How to Use PDCAAS to Calculate Protein %DV: A Complete Guide

Protein Digestibility-Corrected Amino Acid Score (PDCAAS) is a widely used method for evaluating protein quality based on the essential amino acid content and digestibility of a protein source. ENTR can automatically calculate the PDCAAS score of a formula. This step-by-step guide will walk you through how to calculate PDCAAS and use it to calculate the percent Daily Value (%DV) of protein in your product.

What is PDCAAS?

PDCAAS stands for Protein Digestibility-Corrected Amino Acid Score. It’s the method designated by the FDA to evaluate a protein’s nutritional quality based not just on how much protein is present, but on how “digestible” it is, or how well it delivers the essential amino acids the body needs.

The PDCAAS score directly affects protein labeling claims. In the U.S., the percent Daily Value for protein must be based on PDCAAS for if the product is making any protein-related claim (like “good source of protein” or “high in protein”) (FDA, 21 CFR 101.9(c)(7)).

The score ranges from 0 to 1 (or 0% to 100%), with higher values indicating better protein quality. A PDCAAS of 1.0 (or 100%) indicates that the protein meets or exceeds human amino acid requirements and is fully digestible.

The use of PDCAAS to calculate the % Daily Value for Protein is outlined in the FDA regulations: 21 CFR 101.9(c)(7)(ii).

The formula for PDCAAS is: 

Total Protein Digestibility of the Formula x Limiting Amino Acid Score of the Formula = PDCAAS

Step 1. Calculate Protein Digestibility

To calculate PDCAAS in a formula or recipe, every ingredient must have a Protein Digestibility Score.

Protein Digestibility Scores

Protein digestibility scores can be obtained from sources such as:

1. The supplier of the ingredient 

2. FAO/WHO references

Calculating the Total Protein Digestibility of the Formula

The formula for calculating the Total Protein Digestibility of your formula or recipe is:

Formula Protein Digestibility = Total Digestible Protein / Total Protein Content

‍
The Total Protein Content is the total amount of protein in grams in one serving of the formula.

To calculate the Total Digestible Protein, the Protein Digestibility Score of each ingredient is multiplied by the amount of protein that each ingredient contributes to a serving of the formula, and then these values are added together.

Total Digestible Protein = (Protein Amount that Ingredient 1 contributes to a serving of the formula x Protein Digestibility Score of Ingredient 1) +  (Protein Amount that Ingredient 2 contributes to a serving of the formula x Protein Digestibility Score of Ingredient 2) + (Protein Amount that Ingredient 3 contributes to a serving of the formula x Protein Digestibility Score of Ingredient 3) + …..

Step 2. Calculate the Limiting Amino Acid Score

The Limiting Amino Acid Score is calculated by:

1. Calculating the Amino Acid Score for each of the relevant amino acids

2. Choosing the lowest Amino Acid Score 

The lowest Amino Acid Score is the Limiting Amino Acid Score. 

Note: This score must be below 100%. If none are less than 100%, 1 can be used in the PDCAAS calculation.

Amino Acid Score (AAS) = Amino Acid Ratio (mg/g) / Reference Amino Acid Ratio (mg/g)

The Amino Acid Ratio

The first step in calculating the Limiting Amino Acid Score is to calculate the Amino Acid Ratio for each of the relevant amino acids. This is done by adding up the total milligrams (mg) of each amino acid in one serving of the formula and then dividing it by the total amount of protein in grams (g) in one serving of the formula.

Amino Acid Ratio = Amino Acid Amount (mg) / Total Protein (g)

The Reference Amino Acid Ratio

Once the Amino Acid Ratios have been calculated, they are divided by the Reference Amino Acid Ratios to calculate the Amino Acid Scores for each of the relevant amino acids. The lowest Amino Acid Score is the Limiting Amino Acid Score. 

‍
Per the 21 CFR regulations, the reference amino acid ratios to use when calculating PDCAAS are found in Table 1 (Column A) (pg 12) from the Rome 1991 guidance of the Joint FAO/WHO Expert Consultation on Protein Quality Evaluation for the 2-5 year old age group.

PDCAAS Relevant Amino Acids

The amino acids that are relevant to determining the PDCAAS are the nine essential amino acids, plus Tyrosine and Cysteine.

Histidine

Isoleucine

Leucine

Lysine

Methionine (+ Cysteine)

Phenylaline (+ Tyrosine)

Threonine

Tryptophan

Valine

Step 3. Calculating PDCAAS

Now that the Total Protein Digestibility of the Formula and the Limiting Amino Acid Score of the Formula have been calculated, you can now calculate PDCAAS using the following formula:

Total Protein Digestibility of the Formula x Limiting Amino Acid Score of the Formula = PDCAAS

Step 4. Calculating the Protein %DV

The formula for % Daily Value for Protein is:

(Protein (g) in one serving of the formula x PDCAAS) / RDI/DRV for Protein = %DV

RDI/DRV for Protein

The Recommended Dietary Intake (RDI) or Daily Reference Value (DRV) varies by demographic group:

50g: Adults aged 4+ years.

11g: Infants under 1 year.

13g: Children aged 1-3 years.

71g: Pregnant and lactating women.

Tips for Accurate PDCAAS Calculations

Use Reliable Data: Ensure amino acid values and digestibility percentages are accurate and obtained from credible sources.

Account for Processing: Processing methods (e.g., cooking, extrusion) can affect digestibility. Use adjusted digestibility scores for processed proteins.

Use Automation: A software like ENTR that specializes in formulation and nutrition labeling for food, beverage, and dietary supplement products can calculate PDCAAS automatically based on your formula and ingredient data, saving a significant amount of time and preventing calculation errors.

Want an Automatic PDCAAS Calculator?

Book a demo today with ENTR, and learn how specialized formulation and nutrition labeling for food, beverage, and dietary supplement teams can save so much time by automatically calculating PDCAAS, Protein DV%, protein nutrient content claims, and more.

‍