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α‐Lactalbumin solubilisation from a precipitated whey protein concentrates fraction: pH and calcium concentration effects
Author(s) -
Fernández Ayoa,
Menéndez Violeta,
Riera Francisco A.
Publication year - 2012
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2011.02865.x
Subject(s) - chemistry , citric acid , precipitation , whey protein , calcium , fractionation , lactalbumin , chromatography , fraction (chemistry) , yield (engineering) , whey protein isolate , dissolution , biochemistry , organic chemistry , materials science , metallurgy , physics , meteorology
Summary The selective precipitation of α‐lactalbumin (α‐La) is the basis for one of the possible methods in whey protein fractionation. Calcium concentration, type of acid added and pH play important roles in α‐La precipitation and on the following resolubilisation. Two washing steps are enough for quantitative removal of β‐lactoglobulin entrapped in the precipitate. α‐La losses are minimised during washing steps (5%) when NaCl is used as washing agent. The most important parameter to control during the resolubilisation step is pH, the maximum amount of the initial re‐dissolved α‐La being 76% when the pH is adjusted to 7.5, CaCl2 concentration is 0.2 m and prior precipitation is carried out adding citric acid. Addition of CaCl2 is not necessary to dissolve α‐La because of the fact that there is enough calcium in the precipitate to join all α‐La; however, its presence improves the solubilisation yield (66% vs. 75%).