Application of Lactose-Free Whey Protein to Greek Yogurts: Potential Health Benefits and Impact on Rheological Aspects and Sensory Attributes.

The application of ß-galactosidase in the fermentation of milk enables the acquirement of lower levels of lactose that are tolerated by lactose maldigesters and can reduce the nutritional consequences of avoiding dairy products. The present study evaluated the viability of the fortification of lactose-free prebiotic Greek yogurt formulas with whey protein concentrate (WPC). Two rotational central composite designs (RCCDs) were applied: one to perform the hydrolysis of the whey protein concentrate and another for the yogurt formulations (α = 2 with 2 central points and 4 axial points). Two ß-galactosidase enzymes obtained from Kluyveromyces lactis were used. The content of lactose, glucose, galactose, and lactic acid were determined in the WPC, milk (pasteurized and powdered), and yogurts. The three best formulations regarding the attributes' viscosity, syneresis, firmness, and elasticity were sensorially evaluated by using a nine-point hedonic scale. A microbiological analysis was performed after 48 h of yogurt production. The characterization of the products and the comparison of the results obtained were evaluated using the Student's T test and the analysis of variance with Tukey's test (p-values < 0.05). The application of a lactose-free WPC promoted viscosity, firmness, and elasticity. The syneresis was reduced, and whey increased the protein and calcium content. Lactose-free WPC can be used as a partial substitute for skimmed powdered milk in yogurts. The obtained results are encouraging with respect to the production of lactose-free Greek yogurts by the dairy industry.

Casein-derived peptides as an alternative ingredient for low-phenylalanine diets.

INTRODUCTION: Introduction: casein-derived peptides can be liberated both in vivo via normal digestion of casein, as well as in vitro via enzymatic hydrolysis. These peptides were suggested to have biological activity. Objectives: the aim of this study was to describe the production and characterization of casein peptides and to explore the potential of these peptides as an option for low-phenylalanine diets. Methods: peptides were produced by tryptic hydrolysis of sodium caseinate and acid precipitation with HCl, followed by precipitation with ethanol or aggregation of CaCl2 or ZnSO4. Results: the amino acid analysis revealed a significant reduction in the amount of phenylalanine from the original protein. Conclusion: casein-derived peptides could be a future alternative of short chain peptides to low-phenylalanine formulations.

INTRODUCCIÓN: Introducción: los péptidos derivados de la caseína se pueden liberar tanto in vivo, a través de la digestión normal de la caseína, como in vitro a través de la hidrólisis enzimática. Se sugirió que estos péptidos tenían actividad biológica. Objetivos: el objetivo de este estudio fue describir la producción y caracterización de péptidos de caseína y explorar el potencial de estos péptidos como una opción para las dietas con bajo contenido de fenilalanina. Métodos: los péptidos se produjeron por hidrólisis tríptica de caseinato de sodio y precipitación ácida con HCl, seguido de precipitación con etanol o agregación de CaCl2 o ZnSO4. Resultados: el análisis de aminoácidos reveló una reducción significativa en la cantidad de fenilalanina de la proteína original. Conclusión: los péptidos derivados de la caseína podrían ser una alternativa futura de los péptidos de cadena corta a las formulaciones con bajo contenido de fenilalanina.