Inhibition Effect Of Ginger Extract On Fresh-cut Potatoes Browning

In this paper, the inhibition effect of ginger extract on browning of fresh-cutpotatoes was studied, and the preparation process of ginger extract was optimized.Fistly, ginger alcohol extract and ginger water extract were achieved using ginger asraw material, ethanol and water as the extraction solvent. On this base, weinvestigated the effects of ginger extract on sensory quality and browning of fresh cutpotato. Then, the superoxide radical scavenging rate，DPPH radical scavenging rateand tyrosinase inhibition rate were test. At last, the single factors and thecorresponding surface optimal design were used to get the best extraction solvent andconcentration, as well as optimum process parameters though ultrasonic-assistedextraction and microwave-assisted extraction of ginger alcohol extract. Gingerols wasused as the indicator. The main conclusions were obtained as follows:(1) Base on the results of sensory quality of fresh-cut potatoes test, browninginhibition test and tyrosinase inhibition test of ginger extacts, we found ginger ethanoland water extract improved fresh-cut potato sensory quality and inhibited fresh-cutpotato browning in a dose depent manner, especial ginger ethanol extract. Gingerethanol extract (1g/mL) inhibited fresh-cut potatoes browning at rate of83.06±6.24%, it was slightly lower than VCgroup. Ginger ethanol extract (1g/mL) inhibitedtyrosinase activity at rate of96.47±3.24%, higher than the VCgroup and waterextract group. Otherwise, ginger water extract only inhibited fresh-cut potatoesbrowning by50.83±3.58%. This indicated that both ginger ethanol and waterextracts had improving fresh-cut potato sensory quality and browning inhibitioneffects. The effects were dure to tyrosinase inhibiton activity. Moreover, ethanol wasbenefit for ginger biochemical extraction(2) Though the antioxidant research on ginger ethanol and water extracts, wefound that both ginger ethanol and water extracts had superoxide anion and DPPHradical scavenging effect in a dose dependent manner. When the concentration was0.3mg/mL, the superoxide anion clearance rate of ginger alcohol and water extractwas88.6±7.62%and37.2±3.51%, respectively. And the DPPH radical scavengingrate of ginger alcohol and water extract was68.60±5.31%and34.52±5.6%,respectively. The superoxide anion clearance rate of ginger alcohol extract was higher than the same concentration of VCby9percent and higher than the sameconcentration of ginger water extract by50percent. The DPPH radical scavengingrate of VCwas higher than the same concentration of ginger alcohol extract by16percent and higher than the same concentration of ginger water extract by50percent.The DPPH radical scavenging rate of ginger alcohol extract was higher than gingerwater extract by34percent. As a result, different ginger extracts had different freeradical scavenging ability. Ginger alcohol extract had stronger antioxidant effectbased on the mechanism of superoxide anion clearance. The results showed that thesensory quality improving effects and browning inhibition effects of ginger extractwere related to its antioxidant activity.(3) The optimization of ginger alcoholic extraction was studied though singlefactor tests and the corresponding surface optimization tests. Among the fiveextraction solvent (ethanol, acetone, methanol, methylene chloride, ethyl acetate),ethanol extract was the best. The yield of gingerol was increased with the increase ofethanol. When ethanol was70%, the yield of gingerol reached the maximum. On thisbasis, using single factor and corresponding surface test, we optimized the ultrasonicextraction factors: solid-liquid ratio of1:10, ultrasonic power of400W, ultrasonictime of30min. Under this circumstance, ginger yield was5.81±0.35%. The optimumconditions of microwave extraction were liquid ratio of1:15, microwave power of500W, microwave time of9min, microwave temperature of50℃. Under thiscircumstance, ginger yield was7.83±0.22%.