Summary: Microcapsules produced from well‐defined emulsion templates are an interesting alternative for lipid encapsulation. This work aimed to produce microcapsules by the freeze‐drying (FD) and spray‐drying (SD) of Pickering emulsions of roasted coffee oil (RCO) stabilised with chitosan nanoparticles produced by self‐aggregation or by crosslinking with tripolyphosphate. The dried microcapsules were characterised in terms of particle size, oil retention and structure; furthermore, the in vitro bioaccessibility of polyphenols from microencapsulated RCO was investigated. The use of chitosan nanoparticles to stabilise the emulsions increased oil retention in the microcapsules giving values between 83.04% and 95.36%. SD produced spherical microcapsules with small particle sizes (˜11 μm), whereas FD microcapsules showed an irregular shape and porous structure. Although FD had the lowest impact on the bioactive compounds, SD promoted better protection for phenolic compounds and antioxidant activity during in vitro digestion.

Food processes have been requiring increasingly more accurately designed operations. Successful design results in products with high quality, in addition to offering energy and cost savings. To these ends, fundamental knowledge regarding the physical properties and thermodynamic mechanisms of the material is essential. The aim of this review was to highlight important concepts and applications of some thermophysical properties (density, specific heat, thermal conductivity and thermal diffusivity), as well as recent methods for their determination. The rheology of fluids and solids is widely discussed according to the concepts, classification, modeling and applications involved in food and equipment design. Herein, we report destructive and non-destructive assays for the evaluation of food properties. Due to the complexity of food systems, the effects of modifications of the structure and physicochemical reactions on the quality of the resulting food are addressed based on thermodynamic aspects. This analytical perspective was adopted in food systems rich in fats, proteins, polysaccharides and simple sugars. Using the information reported in this study, formulations and unit operations can be better designed. In addition, process failures become more predictable when fundamental knowledge is available. Therefore, food losses can be avoided, quality can be maintained and operations can be effectively resumed when deviations from ideal conditions are evidenced.

Antioxidant compounds extraction from coffee husks: the influence of solvent type and ultrasound exposure time

Several plants have been studied as potential sources of natural antioxidants for use in the food industry, especially polyphenols. The aim of this study was to evaluate the effects of hydroalcoholic extract from coffee husk on the oxidative stability of soybean oil when stored in an oven. Samples were maintained at a temperature of 60 °C and their oxidative stability was evaluated once every 5 days for a period of 20 days through the Rancimat equipament and analysis of peroxide value, conjugated dienes and tocopherols retention. The oxidation rate in terms of mass gain was evaluated once every 24 hours for a period of 24 days. Although the antioxidant TBHQ showed a better efficiency in the inhibition of oxidation, coffee husk extract showed a synergistic effect when used with the synthetic, delaying the appearance of degradation products. In addition, the freeze-dried extract showed the ability to reduce the mass-gain rate when used alone as well as when used in combination with the synthetic antioxidant butyl hydroxyanisole (BHA), noting a synergistic effect on oxidative stability between the extract and the BHA. Therefore, coffee husk extract could be considered a source of natural antioxidants for synthetic antioxidants substitution.