Effect of cooking on the in vitro and in vivo protein quality of soy, oat and wheat varieties

Background and Objectives

Soy, wheat, and oats are widely consumed crops globally, but variation between cultivars and processing methods can produce products of varying protein quality. This study cooked two different cultivars of wheat, oats, and soy and compared indices of protein quality as well as quantified differences in antinutritional factors.

Findings

Protein Efficiency Ratio (PER) was highest in cooked soy cultivars and lowest in wheat samples, with cooking having the most impact on soy PER. Protein Digestibility Corrected Amino Acid Score (PDCAAS) of soy was greater than oats which was greater than wheat. Antinutritional factors differed significantly between crops and cultivars, with processing having the greatest impact on soy. In vitro measurements of PDCAAS correlated well with in vivo assessment.

Conclusions

Thermal processing has variable effects on protein quality depending on crop and cultivar selected, primarily due to differences in amino acid composition. In vitro measurement of protein quality can be used as a rapid screening tool.

Significance and Novelty

Direct comparison in protein quality between wheat, oat, and soy is rarely reported. Measuring the protein quality of different cultivars and crops pre and postprocessing provides essential data for product development and dietary formulation.