| Zingiber officinale Roscoe is commonly known as "ginger" worldwide, which has characteristic pleasant flavor and pungency. Co-extraction of ginger essential oil and gingerols from Tongling white ginger were optimized, and drying pretreatment and utilization of ginger juice after the co-extraction were studied at the same time in this study. The main contents were as follows:(1) To establish the determination method of the ginger essential oil and gingerols by GC-MS and HPLC.65 of volatile compounds were detected from ginger essential oil extracted by steam distillation (SD) while 54 were identified from the extraction by headspace solid phase micro-extraction (HS-SPME) and the main volatile compounds are consistent; The content of five main gingerols (zingerone,6-gingerol,8-gingerol,6-shogaol and 10-gingerol) in fresh ginger were detected and the total content was 12.102 mg/g (dry basis).(2) To compare the effect of five drying methods (hot air drying, vacuum drying, microwave drying, infrared drying, freeze drying) on the volatile compounds and content of gingerols. The results of infrared drying (IRD) at 60℃ were that 1.5 h of drying time,9.18 of drying ratio,5.35 of rehydration ratio,34.99 of browning index (BI),85.1% of retention of gingerols and 30.103% of the relative content of Zingiberene. Consider the cost and quality comprehensively, IRD at 60℃ should be adopted as the best method to dry fresh ginger.(3) To optimize the co-extraction of ginger essential oil and gingerols by orthogonal experiment. The optimum conditions of extraction of ginger essential oil by SD assisted with enzyme was as follows:1:25 of material to liquid ratio,0.25% of enzyme dosage,100 min of distillation time and pH 5.4 with the yield of ginger essential oil of 3.11%(dry basis) compared with 2.61%(120 min of distillation time) by SD directly; The optimum conditions of extraction of gingerols by solvent assisted with ultrasonic were as follows:95% ethanol of extraction solvent,1:25 of material to liquid ratio,100 W of ultrasonic power,35 min of extraction time and 50℃ of extraction temperature with the yield of gingerols of 0.85%(dry basis) compared with 0.80%(240 min of extraction time) by solvent directly.(4) To optimize the formula of ginger beverage and the amount of stabilizer for the ginger beverage by response surface method with fuzzy mathematics and orthogonal experiment respectively. The optimum formula of ginger beverage was as follows:18.2% of ginger juice,7.29% of sugar and acid (sugar/acid=100),0.005%o of gingerols,0.034%o of ginger essential oil with the sensory score of 92.36; The optimum amount of stabilizer for the ginger beverage was as follows:0.02% of xanthan gum,0.08% of sodium alginate,0.10% of CMC-Na with the value of stability of 0.238.(5) To detect the volatile compounds and content of gingerols in the ginger powder beverage by HS-SPME-GC-MS and HPLC respectively. The results were that the volatile compounds of fresh ginger beverage and ginger powder beverage were different slightly, but the sensory score of the two kinds of beverage were both more than 90, it meant that both of them were recognized by the consumers. The total content of gingerols in the ginger beverage decreased while the content of 6-shogaol and zingerone increased during the storage time of six months at 25℃. |
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