ABSTRACT
Pumpkin seeds are rich in protein (24-36.5%). Some of them are consumed as nuts, while others are regarded as waste and used for feeding animals. Protein hydrolysates from pumpkin seeds possess some bioactive properties, such as anti-oxidant activity. In this work, various composite alginate hydrogels contain Aloe vera, CMC, and tragacanth have been employed to protect PSPH against degradation in simulated gastrointestinal digestion (SGI) and regulate its release rate. The encapsulation efficiency of PSPH in plain alginate and beads with Aloe vera, CMC, and tragacanth combinations was 71.63, 75.63, 85.07, and 80.4%, respectively. The release rate of the plain alginate beads was %30.23 in the SGF and %52.26 in the SIF, and decreased in the composite-based beads. The highest decreasing rate in the antioxidant activity during SGI was observed in free PSPH, and the decreasing rate slowed down in the alginate-based composites. The swelling rate in plain alginate was %-23.43 and %25.43 in the SGF and SIF, respectively, and increased in the composite-based beads. The FTIR spectra of hydrogels before and after loading with PSPH showed identical absorption patterns and were similar to each other. Based on the data for SEM, it was revealed that substituting other polymers in polymer combinations with alginates resulted in a porosity reduction of the beads and smoother and more uniform surfaces. Based on the results, the combination of polysacchared with alginate could protect and increase the applicability of PSPH as a functional component in the food industry.
ABSTRACT
This study was conducted to investigate the impact on the techno-functionality over sodium caseinate (NaCS) when are conjugated with soluble soybean polysaccharides (SSPS). NaCS/SSPS conjugates were prepared through the Maillard reaction using dry heating. The formation of covalent binding between NaCS and SSPS and structural changes of NaCS during glycation were confirmed via SDS-PAGE and ATR-FTIR. A positive correlation was observed between the increase in the browning index of samples and Amadori compounds formation over time, based on the colorimetric results. Emulsions stabilization using conjugates with a higher NaCS/SSPS ratio led to a decreasing trend in the droplets' size and creaming index. Meanwhile, higher viscosity and shear-thinning behavior were observed in conjugate-based emulsions. Finally, conjugates prepared with the NaCS/SSPS ratio of 9/1 at an incubation time of 24 h presented a higher pH and thermal stability and better performance in emulsion stabilization in comparison with each of the biopolymers alone.
