Macroalgae suspensions prepared by physical treatments: Effect of polysaccharide composition and microstructure on the rheological properties

The use of macroalgae in food products is growing due to their techno-functionality and nutritional properties. In this context, an increased understanding of the rheological properties which are relevant for manufacturing and texture is needed. Here we investigated the impact of thermal and mechanical treatments, including high pressure homogenisation (HPH), on the polysaccharide composition, microstructure, and rheological properties of brown algae Laminaria digitata suspensions (5 wt %). Monosaccharide analysis and immunolabeling of alginate in combination with confocal laser scanning microscopy, revealed a sequential release of different polysaccharides as result of the applied shear. Results showed that thermal treatment (70 \ub0C 1 h) and mild shear lead to suspensions of clusters of cells and release of fucoidan and laminarin into the liquid phase, conferring shear thinning properties to the suspensions. High pressure homogenisation was able to completely break the macroalgae cells, reducing particle size and releasing other soluble polysaccharides, in particular alginate, conferring gel properties (G\u27>G\u27\u27) to the suspensions. This study contributes to the knowledge of how to design sustainable, innovative and nutritious liquid/semiliquid food products containing macroalgae biomass

Maximizing the oil content in polysaccharide-based emulsion gels for the development of tissue mimicking phantoms

Formulations based on agar and κ-carrageenan were investigated for the production of emulsion gels applicable as tissue mimicking phantoms. The effects of the polysaccharide matrix, the oil content and the presence of surfactants on the micro-/nanostructure, rheology, and mechanical and dielectric properties were investigated. Results showed a high capacity of the agar to stabilize oil droplets, producing gels with smaller (10−21 μm) and more uniform oil droplets. The addition of surfactants allowed increasing the oil content and reduced the gel strength and stiffness down to 57 % and 34 %, respectively. The permittivity and conductivity of the gels were reduced by increasing the oil content, especially in the agar gels (18.8 and 0.05 S/m, respectively), producing materials with dielectric properties similar to those of low-water content tissues. These results evidence the suitability of these polysaccharides to design a variety of tissue mimicking phantoms with a broad range of mechanical and dielectric properties

Rheological and structural characterization of carrageenan emulsion gels

Carrageenan emulsion gels containing sunflower oil were prepared using three different commercial carrageenan grades (κ-C, ι-C and λ-C). The effect of the carrageenan and salt content, as well as the oil:water ratio, on the emulsion gel strength was evaluated through a response surface methodology. Moreover, the rheological properties and the micro- and nanostructure from the stronger emulsion gel formulations were investigated and compared to their analogous hydrogel formulations. Interestingly, emulsion gels formed stronger and more thermally stable networks than the hydrogels, being this effect more evident in ι-C and λ-C. The results indicate that this was mainly due to a polysaccharide concentration effect, as no evidence of interactions between the carrageenan and the oil phase was found. Consequently, the rheological behaviour of the emulsion gels was mostly determined by the type of carrageenan. The association of carrageenan molecular chains was favoured in κ-C and λ-C (due to the presence of κ-carrageenan in the latter) and promoted by the addition of KCl. In contrast, a lower degree of chain association, mostly driven by ionic cross-linking, took place in ι-C. These results evidence the relevance of the gelation mechanism on the properties of emulsion gels and provide the basis for the design of these systems for targeted applications within the food industry. \ua9 2020 Elsevier B.V

Outcomes from elective colorectal cancer surgery during the SARS‐CoV‐2 pandemic

Aim This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic. Method This was an international cohort study of patients undergoing elective resection of colon or rectal cancer without preoperative suspicion of SARS-CoV-2. Centres entered data from their first recorded case of COVID-19 until 19 April 2020. The primary outcome was 30-day mortality. Secondary outcomes included anastomotic leak, postoperative SARS-CoV-2 and a comparison with prepandemic European Society of Coloproctology cohort data. Results From 2073 patients in 40 countries, 1.3% (27/2073) had a defunctioning stoma and 3.0% (63/2073) had an end stoma instead of an anastomosis only. Thirty-day mortality was 1.8% (38/2073), the incidence of postoperative SARS-CoV-2 was 3.8% (78/2073) and the anastomotic leak rate was 4.9% (86/1738). Mortality was lowest in patients without a leak or SARS-CoV-2 (14/1601, 0.9%) and highest in patients with both a leak and SARS-CoV-2 (5/13, 38.5%). Mortality was independently associated with anastomotic leak (adjusted odds ratio 6.01, 95% confidence interval 2.58–14.06), postoperative SARS-CoV-2 (16.90, 7.86–36.38), male sex (2.46, 1.01–5.93), age >70 years (2.87, 1.32–6.20) and advanced cancer stage (3.43, 1.16–10.21). Compared with prepandemic data, there were fewer anastomotic leaks (4.9% versus 7.7%) and an overall shorter length of stay (6 versus 7 days) but higher mortality (1.7% versus 1.1%). Conclusion Surgeons need to further mitigate against both SARS-CoV-2 and anastomotic leak when offering surgery during current and future COVID-19 waves based on patient, operative and organizational risks