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Kinetics, aggregation behavior and optimization of the fractionation of whey protein isolate with hydrochloric acid

Permanent URL:
http://handle.nal.usda.gov/10113/59492
File:
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Abstract:
Concentrated WPI solutions (10%, w/w) containing approximately 50% beta-lactoglobulin (β-LG) and 26% alphalactalbumin (α-LA) were fractionated with HCl at acidic pH and moderate temperature to obtain enriched α-LA and β-LG fractions. Aggregation behavior and kinetics of protein precipitation and aggregate formation were analyzed as a function of four process parameters: pH (3.0–5.5), temperature (50–70 ◦C), reaction time (0–180 min) and protein concentration (10–29%). The precipitation and aggregation of α-LA appeared rate-limited, with a logarithmic dependence of time and possible bimodal nucleation rate, and varied considerably with pH and temperature. Aggregates as large as ∼300µm were noted after 120 min at pH 4, 60 ◦C. Processing parameters were optimized to obtain both a high aggregate yield and optimal composition of the aggregate fraction. The optimally enriched solid and liquid fractions contained 58% α-LA and 76% β-LG, respectively, with 99% and 74% recovery ratios. Over the pH range studied, β-LG aggregation was found negligible at 60 ◦C and β-LG recovery in the aggregates attributed to liquid holding. Increasing WPI concentration accelerated α-LA aggregation, demonstrating a concentration-dependent aggregation mechanism, and reduced aggregate purity. Enriched whey protein fractions are valuable health-enhancing food ingredients.
Author(s):
Laetitia M. Bonnaillie , Peggy M. Tomasula
Note:
USDA Scientist Submission
Source:
Food and bioproducts processing 2012 10 v.90 no.4
Language:
English
Year:
2012
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.