Physicochemical characterization and sensory evaluation of yogurts incorporated with beta-carotene-loaded solid lipid microparticles stabilized with hydrolyzed soy protein isolate.

Beta-carotene is an extremely interesting bioactive compound in the food industry due to its antioxidant capacity and pro-vitamin A activity. However, its incorporation into food products can be challenging, as it is highly hydrophobic and chemically unstable. The aim of this study was to evaluate the feasibility of incorporating beta-carotene-loaded solid lipid microparticles (SLMs) stabilized with a hydrolyzed soy protein isolate in yogurt. The SLMs were produced using palm stearin as the lipid phase. Microparticle dispersions containing only beta-carotene and both beta-carotene and alpha-tocopherol were incorporated into yogurts, comprising 5% of its total mass. This addition itself was efficient to provide color, and the presence of the lipid microparticles did not change the physicochemical or the rheological characteristics of the product. Based on the sensory evaluation, the panelists approved the yogurt, as average grades of global acceptance were around 8.0 ("liked it very much") on the hedonic scale.

Stability of curcumin encapsulated in solid lipid microparticles incorporated in cold-set emulsion filled gels of soy protein isolate and xanthan gum.

The objective of this study was to investigate the feasibility of producing cold-set emulsion filled gels (EFG), using soy protein isolate (SPI) and xanthan gum (XG) and incorporating curcumin-loaded solid lipid microparticles (SLM). For this purpose, the formulation GXG (15%, w/v SPI, 0.1%, w/v XG and 5mM CaCl2) was selected for the production of EFG. A comparative study on the rheological and microstructural properties of non-filled gels and EFG revealed that SLM stabilized with Tween 80-Span 80 behaved as active fillers in the gel matrix, increasing the Young's modulus from 1.1 to 2.3kPa, and also increasing the values of storage and loss moduli. The incorporation of SLM also affected the microstructural organization of the systems. Whereas unfilled gels presented a microstructural organization similar to that of interpenetrated networks, EFG exhibited a microstructure with clear phase separation. The stability of encapsulated curcumin in EFG was monitored using a colorimetric test and it was confirmed that the bioactive component showed a high stability for 15days. After that period, the color started to change, indicating a decrease in curcumin concentration. The instability of curcumin was probably related to structural alterations of the EFG, which led to decreases of hardness after 7days of storage at 10°C, and to the collapse of the structures after 30days. Although formulation improvements are required, the results indicate that the encapsulation of curcumin in SLM incorporated in EFG is a potential alternative for the replacement of yellow artificial dyes in gelled food products.

Rheology of Emulsion-Filled Gels Applied to the Development of Food Materials.

Emulsion-filled gels are classified as soft solid materials and are complex colloids formed by matrices of polymeric gels into which emulsion droplets are incorporated. Several structural aspects of these gels have been studied in the past few years, including their applications in food, which is the focus of this review. Knowledge of the rheological behavior of emulsion-filled gels is extremely important because it can measure interferences promoted by droplets or particle inclusion on the textural properties of the gelled systems. Dynamic oscillatory tests, more specifically, small amplitude oscillatory shear, creep-recovery tests, and large deformation experiments, are discussed in this review as techniques present in the literature to characterize rheological behavior of emulsion-filled gels. Moreover, the correlation of mechanical properties with sensory aspects of emulsion-filled gels appearing in recent studies is discussed, demonstrating the applicability of these parameters in understanding mastication processes.

Production and structural characterization of solid lipid microparticles loaded with soybean protein hydrolysate.

The aims of this study were to produce and evaluate solid lipid microparticles (SLMs) loaded with soy protein hydrolysate (HP). The SLMs were produced by spray chilling with an active material and carrier ratio of 1:5 and 1:10 and in two feed preparations: emulsion and suspension. The rheological parameters of the feeds produced by emulsions were studied, morphological characteristics of the SLMs were examined via scanning electron microscopy (SEM) and confocal microscopy, the particle size and distribution were measured via laser light diffraction, and the structural properties of the SLMs were characterized via infrared (FTIR) spectroscopy and X-ray diffraction (XRD). SEM images showed that SLMs were spherical and agglomerated. The analysis of X-ray diffraction indicated that the microparticles after 90days of storage had ß polymorphic form. The preparation methods for feeds, emulsion and suspension, had no influence on the rheological parameters, and the median particle size of the SLMs and interactions between the ingredients were not detected via FTIR spectroscopy; however, the SLMs prepared by emulsion contained pores and had a higher incorporation efficiency of HP. The spray chilling technique is suitable method for microencapsulation of soy protein hydrolysate. So, this technique could be useful for attenuating HP unpleasant taste, for its protection and also for promoting its release in the intestine, during fat digestion.