A comparative study on the encapsulation of black carrot extract in potato protein-pectin complexes.

This manuscript reveals the effect of the emulsification step on the black carrot extract (BCE) stabilization by potato protein isolate (PPI)-citrus pectin (CP) coacervates. The effect of core-to-wall ratio and concentration of wall material were also investigated. This was the first attempt to compare the characteristics of emulsified core particles (ECP) and non-emulsified core particles (NECP) coated with complex coacervates. Potato protein was used as an encapsulating agent by complex coacervation for the first time, and it showed excellent characteristics for the encapsulation. Non-hygroscopic particles were produced with emulsification while most of NECPs were slightly hygroscopic. The mean particle diameter of powders ranged from 65.05 to 152.47 µm which is suitable with SEM micrographs. ECPs showed lower particle size values with increased wall concentration at the constant core-to-wall ratio. Encapsulation efficiency (EE) increased, and anthocyanin retention (AR) decreased when emulsification was included. EE of NECP and ECP was between 69.26-82.84% and 85.48-90.15% while AR was between 79.08-102.16% and 53.90-83.37%, respectively. FT-IR and ζ-potential values proved the complexation between PPI and CP in ECPs as well as the interaction of PP, CP, and BCE in NECPs. DSC thermograms proved the success of the encapsulation procedure and thermo-stability of the BCE-loaded particles. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05787-z.

The impact of pH and biopolymer ratio on the complex coacervation of Spirulina platensis protein concentrate with chitosan.

Spirulina platensis is one of the most significant multicellular blue-green Cyanobacterium microalgae with a high protein content. The complex coacervation as an encapsulation technique allows the formation of proteins with improved functional properties and thermal stability. In this study, the effects of pH and Spirulina platensis protein concentrate (SPPC)-chitosan ratio on complex coacervation formation were examined in terms of ζ-potential, turbidity, visual observation and microscopic images. Based on the results, the strongest interaction between SPPC and chitosan occurred at pH of 5.5 and SPPC-chitosan ratio of 7.5:1 with a precipitation in the test tubes. Stable dispersions were obtained at a pH range of 2-4 for the SPPC-chitosan ratio of 7.5:1 inhibiting the precipitation which occurs at individual SPPC solutions at this pH range. Characteristic organic groups in the individual SPPC and chitosan solutions as well as the SPPC-chitosan coacervate formed at the optimal conditions were identified by using Fourier Transform Infrared (FT-IR) spectroscopy technique. Furthermore, thermal stability of the individual SPPC and chitosan solutions and the SPPC-chitosan coacervates were investigated using differential scanning calorimetry (DSC). The glass transition temperature and enthalpy were 209.5 °C and - 3.414 W/g for the complex coacervates and 180.5 °C and - 0.877 W/g for SPPC. It means that complex coacervation provided more thermally-stable SPPC in chitosan-SPPC coacervate than that of the individual SPPC. Our results might have important implications for the utilization of Spirulina platensis proteins especially for acidic beverage applications.

Modulation of the bitterness of pea and potato proteins by a complex coacervation method.

The incorporation of novel plant-based proteins into foods is often challenging due to an unacceptable bitter sensation. Typically, a combination of electrostatic and hydrophobic forces contributes to the proteins' bitterness. The current study therefore focuses on the development of electrical properties on cationic plant proteins to reduce their overall bitterness in order to improve the perceived sensorial acceptance. As such, we utilized a simple mixing process to induce complex coacervation of oppositely charged biopolymers under acidic conditions. Pea and potato protein stock solutions were mixed with apple pectin (DE 71%) solutions at various biopolymer ratios to modulate the electrical, rheological, and sensorial properties of the complexes. Whey protein hydrolyzate was used as a control sample. Surface charge measurements revealed a transition from positive to negative values as the pectin concentration was increased regardless of the plant protein, whereas stable dispersions without sedimentation were observed above a critical pectin : protein ratio of 1. Low and intermediate biopolymer ratios (<1) promoted aggregation and led to rapid sedimentation. Sensory evaluation showed that bitterness scores depended on protein type and decreased from pea protein > potato protein > whey protein. Moreover, bitter off-notes were increasingly reduced with increasing pectin : protein ratios; however, high dispersion viscosities above 0.05 Pa s led to undesirable texture and mouthfeel of the biopolymer dispersions. Our results might have important implications for the utilization of novel plant proteins in food and beverage applications.