Cold Gelation of β‐lactoglobulin in the Presence of Iron

Abstract

To protect and transport iron, we investigated the trapping properties of a network formed from ␤ ␤ ␤ ␤ ␤-lactoglobulin. We studied the influence of different parameters-pH, iron, and protein concentrations-on gel properties (optical and mechanical properties, WHC, and microstructure). For all conditions tested, the results show the formation of a cold gel in the presence of iron. The mechanical properties reveal that the elastic behavior and the strength of rupture increase with higher protein concentrations and decrease with higher iron concentrations. The water-holding capacity is high for low iron concentrations. The microstructure shows that, at low iron/protein ratios, a homogeneous filamentous network is obtained whereas, at high iron/protein ratios, more random aggregated particles are present.

Molecular mechanisms of Fe2+‐induced β‐lactoglobulin cold gelation

“…10,[12][13][14] In a previous study, we investigated the cold gelation of ␤-lg induced by the addition of Fe 2ϩ , in order to protect iron from environmental conditions. 15 Our results show that the macroscopic properties obtained for Fe 2ϩ -induced ␤-lg cold gels exhibit similarities with those obtained in studies with different cation (Ca 2ϩ , Mg 2ϩ , Na ϩ )-induced cold gels, suggesting that the cation-protein interactions would be of similar nature, where the electrostatic interaction would play a predominant role. 10,11,15,16 Moreover, we demonstrated that different types of gels could be obtained depending on pH conditions and protein and/or iron concentration.…”

“…15 Our results show that the macroscopic properties obtained for Fe 2ϩ -induced ␤-lg cold gels exhibit similarities with those obtained in studies with different cation (Ca 2ϩ , Mg 2ϩ , Na ϩ )-induced cold gels, suggesting that the cation-protein interactions would be of similar nature, where the electrostatic interaction would play a predominant role. 10,11,15,16 Moreover, we demonstrated that different types of gels could be obtained depending on pH conditions and protein and/or iron concentration. When iron/protein ratios were low and the pH value close to 7, gels were homogeneous and characterized by an elastic behavior and a high resistance to rupture, suggesting that strong particle-particle interactions occurred.…”

Design of whey protein nanostructures for incorporation and release of nutraceutical compounds in food

“…These include the chemical environment of aqueous solution (pH, protein concentration and ionic strength), and/or addition of electrically charged species (cold gelation) (Debeaufort et al, 1998;. Development and production of whey protein nanosystems can be tailored by small changes in these external factors (Mulvihill and Kinsella, 1988;Lef' evre and Subirade, 2000;Remondetto et al, 2002). Temperature.…”

“…Concentration plays an important effect in protein aggregation, particularly when denaturation is induced by heat; in this case, the tendency of a protein to aggregate is higher when its concentration is high (Wehbi et al, 2005). Equally, when a salt is added to a heat-denatured protein solution, the concentration of protein has a major influence on the rheological properties of the solutions; at low protein concentrations the heat-denatured protein will tend to form a viscous solution-yet above the critical protein concentration, a gel is obtained (cold gelation) (Remondetto et al, 2002;Ramos et al, 2012b The salt type to adjust ionic strength is other condition that should be considered. For instance, calcium and magnesium (divalent ions) can induce aggregation via electrostatic shielding, ion/hydrophobic interactions and cross linking with negatively charged carboxylic groups of neighboring whey protein molecules-leading to the establishment of protein-cat-ion-protein bridges.…”

Whey protein aerated gels as a new product obtained using ambient temperature magnesium and iron(II) induced gelation

“…Sodium or calcium ion induced or "cold-set" gels obtained from whey protein were extensively investigated (BArBut & Foegeding, 1993;BryAnt & MCCLementS, 1998;Foegeding, 2007). There is very little research done on "cold-set" gels Acta Alimentaria 43,2014 obtained by using other cations like magnesium or iron (Remondetto et al, 2002;Remondetto & SuBirAde, 2003;DA SiLvA & DeLgAdo, 2009). No results were presented on aerated gels obtained by the addition of the above ions.…”