Encapsulation of phenolic and antioxidant compounds from spent coffee grounds using spray-drying and freeze-drying and characterization of dried powders.

Spent coffee grounds (SCG) are a coproduct that causes environmental impacts worldwide. Thus, consciously reusing the SCG is an eminent need. This work aimed to encapsulate phenolic compounds and antioxidants obtained from SCG extracts through spray- and freeze-drying techniques using different isolated and combined wall materials. The dried powders produced were evaluated for moisture content, water activity, bulk density, hygroscopicity, color, content of phenolic compounds and antioxidants, and the results were compared. The results showed that all evaluated treatments resulted in a powdered product with low values of bulk density, moisture and water activity, especially for freeze-drying. The freeze-dried product also showed higher hygroscopicity. Regarding the content of phenolic compounds and antioxidants, both drying methods showed high levels of these compounds in the dried product and good encapsulation efficiency, reaching 83.43%. In most cases, spray-drying and freeze-drying did not differ statistically (p > 0.05) in relation to bioactive compound content and encapsulation efficiency. In relation to wall materials, albumin showed the worst performance in the retention of bioactive compounds. On the other hand, pure gum arabic combined with maltodextrin led to better preservation of these compounds. PRACTICAL APPLICATION: Spent coffee grounds are a coproduct generated in large quantities in the world. The encapsulation of phenolic and antioxidant compounds protects and enables their application in different food matrices. Therefore, the evaluation of different encapsulation methods and wall materials is important to define good process conditions.

Encapsulation of safflower oil in nanostructured lipid carriers for food application.

Safflower oil (SO) is mainly rich in linoleic acid (ω-6), oleic acid (ω-9), and other bioactives with potential antioxidant, antidiabetic, thermogenic, anti-inflammatory, cardioprotective and anticancer activities. The reduced aqueous solubility and high susceptibility to oxidative degradation are undesirable for food applications and can be overcome by incorporation in lipid nanoparticles. Thus, the main goal was to develop and characterize SO-loaded nanostructured lipid carriers (NLC-SO) and to evaluate their potential for protection of the antioxidant activity of the bioactive. NLC-SO showed average size of 222 ± 2.0 nm, zeta potential of  43 ± 3.5 mV and the encapsulation efficiency was 49.0 ± 2.8%, combined with high thermal compatibility (up to 228 °C) and physical stability for up to 60 days in aqueous dispersion. Besides, the NLC-SO showed threefold reduction in the DPPH radical scavenge activity after encapsulation, indicating protection of the antioxidant components of the SO and preservation of the bioactives. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13197-021-05078-5.

Matrix structure selection in the microparticles of essential oil oregano produced by spray dryer.

The goal of this work was to select the best combination of encapsulants for the microencapsulation of oregano essential oil by spray dryer with the addition of Arabic gum (AG), modified starch (MS) and maltodextrin (MA). The simplex-centroid method was used to obtain an optimal objective function with three variables. Analytical methods for carvacrol quantification, water activity, moisture content, wettability, solubility, encapsulation efficiency (ME) and oil retention (RT) were used to evaluate the best combination of encapsulants. The use of AG as a single wall material increased ME up to 93%. Carvacrol is the major phenolic compound existent in the oregano essential oil. Carvacrol exhibits a maximum concentration of 57.8% in the microparticle with the use of 62.5% AG and 37.5% MA. A greater RT (77.39%) was obtained when 74.5% AG; MS 12.7% and 12.7% MA were applied, and ME (93%) was improved with 100% of gum.