Starches in the encapsulation of plant active ingredients: state of the art and research trends

As a natural polymer, starches and their derivatives have received widespread attention in the cosmetic and pharmaceutical industries, particularly for their use as a coating material. In this sense, as an encapsulating agent, starches stand out, considering the number of compounds that they can trap. Additionally, they provide a nutritional contribution and may improve acceptance by patients. As such, this type of material may serve as an alternative to overcome gaps such as loss of activity of the active principles, low assimilation, or deterioration under environmental and physiological conditions. In this paper, we aim to present the state of the art and research trends on the use of starch as a wall material for the encapsulation of active principles of plant origin. It was found that the most-encapsulated active principles are essential oils and polyphenols; native or modified starches are typically used, either as the sole wall material or in combination with other polymers; and the most widely used methodology is spray drying. The reviewed studies indicate the potential of starches for their use in active ingredient encapsulation processes, improving their viability and expanding their range of applications in different industries, as well as showing a clearly increasing publication trend over the last 10 years.

Graphical abstract

Protein-polysaccharides based nanoparticles for loading with Malus baccata polyphenols and their digestibility in vitro

The poor solubility, instability and low absorption rate obstruct the bioavailability of polyphenols isolated from Malus baccata (MBP) during gastrointestinal digestion. In order to solve the limitable problems, the food-grade nanoparticles were fabricated by mucin (MC) and Hohenbuehelia serotina polysaccharides (HSP) for delivery of MBP (MBP-NPs). The physicochemical properties and morphology of MBP-NPs prepared by different condition were respectively characterized. During gastrointestinal digestion in vitro, the release characteristic and variation in phenolic composition of MBP-NPs were evaluated. The results showed that MBP-NPs formed by hydrogen bonding and hydrophobic interaction possessed the regularly spherical shapes and smooth surfaces and semi-crystalline properties. Moreover, MBP-NPs presented the excellent physicochemical stability. During simulated gastrointestinal digestion in vitro, MBP-NPs exhibited the sustained release characteristics of phenolic compounds, which were confirmed by SDS-PAGE measurement. Compared with that of unencapsulated MBP, the significant variation was occurred in the phenolic composition of MBP-NPs, indicating that MBP-NPs could prevent the degradation and transformation of phenolic compounds. This study provides a novel strategy to improve the bioavailability of polyphenols.

Synthesis, characterization and in vitro digestion of folate conjugated chitosan-loaded proanthocyanidins nanoparticles

Proanthocyanidins have significant biological activity and pharmacological effects and are widely used in food, medicine, and cosmetics. Chitosan nanoparticles loaded with proanthocyanidins have been proven to improve their biological activity. Given some deficiencies of chitosan (CS), the modification of chitosan by folic acid (FA) can obtain new variants with different functions. For this objective, the folic acid conjugated chitosan was designed, and in vitro properties of proanthocyanidins loaded nanoparticles were studied systemically. Firstly, folic acid-chitosan conjugate (FA-CS) was synthesized and characterized. Folate-coupled chitosan-loaded proanthocyanidin nanoparticles (PC-CS/FA-NPs) were prepared by ionic gelation technique using FA-CS as a carrier. The successful nanoparticle synthesis was characterized by dynamic light scattering (DLS) techniques and Fourier transform infrared (FT-IR) spectroscopy. The synthesized nanoparticles exhibited a spherical shape and smooth and uniform distribution features with a size range of less than 300 nm, as observed by a scanning electron microscope (SEM). Meanwhile, PC-CS/FA-NPs had good thermal and gastrointestinal digestive stability and had a protective effect on AAPH-induced erythrocyte oxidative hemolysis. In conclusion, folic acid decorated chitosan nanoparticles improved the stability and bioavailability of proanthocyanidins in gastrointestinal digestion.

