Impact of pretreatments with ethanol and freezing on drying slice papaya: drying performance and kinetic of ultrasound-assisted extraction of phenolics compounds.

BACKGROUND: Pretreatments of drying can represent an alternative to minimize the negative aspect process on the dry samples. Thus, the influence of ethanol (ET) and freezing (FG) as drying pretreatments was analyzed for slices of papaya. The slices (5 mm) were submitted for drying kinetics (60 °C and 1.5 m s-1 ). Drying kinetics experimental data were fitted using Page's model and a diffusive model with boundary condition of types I and III. Also the thermophysical properties (thermal conductivity and specific heat) were determined and finally, the kinetics of ultrasound-assisted (40 kHz and 132 W) extraction of total phenolic compounds (TPCs) were realized. RESULTS: The combined method (ET + FG) was more efficient in reducing the drying time of papaya slices (48%) and the model 2 simulating the boundary condition of the third type (type III) showed the best fit to the experimental data. Effective diffusivity and convective coefficient were higher for ET + FG, where the maximum reduction in water content was 91% compared to fresh slices. The pretreatments did not influence the thermal conductivity, however, they were significant in the specific heat and in the extraction of TPCs, being higher in the time of 180 min. CONCLUSION: It was confirmed in the results presented that the combined pretreatment ET + FG is the most viable for drying papaya slices. Furthermore, it was found to be the most efficient in minimizing the loss of TPCs. Therefore, this pretreatment has great potential for application in the development of high value-added foods. © 2022 Society of Chemical Industry.

Assessment of the hypoglycemic effect of Bixin in alloxan-induced diabetic rats: in vivo and in silico studies.

The objectives of this study were to extract and purify Bixin from the seeds of Bixa orellana and to evaluate its hypoglycemic activity in vivo, as well as, to conduct an in silico study of selectivity on peroxisome proliferator-activated receptors via molecular docking and molecular dynamics simulations. Oral administration of Bixin (10 mg/kg) significantly reduced their glucose level that was alloxan-induced diabetic rats. Bixin showed in silico selectivity on peroxisome proliferator-activated receptors (PPARs), particularly by the peroxisome proliferator-activated receptor gamma (PPARγ), which supports the hypoglycemic activity of Bixin. From the results obtained, it can be inferred that Bixin presents hypoglycemic characteristics, which was confirmed by the results obtained from the in vivo and in silico tests. Bixin may act by other pathways to control blood glucose and thus it is possible that it presents a different toxicity profile than troglitazone, rosiglitazone and pioglitazone. However, more studies on the activity and toxicity of Bixin are needed to evaluate for further clinical use. Communicated by Ramaswamy H. Sarma.