Bioavailability of bioactive compounds of guava leaves (Psidium guajava) aqueous extract concentrated by gravitational and microwave-assisted cryoconcentration

The effects of gravitational (GC) and microwave-assisted (MWC) cryoconcentration were studied on the total phenolic content (TPC) and antioxidant activity of aqueous guava leaves extract. An increase in the TPC was observed for all the concentrated fractions by both methods. The concentration efficiency for the GC and MWC processes was 80% and 73% and the concentration index obtained for TPC was 3 and 9, respectively. The antioxidant activity also increased next to 3 and 11 folds, for GC and MWC, respectively, after cryoconcentration. Catechin and vescalagin were the main compounds found. Although both the cryoconcentration processes generated extracts rich in TPC, the bioaccessibility was greater for the MWC concentrated extract during the in vitro simulated gastrointestinal condition steps, which characterizes this extract at the fourth stage as the one with the best functional properties. Practical applications Several emerging technologies have been studied as alternatives to the conventional concentration process, such as cryoconcentration. In this context, the use of cryoconcentration to concentrate bioactive compounds of guava leaves aqueous extract may represent a way to increase and maintain the antioxidant properties. This study demonstrated that cryoconcentration assisted by microwave reduced the processing time in half, which generates energy savings, maintenance of compounds, and an increase in the antioxidant capacity next to 11-times. The study contributes to recent research that suggests cryoconcentration as a promising technology to be adopted in the food industry.

Automated summary

The study showed that both GC and MWC cryoconcentration increased the total phenolic content and antioxidant activity of guava leaves extract. The MWC process generated extracts with higher bioaccessibility during gastrointestinal conditions.