Development Of High Performancy Extraction And Enrichment Techniques For Lycopene

For the problems in traditional extraction and praperation of liposoluble natural pigments, such as low extracting efficiency and solvent existed in pigment products, several relevant modern techniques were investigated in lycopene (a typical liposoluble natural pigment) extraction and preparation, to sieved more effective and effecient applied techniques.Ultrasound-assited extracting method (UAE), ultrahigh pressure extracting method (UHPE) and ultrasound/microwave extracting method (UMAE) were selected, and compared with conventional extracting method (CE) on the lycopene yield. The optimal conditons of these four extracting methods were showed as follows:CE: the extracting temperature was 87.3℃, the ratio of the solvents to tomato paste was10.8:1 (v/w) and the extracting time should be 65min;UAE: the extracting temperature was 86.4℃, the ratio of the solvents to tomato paste was 8.0:1 (v/w) and the extracting time should be 29.1 min;UHPE: extraction pressure 168 MPa, temperature of pressure medium was 40℃, extraction time was about 2 s, the ratio of the solvents to tomato paste was 17.6:1 and the number of extraction stage was 3;UMAE: 98W microwave power together with 40 KHz ultrasonic processing, the ratio of solvents to tomato paste was 10.6:1 (v/w) and the extracting time should be 367 s.Under these conditions, the percentages of lycopene yield were 94.7%, 89.4%, 94,5% and 97.4%, respectively. After comparison of these four techniques, results implied that UMAE was far more efficient than other extracting methods.An ultrasonic/microwave assisted extraction equipment was designed as the industrial facility, and a initial mass transfer model for UMAE method was developed, based on Fick's second law to simulate and elucidate the specific process of lycopene extraction.For the objective of obtaining free solvent tomato oleoresin, molecular distillation was selected to enrich lycopene followed by methyl esterification, after removing the bulk of solvent in extracts by vacuum evaporation. Central-composite rotary design and response surface methodology (RSM) were used to build a predictive model of the combined effects of molecular distillation's independent variables including evaporating temperature, feed flow rate and wiper rolling speed for the recovery of lycopene from esterified tomato oil. The optimum operating conditions obtained from the RSM models were evaporating temperature 108-112℃,condensing temperatrue 35℃, wiper rolling speed 180 r/min, feed flow rate 52-55 g/h when feed temperature 60℃and vacuum 3 Pa. Under these conditions, free-solvent & high lycopene content product was obtained.