| Pteridium aquilinum var. is a kind of perennial herbaceous natural plant. It'sedible parts are the fold feather leaf and delicate leafstalk growing from the sprout.Peteridium aquilinum has very high nutritional value and medical purposes. As a kindof green uncultivated food resources, which is rich in nutrition and healthy function,Pteridium aquilinum is selling well itself allover the world, more and more countriesare paying attention to the exploit and utilization of pteridium and it will has vastprospect. Nowadays, the way which be used in storing this kind of plant can besummered as the following:cold storage, saline storage, dry storage, and connedstorage, In China, the main method being used to store pteridium aquilinum is theproduction storage, including saline storage, dry storage and canned storage, but thereare few reports about the cold storage. In this research, main factors which effectingthe quality property of pteridium aquilinum are researched including(1)Selection ofraw materials;(2)sample's pre-treatment;(3)freezing rate;(4)storage conditions,The main results as follow.1. Selection of raw materials Different varieties have different storage properties. In order to know how doesthe materials'variety effect the product's quality, this research firstly study thedifferent of the peroxidase activity(PA)in two kinds of breeds, In addition, we studythe effect of pH value, temperature and NaHSO3 to PA, the results showed that the PAof P.revelutum(BL.) is three times than that of pteridium aquilinum(L.), The PA isvery high when it's environments are:pH6～7,temperature:20～30℃. NaHSO3 caninhibit PA in spite of it's concentration, and the higher it's concentration, the strongerit's inhibition.2. Sample's pre-treatment The present research analyzed the effect of pre-treatment to product includingadditives treatment and blanching. The conclusion had been acquired as follow:(1)Some kinds of fixatives were used to protect the color of pteridium aquilinum underthe different concentration, the results of protecting color were compared, When thesample was treated with magnesium acetate for one minute, the best result could beobtained.(2)The changes of peroxidase activity ,vitamin C content and qualityevaluation were studied before and after blanching. The results shows that theoptimum blanching time for the sample was1~2 minutes under the temperature 95～100℃, about 90 percent POD activity decreased with 30 seconds blanching time inboiling water. The influence of blanching on the vitamin C of pteridium aquilinum isthis:more higher the temperature and more longer the time last, VC contents reducedmuch more.(3)Organic index is poor when the blanching time and temperature wasrespectively 1～2 min and 90℃, when the blanching temperature increase to 95～100℃, sample's organic index will increase, the optimum blanching time for pteridiumaquilinum is1~2min under 95~100℃. In one word, the optimum blanching time for sample is one minute, It isnecessary to use magnesium acetate additives for quick-frozen production. Only inthis way, can we reduce the loss of vitamin C contents and can we develop thesample's organic index.3. Freezing rate The influence of freezing rate on peroxidase activity of pteridium aquilinum arestudied and concludes:freezing produces significant change is soluble POD activity,texture, organic index and ability of keeping water according to different freezing rate,POD activity goes down to 68.9% when the sample were slowly frozen, on thecontrary, POD activity respectively goes up to 120.6% and 170.9% when the samplewere quickly frozen and ultra-quick frozen . Sample's texture, organic index andability of keeping water under quick freezing is better than that under ultra-quickfreezing and slowly freezing.4. Storage conditions In the study on the changes in nutrients texture, organic index and ability ofkeeping water of sample stored u... |
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