Study Of Application Of Pulsed Electric Field On Honey Processing And Its Quality Dynamics

Honey is not only a precious natural healthy product, but also has somepharmacological effects. However, the traditional honey processing has greatlydamaged the quality of the honey. Pulsed electric field (PEF), a kind of non-thermaltechnology was used to obtain the fully brewed honey with well-kept quality. In thispaper, longan honey, litchi honey and the honey of rape flowers as research materials,the effect of PEF processing on yeast of honey was investigated. And the litchi honeywas chosen as the object of physiochemical identification, to study the organolepticinvestigation and physiochemical identification of treated litchi honey. After the litchihoney was treated under the PEF processing and the heat treatment respectively, thedifferences of each physicochemical index and the results of organoleptic analysiswere compared. Finally, changes of each physicochemical index of the litchi honeywere observed in the storage period, and the changes of regular pattern quality oflitchi honey were described in this period. The dynamic model of storage quality wasestablished and how the time and temperature influenced the quality of PEF-treatedlitchi honey in the storage period were studied. Finally, the storage time ofPEF-treated litchi honey was investigated under different temperature. The resultswere as follows:1. Effects of PEF intensity, treatment time, temperature, electrical conductivity andpH value of honey on inactivation of yeast were investigated. The results showedthat, sterilizing effect of PEF on yeast increased as intensity and treatment timeincreased. Intensity and treatment time were significant factors to PEFinactivation of yeast, and the former had a more significant effect. The temperature alsohad an effect on it, but the impact was not significant. Electrical conductivity andpH value also had an effect on inactivation of yeast.2. PEF was used to treat different kinds of honey. The results showed that, PEF hadan inactivation effect on yeast in the honey, but the effect to the litchi honey is thebest. When intensity was53kV/cm and treatment time was1.28ms, counts ofyeast reduced4.56lg. And the next was the longan honey, and finally the honey of rape flower.3. A variety of quality changes in litchi honey were researched after differenttreatments. Triangle different test methods and Wilcoxon Test methods were usedfor significance analysis, as well as the color, aroma and taste of sample. Theresults showed that, compared to thermal treatment, PEF processing can bettermaintain the quality of litchi honey, there were distinguished differences aboutsensory evaluation between thermal treatment and PEF processing. And it wasclear that PEF-treated litchi honey had better color, aroma and taste thanheat-treated honey did.4. A variety of quality changes in litchi honey were researched after forty days.Whether the contents of fructose and the glucose would rise by the action of theenzymes were studied. And the sensory evaluation of different treatments litchihoney was studied. The results showed that, fructose and glucose content of litchihoney by heat-treatment tended to increase, but it increased more with the PEFprocessing. Forty days later the fructose and glucose content of PEF-treated litchihoney was68.56%, but the heat-treated litchi honey was only63.39%. And afterforty days, there were high significant differences about sensory evaluationbetween them. While PEF-treated litchi honey had better color, aroma and tastethan thermal treatment did.5. The differently treated litchi honey was stored for a long time to research thechanges of physicochemical indexes. The DPS software was used to describe therule of quality changes in litchi honey treated with different methods. And thedynamic model of storage quality was established to research how the time andtemperature influenced the quality of PEF-treated litchi honey. Finally the storagetime of PEF-treated litchi honey was obtained under different temperature, and thestorage time of PEF-treated litchi honey was371days at normal temperature.