Processamento de gelado comestível utilizando soro de leite e suco de melancia (Citrullus vulgaris Schrad) concentrado a vácuo em diferentes temperaturas

Abstract

The rich chemical composition and the high moisture content make the watermelon has a limited useful life. The production of a concentrate can avoid fruit wastage, available it in the off season and concentrate important bioactives, such as lycopene and citrulline that can be used in the production of foods with high nutritional and functional value. The whey becomes a potent environmental pollutant when improperly scorned. In addition, the discard means loss of great technological and functional potential, especially of the benefits attributed to proteins. The popsicles are widely appreciated throughout the world. When incorporated the whey and the watermelon in the formulation of these dairy desserts we are adding the flavor and color from the fruit, besides other technological and biological functionalities of these ingredients. This study aimed was to develop popsicles using the whey and concentrated watermelon juice under vacuum at different temperatures (45ºC, 55ºC and 65ºC, coded A, B and C, respectively). Physicochemical analyzes were carried out, including phenolic compounds, lycopene, citrulline, antioxidant capacity, volative compounds, color and melting parameters, sensory analysis of acceptance and preference and the free listing for consumer study. The vacuum concentration was considered an effective alternative for concentration of bioactive compounds, all temperatures used promoted good results and were promising for the production of watermelon juice concentrates. Only lycopene was negatively affected by the strong negative correlation with the concentration temperature, being its best retention at 45 ºC. The developed popsicles also obtained good physico-chemical and functional composition, with emphasis on the whey protein content and preservation of the contents of phenolic compounds, lycopene and citrulline even after the pasteurisation and freezing stages. The sensory analysis indicated preference for in natura popsicle, differing from A popsicle only by the lower acceptance of the aroma attribute. This difference was justified by the lower quality of the volatile profile of the A popsicle, in which the 3,6-nonadienol alcohol, responsible for the sweet peeled watermelon aroma, was absent only in this popsicle. No significant difference (p<0.05) was observed between A, B and C popsicles regarding preference and sensorial acceptance for all attributes. The free listing revealed that the descriptors characteristic flavor of watermelon, sweet taste and soft texture were the most frequently cited, being the most relevant for the popsicles developed from the watermelon juice and the whey. As for the color parameters, the in natura popsicle was identified as the reddest. According to the melting analysis, the A popsicle was considered the most resistant to initial melting, an important characteristic for these products. We concluded that all the concentrates were considered suitable for the reconstitution and development of the popsicle, since they were able to offer good physicochemical and functional composition and to preserve the sensorial characteristics of the watermelon.