Andean blueberry is a promissory fruit native to South America. The current work aimed to characterize starches isolated from Colombian native potatoes and to evaluate the effect of the application of starch edible coatings on the changes in the physicochemical quality parameters of the Andean blueberry during storage. Starches were isolated from three different potatoes varieties (pacha negra, mora, and alcarrosa) and characterized. Then, starch-based coatings were applied to Andean blueberries, and the changes in their quality parameters were monitored during 12 days of storage. Despite the phenotypical differences in the starch sources used, starches were similar in terms of their granule morphology, amylose content (~19%), crystallinity degree (~46%), and thermal properties. Coatings were able to reduce the gaseous exchange of the fruit, and, thus, the respiration rate of all coated blueberries was ~27% lower compared to the uncoated fruits (p < 0.05) at the end of the storage. While the application of starch coatings did not prevent water loss, all samples reached water loss of up 20%. Besides, the coated fruits showed soluble solids contents ~14% higher compared to the control one, as well as better bright and firmness. The new edible coatings can help add value to the Andean blueberry.
The detection of emerging contaminants in bodies of water has steadily increased in recent years, becoming a severe problem threatening human and ecosystem health. Developing new materials with adsorption properties to remove these pollutants represents an important step toward a potential solution. In this paper, a polybutylene adipate terephthalate (PBAT) nanofibrous membrane incorporating clinoptilolite zeolite was developed and its excellent performance in removing tetracycline (TC) and methylene blue (MB) from water was demonstrated. The composite membrane was prepared in two steps: firstly, a homogeneous dispersion of clinoptilolite (1 wt% respect to polymer) in a PBAT solution (12.6 wt%) was electrospun; secondly, the electrospun membrane was subjected to an acid treatment that improved its wettability through the protonation of the surface silanol groups of clinoptilolite. The resulting membrane was hydrophilic and showed higher adsorption for TC (800 mg/g) and MB (100 mg/g), using a low dose (90 mg/L) powdered zeolite. The maximum removal capacity was obtained at neutral pH, being the cation exchange reaction the main adsorption mechanism. Pseudo-second-order kinetics and Henry’s law agree well with the proposed chemisorption and the high affinity of TC and MB for the adsorbent. The material can be reused after the removal process without generating additional contamination, although losing some effectivity.
Starch constitutes a promising resource for biodegradable packaging, but it presents several processing drawbacks when using conventional industrial equipment, such as flat‐die extrusion. This work demonstrates that the replacement of native cassava starch (NS) with commercial hydrolyzed (HS) or carboxymethyl (CMS) starches diminishes the amount of energy required to process starch granules into thermoplastic films by extrusion. Homogeneous films with starch‐glycerol interaction improvements are obtained when using HS or CMS instead of NS. HS films exhibit the lowest crystallinity and the highest susceptibility to water among the studied systems. Likewise, CMS films maximize Vh crystalline structure fraction and present higher Young's modulus and stress at break, and lower water vapor permeability values. In order to combine the positive properties and to overcome the limitations of each modified starch, blend films from HS:CMS (50:50 wt%) are also developed and investigated. Phase separation is observed in this system, and there are no improvements in the overall properties. The results of this investigation show that employing commercial CMS, even in very low carboxymethylation degree represents a successful strategy to improve mechanical and barrier properties of flat‐die extruded films, while HS can be used to obtain water‐soluble films for specific applications.
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