Influence of protein standardisation media and heat treatment on viscosity and related physicochemical properties of skim milk concentrate

Characterization and gelling properties of a bioactive extract from Ascophyllum nodosum obtained using a chemical-free approach

The bioactivity and gelling properties of a carbohydrate-rich algal extract obtained from locally harvested Ascophyllum nodosum seaweed using a chemical-free approach were investigated for its potential interest in food applications. Physicochemical characterisation and compositional analysis of the extract, using FTIR, biochemical methods and monosaccharide analysis, confirmed the presence of alginates and fucoidans, although the main polysaccharide present in it was laminarin. Significant amounts of phenolic compounds (~9 ​mg phloroglucinol/100 ​mg sample) were also detected. As a result, the extract exhibited good antioxidant activity. It also showed promising prebiotic potential, promoting the growth of beneficial Lactobacillus sp. and Bifidobacteria sp. when compared with commercial prebiotics, but not that of pathogenic bacteria such as E. coli or P. aeruginosa. The gelling properties of the raw extract were explored to optimize hydrogel bead formation by external gelation in CaCl₂ solutions. This was enhanced at neutral to alkaline pHs and high extract and CaCl₂ concentrations. The mechanical strength, nano- and microstructure of the hydrogel beads prepared under optimised conditions were determined using compression tests, synchrotron small- and wide-angle X-ray scattering (SAXS/WAXS) and scanning electron microscopy (SEM). It was concluded that the raw algal extract at neutral pH had potential for use as a gelling agent, although further enrichment with alginate improved the mechanical properties of the obtained gels. The advantages and disadvantages of applying the non-purified algal extract in comparison with purified carbohydrates are discussed.

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Carbohydrate-rich extract from A. nodosum obtained using a chemical-free process.

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The algal extract exhibited in-vitro antioxidant and prebiotic properties.

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Beads were obtained by external gelation of the extract at neutral to alkaline pH.

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Enrichment with alginate improved the mechanical properties of the gels.

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Components of the extract acted as fillers, reducing structural changes upon drying.

Impact of cold plasma on the techno-functional and sensory properties of whey dairy beverage added with xylooligosaccharide

This study aimed to evaluate the impact of cold plasma (0, 5, 10, or 15 min) on the techno-functional and sensory properties of whey dairy beverages added with xylooligosaccharide (XOS, 1.5% p/v). Untreated and pasteurized whey beverages were also evaluated. The products were evaluated for physicochemical characteristics, bioactive compounds, XOS stability, rheological properties, and sensory characteristics. Cold plasma and pasteurized products presented lower color intensity (L*=87.4-87.9, a*=-0.24- -0.60, b*=2.41-5.19), reduced consistency (K = 4.31-42.21 mPa.sⁿ and N = 0.57-0.95), and similar apparent viscosity, XOS chemical stability, and sensory characteristics compared with the untreated product. However, the cold plasma-treated beverages presented lower heat load indicators (hydroxymethylfurfural [HMF] values of 1.91-2.10 µmol/L and whey protein nitrogen index [WPNI] of 6.09-6.66 µmol/L) and a higher concentration of bioactive compounds (antioxidant activity [5.31-9.30%], and inhibition of ACE [14.17-22.53%], α-amylase [18.52-25.67%] and α-glucosidase [22.50-27.50%] activities) than the pasteurized product, being the effects more pronounced for the higher exposure times. Overall, cold plasma has important advantages for the processing of whey beverages added with XOS.