruno Aguiar
• Date: 2012
• Persistent ID: http://hdl.handle.net/10400.5/5359
• Origin: Repositório da UTL
• Subject(s): breakfast cereals substitutes; extrusion-cooking; tomato pomace; chestnut flour; antioxidant activity
• Document Type: Master thesis
• Language: Portuguese
• Advisor(s): Barros, Sara Beirão da Costa Teixeira; Martins, Margarida Moldão
• Contributor(s): Repositório da Universidade de Lisboa

Description

Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia

The main objective of the present work is the development of a gluten-free breakfast cereals substitutes made from tomato pomace and chestnut flour. The breakfast cereals substitutes were produced in a Brabender single screw extruder with a circular die with a 3mm internal diameter. A central composite rotatable design was used to test the effect of different parameters on products characteristics. The independent factors were: barrel temperature (110-150oC); sample composition (10-50% of tomato pomace); screw speed (100-204 r.p.m). The tested dependent variables were color, expansion rate, texture, milk absorption ability, microstructure and antioxidant activity. The statistical analysis of the data showed that all the analyzed dependent variables were mainly affected by the mixture composition and the process temperature. Extrudates with higher chestnut flour concentration presented a darker color, high hardness and a continuous and dense structure. The extrudates with higher levels of tomato pomace presented a lighter color, low hardness and a brittle structure. Extrudates produced under higher temperatures showed a higher porous structure that led to a higher milk absorption capacity and to a higher breakdown on the hardness levels after milk immersion. Antioxidant activity of the extrudates was mainly affected by process temperatures, showing that extrudates processed at higher temperatures presented greater antioxidant activity.