Physicochemical characterization and extrusion processing of Quinoa varieties

Nicole Ashly Aluwi

Quinoa has recently regained interest among consumers due to its recognized nutritional attributes. Often times, studies reporting the use of quinoa flour in food products do not mention the variety used or report on only a select few varieties. However, quinoa composition may vary significantly depending on factors such as variety and growing location, and therefore can exhibit different processing characteristics. The objective of this research was to understand the processing characteristics of 28 quinoa varieties by studying their composition and physicochemical properties. Physicochemical properties such as water absorption index (WAI), water solubility index (WSI), flour swelling power (FSP), pasting properties (MVAG), and differential scanning calorimetry (DSC) were used to group the 28 varieties into four clusters by Hierarchical Cluster Analysis. This allowed the grouping of the varieties based on their processing characteristics to be related to the potential food product categories for which they would be most suitable. Further, the performance of the select quinoa varieties in extrusion processing was evaluated. This study focuses on the extrusion of the individual quinoa varieties, Cherry Vanilla and Black, as well as a mixed variety named Bolivian Royal. The Cherry Vanilla and Black varieties were extruded in whole and scarified flour form, while the Bolivian Royal was extruded in scarified and degermed flour form. Experiments were carried out at 140°C barrel temperature, three screw speeds (100, 150, and 200 rpm), and three moisture contents (15, 20, and 25%). Scarification of the Cherry Vanilla and Black varieties elicited opposing responses in expansion ratio. This was attributed to the subsequent differences in loss of the seed outer layer during scarification, which was related to the differences in seed hardness. Removal of fat, protein, and fiber due to the degermination process resulted in a significantly higher expansion ratio in the Bolivian Royal extrudates. Further understanding of quinoa variety flours and their performance in food products will benefit growers and food industries in selecting varieties for development of quinoa incorporated products. This will help in the establishment of a robust quinoa industry from the farm to the consumer in the United States.

Physicochemical characterization and extrusion processing of Quinoa varieties

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