Effect of Maltodextrin Concentration and Inlet Air Temperature on Properties of Spray Dried Powder from Reverse Osmosis Concentrated Sweet Orange Juice

Abstract

Sweet orange juice is an important part of diet since it is nutritious beverage offering good taste and play significant part in a healthy diet. High hygroscopicity, thermo-plasticity and presence of low molecular weight components in sweet orange juice offer low glass transition temperature (T_g), likely to form soft particle with sticky surface leading to sticky powder during drying. Maltodextrins are amorphous drying aids that tend to inhibit sugar crystallization and form a high T_g product after drying. In this study, the effect of the different spray drying parameters on the quality of powder derived from control and concentrated juice at three inlet air temperatures 120, 130 and 140 ^°C and at three levels of juice total soluble solids (TSS): maltodextrin levels at 1:0.5; 1:1 and 1:1.5 were studied. The impact of inlet air temperature and maltodextrin concentration has significantly affected various properties of sweet orange powder. For control juice, process yields increased with increase in inlet air temperature and maltodextrin concentration. However, for reverse osmosis (RO) concentrate, process yield increased with increase in maltodextrin concentration and decreased with increase in inlet air temperature. For control juice, process yields obtained were in the range of 12.59-41.16% and in case of concentrated juice, the process yield obtained was in the range of 21.35-56.95% at different combinations of inlet air temperature and maltodextrin concentrations. Spray-dried powder was considered as “possible” and “fair” in terms of flowability and cohesiveness. Vitamin C retention was high at lower inlet air temperature with lower concentration of maltodextrin.

Keywords:
sweet orange; spray drying; process yield; moisture content; vitamin C content; Hausner’s ratio; Carr index; solubility time; water solubility index; water absorption index ( 3-10)