Valorization of Flaxseed Oil Cake Residual from Cold-Press Oil Production as a Material for Preparation of Spray-Dried Functional Powders for Food Applications as Emulsion Stabilizers

Flaxseed oil cake extract (residual from cold-press oil production and rich in proteins and polysaccharides) was evaluated as a potential substrate for the preparation of spray-dried powders with emulsifying activity. Three variants of powders were obtained using different spray-drying process inlet temperatures: 160 °C, 180 °C, and 200 °C. The influence of temperature on physicochemical features (water holding capacity, oil binding capacity, water activity, solubility, color, chemical composition, antioxidant activity, and surface morphology) of the powders was estimated. Additionally, the emulsifying activity of the powders and the stability of oil-in-water emulsions prepared with their various content (0.5%, 1%, and 3%) were determined. Results showed that inlet temperature had significant influence on all physicochemical and functional properties of the powders. Increased inlet temperature decreased solubility and antioxidant activity but increased water-holding capacity, oil-binding capacity, and emulsifying activity. The emulsions prepared with the powder obtained at 200 °C showed the highest stability. SEM images showed the production of relatively spherical particles which were folded or wrinkled with a lot of dentures. This study could open a promising pathway for producing natural and plant-based spray-dried powders for food applications as emulsion stabilizers.

Development, Characterization, and Bioactivity of Non-Dairy Kefir-Like Fermented Beverage Based on Flaxseed Oil Cake

Flaxseed oil cake (FOC) was evaluated as a potential substrate for the production of a novel kefir-like fermented beverage. Three variants containing 5%, 10%, and 15% (w/w) of FOC were inoculated with kefir grains and incubated at 25 °C for 24 h. After processing, beverages were stored in refrigerated conditions (6 °C) for 21 days. Changes in microbial population, pH, acidity, levels of proteins, polyphenolics, flavonoids, ascorbic acid, and reducing sugars were estimated. Additionally, viscosity, firmness, color, and antioxidant properties were determined. Results showed that lactic acid bacteria as well as yeast were capable of growing well in the FOC without any supplementation. During refrigerated storage, the viability of the microorganisms were over the recommended minimum level for kefir products. As a result of fermentation, the beverages showed excellent antioxidant activity. Because of the functional characteristics conferred to the FOC beverages, the use of kefir grains showed adequate potential for the industrial application. Therefore, this beverages could be used as a new, non-dairy vehicle for beneficial microflora consumption, especially by vegans and lactose-intolerant consumers.

The Influence of Accelerated UV-A and Q-SUN Irradiation on the Antimicrobial Properties of Coatings Containing ZnO Nanoparticles

The influence of accelerated UV-A and Q-SUN irradiation on the antimicrobial properties of coatings containing ZnO nanoparticles was investigated using a polyethylene (PE) film covering. The results of the study showed that Methyl Hydroxypropyl Celluloses (MHPC) coatings did not influence the growth of S. aureus, B. cereus, E. coli, P. aeruginosa or C. albicans cells. MHPC coatings containing ZnO nanoparticles inhibited the growth of bacterial strains and reduced the number of C. albicans strains. Accelerated Q-SUN and UV-A irradiation had no influence on the antimicrobial effect of nano ZnO coatings against S. aureus, B. cereus and E. coli. Q-SUN irradiation decreased the activity of MHPC coatings containing nanoparticles against P. aeruginosa and C. albicans. An FT-IR analysis clearly showed that ZnO nanoparticles shielded the MHPC coating during Q-SUN irradiation.