Abstract:
Penthorum chinense Pursh (PCP) leaf was a new food material for botanical beverage production, with bioactivities of antioxidant, hepatoprotective and anti-alcoholism but showing unpleasant flavors, especially for the high-temperature aqueous extracts. Accordingly, to reduce its unfavorable flavor with no effect on its health benefiting, the low-temperature aqueous extract (PLE
50) was prepared by optimal low-temperature extraction. With the maximum aqueous solubility at 14.2 mg/mL, PLE
50 showed the concentrations of phenols, flavonoids, gallic acid, quercetin, and pinocembrin at 1.90, 1.41 mg/mL, 49.98, 23.57 and 11.93 μg/mL, respectively, being significantly (
P<0.05) higher than water brewed PCP soup. The results of HS-SPME-GC-MS revealed that safranal and 2,4-ditert-butylphenol were the primary sources of the unfavorable flavors in the boiling water extract of PCP leaves (PLE
95), which contributed 54.43% and 5.89% to the overall flavor, respectively. Conversely, PLE
50 showed little contents of safranal and 2,4-ditert-butylphenol with flavor contribution less than 0.1%. The major aroma components of PLE
50 include decanal,
β-cyclocitral, linalool,
β-ionone, undecanal, 2-undecanone, 2-decanone, D-limonene, and dodecanal, contributing 76.97% to its flavor, which significantly (
P<0.05) improved the sensory acceptability of PLE
50. Besides, PLE
50 showed the half scavenging concentrations for DPPH, ABTS
+, and hydroxyl radicals at 0.034, 0.087, and 0.91 mg/mL, respectively, with 2.26 mmol/L ferric ion reducing power at the concentration of 1.6 mg/mL. PLE
50 at 14.2 mg/mL exhibited the maximum activation rates at 183.33% for alcohol dehydrogenase and 951.88% for aldehyde dehydrogenase, being better than PLE
95 at the same concentration. In summary, the optimal low-temperature aqueous extraction improved the flavor and sensory acceptability of PCP extracts, and maintained its
in vitro antioxidant activity, as well as its activation capabilities for alcohol dehydrogenase and aldehyde dehydrogenase.