Extruded samples of starch-casein blends were processed by using a single-screw extruder. The independent variables in the process were temperature (126-1947C), moisture content (18-29%) and starch-casein blend (5-95%). These independent variables affected significantly the physicochemical and textural properties of the biopolymers. The highest values for expansion (EXP) and water absorption index (WAI) were found when a higher starch proportion was present in the blends, at 1267C barrel temperature and moisture content higher than 25%. By increasing the barrel temperature, from 1267C to 1947C, the water solubility index (WSI) and color parameter were increased. Initial viscosity (IV) and viscosity at 907C (V90) were mainly affected by the barrel temperature at 1947C. However, the viscosity at 507C (V50) was affected neither by the different extrusion variables nor by the biopolymer proportion in the blends. Compression force (CF) was strongly dependent on moisture content and casein proportion in the blend. The higher CF values were found at starch concentrations around 50% and 25% moisture content, for higher or lower values than these the obtained extruded products were softer and consequently had lower CF values.

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The aim of this work was to synthesize silver nanoparticles (NPs) through a green synthesis method using starch as a capping agent. The influence of the glucose content, temperature, and pH on the size of the NPs was evaluated by means of a response surface methodology. The obtained nanomaterials were characterized by UV-Vis spectroscopy, XRD, and TEM, and the crystalline structure of the silver was determined by XRD. The optimum synthesis time was after 3 h of reaction time the colloidal solution, did not show any further significant variation in the optical absorption peak (l max ). Response surface results indicate that the reducing agent (glucose) concentration was the most important factor influencing the NPs size, which ranged from 2 to 24 nm. TEM images show that NPs had predominantly spherical shapes, but also polyhedral shapes were present in smaller quantities. Analysis of Raman spectra infers that the glucose initially reduces silver ions to elemental silver. Then the starch undergoes hydrolysis providing primary hydroxyl that contributes to the reduction of silver. The carboxyl and hydroxyl groups of glucose and hydrolyzed starch stabilize the silver NPs by passivating their surface, so that they do not aggregate and remain uniformly distributed.

Materials used for wound care have evolved from simple covers to functional wound dressings with bioactive properties. Electrospun nanofibers show great similarity to the natural fibrillar structure of skin extracellular matrix (ECM); therefore, by mimic, the morphology of ECM, nanofibers show high potential for facilitating the healing of skin injuries. Besides morphology, scaffold composition is another important parameter in the production of bioactive wound dressings. Collagen type I is the main structural protein of skin ECM is biocompatible, biodegradable, and its extraction from animal sources is relatively simple. The fabrication of electrospun wound dressings based on collagen and its blends have been studied for skin tissue engineering applications. This review focus on the new advances of collagen electrospun materials for skin wound treatment. It summarizes the recent research on pristine collagen, collagen blends, and collagen surface modifications on nanofibers mats. Finally, the strategies for three‐dimensional nanofibers production will also be discussed.

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Betalains were extracted and analyzed from Opuntia joconostle (the prickly pear known as xoconostle in Mexico). For the extraction, two solvent systems were used, methanol/water and ethanol/water. A three-variable Box-Behnken statistical design was used for extraction: solvent concentration (0-80%, v/v), temperature (5-30 °C), and treatment time (10-30 min). The extraction and stability of betalains from xoconostle were studied using response surface methodology (RSM). Techniques such as UV-vis, column chromatography, and HPLC were employed for the separation and analysis of the main pigments present in the extracts. Maximum pigment concentration (92 mg/100 g of fruit) was obtained at a temperature of 15 °C and a time of 10 min for methanol/water (20:80), whereas maximum stability of the pigment was observed at pH 5 and a temperature of 25 °C. HPLC chromatograms showed the main betalains of the xoconostle characterized were betalain, betanidin, and isobetalain.

BACKGROUND: Several storage techniques have been developed to extend the post-harvest shelf life of horticultural products. One method involves the use of edible or biodegradable coatings. Such coatings are made of biological materials that are used to coat fresh products, providing a semi-permeable barrier to water vapour and gases, e.g. O 2 and CO 2 . The influence of starch concentration, glycerol content and pH on the carbon dioxide permeability (CO 2 P) and mechanical properties of gelatine-starch edible films were evaluated.