المشاركة الأصلية كتبت بواسطة napoleon2009
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واسأل الله العظيم ان يجازيكم خيرا عما تعملون من انفاق العلم والخبره وان يرزقكم البر
آآآمـــــــــــيــــــــــــــن
استفسار اخر :-
وهو كثيرا ما أجد مكتوب على عبوات المنفحة الجافة 2200IMCU/g
ومكتوب على اكياس البادئ 100DCUأو 50U
فماذا تدل هذه الرموز ( IMCU/g,DCU,U) ?
اخي بارك الله فيك واليك الجواب :.
معنى imcu/g يعني بالانكليزية international milk clotting units IMCU/ml وتعني بالعربية هي الوحدة الدولية لتخثر الحليب واليك طريقة العمل الرئيسية لها
Application and Principle : This test is to measure the activity of milk clotting enzyme that is obtained from cows. Activity test is based on clotting time of reaction mixture of rennet standard and enzyme using defatted dried milk at pH 6.5.
Preparation of Test Solution : Test Solution is prepared using acetate buffer solution so that the clotting time falls within ± 40 seconds of mixed standard solution.
Test Procedure : 25 ml each of substrate solution is placed in 2 flasks, which are set up in a rotational apparatus. The flasks are hung in a 32 ± 0.2° water bath and tilted at an appropriate angle. While rotating, substrate solution is isothermalized for at least 12 minutes (maximum 20 minutes). 0.5 ml each of Test Solution and Standard Solution is added to each flask, which is then rotated and clotting time is measured. Clotting time is the time when fine particles are adsorbed on the inner wall of the flask. Activity is obtained by the following equation.
IMCU/g or ml = 1,000 x (Ts / Tc) x (Ds / Dc)
1000: activity of milk clotting enzyme standard
Ts/seconds : clotting time of mixed standard solution
Tc : clotting time of test solution
Ds/g/ml : concentration of mixed standard solution
Dc/g/ml : concentration of test solution
[Agents and Solutions]
Calf rennet standard (1,000 IMCU, IDF standard) : Should contain not less than 98% of chymosin and not more than 2% of bovine pepsin.
Adult bovine rennet standard (1,000 IMCU, IDF standard) : Should contain not more than 1% of chymosin and no less than 99% of bovine pepsin.
Substrate Solution : 110 g of milk (defatted at low temperature) is placed in a 2,000 ml beaker, where 100 ml of 0.05% calcium chloride solution is added and homogenized. 900 ml of 0.05% calcium chloride solution is added and stirred for 30 minutes (care must be taken to prevent excessive foaming). The resulting solution is set aside for 30 minutes in a dark place. When pH is measured, it should be approximately 6.5 (pH should not be adjusted). This solution should be used within 4 hours.
Mixed Standard Solution: Mixed standard solution is prepared by obtaining a proper ratio between calf rennet standard solution and adult bovine rennet standard solution. Mixing ratio is obtained by applying chymosin content (%) to Fig 1.
Calf rennet Standard Solution : 2.5 g of calf rennet standard is precisely weighed and dissolved in 15~20 ml of acetate buffer solution in a 50 ml flask. The total volume is brought up to 50 ml with acetate buffer solution. 3 ml of this solution is further diluted to 50 ml with acetate buffer solution.
Adult bovine rennet Standard Solution : It is prepared by the same method as calf rennet standard solution using adult bovine rennet standard.
Acetate buffer solution (pH 5.5) : 10 ml of 1 M acetic acid and 10 g of sodium acetate (3 hydrate) 10 g are mixed and water is added to bring the total volume to 1,000 ml. pH of this solution should be 5.5 and should be adjusted if necessary.
المخططات بالمرفقات
اما المعنى الثاني DCU فيعني Danisco Cultor Cultures وهو وحدة خاصة بالمزارع البكتيرية والبادئات
والاخرU يعني وحدة فقط
تحياتي