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Study on Technologies of Processing Green Color Vegetables Storing in Normal Temperature

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Tutor: YinYongGuang
School: Jilin University
Course: Agricultural Mechanization Engineering
Keywords: microwave pulse spacing,HPEF,nano-zinc stearate,chlorophyll,beans,spinach
CLC: S63
Type: PhD thesis
Year:  2007
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Abstract:
Vegetables are rich in nutrients and the human diet is an indispensable component. The color change from bright green to olive brown during the processing and storage is mainly due to the degradation of chlorophyll to pheophytin by the replacement of magnesium in the chlorophyll by hydrogen and further formation of the degradation products. There are two kinds of methods for protecting green color, which were alkali and metal ions methods. Alkali method was that chlorophyll came into be a stable green acid in alkaline, but it will be significant loss of the nutritional content of vegetables, and can not storage for a long time. Metal ion method is the application of metal ions to form a stable chlorophyll metal complex, and it is rather difficult to reach the satisfied green color when the concentration of zinc ion is below 75ppm by using this method to process green vegetables. However,the amount of added zinc in canned vegetables higher 75 ppm is limited by the Food and Drug Administration of US. For maintaining the most nutrients of vegetables, and extend the shelf life of vegetables. In this paper, the interval pulsed microwave and HPEF pilot study:1. Based on the chlorophyll degradation and chemical reaction kinetics, a corner with color Blanching time and temperature changes in response to the more dynamic model. Application and more dynamic response model, the beans in the 60¡æ, 70¡æ, 80¡æand 90¡æwith color blanching time to change the equation. Of the regression equation parameters as initial values are incorporated into the iterative equation, which is blanching temperature 60-90¡ãC, Blanching time in a row 0-tmax the kinetic model.2. Based on the beans in 90¡æblanching dynamics model, blanching process for the division rose color, smooth and fall times three, By comparing and blanching three stages of microwave pulse spacing methods color processing beans, Keeping Green reached base and zinc maintining blanching method in the stable phase, when blanching temperature of 90¡æ, Blanching time 8-12min, maintining the best results. 3. Based on microwave pulse interval method of beans color effect of the research, Through the beans the color of single factor and color degradation kinetics analysis of the model, Zinc maintining beans come in the color during storage with the speed of degradation of microwave frequency (0-3) slowed down the increase, With storage temperature (10¡æ, 20¡ãC, 37¡æ) to accelerate the increase, Degradation and beans color with the time of storage obey a kinetic model; But alkali maintining beans, microwave frequency and storage temperature on the color of smaller beans. With the traditional method of heat treatment contrast, zinc keeping green beans at 20¡æ, seven days of color than the traditional method of heat treatment significantly improved, But alkali maintining heat treatment methods and traditional methods of color very long beans.4. In this paper, the method of microwave pulse interval bactericidal effect of the research, By comparing each processed beans microwave microbial residue test, the 3rd microwave effective disinfection, and can greatly reduce the additives on the microbial activity. Alkali processing method of preserving green beans, 3rd microwave microbial inactivation rate reaching over 90%. and a meeting of microwave inactivation of bacteria 40%; Application methods maintining zinc processing beans, Application of the 3rd microwave microbial inactivation rate of 95%, and a meeting of microwave microbial inactivation rate at about 57%.5. In this paper, the method of microwave pulse interval Kingston-effect analysis By comparing each microwave treatment peroxidase residue test, the microwave pulse interval effective sterilization method. Application processing method alkali maintining beans, 3rd microwave peroxidase inactivation rate reaching over 90%. and a meeting of microwave peroxidase inactivation rate of about 38%. Application Alklian method and zinc processing method, 3rd microwave peroxidase inactivation rate of 93%. and a meeting of microwave peroxidase inactivation rate was only about 35%.6. Based on microwave pulse spacing on vitamin C content of a single factor analysis, Vitamin C content with the draw microwave increase in the number of lower However, the vitamin C during storage with the speed of degradation of the increased frequency microwave and slow down. Microwave pulse spacing of zinc keeping green beans Vc destructive relatively small, but the base of preserving green beans Vc great damage.7. Based on solid powder additive color of the beans, comparing the two states beans added to the storage time, powder additive derived form effective protection of the green beans. Storage at room temperature and color degradation rate at far below the liquid additives. Application of powder additives beans for 20 days when color was only after blanching more than 70%, while the use of additives in liquid form, Storage at room temperature only two days. 8. Based on the solid powder additive to extend the storage time of long beans pilot, In this paper, a solid powder maintining to explore the mechanism, By comparison powder and liquid additives (zinc stearate) before and after processing in the particle size, beans come to the reasons for long-term storage is processing formation of nano powder.9. This paper studies of nano-particles