RESUMO

Plant proteins with improved solubility, foaming, and emulsifying properties are required to meet the demand for plant-based foods. This study evaluated the influence of alkaline extraction combined with enzyme- and ultrasound-assisted extraction on lentil protein structure and functionality. Enzyme- and ultrasound-assisted extractions were not capable of increasing the protein yield compared to alkaline extraction alone. However, the purity of isolated protein was dependent on the extraction process, ranging from 82.7% to 90%. Although the molecular mass, zeta potential profiles, and denaturation temperature were not dependent on the extraction method, the enthalpy of denaturation for protein obtained solely by alkaline extraction was significantly lower than that for assisted processes, indicating that protein denaturation is caused by an alkaline process. Changes in protein structure were also suggested by solubility analyses that showed that lentil proteins obtained by enzyme-assisted and ultrasound-assisted extraction have better solubility at pH 7 when compared to alkaline extraction alone. The surface activity of lentil protein was evidenced by interfacial and surface analysis, and it was influenced by the extraction process applied. We demonstrated that combining alkaline extraction with assisted processes, especially ultrasound technology, results in concentrates/isolates with higher solubility as compared to ones obtained solely by the traditional alkaline method, even though the choice of extraction method should depend on the desired functionality.

RESUMO

Surfactant-polyelectrolyte complexes (SPECs) based on lecithin and sodium caseinate were produced and the effects of such binding on the physical, chemical and emulsifying properties were evaluated and compared with the two ingredients in isolation. Negative, neutral, and positive charged SPECs were obtained. Zeta potential values and size distributions of the SPECs were dependent on the mass ratio between compounds. Electrostatic association decreased the polydispersity index in comparison with pure compounds solutions. Analysis of interfacial properties showed that solutions containing SPECs promoted a greater reduction of surface tension and interfacial tension with sunflower oil when compared with pure compounds solutions. Emulsions produced with SPECs in 10:1 lecithin:sodium caseinate ratio proved to be more stable than emulsions prepared with pure compounds. Thus, the complexation improved the emulsifying properties of lecithin and sodium caseinate establishing SPECs as potential natural emulsifiers.

RESUMO

The viability of Lactobacillus acidophilus when co-encapsulated with fructooligosaccharides in alginate-gelatin microgels, for incorporation into liquid, Greek, and frozen yogurts, during storage and in vitro-simulated digestion was studied. Liquid yogurt provided the highest viability for the encapsulated probiotics during storage, followed by frozen and Greek formulations when compared to free probiotics, highlighting the influence of microencapsulation, yogurt composition, and storage conditions. Addition of up to 20% of probiotic (AG) and symbiotic (AGF) microgels did not cause significant changes in the liquid and frozen yogurts' apparent viscosity (ηap ); however, it decreased ηap for the Greek yogurt, indicating that microgels can alter product acceptability in this case. Both AG and AGF microparticles improved viability of cells face to gastric conditions for liquid and frozen yogurts, delivering cells in the enteric stage. Summarizing, liquid yogurt was the most appropriate for probiotic viability during storage, while frozen yogurt presented better protection along digestibility.

Assuntos

RESUMO

Xylooligosaccharides (XOS) are emerging prebiotic that may improve structural features of biopolymer blends. The investigation around the conformation of XOS into the matrix of alginate and gelatin clarifies the potential applications of this formulation in the food industry as texture modifiers or encapsulation systems. Structural properties verified by flow behavior, SEM, XRD, and FT-IR demonstrated that the add up to 3% XOS into the alginate-gelatin blend formed a cohesive matrix, with smaller pores and crystalline structure, confirming the potential of xylooligosaccharides hydrogels for the development of functional and synbiotic foods.

Assuntos

RESUMO

In this work, we developed biopolymeric structures, based on electrostatic attraction, through dripping gellan gum into hydrolyzed collagen (HC), to deliver hydrophilic compounds. Moreover, we evaluated the influence of starch addition on the polymeric network as well as the coating effects promoted by an outer gellan layer. The lowest tested gellan gum concentration in the core (0.5% w/w) was the best one to build spherical beads, with high retention of bioactives (>84% for anthocyanin and >68% for HC). Moreover, the minimum HC concentration (2.5% w/w) in the gelling bath allowed the saturation of active sites of gellan gum presented in the core, as regardless of the HC concentration in the peptide bath, particles presented the same amount of adsorbed peptide. Starch disturbed the interactions between HC and gellan, increasing porosity and pore size, but it presented an important role in retaining anthocyanin in the particle's core. Finally, we demonstrated that addition of a gellan coating layer affected the structure of beads: Peptide molecules (positively charged), already adsorbed onto the beads, diffused out of the core, attracted by the negatively charged gellan coating layer. Consequently, it decreased particle size and increased pore size in the outer part of the particles, which was associated with a reduction in the retention of bioactives. These findings bring important contributions to particle engineering: A new process for particle production was proposed, in which hydrogels were produced by dripping the polysaccharide into the protein bath to be externally gelled, without previous crosslinking with salts.

Assuntos