Roca López-Cepero, MaríaHerrera Jiménez, Marta2024-09-102024-09-1020242024-06-28https://hdl.handle.net/10433/21671Programa de Doctorado en Biotecnología, Ingeniería y Tecnología Química Línea de Investigación: Biotecnología en la Agricultura, el Medioambiente, la Industria y la Alimentación Clave Programa: DBI Código Línea: 109In recent years there has been a great increase in the use of food colors in food industry, although their use started centuries back. It is estimated that the food coloring industry market will continue to grow at a great rate in the coming years. One of the most commonly used colors today is green, due to its correlation with natural foods, and consequently healthier products. This scenario has led to the emergence of new sources of green color and new techniques to obtain it, but there is a lack of information about the complete composition and the formulation of these new green colors. In the present thesis, in Chapter 1, an experimental study was carried out, in which analysis of the different alternatives to obtain green color in commercial foods, focusing on the Clean Label trend and the new natural color, was performed. The obtained results have shown differences between the declared colors in the product labels and the real components present in the foods, which has shown the scarce knowledge regarding these substances. Regarding natural (E140) and semi-synthetic (E141) chlorophyll-based green food colors currently authorized in Europe, there is a lack of information on their digestion and metabolism, due to the fact that in the pioneer studies it was established that chlorophyll-derived compounds were not absorbable. However, in recent years it has been shown not only that they can be absorbed, but also that they can be accumulated in different organs and tissues (Egner et al., 2000; Viera et al., 2018). In the development of this thesis, different parameters and key steps during in vitro digestion of chlorophylls have been studied in Chapter 2, giving as a result an adaptation of the standardized INFOGEST 2.0 in vitro digestion protocol to chlorophylls. This adaptation of the in vitro protocol has allowed the study of the bioaccessibility of foods rich in natural chlorophyll and the interaction and influence of the food composition on this process in Chapter 3. Thus, salt content has been stated to play an essential role on chlorophyll stability during digestion. Moreover, the bioaccessibility of the green colors authorized in Europe E140ii, E141ii and three commercial food colorings have been assessed in Chapter 4 using the adapted protocol, leading to the conclusion that E141i colorants present higher digestive stability, but lower micellization ability than the E141ii and E140ii colorants and the food colorings. Previous studies have dealt with chlorophyll intestinal absorption (Egner et al., 2000; Ferruzzi and Blakeslee, 2007; Ferruzzi et al., 2002, Gomes et al., 2009), but there is a gap in the knowledge about the mechanisms and chemical specificity behind this transport. In this thesis, the study of the absorption of the main chlorophyll derivatives found in the authorized green food colors in Europe (E140 and E141) has been performed in Chapter 5, showing for the first time the transport mechanism for several chlorophyll derivatives found in the commercial chlorophyll colorants. In addition, the influence of the phytyl chain on chlorophyll transport inside the Caco-2 cell model has been also shown, demonstrating the higher ability for phytylated chlorophylls to be included in lipid micelles prior to absorption. Finally, several studies are arising showing the importance of the intestinal microbiota in the maintenance of the host physiology homeostasis, as well as its role in the metabolism of certain dietary components. Some of these studies have focused on analyzing the effects of dietary chlorophyll on the gut microbiota, mainly conducted in animal models, and using natural chlorophyll. In the current study, the interaction between the copper chlorophyll colorants authorized in Europe, E141ii and E141i, and the human microbiota has been in vitro studied for the first time in Chapter 6, using an in vitro model of colonic fermentation. This work has demonstrated the existence of an interaction between the colorants and the microorganisms that have been reflected in slight changes in microbial activity. Moreover, E141ii have shown more interaction/degradation with microorganisms, while E141i seemed to be less consumed/degraded.application/pdfesAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Biotecnologia de alimentosColorantes en la alimentacionCultivo celularBioquimica de pigmentos alimentariosdoctoral thesisopen access