Encapsulation of Arctium lappa L. root extracts by spray-drying and freeze-drying using maltodextrin and Gum Arabic as coating agents and it’s application in synbiotic orange-carrot juice

The aim of this study was to investigate the effect of burdock root encapsulated extracts (microcapsules and Nanocapsules in concentrations of 0.5 and 1%) on the viability of probiotic bacteria, TPC, formalin and sensory properties of orange-carrot juice containing Lactobacillus acidophilus during cold storage. The tow coating materials, namely gum Arabic and maltodextrin were used to encapsulate extracts using spray-drying and freeze-drying techniques. The results of encapsulation phase showed that Nanocapsules had higher efficiency and antioxidant activity than microcapsules, but their density and moisture content were lower (p < 0.05). The highest level of phenolic compounds (0.385 mg GAE/g), antioxidant activity (IC50 = 0.0241 mg/mL) and the smallest capsule particle size (14.33 ± 0.22 µm) were observed in Nanocapsules prepared with gum Arabic (T10). The SEM images showed that the produced capsules in terms of microstructure, had flaky/glassy and angular surfaces and did not have a regular shape. The results of the enrichment phase showed that the carrot-orange juices fortified with encapsulated extract in different forms (free/micro/Nano) were significantly improved in terms of probiotic viability, TPC and formalin index during cold storage compared to the control, so that in the T10 sample, the highest values of these parameters at the end of storage were equal to 7.38 ± 0.012 Log CFU/mL, 1.14 ± 0.011 mg GAE/g and 3.60 ± 0.00 mg/kg, respectively. Addition of different forms of burdock root extract did not have an adverse effect on the flavor and odor of the samples and just T10 treatment led to a darker color of the beverage, however, all juice samples in all studied times received acceptable scores in terms of sensory characteristics (score = 6.9–8.8). Therefore, based on the results of this study, it can be stated that encapsulated burdock root extracts, especially in the form of nanocapsulation, can be used to increase the viability of probiotics and enhancement the antioxidant activity of functional foods.