Estudio de la digestibilidad in vitro del aislado proteico de pan liofilizado tipo tapado elaborado con masa madre de distintos tiempos de fermentación

Abstract

Bread, an ancestral and globally consumed food, has evolved with industrialization, replacing natural yeasts with industrial yeasts and chemical agents. This change has renewed interest in natural fermentation, sought by consumers informed about nutritional quality and its impact on health. Sourdough, an ancient fermentation technique, improves the shelf life, nutritional value, and texture of wheat bread, thanks to cultures of lactic acid bacteria or yeasts. Protein isolates were obtained from freeze-dried tapado bread, made with sourdough of different fermentation times. Protein digestibility was evaluated in vitro through simulated gastric and intestinal digestion. Protein concentrates were determined by isoelectric precipitation and quantified using the Dumas method. Protein quality was assessed with SDS-PAGE electrophoresis and the amino acid profile was determined using high-performance liquid chromatography. The study investigates the in vitro digestibility of protein isolate from freeze-dried tapado bread, evaluating the effect of different sourdough fermentation times. A slight influence of pH on protein yield was observed, while fermentation time significantly affected the amount of protein extract obtained. SDS-PAGE electrophoresis revealed differences in protein profile and the amount of soluble proteins, with complete digestion of proteins occurring on the fifteenth day. High-performance liquid chromatography revealed a significant reduction in amino acids such as glutamic acid, glutenin, among others, and an increase in amino acids such as proline and alanine.