Development and evaluation of a drinkable yoghurt added of lyophilized extract of Justicia spicigera as natural coloring

Abstract

Some functional foods are produced by the addition (enrichment or fortification) of nutrients or natural additives that enhance sensory attributes. In this way yogurt is an attractive food for both consumers and the industry to innovate in their formulations. The aim of the research was to develop the formulation of a drinkable yogurt, adding a lyophilized hydroetanolic extract from Justicia spicigera as a substitute for color, and to evaluate the physicochemical and sensory yogurt. Methodology: Fresh leaves were obtained from Justicia spicigera, dehydrated in a drying oven for 48 hours at a temperature of 35 °C. The dehydrated leaves were ground and macerated in a hydro alcoholic solution (H₂O/EtOH) (70:20 v/v). It was left under constant stirring at 150 rpm, 25 °C, and 48 h. The extract was filtered and the ethanol was recovered by means of a rotary evaporator. The extract was lyophilized and kept under freezing (-16 ° C) until its use. Two formulations of low-fat drinking yoghurt were prepared using a standardized process: without and with the addition of the lyophilized extract, as a 0.5% dye. Physicochemical analysis of moisture, ash, protein, butterfat, pH, Bx, titratable acidity and viscosity were carried out according to the techniques established by A.O.A.C. (1990). The approximate nutritional content was estimated. Results: The process of obtaining the lyophilized extract of Justicia spicigera and its incorporation into yogurt was standardized. The sensory characteristics were: purple color, characteristic texture, the predominant smell was herbal thanks to the extract, the acid taste was characteristic with a herbal note and the liquid characteristic consistency. The acidity reached by the control group was 4.42, while that of the of the lyophilized extract was 4.90. Regarding its nutritional composition, the protein content was 3 %, lipids 2 % and carbohydrates 4.5 %. Conclusions: The lyophilized extract of Justicia spicigera was obtained, which was included in a suitable way as a natural coloring to drinkable yoghurt.