Research Article

Spray Drying of Rhodomyrtus tomentosa (Ait.) Hassk. Flavonoids Extract: Optimization and Physicochemical, Morphological, and Antioxidant Properties

Table 5

Representative literatures regarding microencapsulated plant extract/juice using gum Arabic and/or maltodextrin in spray drying process.

Plant extractFormula of emulsion*Drying conditionResulted encapsulationReference

Purified flavonoids extract from R. tomentosa berriesMaltodextrin (5–10 DE) to gum Arabic ratio 1 : 1.3; solid content 27.4%; glycerol monostearate content 0.25%; core : coating material ratio 3 : 7.40 MPa homogenization for 5 min; 0.7 mm diameter nozzle; 150°C inlet temperature and 100°C outlet temperature; 4.0 MPa atomization pressure; feeding rate 30%.91.75% encapsulated flavonoids; milky white powder; irregularly sphere shape; particle size <20 µm; 0.35 g/cm3 bulk density; 3.27% moisture content; 92.35% solubility; 95% retention of DPPH radical scavenging activity; effectively retarded lipid oxidation.This study

Pomegranate juice (15.97°Brix)20.1% maltodextrin (12–20 DE) in coating solution; core : coating ratio 1 : 1.1400 ×g homogenization speed for 5 min; 153°C inlet temperature; 600 L/h air flow; 10 mL/min feeding rate; 20 psi atomization pressure.53.5% encapsulated polyphenols; 86.6% encapsulated anthocyanins; irregularly sphere shape.[17]

Pomegranate ethanol extract (13.80°Brix)24.3% maltodextrin (12–20 DE) in coating solution; core : coating ratio 2 : 1.1400 ×g homogenization speed for 5 min; 153°C inlet temperature; 600 L/h air flow; 10 mL/min feeding rate; 20 psi atomization pressure.71.0% encapsulated polyphenols; 82.0% encapsulated anthocyanins; irregularly sphere shape.[17]

Black mulberry juice (40 kDa, adjusted to 11°Brix)Maltodextrin (6 DE) to gum Arabic ratio 3 : 1; total solid 8%; 1.5% (w/w) microcrystalline cellulose in the juice.130 inlet temperature; 800 L/h air flow rate; 925 N/m2 aspiration rate; 20°C feeding temperature; 150 mL/h feeding rate; 65.3 psi atomization pressure. 82% drying yield; 87% solubility; 4.4 μm particle size; 76.4°C glass transition temperature (Tg). [15]

Anthocyanin ethanol extract from Cabernet Sauvignon (pH 2.4)Maltodextrin (19 DE) to gum Arabic ratio 1 : 1.5; extract to maltodextrin ratio 1 : 1.100 rpm homogenization speed for 2.5 hour; 150°C inlet temperature; 50°C outlet temperature; 25°C feeding temperature; 25% pump power; maximum aspirator rate.Long half-life in soft drink; high retention of anthocyanins after 40 days of storage test; first-order kinetic degradation in soft drink; small and more sphere particles.[18]

Purified anthocyanins extract from Hibiscus sabdariffa L. (8°Brix)Maltodextrin (11–15 DE) to gum Arabic ratio 3 : 2; final solid content 20%.14,000 rpm homogenization speed for 1 hour; 150°C, 500 feeding volume; 9.5% flow rate.99.87% encapsulation efficiency; 3.7% degradation rate at 4°C; strong color stability; high retention of anthocyanins over 3-month periods; 6.2 and 5.4 months half-life under 4°C and 25°C, respectively. [19]

Filtered açai pulp (3% solid content)6% maltodextrin 10 DE in the pulp.140°C inlet temperature; 78°C outlet temperature; 73 mL/h air flow and 0.06 MPa compressor air pressure; 15 g/min feed flow rate; 35°C storage temperature.0.39 g/mL bulk density; 1.531 g/mL absolute density; 74.5% porosity; 3436.85 mg/100 juice dried matter; 1165.84 μmol TE/g juice dried matter; 80% retention of antioxidant activity under 0.328 water activity and 35°C storage condition.[20]

Filtered açai pulp (3% solid content)Two best formulas: (1) 6% maltodextrin 20 DE in the pulp and (2) 6% gum Arabic in the pulp.140°C inlet temperature; 78°C outlet temperature; 73 mL/h air flow and 0.06 MPa compressor air pressure; 15 g/min feed flow rate. (i) 20 DE maltodextrin formula: 2.88% moisture content, 0.245 water activity; 96.12% solubility; 19.69% hygroscopicity; 9.33 μm particle size; 100% retention of total polyphenolics and antioxidant activity after 15 days in both high and low water activity environments.
(ii) Gum Arabic formula: 3.04% moisture content; 0.244 water activity; 94.78% solubility; 19.74% hygroscopicity; 9.41 μm particle size; 100% retention of total polyphenolics and antioxidant activity after 15 days in both high and low water activity environments.
[21]

Ethanolic anthocyanin rich extracts from black carrot (6% solid content)Glucodry 210 (20–23 DE); 20% of final solid content in the emulsion.160°C inlet temperature; 107°C outlet temperature; 120% pump power; 5 mL/min feeding rate; 25°C feeding mixture. 630 mg/100 g anthocyanin content; 17.12 mg sample/mg DPPH EC50 antiradical activity; 6.03% moisture content; 76.64% hygroscopic moisture; high retention of anthocyanins (84% at 4°C and 67% at 25°C) after storage 64 days. [12]

Formula of emulsion stands for the optimal formula for microencapsulation if optimization study was conducted.