The objective of this study was to evaluate the effect of cryoconcentration assisted by centrifugation-filtration on the bioactive compounds and the microbiological quality of aqueous maqui (Aristotelia chilensis (Mol.) Stuntz) and calafate (Berberis microphylla G. Forst) extracts pretreated with high-pressure homogenization (HPH). Aqueous extracts were prepared from fresh fruits which were treated with HPH (predefined pressure and number of passes). The best pretreatment was determined by aerobic mesophilic, fungal, and yeast counts. Treated extracts were frozen at −30 °C in special tubes and centrifuged at 4000 rpm for 10 min to obtain the cryoconcentrated product. The optimal pretreatment conditions for HPH were 200 MPa and one pass in which the extracts exhibited no microorganism counts. Cryoconcentration by freezing and subsequent centrifugation-filtration in a single cycle showed high process efficiency (>95%) in both soluble solids and bioactive compounds (total polyphenols and anthocyanins) and antioxidant capacity of the fresh fruits and extracts. The HPH treatment and subsequent cryoconcentration assisted by centrifugation-filtration is an efficient technology to obtain concentrates with good microbiological quality and a high content of bioactive compounds.
Maqui (Aristotelia chilensis (Mol.) Stuntz) is a Chilean berry rich in antioxidants, which are mostly found in the pulp and skin of the fruit. The objective was to evaluate the cryoconcentration process by centrifugation–filtration as a simultaneous, efficient, and innovative method to increase the content of thermosensitive bioactive compounds of aqueous maqui extract. Cryoconcentration separated the concentrated solute from the aqueous maqui extract with an efficiency of more than 95%; it increased the content of total polyphenols and total anthocyanins and antioxidant capacity by 280%, 573%, and 226%, respectively. Although the concentrates obtained by evaporation at 50, 70, and 80 °C increased the content of bioactive compounds, they did so in a lower percentage than the cryoconcentrate. Furthermore, cyanidin 3,5-diglucoside was degraded at 70 and 80 °C. In conclusion, cryoconcentration by centrifugation–filtration as a simultaneous process efficiently separates the solutes from the frozen matrix of aqueous maqui extract, and it maintains and increases the contents of polyphenols and anthocyanins and antioxidant capacity. This method is recommended for concentrating natural berry extracts with thermosensitive compounds.
The effects of thermal and non-thermal pretreatments combined with different drying methods on the drying kinetics, physicochemical properties, and bioactive compounds of the Chilean wild mushroom Morchella conica were investigated. Fresh samples were subjected to hot-air drying (HAD, 60 °C), freeze-drying (FD), and a hybrid process (FD–HAD), applied directly or after pretreatments including thermal pre-drying (55 and 75 °C), ultrasound (US, 10 and 20 min), and high hydrostatic pressure (HHP, 600 MPa). Drying curves were successfully fitted using the Weibull model (R2 > 0.987), showing that HAD combined with thermal and ultrasound pretreatments increased drying rates, while FD–HAD reduced total drying time. Freeze-drying better preserved color (ΔE < 2) and minimized shrinkage (<8%), whereas HAD produced darker samples and greater structural deformation. Water activity decreased below 0.30 in most treatments, ensuring microbiological stability. Thermal pretreatments enhanced total phenolic content, while FD preserved antioxidant capacity. Principal component analysis explained 62.2% of the total variance, revealing distinct quality profiles among drying methods. Overall, FD and hybrid FD–HAD combined with moderate pretreatments showed the best balance between drying efficiency and quality preservation, while HHP improved antioxidant properties under specific conditions. These findings highlight the potential of integrating innovative pretreatments with drying technologies to optimize processing of Morchella conica.
The effects of thermal and non-thermal pretreatments combined with different drying methods on the drying kinetics, physicochemical properties, and bioactive compounds of the Chilean wild mushroom Morchella conica were investigated. Fresh samples were subjected to hot-air drying (HAD, 60 °C), freeze-drying (FD), and a hybrid process (FD–HAD), applied directly or after pretreatments including thermal pre-drying (55 and 75 °C), ultrasound (US, 10 and 20 min), and high hydrostatic pressure (HPP, 600 MPa). Drying curves were successfully fitted using the Weibull model (R² > 0.987). The highest drying rates were observed in HAD combined with thermal and ultrasound pretreatments, whereas the FD–HAD process significantly reduced the total drying time. Freeze-drying preserved color (ΔE < 2) and minimized shrinkage (< 8%), while HAD resulted in darker samples and greater structural deformation. Water activity decreased below 0.30 in most treatments, ensuring microbiological stability, with the lowest values observed for HPP–FD and US 20 min–FD (0.10–0.11). Thermal pretreatments enhanced total phenolic content, whereas FD preserved antioxidant capacity. Principal component analysis explained 68.9% of the total variance and revealed distinct quality profiles among drying methods. These findings indicate that combining moderate pretreatments with freeze-drying or hybrid drying processes improves the technological efficiency and functional quality of Morchella conica.