Associate Professor North Dakota State University Fargo, ND, United States
Abstract: Cannabidiol (CBD) from industrial hemp is a promising functional ingredient that exhibits several biological activities, such as anti-cancer and anti-inflammatory effects. However, its poor chemical stability and bioaccessibility hinder its nutraceutical applications.
Objective In this study, protein–polysaccharide complexes were generated using hemp protein isolate (HPI) and gum Arabic (GA), aiming to microencapsulate CBD to improve its stability and bioaccessibility.
Methods The impact of HPI to GA ratio and pH on the complex coacervation formation were investigated using the phase diagram and zeta potential. The results showed that the 5:1 ratio (HPI:GA) and pH 3.0 were ideal conditions to form complex coacervates for the following experiment. The generated HPI-GA complexes were encapsulated with CBD at different wall/core ratios (6:1, 8:1, 10:1). To understand the influence of wall to core ratio on physicochemical properties of microencapsulated CBD, the encapsulation efficiency, morphological properties, molecular interactions, chemical stability, and in vitro gastrointestinal digestion were performed.
Results The HPI-GA complexes displayed remarkable encapsulation efficiency ranging from 80.90 – 91.25%, indicating their suitability for microencapsulation. The morphological analysis performed using the scanning electron microscope revealed the non-porous smooth surface of microcapsules, and the confocal laser microscopy confirmed the distribution of CBD within the capsules. Fourier transform infrared spectroscopy identified the molecular interactions between the wall materials. The HPI-GA complexes well maintained the chemical stability of CBD for 30 days at tested temperatures (4, 25, and 37 ℃) compared to the HPI controls. Notably, the bioaccessibility of CBD increased up to 63.27 % after encapsulating into the HPI-GA complexes.
Significance The HPI-GA complexes acted as a carrier for CBD and enhanced its chemical stability and bioaccessibility. The results indicate that the HPI-GA complexes could act as a novel delivery vehicle for microencapsulating lipophilic bioactive compounds.
