Study On A Process Of High-pure-degree Pectinesterase Production From Commercial Pectinase Preparation

Pectinesterase(PE) exists in the plant,fungi and the germ widely.In some fruits and vegetable processing,the natural PE has the function of protecting the texture.The PE production of high pure degree is mainly applied to preserve the fruit and vegetable,product low methyl oxygen pectin,study the basic relationship of PE's behavior pattern and the pectin's structure and function property,and so on.This research investigated a kind of production craft that makes a high pure degree PE production from commercial pectinase preparation.The PE and Polygalacturonase(PG) of Pc-3 were isolated by ultrafiltration and SP Sepharose(?) Fast Flow—one sort of intense cationic gel filtration chromatography.After ultrafiltration,the PE activity was raised from 11.22U/ml to 98.12U/ml and the total activity was descended from 1402.5 to 1349.15.The PG activity was raised from 17.46U/ml to 156.35U/ml and the total activity was descended from 2182.5 to 2110.73.But the activity ratios(PE:PG) are both 0.64.At pH4.2,the adsorption ratio of PE in the crude enzyme solution was 43.08%and that of PG was 71.08%.The maximal activity ratio(PE:PG) was obtained at 0.25ml/min and the value was 3.69.But the yield of PE was only 55.97%.They were not separated completely.The thermal Characterization of PE and PG of Pc-3 was studied.The optimal temperature of PE is 43℃.PG has two optimal temperatures:30℃and 50℃.The study on stability of PE and PG at different temperatures declared that PE is thermal unstable and PG has two sorts:thermal stable and thermal unstable.After treated 10min at 55℃,PE activity retained 78.16%and PG activity remained only 9.98%.It proves we can obtain high PE activity production through proper thermal treatment.The inhibiting effect on PE and PG activity of commercial pectinase preparation by Iron(â…¢) chloride hexahydrate,Iron(â…¡) sulfate heptahydrate,glycine,L-Glutamic acid sodium salt and urea was studied. Iron(â…¢) chloride hexahydrate,Iron(â…¡) sulfate heptahydrate and L-Glutamic acid sodium salt have the obvious and similar inhibiting effect:their inhibiting abilities increased companied with their concentration in a certain range and kept unalterable out of the range.Glycine has unstable inhibiting ability.The above four reagents have no inhibiting effect on PE.Urea has the inhibiting effect on two enzymes and the effect on PG is stronger.Considering to safe,FeSO₄·7H₂O is the best inhibitor among them.When it's concentration was 1mmol/L,the PG activity dropped off to 33.15%and When it's concentration was 5mmol/L,the PE activity remained 92.7%.The optimum processing conditions of high PE activity production was studied and obtained as-following:temperature:55℃,FeSO₄·7H₂O concentration:1mol/L,time:10min.At this condition,the PE residual activity(%) was 80.57%and the PG residual activity(%) was 8.29%respectively。The influence on the hardness of pineapple grain by the self-made PE production was studied.Under the optimal condition(PE concentration:0.5%,the lactic acid calcium concentration:0.3%,time:25min.), the hardness increased 84.29%after bestowed 1 week.Rapidase(?) FP Super made the hardness raised 163%with the equal PE activity.