There are slight differences in the meanings of these terms, but they are often used interchangeably. 1  Independent Variable: It implies causality: the independent variable affects the dependent variable. 2  Used predominantly in ANOVA, but often in regression as well. 3  It can be either continuous or categorical.
Protein Quality. Collagen is not a complete protein because it is lacking in the amino acid tryptophan. A Protein Digestibility Corrected Amino Acid Score (PDCAA) of a complete protein is 1.0.ollagen is a protein found in the muscle and connective tissue of animals. Hydrolyzed collagen protein supplements are typically made from the bones and skin of cows, horses or pigs.
Collagen is the most abundant protein in the human body and is the substance that holds the whole body together. Protein makes up around 20% of the body's mass, and collagen makes up around 30% of the protein in the human body. 2  There are at least 16 types of collagen, but 80-90% of the collagen in the body consists of types I, II, and III. 3  Type I collagen fibrils are stronger than steel (gram for gram).