Relevance of ions in pressurized fluid extraction of carbohydrates and phenolics from barley hull

Ultrasound processing of rutin in food-grade solvents: Derivative compounds, antioxidant activities and optical rotation

The effect of ultrasound was studied on the flavonoid rutin to understand its hydrolysis to aglycones, antioxidant capacity and optical rotation. The total phenolic content increased >56% at 3.6-36 kJ/cm³, indicating production of phenolic compounds. In the water media, at 27 kJ/cm³ and 47 °C, the total flavonoid content increased from control 0.26 ± 0.01 to 0.45 ± 0.02 mg catechin equivalent/mg rutin hydrate. Quercetin yield in citric acid media increased with change in energy density from 0.34 ± 0.09% at 0.1 kJ/cm³ (68 °C) to 2.23 ± 0.04% at 7.0 kJ/cm³ (86 °C). A plummeting effect was only observed in water media after 27 kJ/cm³ by FRAP (47 °C) and DPPH (86 °C) antioxidant activities, indicating that the presence of solutes (citric acid and NaCl) after 27 kJ/cm³ reduced degradation of flavonoids. Furthermore, ultrasonication increased levorotatory rutin enantiomers, that can be used to further modify physico-chemical properties of other food components.

Pressurized liquid extraction of cyclitols and sugars: optimization of extraction parameters and selective separation

Cyclitols and sugars were obtained as a mixture from Medicago sativa L., in a comparative study by using maceration, and pressurized liquid extraction, as a modern and green extraction techniques. The influence of extraction parameters including: extraction temperature, time and number of cycles on the content of sugars and cyclitols was investigated based on response surface methodology. The highest total amount of sugars and cyclitols (62.27 ± 2.30 and 50.35 ± 0.77 mg/g of dry material, respectively) was obtained when extraction was performed at 88°C, for 22 min, in two cycles. The methodology used involved extraction, purification, selective separation (using yeast and anion exchange resin) and derivatization, followed by gas chromatography -mass spectrometry analysis. The use of yeast treatment realized an effective fractionation of cyclitols and sugars, which allowed the removal of most sugars. The involvement of anion exchange resin after yeast allowed the removal of sugar alcohols and lactose, together with other sugar traces remained and to obtain a solution containing six cyclitols. The recrystallization of dry residue after solvent evaporation, from ethanol, allowed us to obtain 14.65 mg of white pure crystals identified with NMR spectroscopy, liquid chromatography with mass spectrometry, gas chromatography with mass spectrometry, optical rotation and melting point as analysis D-pinitol.