Abstract This study investigated the impacts of centrifugal block freeze concentration (CBFC) and evaporation processes on physicochemical properties, bioactive compounds and antioxidant activity applied to fresh blueberry juice. After three concentration cycles, the solutes were approximately 3.6 times to the initial condition (12 °Brix) and the final color (ΔE*>4.7) was darker than the fresh juice. In all cycles, CBFC obtained higher bioactive compound concentration than evaporation, with values, in the last cycle, close to 610 mg GAE/100 mL, 57 mg M3G/100 mL and 279 mg CEQ/100 mL for total polyphenol, anthocyanin and flavonoid content, respectively, causing a retention over 70%. Similarly, as the cycles progressed, DPPH assay presented values from 1916 to 5700 μmol Trolox equivalents/L, which were higher than those reported by the treatment at high temperatures (1916 to 4600 μmol Trolox equivalents/L), resulting in good antioxidant activity in the cryoconcentrates achieved at low temperatures. Moreover, a significant correlations between CIELab parameters, bioactive compounds and antioxidant activity were observed. Thus, CBFC is an interesting and novel technique to preserve important quality properties from fresh fruit juices.

A study was developed to formulate a low calorie gelling paste that allows giving aggregate value to discarding blueberries. Eight formulations were done after the characterization of the fruit that shows a high proportion of calcium/pectin, of great importance in the gelation capacity. The results show three formulations without significant differences in their shelf life of around forty days, From them, the formulation 8 (pH 4.3, 1 g/kg of potassium sorbate and 2% of glycerol) presents the best condition of pH for calcium gelation. This formulation presents a typical curve of the texture profile analysis (TPA) with a high hardness and a caloric content of 26.04 kcal/100g that indicates that its hypocaloric characteristics. The study shows that it is possible to obtain formulations with a reasonable shelf life and different consistency to be used in diverse alimentary preparations according to requirements.

Se efectuó un estudio para formular una pasta gelificada de bajas calorías que permita aumentar su valor añadido de descartes de arándanos. Se realizaron ocho formulaciones después de efectuar la caracterización del fruto, la que muestra una adecuada relación entre calcio y pectina, de gran importancia en el mecanismo de gelificación. Los resultados muestran tres formulaciones sin diferencias significativas en su vida útil de alrededor de 40 días. De ellas se eligió la formulación 8 (pH 4.3, 1 g/kg de sorbato de potasio y 2% de glicerol), que presenta la mejor condición de pH para la gelificación de los iones calcio. Esta formulación presenta una curva típica en el análisis de perfil de textura (TPA) con una elevada dureza. Además presenta un contenido calorífico de 26.04 kcal/100g que indica características hipocalóricas. El estudio muestra que es posible obtener formulaciones con una razonable vida útil y distinta consistencia que permite su uso en diversas preparaciones alimentarias según los requerimientos.