Incorporation of Locust Bean Gum and Solid Lipid Microparticles as Strategies to Improve the Properties and Stability of Calcium-Rich Soy Protein Isolate Gels.

The present study aimed to investigate the properties of calcium-rich soy protein isolate (SPI) gels (14% SPI; 100 mM CaCl2), the effects of incorporating different concentrations locust bean gum (LBG) (0.1-0.3%, w/v) to the systems and the stability of the obtained gels. Also, the incorporation of solid lipid microparticles (SLMs) was tested as an alternative strategy to improve the system's stability and, therefore, potential to be applied as a product prototype. The gels were evaluated regarding their visual aspect, rheological properties, water-holding capacities (WHCs) and microstructural organizations. The CaCl2-induced gels were self-supported but presented low WHC (40.0% ± 2.2) which was improved by LBG incorporation. The obtained mixed system, however, presented low stability, with high syneresis after 10 days of storage, due to microstructural compaction. The gels' stability was improved by SLM incorporation, which decreased the gelled matrices' compaction and syneresis for more than 20 days. Even though the rheological properties of the emulsion-filled gels (EFGs) were very altered due to the ageing process (which may affect the sensory perception of a future food originated from this EFG), the incorporation of SLMs increased the systems potential to be applied as a calcium-rich product prototype.

Saltiness perception in gel-based food systems (gels and emulsion-filled gels).

Reducing salt in food without compromising its quality is a huge challenge. Some review articles have been recently published on saltiness perception in some colloidal systems such as emulsions. However, no published reviews are available on saltiness perceptions of gel-based matrices, even though salt release and perception in these systems have been extensively studied. This article reviews the recent advances in salt perception in gel-based systems and provides a detailed analysis of the main factors affecting salt release. Strategies to enhance saltiness perception in gels and emulsion-filled gels are also reviewed. Saltiness perception can be improved through addition of biopolymers (proteins and polysaccharides) due to their ability to modulate texture and/or to adhere to or penetrate through the mucosal membrane on the tongue to prolong sodium retention. The composition of the product and the distribution of salt within the matrix are the two main factors affecting the perception of salty taste. Food structure re-design can lead to control the level of interaction between the salt and other components and change the structure, which in turn affects the mobility and release of the salt. The change of ingredients/matrix can affect the texture of the product, highlighting the importance of sensory evaluation.

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.

Encapsulation of Beta-carotene in Lipid Microparticles Stabilized with Hydrolyzed Soy Protein Isolate: Production Parameters, Alpha-tocopherol Coencapsulation and Stability Under Stress Conditions.

The objectives of this research were to study the encapsulation of beta-carotene (BC) in solid lipid microparticles (SLM) of palm stearin (PS) and stabilized with hydrolyzed soy protein isolate (HSPI), and also to investigate the effect of alpha-tocopherol (TOC) addition to the systems. Through the characterizations of SLM produced with different formulations, it was verified that systems with 5% (w/v) PS, 1.0% (w/v) HSPI, and 0.3% (w/v) xanthan gum (XG) presented the highest stability, with average diameters of approximately 1.2 µm. This formulation was applied for the production of BC-loaded SLM, with different concentrations of TOC. In SLM containing TOC, nearly 75% of encapsulated BC was preserved after 45 d of storage. The kinetic profiles for degradation of encapsulated BC were fitted to a pseudo-1st-order model, and the results showed that the main difference among the systems with different BC:TOC ratios was the residual concentration of BC. The stability of the BC-loaded SLMs was also studied after stress conditions, and the results showed that the SLMs were able to support thermal treatments over 60 °C but presented low stability after different ionic strength stresses.