Study On Thermostability, Rheological Behaviour And Vacuum Dehydration Characteristic Of Honey

The phsico-chemical characteristics of honey are related with its plant resource and produced place. The phsico-chemical characteristics of honey are changed with the changing of its kind or produced place. To choose the suitable conditions of producing, processing and saving honey according to the phsico-chemical characteristics of honey is necessary and the key of improving the quality of honey.To determine the variations of diastase and invertase activities of Chinese honeysuckle honey, date honey, astragali honey, medlar honey, acacia honey and bass honey during heat treatment with spectrophotometer and titration of kaliumferricyanide. Then to operate on data and obtain the kinetics models of thermo-deactivation of the diastase and invertase in them. To determine the change of the HMF content of the six kinds of honey during heat treatment by HLPC. Then to analyse the mechanism of producing HMF in honey, and set up the kinetics model of producing HMF in honey. To determine the viscosity of the six kinds of honey at different temperatures by rheometer and with sequential programme temperature transformation. Then to analyse and operate on data, and set up the model of rheological behavior of honey. To determining the saturated vapor pressure of honey at different temperatures with static state pressure method, and the curves of vacuum dehydration and dehydration rate of honey with vacuum microwave dehydration method. Then to analyse and operate on data, and get the models of saturated vapor pressure-temperature- water content and vacuum dehydration of honey.The results show:1. During heat treatment at above 313.15K, the kinetics model of thermo-deactivation of diastase in honey is K_d = k_fd·exp [-164353.92/(RT) ] and [RA]_d =100·exp[-k_fd·exp(-164353.92/(RT)·t]. During heat treatment at above 303.15K, the velocity equation and equation of thermo-deactivation of invertase in honey are k_i = k_fi·exp [-160353.50/(RT)] and [RA]_i=100·exp[-k_fi·exp(-160353.50/(RT)·t]. [RA]_d and [RA]_i are the reduced activities of diastase and invertase in honey, and k_d and k_i are the velocities of thermo-deactivation of diastase and invertase in honey. The apparent frequency constants k_fd of thermo-deactivation of diastase in Chinese honeysuckle honey, date honey, astragali honey, medlar honey, acacia honey and bass honey are respectively 7.56×10¹⁹s^-1, 5.82×10²⁰s^-1, 1.02×10²¹s^-1, 3.59×10²⁰s^-1, 5.53×10²⁰s^-1, 8.51×10²⁰s^-1. The apparent frequency constants k_fi of thermo-deactivation of invertase in these honey are respectively 2.25×10²¹s^-1, 4.72×10²²s^-1, 6.79×10²¹s^-1, 5.54×10²²s^-1, 2.66×10²²s^-1, 3.01×10²²s^-1.2. During heat treatment at above 343.15K, the velocity equation and equation of producing HMF in honey are k_h=k_fh·exp[-97640.93/(RT)] and [HMF]_t=[HMF]₀·exp[k_fh·exp(-811786.69/T)·t]. [HMF]₀ and [HMF]_t are the HMF contents of honey at 0 minute and t minute. And k_h is the velocity of producing HMF in honey. The apparent frequency constants k_fi of producing HMF in Chinese honeysuckle honey, date honey, astragali honey, medlar honey, acacia honey and bass honey are respectively 9.33×10¹⁰s^-1, 5.64×10¹⁰s^-1, 1.45×10¹¹s^-1, 1.83×10¹⁰ s^-1, 4.05×10⁹, 8.81×10⁹s^-1.3. The models of rheological behaviour of Chinese honeysuckle honey, date honey, astragali honey, medlar honey, acacia honey and bass honey are respectivelyμ=0.0532w^8.4414·exp[22468w^-0.6178/(RT)],μ=0.0358w^8.8304·exp[24273w^-0.6008/(RT)],μ=0.0151·w^8.0985·exp[24811w^-0.5783/(RT)],μ=0.0273·w^8.3971·exp[22758w^-0.6008/(RT)],μ=0.033·w^8.3737·exp[23585w^-0.5983/(RT)], andμ=0.0415·w^9.0215·exp[24449w^-0.6029/(RT)].μis the visicidity of honey and its unit is cp, and w the water content of noney and its unit mass percentage, and T temperature of honey and its unit K.4. The model of saturated vapor pressure-temperature-water content of honey is Inp^s=-A/T+B. p^s is saturated vapor pressureof honey, and its unit is kpa. T is temperature of honey, and its unit K. A and B are loading thickness constants. When the content of honey is 16% or 19% or 22% or 25% or 27%, constant A is 5377.4, 5370.5 or 5347.3 or 5345.4 or 5355.0 or 5367.1. constant B is 18.48 or 18.53 or 18.53 or 18.59 or 18.69 or18.79.5. The model of vacuum dehydration of honeys, that is MR-t equation, is MR=0.0133·exp(0.0135T)·exp[-t·(7×10^-27)·(1/T)^-δ]. MR is the ratio of water contents of honey, and t vacuum dehydration time, and the unit of t is minute, andδlanding thickness constant. When landing thickness of honey is (2.3-2.4)mm or (3.4-3.6)mm or (4.6-4.8)mm,δis 9.5646 or 9.3135 or 9.9289.