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Background and Objectives: The objective of this work was to evaluate the processing of black rice grains to obtain flour and to verify the influence of pretreatments on mass transfer, in vitro digestibility, and technological properties. The grains were submitted to heat moisture treatment (HMT) with a final humidity of 30% at 110°C for 2 h, black rice pretreatment with ethanol (BRE) in the proportion 1:1 (wt/wt) for 5 min/25°C, and high hydrostatic pressure (HHP) under conditions of 200 MPa for 10 min/25°C. Then, the grains were dried at 60°C at an air velocity of 1.5 m/s and ground in an electric multigrain grinder. Was analyzed the mass transfer, in vitro digestion, water, oil, and milk retention capacity, total phenolic compounds (TPC), total anthocyanins (TA), antioxidant activities by (2,2′‐azino‐bis‐(3‐ethylbenzothiazoline‐6‐sulfonic) acid, 2,2‐diphenyl‐1‐picrylhydrazyl, ferric‐reducing antioxidant power, and oxygen radical absorbance capacity Surface appearance by scanning electron microscopy, and thermal analysis by differential scanning calorimetry was carried out. Findings: The grains when submitted to the HHP obtained a reduction of 58.82% in the drying time, while the HMT promoted an increase of 23.5% when compared to the control. The pretreatments influenced the in vitro digestibility, where the HHP had the highest value (86.33), as well as the highest water, oil, and milk retention capacities. BRE positively impacted TPC, TA, and antioxidant activities regardless of the methods used. HMT promoted the formation of cavities, fissures, and holes on the surface, resulting in a rough appearance and presenting greater thermal resistance with an enthalpy of 12.35 J/g. Conclusions: This research paved the way for potential commercial applications of black rice flour as an ingredient in functional foods. Significance and Novelty: This study adds to the significance and novelty of research on black rice processing by evaluating the influence of different pretreatments on mass transfer, in vitro digestibility, and technological properties. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of temperature on the drying kinetics of achachairu peels. Empirical and diffusive models were used to describe the drying kinetics and the thermodynamic properties of the process. Both fresh and dehydrated samples were characterized according to their bioactive compounds and antioxidant activity. The drying was carried out in an air circulation oven at a speed of 1.5 m s−1 at temperatures ranging from 40 to 80°C. Parameters of the effective diffusivity and activation energy were calculated considering the first six terms of Fick's model, and the thermodynamic properties are as follows: enthalpy, entropy and Gibbs free energy. Total phenolic compounds, antioxidant activity by ABTS•+ and DPPH•, and total tannins using aqueous and hydroalcoholic extracts were analysed for both fresh peels and the dehydrated. Page's model was considered to be the most appropriate for describing the drying process that occurred at a decreasing rate from the initial phases until the end of the process; Fick's model showed a higher diffusivity value at a temperature of 80°C. The activation energy of the process ranged from 27.773 to 27.569 kJ mol−1 depending on the number of terms used in Fick's model. The thermodynamic properties indicated that the process is endothermic and not spontaneous. The extraction process using solvents with different polarities (water and ethanol) enabled the extraction of phenolic compounds; however, the extraction by 'AE' revealed superior results for AA‐ABTS•+, TT and AA‐DPPH•, the latter not being capable of identifying differences in the fresh sample. [ABSTRACT FROM AUTHOR]