Location: Cereal Crops ResearchTitle: Effect of alkaline extraction pH on structure properties, solubility, and beany flavor of yellow pea protein isolate
|GAO, ZILI - NORTH DAKOTA STATE UNIVERSITY|
|SHEN, PEIYI - NORTH DAKOTA STATE UNIVERSITY|
|LAN, YANG - NORTH DAKOTA STATE UNIVERSITY|
|CUI, LEQI - NORTH DAKOTA STATE UNIVERSITY|
|CHEN, BINGCAN - NORTH DAKOTA STATE UNIVERSITY|
|RAO, JIAJIA - NORTH DAKOTA STATE UNIVERSITY|
Submitted to: Food Research International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/27/2020
Publication Date: 1/29/2020
Citation: Gao, Z., Shen, P., Lan, Y., Cui, L., Ohm, J., Chen, B., Rao, J. 2020. Effect of alkaline extraction pH on structure properties, solubility, and beany flavor of yellow pea protein isolate. Food Research International. 131:109045. https://doi.org/10.1016/j.foodres.2020.109045.
Interpretive Summary: The use of pea protein is limited in food applications because of smelly flavor and poor technical functionality. The common method for preparing pea proteins is to separate proteins from pea flour using an extraction solution. However, there is a lack of systematic studies on how extraction conditions impact yield, functionality and the flavor profile of the pea protein isolates. Therefore, this research investigated the impact of the acid level of the extraction solution on the properties of pea protein isolates. This research determined the optimal acid level of the extraction solution to produce premium quality pea proteins. This information will be valuable to enhance the utilization of pea proteins in food applications.
Technical Abstract: There is a growing interest in utilization of pea protein as alternatives of animal protein due to health benefit, allergen and gluten free claim that can be made on food. However, pea proteins are still underutilized in food applications owing to its characteristic beany flavor and poor technical functionality. The common method for preparing pea protein isolate (PPI) involves alkaline extraction followed by an isoelectric precipitation (AE-IP). However, there is a lack of systematic studies on how extraction parameters impact their yield, functionality and flavor profile. The impact of extraction alkaline pH (8.5-9.5) on the protein composition and molecular structures of PPI was investigated using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), size exclusion chromatography with multi-angle static light scattering and refractive index (SEC-MALS-RI), and circular dichroism (CD) spectrum. The results demonstrated that protein yield increased as the extraction pH increased from 8.5 to 9.5. However, increasing the extraction pH promoted the formation of protein aggregates resulting in the decrease of percent protein solubility although there was no influence on secondary structure. PPI extracted at pH 9.0 possessed the lowest beany flavors and lipoxygenase (LOX) activity as reveled by selected six beany flavor markers including alcohols, aldehydes, ketones and pyrazine. Therefore, pH 9.0 was found to be optimal for AE-IP extraction process to prepare premium PPI in terms of yield, functionality and flavor profile. Our results could have fundamental implications for the utilization of pea proteins in food applications.