Phenolic profile and physicochemical characterization of quince (Cydonia oblonga Mill) fruits at different maturity index

The ripening of fruits is a determinant factor on the composition of phytochemical compounds such as phenolic compounds. In this study the phenolic profile of quince fruits was determined as a function of its maturity index. Based on the total soluble solids (TSS) and the acidity (TA) of the fruits, four maturity indexes were established (12.55, 14.56, 21.86 and 24.77), using the ratio of TSS/TA. The phenolic profile of quince fruits with different maturity indexes were obtained by a reversed-phase HPLC-DAD and HPLC-DAD/MS. A PCA loading plot was generated to explain the relationship between physicochemical parameters and the phenolic compounds. The phenolic compounds identified in the quince fruits were 3-0-caffeoylquinic acid, catechin, 4-0-caffeoylquinic acid, 5-0-caffeoylquinic acid, coumaric acid, quercetin-3-0-rutinoside and quercetin-3-0-glycosides. The maturity index increase caused in general a reduction of phenolic compounds, these compounds were also influenced by pH and acidity of fruits. Quince is a valuable source of natural phenolic antioxidants, and can be used as raw material to elaborate diverse food products, providing important functional properties

In vitro bioaccessibility of health-related compounds from beverages based on fruit juice, milk or soymilk: Influence of food matrix and processing

La present tesi doctoral s’ha centrat en avaluar la digestibilitat i la bioaccessibilitat in vitro de compostos bioactius hidròfils (vitamina C, compostos fenòlics i isoflavones) i lipòfils (carotenoids) en begudes elaborades a base de sucs de fruites, llet o llet de soja, així com en la determinació de la influència de la matriu alimentària (aigua, llet i llet de soja) i del processat (pulsos elèctrics d’alta intensitat de camp [HIPEF], altes pressions hidrostàtiques [HPP] i tractament tèrmic [TT]) sobre la bioaccessibilitat d’aquests compostos. La digestió gàstrica va millorar la concentració d’alguns dels constituents bioactius, com els compostos fenòlics i les isoflavones. No obstant, es van observar pèrdues significatives en tots els components bioactius analitzats durant la digestió intestinal. Els compostos bioactius hidròfils van ser més bioaccessibles en les matrius que contenien aigua i llet de soja, mentre que la matriu de llet va millorar la bioaccessibilitat dels compostos lipòfils. Les tecnologies no tèrmiques (HIPEF i HPP) van ser més efectives que el TT per preservar la concentració i la bioaccessibilitat de la majoria dels compostos bioactius analitzats. Els resultats han demostrat que la bioaccessibilitat dels constituents bioactius de les begudes va ser modulada tant per la matriu alimentària com pel processat.This research was focused on evaluating the in vitro digestibility and bioaccessibility of hydrophilic (vitamin C, phenolic compounds and isoflavones) and lipophilic bioactive compounds (carotenoids) of fruit juice-, milk-, or soymilk-based beverages; and on determining the influence of food matrix (water, milk and soymilk) and processing (high-intensity pulsed electric fields [HIPEF], high-pressure processing [HPP] and thermal treatment [TT]) on the bioaccessibility of these constituents. Gastric digestion improved the concentration of some bioactive constituents, such as phenolic compounds and isoflavones. However, significant losses in the concentration of all the analyzed substances during the small intestinal digestion were observed. Hydrophilic bioactive compounds showed their highest bioaccessibility in matrices containing water and soymilk, while a milk matrix improved the bioaccessibility of lipophilic substances. Non-thermal technologies (HIPEF and HPP) were more effective than TT to preserve the bioaccessibility of most of the analyzed compounds. Results showed that both food matrix and processing modulated the in vitro bioaccessibility of bioactive compounds from blended beverages.La presente tesis doctoral se centró en evaluar la digestibilidad y la bioaccesibilidad in vitro de compuestos bioactivos hidrofílicos (vitamina C, compuestos fenólicos e isoflavonas) y lipofílicos (carotenoides) en bebidas elaboradas a base de zumos de frutas, leche o leche de soja; así como en determinar la influencia de la matriz alimentaria (agua, leche o leche de soja) y del procesado de alimentos (pulsos eléctricos de alta intensidad de campo [HIPEF], altas presiones hidrostáticas [HPP] y tratamiento térmico [TT]) sobre la bioaccesibilidad de estos compuestos. La digestión gástrica incrementó la concentración de algunos constituyentes bioactivos, tales como compuestos fenólicos e isoflavonas. Sin embargo, se observaron pérdidas significativas en todos los compuestos bioactivos analizados durante la digestión intestinal. Los compuestos bioactivos hidrofílicos mostraron su mayor bioaccesibilidad en matrices conteniendo agua y leche de soja, mientras que, la matriz de leche mejoró la bioaccesibilidad de compuestos lipofílicos. Las tecnologías no térmicas (HIPEF y HPP) fueron más efectivas que el TT para preservar la bioaccesibilidad de la mayoría de los compuestos bioactivos analizados. Los resultados mostraron que tanto la matriz alimentaria como el procesamiento modularon la bioaccesibilidad in vitro de los compuestos bioactivos presentes en bebidas mixtas