In vitro assay for predicting protein efficiency ratio as measured by rat bioassay: collaborative study

Area of Science:

• Nutritional biochemistry
• Food science
• Animal nutrition

Background:

• Accurate protein quality assessment is crucial for human and animal nutrition.
• Traditional rat bioassays for protein efficiency ratio (PER) are time-consuming.
• Calculated methods (C-PER, DC-PER) offer potential for faster protein quality evaluation.

Purpose of the Study:

• To collaboratively validate the accuracy and reliability of calculated protein efficiency ratio (C-PER and DC-PER) methods.
• To compare C-PER and DC-PER predictions against rat bioassay PER values across diverse food matrices.
• To assess the intralaboratory variation for various protein analysis methods.

Main Methods:

• Seven laboratories participated in a collaborative study.
• Analysis included in vitro apparent protein digestibility, amino acid composition, and rat bioassay PER.
• Tested foods: nonfat dry milk, chicken muscle, protein-fortified cereal, textured soy protein, oat cereal, and durum wheat flour.

Main Results:

• Statistical analysis evaluated intralaboratory variation for each analytical method.
• The predictive capability of C-PER for rat PER was assessed.
• The study provided data for the official adoption of C-PER and DC-PER methods.

Conclusions:

• The C-PER and DC-PER methods demonstrated acceptable performance in predicting rat PER across multiple laboratories and food types.
• These calculated methods offer a viable alternative for rapid protein quality assessment.
• The C-PER and DC-PER methods were officially adopted as first action methods.