Encapsulation of tannins and tannin-rich plant extracts by complex coacervation to improve their physicochemical properties and biological activities: A review

As a major class of dietary polyphenols, tannins are demonstrated to have various health-promoting properties. Although tannins have been widely utilized in food, pharmaceutical and many other industries, the applications of tannins are quite limited due to their poor stability, sensory attributes and bioavailability. Encapsulation helps improve all of these properties. Complex coacervation, one of the most effective encapsulation techniques, is known for its simplicity, low cost, scalability and reproducibility in encapsulation of functional components. In recent years, complex coacervation has been successfully used for encapsulation of tannins and tannin-rich plant extracts. In this article, the research progress in encapsulating tannins and tannin-rich plant extracts by complex coacervation to improve their physicochemical properties and biological activities is critically reviewed for the first time. Encapsulation of tannins and tannin-rich plant extracts can effectively improve their sensory characteristics, stabilities, bioavailability, anti-hypercholesterolemia, anti-diabetic, antioxidant, anticancer and antimicrobial activities. In particular, the enhancement of biological activities of tannins and tannin-rich plant extracts is usually correlated to their improved physicochemical properties imparted by the encapsulation technique. Moreover, we introduce the issues that need to be further resolved in future studies on encapsulation of tannins and tannin-rich plant extracts by complex coacervation.

Construction of Hohenbuehelia serotina polysaccharides-mucin nanoparticles and their sustain-release characteristics under simulated gastrointestinal digestion in vitro

In this study, Hohenbuehelia serotina polysaccharides-mucin nanoparticles (HSP-MC NPs) were fabricated based on hydrogen bonding and hydrophobicity effects for improving the bioavailability of HSP. The structural characteristics and morphology of HSP-MC NPs prepared by different conditions were respectively identified and observed. The results showed that HSP-MC NPs (HSP/MC, 1/1, w/w) presented the optimal physicochemical characteristics, with the encapsulation efficiency of 88.09 ± 0.01%, average particle size of 509.4 ± 9.76 nm and zeta potential of -20.6 ± 0.7 mV. Furthermore, HSP-MC NPs (HSP/MC, 1/1, w/w), belonged to non-crystalline substances, exhibited the excellent physicochemical stabilities against temperature, pH and ionic strength, and had the uniform spherical morphological characteristics. In addition, under simulated gastrointestinal digestion in vitro, HSP-MC NPs (HSP/MC, 1/1, w/w) showed the good sustained release performances, that might effectively improve the absorption rate of HSP. The present research is meaningful for designing the polysaccharides-loaded nano-delivery system based on natural non-toxic carrier that can be used in function food field.

Construction and characterization of Juglans regia L. polyphenols nanoparticles based on bovine serum albumin and Hohenbuehelia serotina polysaccharides, and their gastrointestinal digestion and colonic fermentation in vitro

Herein, we report the construction and characterization of nanoparticles based on bovine serum albumin and Hohenbuehelia serotina polysaccharides for the delivery of polyphenols isolated from the shells of Juglans regia L. (BSA-JRP-HSP NPs). We also systematically investigated their gastrointestinal digestion and colonic fermentation characteristics in vitro. BSA-JRP-HSP NPs, with amorphous properties and regular spherical morphological features, have a high encapsulation efficiency of 88.47 ± 0.04%, average particle size of 285.7 ± 3.1 nm, and zeta potential of -12.20 ± 0.61 mV, and they exhibit excellent photothermal stabilities and strong mucin adhesion capacity. Through measurements of gastrointestinal digestion and colonic fermentation in vitro, the results suggest that BSA-JRP-HSP NPs presented well-sustained release characteristics for preventing the biodegradation of JRP during gastrointestinal digestion. After gastrointestinal digestion, BSA-JRP-HSP NPs could modulate the composition and structure of gut microbiota, promoting the growth of beneficial bacterial (e.g. Prevotella, Dialister, Akkermansia, etc.) and inhibiting the growth of pathogenic bacteria (e.g. Bacteroides, Phascolarctobacterium, Lachnospiracea incertae sedis, etc.). The production of short-chain fatty acids (SCFAs) including acetic acid, propionic acid, and butyric acid was remarkably enhanced by treatment with BSA-JRP-HSP NPs. This study has proved that BSA-JRP-HSP NPs can serve as a novel candidate for improving the bioavailability of JRP.

