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β‐Lactoglobulin Gelation and Modification: Effect of Selected Acidulants and Heating Conditions
Author(s) -
Resch Jeffrey J.,
Daubert Christopher R.,
Foegeding E. Allen
Publication year - 2005
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.2005.tb09025.x
Subject(s) - rheology , phosphoric acid , lactic acid , chemical engineering , chemistry , hydrochloric acid , gel point , isothermal process , phosphate , materials science , chromatography , composite material , organic chemistry , thermodynamics , physics , biology , bacteria , engineering , genetics
The effect of acidulant selection, heating temperature, and heating rate on the properties of low‐pH β‐lactoglobulin (β‐Lg) gels and powders derived from these gels was investigated by rheological and microscopic techniques. As isothermal gelation temperature was increased from 75 to 85 °C, gels made with hydrochloric and lactic acid showed more rapid gel formation and increased stress at gel fracture. Thickening and water‐holding properties of powders derived from these gels also increased with temperature. Increases in gel strength and derivatized powder functionality appeared to plateau above 85 °C. Gels and derivatized powders prepared with phosphoric acid exhibited attributes similar to samples prepared with HCl and lactic acid at lower temperatures. The ion‐specific ability of phosphate to increase denaturation temperature was responsible for the shift in properties of gels made with phosphoric acid. Microscopy revealed temperature effects on network building block size, but variations in rheological properties could not be linked to changes in gel micrographs. Alteration of heating rates from 2.0 to 0.2 °C/min during gelation affected the observed gelation temperature, but had little effect on final gel mechanical properties. Acid selection and gelation temperature offer alternatives to control β‐Lg gel strength and the functional properties of instant thickening protein ingredients.