Džiovintų mėlynių sulčių miltelių spalva ir antocianinų kiekis juose

Abstract

The research was carried out in 2020 at Vytautas Magnus University Agriculture Academy, Open Access Joint Research Center for Agriculture and Forestry, in the Laboratory of Raw Plant Materials Quality. Corn maltodextrin (14–17 eqv.) and chicory inulin were used for the experiment. The blueberry juice was mixed with 10, 20 and 30% of maltodextrin, also with 10, 20 and 30% of maltodextrin and inulin at the ratio 1:1. The same additives were added to the blueberry juice before dissolving them in distilled water at the ratio 1:2 (The additive:distilled water). The juice with additives was dried with the spray dryer. Juice drying parameters: liquid flow – 436.5 ml h-1 or 7.275 ml min-1 (± 10%); air flow – 87.6 m3 h-1. Inlet and outlet temperature 140°C / 70°C. Drying of the blueberry juice with the addition of 10% maltodextrin and inulin (1:1) was unsuccessful. The color of dried blueberry juice powder was measured using ColorFlex spectrophotometer. L * – from white to black, a * – from green to red, b * – from blue to yellow. Other color parameters were also calculated: The total color difference ΔE, chroma (C *), hue angle (h°), browning index (BI) (Lee, Coates, 1999; Lee, Castle, 2001; Correia et al., 2017; Luchese et al., 2017). The total anthocyanin content was determined by pH differential spectroscopic method (Gollucke, 2010). The darkest blueberry juice powder was determined with 10 % maltodextrin (25.07 NBS units), and the lightest with 30% dissolved maltodextrin additive (L * – 48.92 NBS units). As the amount of additive increases, the powder lightens. The additive and dissolution in water resulted in a lighter color of the powder. The highest anthocyanin content was determined in a powder with 10% maltodextrin (328.03 mg per 100 g-1). Higher additive concentrations and the dissolution in water reduced the amount of anthocyanins content in the powder.[...]