Evaluation of acrylamide in foods and development of some strategies for its reduction

Abstract

A mis directoras, Ana Andrés y Ana Heredia por confiar en mí y transmitirme vuestros conocimientos y forma de trabajar tan rigurosa y modélica.A mi familia, y ahí te incluyo a ti Fernan, por vuestro apoyo incondicional, por enseñarme a esforzarme y no rendirme y por contagiar la actitud positiva para afrontar y resolver los problemas.A mi prima Mª José, por meterme el gusanillo del mundo de la ciencia. Victoria, Ruth M., Susana, Laura C., Salva, Irene, Eva, Ester, Andrea, Carolina, Quim, Raúl, Bruno, Sara, Laura A mis compañeros de laboratorio y de planta L., Ruth, Virginia que hemos pasado tanto juntos, por las risas, los buenos momentos además de los consejos y apoyo. A Victoria y Ester, por el tiempo que hemos compartido en Cesena, hicisteis que todo fuera más fácil y divertido con vosotras allí.Al grupo del Prof. Marco Dalla Rosa (Ula, Fede, Virginia, Cinzia, Silvia, Nicolò Santina, Pietro) In the last decade, both health authorities and the scientific community have made great efforts in scientifically establishing limits of toxicity as well as exploring strategies aimed at reducing acrylamide formation. The purpose of this doctoral thesis is framed in this last sense. On the one hand, our work has been focused on searching new strategies for acrylamide mitigation, in two different types of food: fried potatoes and battered products. The effect of an emerging frying technique, named air frying, as well as pre-frying treatments, were studied in fried potatoes. In the case of batters however, the strategy consisted in modifying their composition by adding a hydrocolloid, chitosan, after having tested its potential in model systems. Furthermore, the effect of chitosan addition on the physical properties of the batter formulations and on the quality of the final product was evaluated.Finally, acrylamide bioaccessibility of the food products with the highest acrylamide content was addressed. These food products were subjected to an in vitro gastrointestinal simulation in order to study how acrylamide content progressed throughout the digestion process.Results showed that air fried potatoes as well as chitosan addition to batter formulations reduced the formation of acrylamide by about 90 and 60 %, respectively. The modification of the characteristics of chitosan (molecular weight and deacetylation degree) conditioned its ability to reduce the formation of acrylamide. Furthermore, the incorporation of chitosan to batters reduced the absorption of fat during frying. Chitosan increased viscosity and consistency of batters but, the color and texture of the fried products were not significantly altered.The total replacement of wheat flour by rice flour allowed to obtain gluten-free batters with similar viscosity, when adding chitosan. This new formulation could be adjusted to gluten-free battered products.The simulation of in vitro digestion showed a significant increment of acrylamide after the gastric stage in a wide range of foods. However, acrylamide bioaccessibility (after the intestinal stage) was red...