Hesperetin (citrus peel flavonoid aglycone) encapsulation using pea protein-high methoxyl pectin electrostatic complexes: complex optimization and biological activity.

BACKGROUND: Orange pomace polyphenols have potential for use as nutraceutical ingredients in functional foods and beverages. However, owing to their low water solubility and bioaccessibility, they are not being utilized to their full potential. The goal of this research is to assess the impact of encapsulation on hesperetin (HT - a model orange polyphenol) water solubility, antioxidant activity, and in vitro bioaccessibility. RESULTS: In this study, a citrus flavonoid aglycone, HT, was encapsulated within water-dispersible colloidal complexes (d = 350 ± 8 nm) formed by electrostatic attraction of pea protein isolate and high-methoxyl pectin at a mixing ratio of 1:1 (v/v) and pH 4. The maximum amount of HT that could be dispersed in water was much higher for the encapsulated form (99 ± 7 µg mL-1 ) than the non-encapsulated form (<10 µg mL-1 ). The radical scavenging activity of the encapsulated HT (>90%, pH 4) was much higher than the non-encapsulated form (<15% at pH 4 or 7). The in vitro bioaccessibility of encapsulated HT (27 ± 7%) was also much higher than the non-encapsulated form (<7%). CONCLUSION: These results suggest that a well-designed, biopolymer-based delivery system may improve the effective incorporation of HT, and potentially other orange pomace polyphenols, into food and beverage products. This could provide an additional high-value use for orange juicing by-products while introducing a new nutraceutical product to the food and beverage industry. © 2022 Society of Chemical Industry.

Encapsulation and delivery of bioactive citrus pomace polyphenols: a review.

Citrus pomace consists of the peel, pulp, and membrane tissues remaining after juice expression. Globally, around one million tons of citrus pomace are generated annually, which contains a variety of bioactive constituents that could be used as value-added functional ingredients in foods. However, the polyphenols in citrus pomace are not currently being utilized to their full potential, even though they can be used as nutraceuticals in functional foods and beverages. Citrus phenolics face significant roadblocks to their successful incorporation into these products. In particular, they have poor water solubility, chemical stability, and bioavailability. This review describes the diverse range of colloidal systems that have been developed to encapsulate and deliver citrus phenolics. Examples of the application of these systems for the encapsulation, protection, and delivery of polyphenols from citrus pomace are given. The use of colloidal delivery systems has been shown to improve the stability, dispersibility, and bioaccessibility of encapsulated polyphenols from citrus pomace. The selection of an appropriate delivery system determines the handling, storage, shelf life, encapsulation efficiency, dispersibility, and gastrointestinal fate of the citrus polyphenols. Furthermore, the purity, solubility, and chemical structure of the polyphenols are key factors in delivery system selection.

Comparison of legume and dairy proteins for the impact of Maillard conjugation on nanoemulsion formation, stability, and lutein color retention.

While dairy proteins have traditionally been used to stabilize nanoemulsions, there is a trend towards plant-based formulations. Additionally, both types of protein are poorly soluble near their isoelectric point. The main goals of this research were to develop and characterize Maillard conjugates from pea protein (PPI) or caseinate and dextran, and to evaluate the physical stability of nanoemulsions made with such emulsifiers at various ionic strengths, pH = 4.6, and temperatures during storage, as well as lutein color retention over storage. Protein conjugates formed nanoemulsions with diameters of 125 ± 12 nm (PDI = 0.13 ± 0.00) and 269 ± 36 nm (PDI = 0.76 ± 0.42) (pH = 7) for caseinate and PPI, respectively. Conjugation improved the physical stability (droplet size) of emulsions at the isoelectric point, during storage at 4-55 °C, and in ionic solutions. Lutein color degradation was better associated with particle size than conjugation and was lowest for PPI-stabilized emulsions. This study suggests that Maillard conjugation could improve PPI emulsification properties.

Bioavailability of nanotechnology-based bioactives and nutraceuticals.

Bioaccessibility and bioavailability of some hydrophobic bioactives (e.g., carotenoids, polyphenols, fat-soluble vitamins, phytosterols and fatty acids) are limited due to their low water solubility, and in some instances low chemical stability. Nanotechnology involving nanometric (r<500nm) delivery systems, can be used to improve the solubility and thus enhance the bioaccessibility and bioavailability of hydrophobic compounds. Nanometric delivery systems, derived from food grade phospholipids and biopolymers adopt many forms, including liposomes, micelles, micro/nanoemulsions, particles, polyelectrolyte complexes, and hydrogels. The small particle sizes and customized materials used to create delivery systems confer their unique properties such as higher stability and/or resistance to enzymatic activity in the gastrointestinal tract. This chapter provides an overview of bioaccessibility and bioavailability of different classes of hydrophobic bioactive compounds, focusing on nanometric delivery systems and methods of evaluation.