Antioxidant characteristics of extracts of Hibiscus sabdariffa calyces encapsulated with mesquite gum

Abstract

This study compared the stability of extracts of calyces microencapsulated with different concentrations of mesquite gum during storage. Dry Roselle calyces were mixed with 50:50 (v/v) ethanol:water solution to obtain 18°Bx concentrate. This Roselle extract concentrate was mixed with purified mesquite gum (100:1-100:5 v/w). The Roselle extract concentrate-gum (RECG) was spray dried at inlet and outlet temperatures of 180 ± 2 and 104 ± 2.3 °C, respectively, at an air flow rate of 38 m/h. Encapsulated Roselle powders (ERP) were analyzed for moisture content, total monomeric anthocyanins (differential pH), phenolic compounds (Folin and Ciocalteu method), antioxidant capacity (ABTS), and color parameters ([Formula: see text], and [Formula: see text]) after 5 weeks and 1 year of storage. Sorption properties (isotherms) and micrographs of powders were also obtained. The average yield of RECG powders was 15.27 ± 0.81 g/100 mL. During storage, ERP showed average values of phenolic compounds, antioxidant capacity, and anthocyanins of 3.43 ± 0.25 g gallic acid equivalents/100 g, 9.34 ± 1.4 g Trolox equivalents/100 g, and 318.7 ± 20.6 mg cyanidin--glycoside/100 g, respectively. Color parameters remained constant along the storage time.

Microencapsulation of Hibiscus sabdariffa (Roselle) Extracts by Spray Drying Using Maltodextrin and Gum Arabic as Carriers

“…The inlet and outlet air temperatures were 180.01 ± 0.25 and 105.16 ± 3.52°C, respectively. Blends of RE-gum concentrates were fed into the dryer at a flow rate of 10 mL/min (Andrade and Flores, 2004;Ochoa-Velasco et al, 2017). The aspirator power of the drying system was 100% (equivalent to an airflow of 35 m 3 /h), and the spray drying airflow was maintained at 55 mm (equivalent to 670 L/h with a pressure of 1.05 bar).…”

“…Encapsulating agents include natural polymers and derivatives of these or lipids. The most common of these are gum arabic (GA), carrageenin, maltodextrins (MDs), cyclodextrins, dextrins, chitosan, gelatin, sodium caseinate, pregelatinizated starch, carboximethylcellulose, methylcellulose, hydroxypropyl methylcellulose, milk proteins (caseins and whey), lactose, corn syrup (Munin and Edwards-Lé vy, 2011;Selim et al, 2008;Kolanowski et al, 2006;Vega and Roos, 2006), and mesquite gum (Ochoa-Velasco et al, 2017). The ideal substances for microencapsulation are soft and unflavored and have high solubility, emulsifying properties, and characteristics that promote drying.…”

“…Particle sizes of powders obtained by this method are generally in the range of 10-50 μm; however, this size may depend on the process conditions (Gharsallaoui et al, 2007). The main advantages of this process, besides its simplicity, are its suitability for use with heat-sensitive materials because the time required at high temperatures is very short (5-30 s) (Ochoa-Velasco et al, 2017), the equipment needed is readily available, options for encapsulating materials are many, the encapsulation process is efficient, the final product is stable, and there is the potential for continuous large scale production (Santos and Meireles, 2010). The parameters that have the most influence in the spray drying process are nozzle geometry, viscosity of the feeding solution, and the inlet and outlet air temperatures (Munin and Edwards-Lé vy, 2011;Gharsallaoui et al, 2007).…”

“…There is little research on spray drying of Roselle extracts (REs) to obtain powders. Some researchers have found that powders obtained by spray drying using encapsulating agents (mainly MDs) are more stable and have longer lasting antioxidant properties than those obtained without encapsulating agents Chiou, 2008a, 2008b;Farimin and Nordin, 2009;Ochoa-Velasco et al, 2017).…”

Mass transfer modeling of the antioxidant extraction of roselle flower (Hibiscus sabdariffa)

“…Roselle (Hibiscus sabdariffa L.) flower is a natural source of red-purple compounds with antioxidant properties (Ochoa-Velasco et al 2017). This plant is commonly used in several countries against diseases such as diarrhea, dysentery, hypertension, hypercholesterolemia and urinary tract infections because is rich in compounds like phenolics (mainly anthocyanins), polysaccharides and organic acids (Riaz and Chopra 2018).…”