formed in the process, against solid powder in the processing of the analysis, By observing microwave pulse intervals after treatment zinc stearate powder state test reached powder additive to improve the microwave temperature, melting zinc stearate, Microwave processing temperature to 120¡æ.10. In-depth analysis of microwave pulse spacing methods for processing nano-particles in the process, the factors affecting the formation of nano research. By analyzing microwave pulse interval processing and observation powder processing before and after the state test, Nano-affected draw powder form of the main factors : Solid powder additive, zinc stearate reunion. Add sugar and rapid cooling. Nano powder in the process of forming improved microwave processing temperature (120 C), Melting make zinc stearate; the reunion of zinc stearate powder form effects of particle size; Sucrose and cooled to control the reunion of zinc stearate effect.11. By simulating gliding microwave pulse spacing of powder melting process (HTHP) and cooling process (solvent Law) test, proved through microwave pulse interval method can be processed into nano-zinc stearate.12. Chromatography results with the introduction of the nano-zinc stearate. make beans created a lot of green chlorophyll zinc complex, because chlorophyll zinc complex nature stability, So can maintain long green beans; and nano-zinc stearate accelerated zinc complex chlorophyll synthesis rate, So lower zinc content.13. This paper, the method HPEF spinach juice processing test, HPEF against spinach juice to color the effect of single-factor test, come to the addition of zinc ions spinach juice color degradation rate with the addition of Zn2 + concentration increases slowed, With the increased storage temperature accelerated degradation of color; in the store during the green, and greatly reducing the time Minute Green; through adding spinach juice 20ppmCaCl2 20 ppm NaCl and the pilot lowered the stabilizer Yen color degradation.14. This paper HPEF of chlorophyll, the influence of chromatographic analysis, single-factor test, found that high-voltage pulsed electric field strength and pulse a few of adding Zn2+ (70ppm) the impact of different structures of chlorophyll. When PEF higher field strength (0-60kV/cm), the chlorophyll is no change to the structure. But PEF increased pulse (0-6), the pulse number of chlorophyll have a great impact on the structure, When the pulse at 2 pm, the chlorophyll field structure is not affected; When the pulse at 6:00. the potential to destroy the structure of chlorophyll. By the high-pressure pulsed electric fields to add Zn2 + (70ppm) chlorophyll a, b reservation time impact analysis, found the spot for 60kV/cm strong pulse at 2:00, Add Zn2+ (70ppm), spinach juice, fresh spinach chlorophyll closest to the chlorophyll.15. This paper HPEF of chlorophyll content, the influence of spectrophotometer analysis. The single factor experiments, higher than the spot-cm, add and not add the spinach juice Zn2+ chlorophyll a and b content with the field were increased; The addition of Zn2+ 70ppm changed the chlorophyll a and b stability, chlorophyll a in HPEF role of the nature of instability into a relatively stable, spinach juice to the green-maintaining.16. This paper HPEF bactericidal effect was studied by single factor analysis and dynamics, come to E. coli and total bacterial residues with the electric field strength increases slightly. When pulsed electric field strength of 60kV/cm pulse at 2, E. coli death rate of 90%. TBC death rate was 95%; HPEF pulse (2-6) for E. coli bacteria and total mortality (spinach juice) will not be affected. Through the dynamic model, when the pulse at 2, E. coli residues with high-voltage pulsed electric fields in obedience Peleg model. With the total bacterial residues HPEF field of Hulsheger obedience, Peleg and Schrive three models.17. In this paper, the Kingston HPEF effect of enzyme research, The single factor test and HPEF Kingston enzyme kinetics model, derived from chlorophyll, Magnesium-shot from peroxides and the residue with pulsed electric fields and high health declined, With the increased number of pulses and the chlorophyll-residue slightly lower. When the electric field strength of 60kV/cm pulse at 2 pm, chlorophyll activity decreased by 60% Magnesium from chelating activity decreased 80% peroxidase activity decreased by more than 60%. When the pulse was 2, chlorophyll residues with higher intensity pulsed electric fields in obedience Peleg. Hulsheger model; Magnesium Chelate synthase from residues with high-voltage pulsed electric fields obey Peleg. Hulsheger model; peroxidase residues with high-voltage pulsed electric fields obey Peleg model.18. By applying high voltage pulsed electric field on the addition of zinc ions spinach juice some impact on the quality of components changes on the high-voltage pulsed electric field can effectively protect spinach juice in the processing and storage of quality from destruction. Application 60kV/cm,2 the electric pulse processing the addition of zinc ions spinach juice, spinach juice and fresh compared : Vitamin C content increased by 98% amino nitrogen content increased to 31.5 Juicer not change after the spinach juice cell morphology; Zn2 + ions in the absence of major changes, but the content of Mg2+ ions great; carotenoid content did not change; Insoluble Solid content increased 27% spinach juice increased pH stability in 6.3; total acid content increased by 50%.In summary, Using microwave pulse interval - and nano-zinc stearate HPEF method of green vegetables at room temperature storage method exploration and research results show that both methods can be extended vegetables at room temperature storage. and achieve satisfactory green color effect.
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