FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY




Impact of spray drying parameters on the quality of protein hydrolysate


In the paper, the results are presented of the spray drying process of protein hydrolysate, its mixture, and carriers. A maltodextrin (DE = 19) and whey protein were used as carriers. One value of the inlet air temperature (160 oC) and three raw material feed fluxes (0.9, 1.16, and 1.28 cm3/s) were applied. The highest moisture content in powders, above 5 %, was obtained when maltodextrin was added as a carrier, and the lowest, slightly exceeding 2 %, was found in the powders of the protein hydrolysate. It was found that the moisture content in powders increased with the rise in the feed flux. This was connected with the decrease in temperature of air leaving the dryer. The values of loose and tapped bed density did not depend on the feed flux, but they significantly depended on the carrier applied. The powders of the same hydrolysate showed the lowest values of those densities, whereas the powders containing maltodextrin – the highest. The increase in the density of tapped beds was about 50 % compared to loose bed density. The apparent density of powders was the highest when the protein hydrolysate was dried solo, and it was the smallest in the case of materials containing whey protein. Thus, the powder particles of protein hydrolysate were characterized by the lowest internal porosity. No statistically significant impact of the feed flux on the apparent density was reported. The Hausner coefficients obtained proved that the powders produced possessed the properties of coherent powders. The research into the colour of powders using L*a*b system showed that the addition of carriers caused the decrease in the content rates of yellow and red colours, and it strengthened the brightness of powders. In the sole hydrolysate and in the hydrolysate with maltodextrin added, it was found that the yellow and red colour content rates increased and the brightness of powders decreased with the increasing feed flux. The values of saturation were close to the values as obtained for the yellow colour, because this colour predominated in the powders produced and it determined the value of saturation.


protein hydrolysate, carriers, spray drying, feed flux, density, porosity, colour