METHOD FOR DETERMINATION OF PROTEIN WEIGHT FRACTION IN SUGAR COOKIE Russian patent published in 2011 - IPC G01N33/10 

FIELD: food industry.

SUBSTANCE: invention may be used for sugar cookie quality control. 2-5 g of sugar cookie sample is weighed with the result of weighing recorded up to the third decimal sign, placed into a centrifugal tube and poured with petroleum ether in an amount of 30-35 cm³, thoroughly stirred with a glass rod and centrifugated during 10-15 minutes at a rate of 2500-3000 rpm. The supernatant is decanted. One repeats the operation 3 times each time decanting the supernatant. One dries the produced sediment in water bath, proceeds with drying in the drying chamber at a temperature of (100-105)°C, comminutes the produced dried sediment with the glass rod. Then the defatted sediment is added 30-50 cm³ of ammonium sulphate solution to with a weight fraction of 10%; the mixture is thoroughly stirred, extracted during 20-40 minutes and centrifugated during 10-15 minutes at a rate of 2500-3000 rpm. One places the clear solution the clean centrifugal tube for protein sedimentation, adds 0.9-1.1 cm³ of glacial acetic acid and 3.5-4.5 cm³ of tannic acid with a weight fraction of 1.0% to it and stirs the mixture. The protein sediment is separated by centrifugation and dissolved in 10 cm³ of ammonium sulphate with 10% weight fraction. One measures the solution absorption at wave length 260 nm and 280 nm by means of a spectrophotometre. The protein weight fraction in the solution is determined applying Warburg and Christian method accounting for the content of nucleinic acids according to the formula: where M - protein weight fraction in solution, %, 1.55 and 0.76 - empirical coefficient, mg/cm³, A²⁸⁰ - protein solution absorption at wave length 280 nm, A²⁶⁰ - protein solution absorption at wave length 260 nm, 1000 - mg to g recalculation coefficient, ρ - density of protein solution, g/cm³. The protein weight fraction in sugar cookie Y(%) is calculated according to the formula: where m - batch weight, g; V - protein solution volume, cm³; 1.48 - coefficient accounting for losses of soluble protein in the process of baking and insoluble proteins.

EFFECT: accuracy enhancement and analysis acceleration.

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