Dehumidified Air-Assisted Spray-Drying of Cloudy Beetroot Juice at Low Temperature

Abstract

This paper discusses the physicochemical properties of powders obtained by spray drying of cloudy beetroot juice, using dehumidified air in variants with or without carriers. The inlet air temperature was 130 °C or 90 °C, and the addition of the carriers was at a ratio of juice to carrier solids of 3:2. In the obtained powders, the following physicochemical properties were determined: water content and water activity, apparent density, loose and tapped density, porosity, flowability, particle size and morphology, and the content and retention of betalains. It was possible to dry cloudy beetroot juice without the use of carriers at low temperatures (90 or 130 °C). The 100% beetroot powders were characterized by satisfactory physicochemical properties, often better than those with carriers (including lower hygroscopicity and higher color saturation and yield). A lower loss of betalains was found for the powders with the addition of carriers. The best process yields were obtained for the powder without carriers at 130 °C and 90 °C.

Effect of Spray Dryer Scale Size on the Properties of Dried Beetroot Juice

“…Figure 3 compares the particle morphology of two different atomization systems (two-fluid nozzle and centrifugal liquid atomization) at a higher magnification (1000×). Jedli ńska et al [25] obtained particles with similar morphology. The researchers conducted a semi-technical-scale experiment in which they also spray-dried beet juice with a centrifugal liquid atomization system.…”

“…Other researchers who conducted research on laboratory-scale beetroot juice achieved powder yield values in the ranges of 15-18% (Poornima et al [22]), 41.31-54.63% (Bazaria et al [23]), and 41.33-56.55% (Teenu et al [24]). Jedli ńska et al [25] conducted a semi-technical-scale experiment in which they spray-dried cloudy beetroot juice with dehumidified air at low inlet temperatures (90 • C and 130 • C). The temperature of 130 • C resulted in a powder yield of 76.1% and 90%, with and without maltodextrin as a carrier, respectively.…”

“…In the first case, more cracks and wrinkles can be observed on the surface. This is related to the large loss of moisture from the particles and their subsequent cooling [25,26]. The use of the laboratory dryer (ML) resulted in much smaller but more spherical and smoother particles.…”

“…Molecules 2021, 26, x 4 of 15 subsequent cooling [25,26]. The use of the laboratory dryer (ML) resulted in much smaller but more spherical and smoother particles.…”

“…Figure 3 compares the particle morphology of two different atomization systems (two-fluid nozzle and centrifugal liquid atomization) at a higher magnification (1000×). subsequent cooling [25,26]. The use of the laboratory dryer (ML) resulted in much smaller but more spherical and smoother particles.…”