Desenvolvimento e caracterização de preparo sólido para iogurte prebiótico de manga, obtido por liofilização.

Abstract

Milk is one of the most consumed foods in the world, has excellent nutritional value and is used to produce a variety of derivatives, such as powdered milk, milk beverage, yogurt, besides enabling the elaboration of other products. The objective of the study was to develop and characterize solid preparations for mango prebiotic yogurt obtained by lyophilization. It was initially performed the physicochemical and microbiological characterization of mango pulp and milk. Solid preparations were elaborated using a 22 factorial design plus three central points resulting in seven experiments studying mango pulp concentrations (4, 8 and 12%) and sugar (4, 8 and 12 %) as independent variables and the physicochemical characteristics of solid preparations and yogurts and sensory characteristics of yogurts as response variables. Formulations were lyophilized at -40° C for 48 h. After characterization, solid preparations were reconstituted and fermented to obtain yogurts. Yoghurts were subjected to microbiological, physicochemical, sensory and rheological properties in the better accepted yogurt, as well as the water adsorption isotherms of the solid preparation at temperatures of 20, 30 and 40 °C. Microbiological and physicochemical analysis of milk and pulp were within the quality standards required by Brazilian law. The microbiological results of solid preparations were satisfactory showing no microbial contamination, while the physicochemical results showed low levels of water content (3.22 to 4.78%), water activity, acidity, wettability and red intensity, considered lipids, proteins, carbohydrates, ash and yellow intensity and high calories, calcium, potassium, phosphorus, luminosity. Yoghurts are within the microbiological and physicochemical standards with the exception of the protein content, being classified as partially skimmed yoghurts according to the fat content (1.15 to 2.08%). Yogurts showed high acceptance rates being prepared with the highest concentration of pulp and sugar the most accepted. The solid preparation was very hygroscopic and the GAB mathematical model was the most recommended predicting the hygroscopic equilibrium showing Type III behavior. The apparent yogurt viscosity decreased with increasing shear rate, behaving like a pseudoplastic fluid and the Herschel-Bulkley model was best fit to rheological data.