Gelatin and pectin complex coacervates as carriers for cinnamaldehyde: Effect of pectin esterification degree on coacervate formation, and enhanced thermal stability

pH-Induced structural transitions in whey protein isolate and ultrasonically solubilized Persian gum mixture

The present work evidently reports that ultrasonic depolymerization strongly enhanced complex coacervation between Persian gum (PG) and whey protein isolate (WPI). PG was sonicated at 60 °C, operating frequency of 20 kHz and nominal power output of 800 W for various times followed by mixing with WPI. Acid-induced interaction between the two biopolymers was studied by turbidity, light scattering, zeta potential and viscosity measurements over a wide pH range. Sonication of intact PG (IPG) for 10 min considerably reduced the molecular weight from 4.12 × 10⁶ to 0.76 × 10⁶ g/mol. Besides, ultrasonic fragmentation of water insoluble fraction of PG drove protein containing chains into the soluble phase. Sonicated PG (SPG) was shown to be more flexible with higher number of carboxyl groups available for electrostatic interaction with WPI, such that the complete neutralization did not occur even at protein to polysaccharide ratio of 50: 1. Additionally, scattered light intensity and viscosity measurements revealed two maxima in the pH ranges of 4.4-4.85 and 3.27-4.0, being highly intense for the gum sonicated for 10 min and longer. Considering the pH-behavior of WPI components, the former peak was related to interpolymer complex formation between β-lactoglobulin and long chain fraction of SPG, while the latter was attributed to intrapolymer association of α-lactalbumin with the short chain oligosaccharides arising from ultrasonic degradation of PG.

Fabrication, structural characterization and functional attributes of polysaccharide-surfactant-protein ternary complexes for delivery of curcumin

In this study, the nanocomplexes as a novel delivery system for curcumin, were successfully fabricated using high methoxyl pectin (HMP), individual surfactants (rhamnolipid (Rha), tea saponin (TS) and ethyl lauroyl arginate hydrochloride (ELA)) and pea protein isolate (PPI). The optimum mass ratio between PPI and curcumin was 40:1. The HMP-Rha-PPI-Cur, HMP-TS-PPI-Cur and HMP-ELA-PPI-Cur complexes which had particle sizes of 453, 422 and 587 nm, exhibited encapsulation efficiencies of curcumin with 93.46, 92.05 and 86.73%, respectively. The analysis of FTIR revealed that HMP-surfactant-PPI-Cur complexes were formed mainly by hydrogen bonding and electrostatic attraction. XRD result showed that curcumin exhibited a non-crystallized state in the ternary complexes. Moreover, the curcumin within the HMP-Rha-PPI ternary complexes showed better stability under UV-light, thermal and simulated gastrointestinal conditions.

Novel complex coacervates based on Zedo gum, cress seed gum and gelatin for loading of natural anthocyanins

This study aimed to characterize novel complex coacervates based on Zedo gum and cress seed gum as natural polysaccharides with gelatin (type-A and type-B) as potential wall materials for encapsulation of anthocyanins. The coacervates were prepared under optimum conditions (pH and gum to gelatin ratio), freeze-dried, and the resulted powders were analyzed in terms of thermal stability, morphology, and molecular interactions. The thermogravimetric analysis revealed that molecular interaction between polysaccharides and gelatins led to enhance the thermal stability of gums. The morphology of coacervates showed that while ZG-gelatin and CSG-gelatin coacervates resulted in cubic and irregular particles, freeze-drying severely changed the morphology of coacervates. Moreover, SEM images at lower magnification showed big voids for lyophilized coacervates, while SEM images confirmed a compact and dense microstructure of coacervates at higher magnification and BET method. Also, the molecular interaction of polysaccharides and gelatin in aqueous media was assessed using Raman spectroscopy. Furthermore, findings showed that the type-A of gelatin is a more suitable protein to form coacervates with polysaccharides. In the next step, natural anthocyanins from barberry were encapsulated by proposed coacervates as wall material. The encapsulated extract had elevated thermal stability and showed a lower degradation rate.

