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This study investigated the influence of mechanical and physicochemical properties of semi-solid model foods on the detection and temporal perception of texture contrast. Gel-based model foods consisting of two layers were used to systematically vary mechanical contrast and physicochemical properties within bi-layer gels. Fracture stress (σ F ) and strain (ε F ) were modified by changing the concentration of various gelling agents (agar, к-carrageenan, and gelatine). The physicochemical properties of gels varied with respect to syneresis and melting behaviour depending on the type of gelling agent. The detection limit of perceived texture contrast of bi-layer gels was determined using ranking tests. Subjects ranked gels in order of increasing perceived heterogeneity as a measure of texture contrast. The detection limit of texture contrast varied between brittle and elastic gels and between soft (low σ F ) and hard (high σ F ) gels. In soft and brittle agar gels, heterogeneity was perceived already when the difference in fracture stress between layers was small (Δσ F ≥5 kPa). In soft and elastic gels (к-carrageenan, gelatine) and hard gels, heterogeneity was perceived only when the difference in fracture stress between the layers was large (Δσ F ≥12 kPa). The perceived heterogeneity intensity over time was investigated by time-intensity profiling. During mastication, gelatine gels were perceived for a longer period of time with a higher heterogeneity intensity than agar and к-carrageenan gels. We conclude that mainly mechanical properties of gels impact detectability of mechanical contrast as perceived texture contrast (heterogeneity), whereas a combination of mechanical and physicochemical properties influence the dynamic perception of heterogeneity over time. [ABSTRACT FROM AUTHOR]

The effects of different agar and/or carrageenan proportions as wall material and the core-to-wall material ratio on physicochemical properties, delivery and bioaccessibility of microencapsulated brewer's spent grain (BSG) bioactive peptides were evaluated. Also, peptides from BSG hydrolysate were identified by LC-MS/MS. Microencapsulation was carried out by spray drying. All microcapsules exhibited negative charge both, at pH 2.0 and 7.0. Peptide release was higher at pH 7.0 than pH 2.0, showing a higher release at the site of absorption. Higher proportion of agar in the formulation had a positive impact on both, spray drying yield and encapsulation efficiency. Moreover, higher core-to-wall material ratio (1:4) improved encapsulation efficiency and maintained and even increased ABTS scavenging, ACE-I and DPP-IV inhibition, after a simulated gastrointestinal digestion process. Peptides identified from BSG hydrolysate ranged from 8 to 21 residues, contained mostly glutamic and glutamine residues and were rich in hydrophobic amino acids. Using in silico predictions, 16 peptides identified could act as antihypertensive and antidiabetogenic compounds, showing a multifunctional potential of BSG. [Display omitted] • Agar and carrageenan could be used as wall material to obtained microcapsules (M). • M were effective to protected bioactive peptides during in vitro digestion. • Higher protein content improved physicochemical properties and bio-accessibility. • Peptides identified could act as antihypertensive and antidiabetogenic compounds. [ABSTRACT FROM AUTHOR]

Extruded and native wheat flours were combined with agars ( Gracilaria and Gelidium ) and carrageenans (κ-carrageenan and ι-carrageenan) to modify their paste and gel properties. Combinations of extruded flours with hydrocolloids produced an increase in the hydration properties (swelling volume and water holding and water binding capacities). All hydrocolloids (particularly ι-carrageenan) also produced an increase in hydration properties after combination with native flours. With regard to the pasting properties of native flours combinations, all hydrocolloids produced an increase in peak viscosity (particularly Gelidium agar), but only agars decreased the onset temperature of gelatinization and increased breakdown, indicating a different mechanism of action. In the presence of extruded flour, the incorporation of hydrocolloids increased the cold viscosity of flours in very different ways depending on the hydrocolloid. Both native and extruded flours exhibited higher G′ and G″ values and a lower tan δ after the incorporation of carrageenans, which, together with the lower dependence on frequency, would produce stiffer and more stable pastes/gels. Based on gel properties, greatest hardness with native and extruded flours was achieved by the incorporation of carrageenans. In general, carrageenans, besides producing stiffer and more stable pastes, gave rise to harder and clearer gels compared to those made with agar, for both their combination with extruded and native wheat flours. Meanwhile, pastes made with combinations of extruded flours and agar showed higher thixotropy. [ABSTRACT FROM AUTHOR]

Spiced edible gels and films were produced as part of a future technological strategy to improve the quality of pork from entire male by contributing to a decrease in boar taint and improving the texture of the meat. Each formulation, two types of hydrocolloids and two spice mixtures, were tested for their high masking power (mixtures 1 and 2). The thermoreversible hydrocolloids carrageenans (g-C) and agar-agar (g-A) were used in the production of the gels, and maltodextrin + sodium alginate (f-MA) and gelatin (f-G) for the films. The results showed that the films and gels edible had good physical-chemical and mechanical characteristics, providing sufficient stability to act as a vehicle to incorporate spices and condiments into entire male pork, being mixture 2 provided the highest values. While the use of hydrocolloids in the films improved the texture of the meat. [Display omitted] • Gels and films reached correct mechanical properties to act as vehicles of spices. • Films made with hydrocolloids improved the pork sensory texture. • Spice mixture 2 had the greatest sensorial impact on the meat matrix. • Spiced edible films and gels were an alternative to alleviate boar-tainted pork. [ABSTRACT FROM AUTHOR]

Functional films were made by solution casting using three different types of carbohydrates (agar, chitosan, and carrageenan) and curcumin. Field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FTIR) test results showed that curcumin is homogeneously dispersed within the polymer matrix. Addition of a small amount of curcumin (1 wt%) increased the UV-blocking, swelling ratio, surface hydrophobicity, and water vapor barrier property of the carbohydrate-based films. The release rate of curcumin was influenced by the type of polymer matrix, i.e. the carrageenan-based film exhibited the fastest release of curcumin following agar and chitosan-based films. Also, the composite films exhibited high antioxidant activity and some antibacterial property depending on the type of carbohydrate, which was consistent with the release rate of curcumin, water solubility and swelling ratio of the composite films. The curcumin-incorporated carbohydrate films with increased physical and functional properties can be used for active food packaging films. Image 1063 • Curcumin-incorporated various carbohydrate-based composite films were prepared. • UV-blocking, swelling, surface hydrophobicity and WVP properties were enhanced. • Curcumin-incorporated film exhibited strong antioxidant and some antimicrobial activity. • Properties of the composite films depended on the type of carbohydrate polymer matrix. [ABSTRACT FROM AUTHOR]