Study On The Processing Technology And Stability Of Tomato Powder Rich In Cis-isomers Of Lycopene

Lycopene is the main pigment and important nutritional component of mature tomatoes and their products,mainly including all-trans and cis-configuration,in which the cis-configuration lycopene has the characteristics of strong antioxidant and high bioavailability.Therefore,how to increase the content of cis-configuration lycopene in tomato products is currently a research hotspot in this field,and how to prepare tomato powder rich in cis-lycopene has important research significance.In this study,with tomatoes as raw materials,lycopene extracts with different proportions of cis-configuration were prepared by solvent extraction,several E/Z isomers of lycopene were identified,and the biological activity of different proportions of cis-lycopene was compared.Then the processing technology of tomato powder rich in cis-lycopene was optimized.Finally,the stability of tomato powder during powder storage was investigated.The main findings are as follows:(1)The cis-trans isomers of lycopene were well separated by using Cosmosil Cholester columns combined with high performance liquid chromatography instruments,and the isomers of lycopene were identified as:(all-E),(5Z),(9Z),(13Z),(5Z,13?Z).(2)Three kinds of lycopene with different proportions of cis-configuration(5%,30%and 55%)were prepared by solvent extraction,thermal reflux induction and antisolvent low-temperature crystallization methods,respectively.The thermal characteristics,digestibility,oxidation resistance,and anti-cancer effects of the three samples were compared.It was found that lycopene containing 55%cis-configuration had lower melting point,higher bioavailability and greater ability to remove free radicals DPPH and ABTS.It had a significant inhibitory effect on Hep G2 liver cancer cells,a significant reduction in cell number and a noticeable shrinkage of the morphology were observed,and the order of anti-cancer effect was 55%>30%>5%.The above results indicated that the higher the cis-configuration content,the higher the bioactivity.(3)Through single-factor experiment and response surface process optimization,the optimal process conditions of tomato powder rich in cis-lycopene were obtained as follows:microwave heating method,freeze drying,1%addition of maltodextrin,microwave energy 3 W/g,and microwave heating time 6 min.Under these conditions,the total lycopene content in tomato powder was 567.367 mg/(100 g tomato powder),the dissolution rate of lycopene was 11.95%,and the cis-configuration ratio reached28.31%,which was nearly three times higher than that of cis-configuration in raw tomatoes.(4)With color,total lycopene content,cis-lycopene content,antioxidant properties,and digestibility as indicators,the stability changes of tomato powder during storage were investigated by using light,temperature,packaging method and storage time as factors.The order of influence on the quality of tomato powder during storage was:light>ordinary packaging>37 ?>25 ?>4 ?.The best storage method for tomato powder was determined to be vacuum packaging and storing in a dark place at 4 ?.