Impact of acidification and protein fortification on thermal properties of rice, potato and tapioca starches and rheological behaviour of their gels

Producción CientíficaThe impact of acidification and non-gluten protein fortification (egg-albumin and soy-protein isolate) on thermal transitions of rice, potato and tapioca starches as well as the viscoelastic properties of their gels prepared at two casting temperatures, 90ºC and 120ºC, was investigated. The thermal and rheological behaviour of starches depended on their botanical origin and were significantly influenced by the presence and type of protein added as well as by the pH of the aqueous dispersion. Acidification to pH 4.5 increased the gelatinization temperature of rice starch in the presence of albumin or soy proteins, while reduced it in the case of tapioca starch, regardless of the presence of proteins. Acidification of rice starch dispersions decreased significantly the apparent gelatinization enthalpy; this effect was even greater in the presence of proteins. The addition of proteins brought about a structuring effect on tapioca gels leading to higher viscoelastic moduli and lower tan δ values. In general, acidification led to weaker gel structures, with more pronounced effect for potato starch, most likely related to its higher phosphate content (charge screening). Much weaker gels were obtained at 120ºC compared to those processed at lower temperatures; however, protein incorporation reinforced gel structure, an effect that was not observed in gels formed at 90º, as also revealed by microstructure analysis using confocal scanning laser microscopy. In conclusion, protein addition and pH adjustments of aqueous starch dispersions can provide an effective means to modulate the functional and textural properties of gel-like starch-based gluten-free formulations.Ministerio de Economía, Industria y Competitividad - FEDER (Projects AGL2012-35088 and AGL2015-63849-C2-2-R)Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA072P17

Microstructural factors affecting the stability of viscoelastic caseinate emulsions flocculated by polysaccharides

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Ocular Co-Delivery of Timolol and Brimonidine from a Self-Assembling Peptide Hydrogel for the Treatment of Glaucoma: In Vitro and Ex Vivo Evaluation

Effective pharmacotherapy during glaucoma treatment depends on interventions that reduce intraocular pressure (IOP) and retain the IOP lowering effect for sufficient time so as to reduce dosing frequency and enhance patient adherence. Combination anti-glaucoma therapy and dosage forms that increase precorneal residence time could therefore constitute a promising therapeutic intervention. The in-situ gel forming self-assembling peptide ac-(RADA)4-CONH2 was evaluated as carrier for the ocular co-delivery of timolol maleate (TM) and brimonidine tartrate (BR). The hydrogel’s microstructure and mechanical properties were assessed with atomic force microscopy and rheology, respectively. Drug diffusion from the hydrogel was evaluated in vitro in simulated tear fluid and ex vivo across porcine corneas and its effect on the treated corneas was assessed through physicochemical characterization and histological analysis. Results indicated that TM and BR co-delivery affected hydrogel’s microstructure resulting in shorter nanofibers and a less rigid hydrogel matrix. Rapid and complete release of both drugs was achieved within 8 h, while a 2.8-fold and 5.4-fold higher corneal permeability was achieved for TM and BR, respectively. No significant alterations were induced in the structural integrity of the corneas treated with the hydrogel formulation, suggesting that self-assembling peptide hydrogels might serve as promising systems for combination anti-glaucoma therapy

Effects of Cornus and Its Mixture with Oregano and Thyme Essential Oils on Dairy Sheep Performance and Milk, Yoghurt and Cheese Quality under Heat Stress

The effect of a diet supplemented with a novel cornus extract, enriched with essential oils of oregano and thyme, on the performance of Chios cross-bred dairy sheep was investigated during the summer period. The plant extracts were prepared using a “green” method based on aqueous extraction. A total of 45 lactating ewes were allocated into three equal groups in a randomized block design. The three groups were fed the same feed allowance, roughage based on Lucerne hay and wheat straw and a concentrate based on cereals and oil cakes (the control diet). The diet of two groups was fortified with cornus extract, with or without oregano and thyme essential oils, at a level 0.515 g of plant extract/essential oils per kg of concentrate. Individual milk yield was recorded weekly and feed refusals were recorded on a pen basis daily, during a six-week period of lactation. Milk samples were analyzed for the chemical composition of protein, fat, lactose and solids-not-fat constituents, somatic cell counts and total viable bacteria counts. Moreover, the milk of each group was used for yoghurt and Feta cheese production. The lipid oxidative stability, protein carbonyl content and fatty acid composition of milk, yoghurt and cheese samples were also evaluated. The results showed that the incorporation of novel plant extracts and essential oils increased the milk production per ewe. Dietary supplementation with cornus extracts and essential oils lowered lipid and protein oxidation in milk, yoghurt and cheese samples, compared to the control. However, diet supplementation with herbal extracts did not affect the fatty acid profile in milk, cheese and yoghurt or the serum biochemical parameters. In conclusion, dietary supplementation with cornus in combination with oregano and thyme has the potential to improve feed utilization and the performance of high-yield dairy Chios cross-bred ewes reared under heat stress

A floating 3D printed polypill formulation for the coadministration and sustained release of antihypertensive drugs

Polypharmacy is a common issue, especially among elderly patients resulting in administration errors and patient inconvenience. Hypertension is a prevalent health condition that frequently leads to polypharmacy, as its treatment typically requires the co-administration of more than one different Active Pharmaceutical Ingredients (API's). To address these issues, floating hollow torus-shaped dosage forms were developed, aiming at providing prolonged gastric retention and sustained drug release. The dosage forms (polypills) containing three anti-hypertensive API's (diltiazem (DIL), propranolol (PRP) and hydrochlorothiazide (HCTZ)) were created via Fused Deposition Modelling 3D printing. A multitude of the dosage forms were loaded into a capsule and the resulting formulation achieved prolonged retention times over a 12-hour period in vitro, by leveraging both the buoyancy of the dosage forms, and the "cheerios effect" that facilitates the aggregation and retention of the dosage forms via a combination of surface tension and shape of the objects. Physicochemical characterization methods and imaging techniques were employed to investigate the properties and the internal and external structure of the dosage forms. Furthermore, an ex vivo porcine stomach model revealed substantial aggregation, adhesion and retention of the 3D printed dosage forms in porcine stomach. In vitro dissolution testing demonstrated almost complete first-order release of PRP and DIL (93.52 % and 99.9 %, respectively) and partial release of HCTZ (65.22 %) in the 12 h timeframe. Finally, a convolution-based single-stage approach was employed in order to predict the pharmacokinetic (PK) parameters of the API's of the formulation and the resemblance of their PK behavior with previously reported data.</p