Approaches in biotechnological applications of natural polymers

Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

Association of time spent in physical activities and sedentary behaviors with carotid-femoral pulse wave velocity: A systematic review and meta-analysis

Background and aims: Increased arterial stiffness is linked to increased risk of cardiovascular disease and mortality. Studies have reported conflicting results regarding the relationship between arterial stiffness and time spent in sedentary behavior (SB) and physical activity (PA). The objective of this systematic review and meta-analysis was to assess the relationship between objectively measured light PA (LPA), moderate to vigorous PA (MVPA), and SB with the gold standard measurement of arterial stiffness, carotid-femoral pulse wave velocity (cfPWV). Methods: PubMed, Scopus, and Web of Science were searched for relevant studies published until November 2016. Studies reporting the correlation of objectively measured PA and SB with cfPWV in human adults >18 years old were included in this analysis. Correlation coefficients (CCs) were converted to Z scores via Fisher's z values for the analysis of summary effects, using a random-effects model. Results: Twelve studies were included in the systematic review. The meta-analysis showed a negative correlation between cfPWV and LPA (CC -0.16; 95% CI: −0.29 to −0.03; p=0.02) and MVPA (CC -0.16; 95% CI: −0.26 to −0.06; p<0.01), and a positive relationship between cfPWV and SB (CC 0.23; 95% CI: 0.12 to 0.35; p<0.01). Conclusions: Time spent in light and moderate physical activities is associated with lower arterial stiffness, while time spent in SB is related to higher arterial stiffness. It suggests that PA at any intensity is favorable for arterial stiffness, whereas SB leads to increased arterial stiffness. Considering that cfPWV has an independent prognostic value, these associations may have important clinical implications