the method that is widely used for the determination of the protein content of meat and animal food is a. kjeldahl method b. mohr method c. McBride method d. Liebig method
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The Kjeldahl method is a widely used method for the determination of the protein content in food, including meat and animal food. Show more…
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Carbon and hydrogen are estimated by (a) Leibig method (b) Duma's method (c) Carius method (d) Kjeldahl's method
The Kjeldahl method is used in agricultural chemistry to determine the percent protein in natural products. The method is based on converting all the protein nitrogen to ammonia and then determining the amount of ammonia by titration. The percent nitrogen in the sample under analysis can be calculated from the quantity of ammonia produced. Interestingly, the majority of protein molecules in living matter contain just about $16 \%$ nitrogen. A 1.250 g sample of meat is heated with concentrated sulfuric acid and a catalyst to convert all the nitrogen in the meat to $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4} .$ Then excess $\mathrm{NaOH}(\mathrm{aq})$ is added to the mixture, which is heated to expel $\mathrm{NH}_{3}(\mathrm{g}) .$ All the nitrogen from the sample is found in the $\mathrm{NH}_{3}(\mathrm{g}),$ which is then absorbed in and neutralized by $50.00 \mathrm{mL}$ of dilute $\mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq}) .$ The excess $\mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq})$ requires $32.24 \mathrm{mL}$ of $0.4498 \mathrm{M}$ NaOH for its titration. A separate 25.00 mL sample of the dilute $\mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq})$ requires $22.24 \mathrm{mL}$ of $0.4498 \mathrm{M}$ NaOH for its titration. What is the percent protein in the meat?
Describe the difference between the use of a LECO Nitrogen Analyzer and the Kjeldahl method for the determination of protein in feeds?
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