Accelerated solvent extraction (ASE) was used to optimize and determine the effectiveness of an alternative, environmentally friendly extraction procedure using subcritical solvents to recover anthocyanins from freeze-dried, ground Sunbelt red grape pomace. Anthocyanins were extracted from pomace using the following ASE variables: pressure (6.8 MPa), one extraction cycle, and temperature (40, 60, 80, 100, 120, and 140 degrees C). Conventional solvent extraction with methanol/water/formic acid (60:37:3 v/v/v) was compared to four hydroethanolic solvents (10, 30, 50, and 70% ethanol in water, v/v). Anthocyanins in the extracts were identified and quantified by HPLC-MS and HPLC. There was an insignificant interaction between solvent and temperature (p = 0.0663). Solvents containing 70 and 50% ethanol in water extracted more total anthocyanins (463 and 455 mg/100 g of DW, respectively) than other solvents. The total amounts of anthocyanins extracted at 100 degrees C (450 mg/100 g of DW), 80 degrees C (436 mg/100 g of DW), and 120 degrees C (411 mg/100 g of DW) were higher than at the other temperatures. Solvents containing 70 and 50% ethanol in water extracted similar amounts of anthocyanins as conventional extraction solvent.
Water, in its subcritical state, can be used as both a solvent and
reactant for the hydrolysis of
triglycerides. In this study, soybean, linseed, and coconut oils
were successfully and reproducibly
hydrolyzed to free fatty acids with water at a density of 0.7 g/mL and
temperatures of 260−280
°C. Under these conditions the reaction proceeds quickly, with
conversion of greater than 97%
after 15−20 min. Some geometric isomerization of the linolenic
acids was observed at reaction
temperatures as low as 250 °C. Reactions carried out at higher
temperatures and pressures,
up to the critical point of water, produced either/or degradation,
pyrolysis, and polymerization,
of the oils and resultant fatty acids.
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