Application Of Heat Treatment And Ionic Liquids Extraction In Food Processing And Analysis

1.[6]–,[8]–,and[10]–gingerols,as well as[6]–,[8]–,and[10]–shogaols are the main biological composition in Ginger（Zingiber officinale Roscoe）.So far,the comparative antioxidant potencies among shogaols and gingerols have not been studied in detail and reported.Accordingly,this study aimed to examine and compare the antioxidant abilities of the six main compounds.Results showed that[6]–,[8]–,and[10]–gingerols,as well as[6]–,[8]–,and[10]–shogaols exhibited substantial in vitro antioxidant activities.The DPPH^·,ABTS^·+,and FRAP assays results showed that the antioxidant abilities of[6]–shogaol were greatest among the six gingerols and shogaols studied（P<0.05）,and those of[6]–,[8]–,and[10]–shogaols were greater than those of[6]–,[8]–,and[10]–gingerols,respectively,which can be attributed to the presence ofα,β–unsaturated ketones moieties.Moreover,the observation that the antioxidant abilities of[6]–gingerol were greater than those of[8]–and[10]–gingerols（P<0.05）indicated that the short carbon chains of[6]–gingerol and[6]–shogaol played a significant role in making them more potent antioxidants than the other four longer carbon chain compounds.This finding can be attributed to gingerols undergoing dehydration transformations into shogaols during oven drying.Our results provided some new information on the antioxidant abilities of gingerols and shogaols.2.Shogaols are the dehydration products of gingerols that are found in small quantities in ginger root and have more potent bioactive properties than gingerols.In this study,microwave-assisted technology coupled with acidic food condiments was used to improve the contents of 6-,8-,and 10-shogaols.After processing ginger in aqueous tartaric acid solution（0.8 mol/L,8 m L）at 140°C and 1000 W for 10 min,the contents of6-,8-,and 10-shogaols（4.66,1.19,and 1.76 mg/g dry mass,respectively）were approximately 12-,17-,and 19-fold higher in processed ginger than in unprocessed ginger.The antioxidant capabilities of this processed ginger were approximately two times higher than those of unprocessed ginger assayed by antioxidant assays.The processed gingers can be used as high-quality raw materials for the production of various ginger products,as well as for the preparative separation and purification of 6-,8-,and 10-shogaols.3.An ionic liquid-based microwave-assisted extraction（ILMAE）method was developed to extract 6-,8-,10-gingerols and 6-,8-,and 10-shogaols from ginger（Zingiber officinale Roscoe）.A series of water-miscible ionic liquids（ILs）with different kinds of anions and cations were investigated.Results indicated that among the investigated ILs,the carbon chains of alkyl cations remarkably affected the extraction efficiency of the six compounds and 1-decyl-3-methylimidazolium bromide([C₁₀MIM]Br)was the optimal IL.The selected conditions for ILMAE were as follows:[C₁₀MIM]Br concentration,0.80 M;extraction temperature,75°C;irradiation time,30 min;and irradiation power,400 W in the case of solid–liquid ratio of 0.1:10 g/m L.This study showed that compared with methanol marinated extraction（yields of 0.034%–0.299%）and methanol-based microwave-assisted extraction（yields of 0.034%–0.314%）,ILMAE attained higher yields of 0.036%–0.334%and obtained a shorter time of 30 min for extraction of gingerols and shogaols from ginger.This study provides a basis for separating and purifying bioactive components from ginger.Moreover,the use of small amounts of[C₁₀MIM]Br as extraction solution in the method was considered environment friendly.4.A novel and relatively fast and simple method by ionic liquid independent disperse liquid–liquid micro-extraction（IL-IDLLME）coupled with UV–Visible spectroscopy was developed and applied to determination of the synthetic dye Brilliant Blue FCF（E133）in six different kinds of food and cosmetic samples,namely soft drink,candy,jelly,kiwi fruit（Actinidia chinensis）pieces,roasted pea,ice cream,toilet water and shampoo.The samplesweredissolvedinwaterandpreconcentratedsimplyby1-decyl-3-methylimidazolium tetrafluoroborate([C₁₀MIM][BF₄])without a dispersive solvent,heat,ultrasonication or additional chemical reagents.The effects of different parameters such as the volume of[C₁₀MIM][BF₄],p H,KCl concentration,micro–extraction temperature,incubation time and centrifugation time on the micro–extraction of E133(0.12μg m L^–1)were investigated and optimum conditions were established.Linear calibration curve was obtained in the range of 1.5-150μg L^–1 for E133under optimum conditions.Limit of detection（LOD）based on 3Sb was 0.34μg L^–1（n=11）.The relative standard deviation（R.S.D.）for 5 and 140μg L^–1 of E133 was 0.43%and0.82%（n=10）.The method is therefore recommended for use by the quality control departments of food and cosmetic producers using E133.