|Title||Effect of extraction pH on heat-induced aggregation, gelation and microstructure of protein isolate from quinoa (Chenopodium quinoa Willd)|
|Author(s)||Ruiz, Geraldine Avila; Xiao, Wukai; Boekel, Tiny van; Minor, Marcel; Stieger, Markus|
|Source||Food Chemistry 209 (2016). - ISSN 0308-8146 - p. 203 - 210.|
FBR Food Technology
Chair Sensory Science and Eating Behaviour
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||Aggregation - Denaturation - Extraction - Gelation - Protein - Quinoa - Solubility|
The aim of this study was to determine the influence of extraction pH on heat-induced aggregation, gelation and microstructure of suspensions of protein isolates extracted from quinoa (Chenopodium quinoa Willd). Quinoa seed protein was extracted by alkaline treatment at various pH values (pH 8 (E8), 9 (E9), 10 (E10) and 11 (E11)), followed by acid precipitation. The obtained protein isolates were freeze dried. The protein isolates E8 and E9 resulted in a lower protein yield as well as less protein denaturation. These isolates also had a higher protein purity, more protein bands at higher molecular weights, and a higher protein solubility in the pH range of 3-4.5, compared to the isolates E10 and E11. Heating the 10% w/w protein isolate suspensions E8 and E9 led to increased aggregation, and semi-solid gels with a dense microstructure were formed. The isolate suspensions E10 and E11, on the other hand, aggregated less, did not form self-supporting gels and had loose particle arrangements. We conclude that extraction pH plays an important role in determining the functionality of quinoa protein isolates.