Okra polysaccharides/gelatin complex coacervate as pH-responsive and intestine-targeting delivery protects isoquercitin bioactivity

Okra polysaccharides (OPs) belong to RG I pectin branched with neutral saccharide side chains, which possesses distinctive structure and physicochemical properties from the commonly used HG pectin. Until now, the application of RG I pectin as wall material of microcapsule remains unclear. Here, we obtained OPs/gelatin complex coacervate at the maximum yield of 86.8% (pH 3.5, gelatin/OPs ratio 9:1 and 2% (w/v) total polymer concentration) by response surface methodology. Isoquercitin (IQ)-loaded OPs/gelatin complex coacervate (OGIQ) showed porous spongy-like surface structure with average particle size, encapsulation efficiency and surface porosity at 334 nm, 81.6% and 31.9%, respectively. OGIQ was found to be pH-responsive and intestine-targeting. The IQ-release rate of OGIQ was assayed to be 89.4% in intestine fluid and below 2% in acidic and simulated gastric digestion, respectively. Accordingly, embedding in OGIQ protected IQ in digestion and improved its postdigestive α-glucosidase inhibitory rate by 88.7%. The differential scanning calorimetry curves showed that OGIQ effectively prevented IQ from thermal decomposition. The XRD, FT-IR and CD spectra indicated that IQ was embedded in OGIQ in amorphous state by hydrogen bonds and electrostatic interaction. Compared with HG, the neutral saccharide side chains of OPs could induce different secondary conformation change of gelatin during complex coacervation.

Development of high methoxyl pectin-surfactant-pea protein isolate ternary complexes: Fabrication, characterization and delivery of resveratrol

The purpose of this study was to fabricate ternary complexes composed of pea protein isolate (PPI), high methoxyl pectin (HMP) and individual surfactants including rhamnolipid (Rha), tea saponin (TS) and Ethyl lauroyl arginate (LAE), for the delivery of resveratrol (Res). A combination of electrostatic attraction and hydrophobic interaction was dominantly responsible for the formation of HMP-surfactant-PPI complexes. The physicochemical properties of the ternary complexes were affected by surfactant types as well as mass ratios of individual surfactant to PPI. HMP-Rha-PPI_1:1, HMP-TS-PPI_1:1 and HMP-LAE-PPI_1:25 complexes had higher denaturation temperatures of 82.78 ± 0.31, 80.21 ± 0.02 and 79.98 ± 0.86 ℃, respectively. The HMP-Rha-PPI_1:1 ternary complex could be an effective delivery system, which were effective to retard photo- and thermal- degradation of Res as well as delayed the release of Res in in vitro digestion.

Properties of dark chocolate enriched with free and encapsulated chlorogenic acids extracted from green coffee

Abstract To increase the functionality of dark chocolate, chlorogenic acids extracted from green coffee were added in free or encapsulated forms at different concentration (10, 20, 30, 40 and 50 mg/5 kg of free chlorogenic acids and equal quantity of encapsulated form). The extraction of chlorogenic acids was carried out by maceration of ground green coffee beans in distilled water (30 min at 80 °C), then, cooling, filtration and adsorption by active carbon were done. The final step was filtration and desorption from active carbon and rotary drying (at 60 °C and 120 rpm). Encapsulation of chlorogenic acids was done by coacervation of pectin and gelatin. For quality assessment, several analysis on chocolate samples were performed included color index and melting behavior by Differential Scanning Calorimeter. Flow behavior of the chocolate samples melted at 40 °C was determined using stress or strain controlled rheometer. The microstructure of the chocolate samples was analyzed by Scanning Electron Microscope technique at 500-1000x magnification. Particle size distribution and sensory evaluation was also performed. Results showed addition of free and encapsulated forms of chlorogenic acids decreased Tonset, Tpeak and ΔH of dark chocolate. Casson viscosity increased in the case of addition chlorogenic acids. Color indexes of chocolate samples were influenced by addition of chlorogenic acids. Particle size distribution decreased with addition of free form and increased when encapsulated form was added. Sensory characteristics were also influenced by chocolate formulation and samples included encapsulated chlorogenic acids exhibit better sensory properties than samples enriched with free form.

Facile and Green Preparation of Pectin/Cellulose Composite Films with Enhanced Antibacterial and Antioxidant Behaviors

Novel bioactive films based on pectin and cellulose (PC) with different loadings of tea polyphenols and cinnamaldehyde were successfully prepared. A thermal stability was tested, and the results showed that the thermal stability decreased slightly after loading with cinnamaldehyde and tea polyphenols, compared to PC films. The antimicrobial and antioxidant capacities were also investigated. Results showed that PC composite films had good DPPH radical and hydroxyl radical scavenging activities and excellent antibacterial activities against Escherichia coli, Candida albicans and Staphylococcus aureus. Based on the results, the great antioxidant and antibacterial activities of the tea polyphenol and cinnamaldehyde loaded PC films make them suitable for food packaging and preservation.