Thesis
Physicochemical characteristics and direct steam injection processing of selected pea and rice protein isolates
Washington State University
Master of Science (MS), Washington State University
2017
Handle:
https://hdl.handle.net/2376/103442
Abstract
Pea and rice are well recognized as good sources of protein due to their availability and low production cost. The use of pea and rice protein isolates as a food ingredient is limited and more study is needed to promote their application. This study investigated high pressure direct steam injection (DSI) with pH adjustment to create modified pea-rice isolate blends (PR) with enhanced protein functional properties. Furthermore, protein isolates from sixteen varieties of dry peas cultivated in the Pacific Northwest (PNW) extracted by a wet fractionation method, five commercial pea protein isolates, and three commercial rice protein isolates were analyzed for composition and physicochemical properties. A DSI system was used to modify 5% (w/w) slurries of commercial isolates at pea:rice ratio 2:1 (w/w) across a range of steam temperatures (66-107 °C) and pH values (2, 3, 9, 10, 11). Based on protein solubility profiles from pH 3-9, optimal DSI conditions were pea:rice ratio 2:1, pH 11, and steam injection at 107 °C. The essential amino acid composition of 2:1 PR blends after DSI was confirmed by amino acid analysis. DSI treatment did not reduce available lysine (P > 0.05). When the 2:1 DSI-PR blend was compared to the untreated PR, solubility (from 3 to 41%, at pH 7), emulsifying activity index (from 5.9 to 52.5 m2 /g), foam stability (from 68.2 to 82.8%), and oil holding capacity (from 1.8 to 4.9 g/g) values increased (P < 0.05). DSI decreased (P < 0.05) water holding capacity (from 3.4 to 2.5 g/g) and emulsifying stability (from 22 to 12 min). DSI can be used to alter the protein functional properties of blended PR isolates without affecting the essential amino acid composition. Among PNW varieties, Carousel had the highest solubility at acidic (45.07%) and neutral (47.72%) pH values, demonstrating potential for use in beverages. The highest emulsifying activity index (EAI) was recorded for variety Ariel at 33.77 m2 /g. EAI of commercial pea protein isolates ranged from 11.37 m2 /g (Pisane B9) to 25.40 m2 /g (VegOtein). Wet fractionation method produced protein isolates with better functional properties when compared to commercially available pea and rice protein isolates.
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Details
- Title
- Physicochemical characteristics and direct steam injection processing of selected pea and rice protein isolates
- Creators
- Ewa Pietrysiak
- Contributors
- Denise M. Smith (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Food Science, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525015401842
- Language
- English
- Resource Type
- Thesis