Study of the Physical, Chemical, and Structural Properties of Low- and High-Methoxyl Pectin-Based Film Matrices Including Sunflower Waxes.

The development of bio-based materials remains one of the most important alternatives to plastic materials. Although research in this field is growing, reporting various materials and methodologies, it is still necessary to increase exploration. The aim of this work was to expand and complement previous research on the preparation and characterization of high- and low-methoxyl pectin films obtained by casting, with the addition of commercial and recovered sunflower waxes. The results showed that the addition of sunflower waxes to the pectin matrix generated some discontinuity in the aggregate, increasing the thickness and roughness of the film. However, due to their hydrophobic nature, the waxes contributed to lower vapor transmission rate values of the films. On the other hand, the low-methoxyl pectin films had a more crystalline structure, which could help to diminish water vapor permeability values, mechanical resistance and rigidity, and improve their elongation. Regarding chemical characteristics, most of the raw materials' chemical groups were found in the resulting films, and the presence of C-H bending due to pectin gelation was observed. Finally, the compatibility and contribution of pectin and sunflower waxes to the production of the films were demonstrated, as well as the possibility of using materials from industrial waste in food packaging applications.

Characterization and Applications of the Pectin Extracted from the Peel of Passiflora tripartita var. mollissima.

The inadequate management of organic waste and excessive use of plastic containers cause damage to the environment; therefore, different studies have been carried out to obtain new biomaterials from agricultural subproducts. The objective of this work was to evaluate the feasibility of using the pectin extracted from the peel of Passiflora tripartita var. mollissima (PT), characterizing its type and viability for the production of edible biodegradable films. In addition, films of two thicknesses (23.45 ± 3.02 µm and 53.34 ± 2.28 µm) were prepared. The results indicated that PT is an excellent raw material for the extraction of pectin, with high yields (23.02 ± 0.02%), high galacturonic acid content (65.43 ± 2.241%), neutral sugars (ribose, xylose, glucose) and a high degree of esterification (76.93 ± 1.65%), classifying it as a high-methoxy pectin. Regarding the films, they were malleable and flexible, with a water vapor permeability from 2.57 × 10-10 ± 0.046 to 0.13 × 10-10 ± 0.029 g/s mPa according to thickness, being similar to other Passiflora varieties of edible films. The pectin extraction yield from PT makes this fruit a promising material for pectin production and its chemical composition a valuable additive for the food and pharmaceutical industries.

Ultrasound-assisted extraction of oilseeds-sustainability processes to obtain traditional and non-traditional food ingredients: A review.

Oilseeds are sources of not only major compounds such as oil and meal but also of bioactive compounds. Their conventional extraction is related to long extraction time, large non-renewable solvent consumption, high temperature, and therefore, high energy consumption. Ultrasound-assisted extraction (UAE) has emerged as a new and green technology, which can accelerate and/or improve the extraction process of these compounds. Moreover, the possibility of using renewable solvents in the UAE enhances its application and allows obtaining both extracted and remaining products more compatible with current human consumption requirements. This article examines the mechanisms, concepts, and factors that impact oilseeds' UAE with an emphasis on the extraction yield and quality of oil, meal, and bioactive compounds. Furthermore, the effects of combining UAE with other technologies are addressed. Gaps detected in the analyzed literature about oilseed treatment and quality and properties of products, in addition to perspectives about their uses as food ingredients, are also included. Moreover, it highlights the need for increasing research on process scalability, on environmental and economic impacts of the whole process, and on the phenomenological description about the effect of process variables on extraction performances, which will be a key tool for process design, optimization, and control. Understanding ultrasound processing techniques for the extraction of different compounds from oilseeds will serve as useful information for fats and oils and meal scientists in academia and industry to explore the possibility of employing this sustainable approach during the extraction treatment of various crops.

Pectin Films with Recovered Sunflower Waxes Produced by Electrospraying.

Valorization of by-products obtained from food processing has achieved an important environmental impact. In this research, sunflower wax recovered from oil refining process was incorporated to low and high-methoxyl pectin films produced by electrospraying. Film-forming solutions and wax-added electrosprayed films were physical and structurally evaluated. The addition of sunflower wax to the film-forming solutions reduces conductivity while raising surface tension and density, whereas the type of pectin had a larger impact on viscosity, with the low-methoxyl solution having the highest value. These changes in physical solution properties influenced the film characteristics, observing thicker films with lower water vapor transmission rate (WVTR) when adding wax. Micrographs obtained by scanning electron microscopy (SEM) revealed the presence of wax particles as small spherical shapes, having a good distribution through the sectional area of films. According to X-ray diffraction (XRD), atomic force microscopy (AFM) and mechanical properties analyses, the presence of wax had an impact on the degree of crystallinity, producing a more amorphous and rougher film's structure, without affecting the elongation percentage and the tensile stress (p>0.05). These results showed that wax addition improves the physical properties of films, while the suitability of using both pectins and the electrospraying technique was demonstrated.

Edible films based on aqueous emulsions of low-methoxyl pectin with recovered and purified sunflower waxes.

BACKGROUND: Edible films were obtained from aqueous emulsions prepared with low-methoxyl pectin at different concentrations (10, 20 and 30 g kg-1 ) and two sunflower wax samples recovered from two waste samples of filter cakes produced in the winterization process of sunflower oil. The two sunflower waxes samples recovered (from the normal hybrid, NSFW, and from the high-oleic hybrid, HOSFW) were added in three proportions (0.1, 0.2 and 0.3 g g-1 of pectin). Films were evaluated according to their structure, water resistance, water vapor permeability, mechanical properties and thermal behavior. RESULTS: In general, good dispersion of the lipid material was observed in the cross-sections of the film. Increase in the water resistance (lower swelling index and water adsorption) was associated with a greater pectin content crosslinked with Ca2+ and the hydrophobic nature of waxes. The reduction in water vapor transfer rates was influenced by the effect of the wax addition, their fatty acid composition and their good distribution on the film. More resistant, rigid and less flexible films were obtained with lower pectin content, finding an inverse relationship between tensile strength and elongation percentage values. CONCLUSION: These results evidence a promising alternative in the development of innovative strategies to valorize sunflower waxes derived from waste material. © 2020 Society of Chemical Industry.

Emulsions of sunflower wax in pectin aqueous solutions: Physical characterization and stability.

The knowledge of the stability and physical properties of film-forming solutions is necessary for optimizing the process design of films. In order to evaluate their applicability for the production of edible films, the rheological and microstructural properties, particle size and physicochemical stability of aqueous emulsions of low methoxyl pectin and sunflower waxes from normal and high-oleic hybrids were assessed. Emulsions were prepared with different pectin concentrations (1, 2 and 3% w/w) and wax proportions (0.1, 0.2 and 0.3 g/g pectin). The rheological behavior was best described by the power law model. The values of the behavior index (n) were close to 1, exhibiting a behavior close to Newtonian fluids. The addition of waxes caused an increase in viscosity and shear stress. The particle size of the emulsions made with waxes from high-oleic sunflower was smaller than those from the normal hybrid. In most cases, size distributions with greater height and less amplitude were obtained, mainly when the pectin content was higher. Confocal images allowed to observe the presence of waxes and their dispersion in the pectin matrix. Destabilization phenomena such as sedimentation, coalescence and creaming were observed at long test times independent of the wax origin. These results evidence the potential use of these emulsions for the manufacture of edible films.