Evaluation of the Biuret and Dye‐Binding Methods for Protein Determination in Meats

Abstract

SUMMARY The biuret method of protein estimation was compared with the Kjeldahl method. Highly significant positive correlations with Kjeldahl protein of 0.99, 0.99, 0.98, and 0.99 were obtained for ground beef, pork, chicken breast, and cod, respectively. The high correlations between the two methods and the small standard deviations for the biuret values point out the reliability and the accuracy of the biuret method. The same substances were analyzed by the Orange G dye‐binding method with highly significant positive correlations with Kjeldahl protein of 0.90, 0.80, 0.94, and 0.95 for ground beef, pork, chicken breast, and cod, respectively. However, the amount of dye bound per g protein varies with the protein content of the sample, and the precision is poor. Orange G dye binding has possibilities for use in analyzing meat proteins only if the preparations and procedures are carefully standardized and the protein content does not vary more than a few percent. With Amido Black 10B, the amount of dye bound was too strongly dependent upon sample size to justify further investigation of this dye for estimation of the protein content of comminuted meats.

Fractionation and characterisation for antioxidant activity of hydrolysed whey protein

“…Protein concentrations in all mixed protein solutions as well as in column-separated fractions (described below) were determined by the biuret method. 15 After inactivation of the enzymes (80 • C for 20 min) the hydrolysates were freeze-dried for later separation. The resulting degrees of hydrolysis for W/A, W/P and W/F were 0.15, 0.075 and 0.2 g ml −1 respectively.…”

The effects of salt concentration on conformational changes in cod (Gadus morhua) proteins during brine salting

“…The mixture was homogenised in an Ultra-Turrax homogenizer (Kika Labortechnik, T25 basic, Staufen, Germany) for 65 s. The homogenate was centrifuged at 0-5°C for 15 min at 10,000Âg by using an Avanti Centrifuge J-20 XPI (Rotor 10, Beckman Coulter, Fullerton, California (CA), 92834, USA). Protein concentration of the supernatants was determined using the Biuret method (Torten & Whitaker, 1964). The standard curve was determined with various known concentrations of bovine serum albumen (BSA, Fraction V, Approx.…”

Comparative study on the effect of acid- and alkaline-aided extractions on mechanically separated turkey meat (MSTM): Chemical characteristics of recovered proteins

“…The total protein content of both the raw material and final protein isolates from different solubilization methods was estimated by the Biuret procedure [14,17]. Meat sample (1 g) was dispersed in 20 mL of 0.5 M NaOH, heated in the boiling water for 10 min and cooled in an ice-water bath.…”