Preparation, Characterization and Antioxidant Activities of Kelp Phlorotannin Nanoparticles

Phlorotannins are a group of major polyphenol secondary metabolites found only in brown algae and are known for their bioactivities and multiple health benefits. However, they can be oxidized due to external factors and their bioavailability is low due to their low water solubility. In this study, the potential of utilizing nanoencapsulation with polyvinylpyrrolidone (PVP) to improve various activities of phlorotannins was explored. Phlorotannins encapsulated by PVP nanoparticles (PPNPS) with different loading ratios were prepared for characterization. Then, the PPNPS were evaluated for in vitro controlled release of phlorotannin, toxicity and antioxidant activities at the ratio of phlorotannin to PVP 1:8. The results indicated that the PPNPS showed a slow and sustained kinetic release of phlorotannin in simulated gastrointestinal fluids, they were non-toxic to HaCaT keratinocytes and they could reduce the generation of endogenous reactive oxygen species (ROS). Therefore, PPNPS have the potential to be a useful platform for the utilization of phlorotannin in both pharmaceutical and cosmetics industries.

Extraction, characterization and antimicrobial activity of chitosan from pen shell, Pinna bicolor

Chitosan is a biopolymer discovered abundantly on earth specifically in the exoskeleton of shrimps, crabs and insects. In the present study, isolation and characterization of chitosan from the pen shell Pinna bicolor was carried out. In addition to this, the chitosan acquired from the pen shell was tested for its antibacterial activity against five bacterial strains. The FTIR analysis confirmed the presence of NH out of plane bending (872 cm^-1) and C-O-C stretching (1016 cm^-1) for chitosan with 59.76% degree of deacetylation. The Micro Raman showed peaks at 1658 cm^-1, 1595 cm^-1 and at 954 cm^-1 corresponding to chitosan. The XRD was able to establish the crystallinity of the chitosan sample with a maximum peak at 29.3°. The elemental analysis of chitosan sample confirmed higher level of carbon (10.75%) when compared to other elements such as nitrogen, hydrogen and sulphur. The antimicrobial activity of extracted chitosan was evident with greater zone of inhibition against Salmonella typhi (20 mm) and least against Shigella dysenteriae. Thus, the present study unravels the properties of chitosan extracted from P. bicolor thereby paving way for its further use in the field of biomedical science and nanotechnology.

Anti-proliferation activities of Oryza sativa L. anthocyanins-Hohenbuehelia serotina polysaccharides complex after in vitro gastrointestinal digestion

In order to improve the bioavailability of Oryza sativa L. anthocyanins, we fabricated Oryza sativa L. anthocyanins-Hohenbuehelia serotina polysaccharides (OSA-HSP) complex and investigated its anti-proliferation activities taking into account its changes along simulated gastrointestinal digestion in vitro. Results showed that OSA mainly composed by delphinidin, cyanidin, petunidin, malvidin and their derivatives was combined with HSP through electrostatic interaction. OSA-HSP complex belonged to non-crystalline substance, and had compact and laminar structural characteristics. Under simulated gastrointestinal digestion, OSA-HSP complex significantly prevented the degradation of anthocyanins, and presented sustain release effect. However, the anti-proliferation activities of OSA-HSP complex digested by different gastrointestinal process were remarkably changed, especially after small intestinal digestion. HeLa cells treated with OSA-HSP complex exhibited pro-apoptosis characteristics by triggering endogenous mitochondrial apoptosis pathway through activating the expressions of Bax, cytochrome c and Caspase-3 as well as inhibiting the expression of Bcl-2. These findings provided new insight to improve the bioavailability of anthocyanins in functional foods and tumor therapy.