Cow's milk-based infant formulas have a long tradition in infant nutrition, although some infants are unable to use them due to presence of several known allergens. Various processing methods have been identified capable of reducing cow's milk protein allergenicity including thermal and non-thermal methods and their combinations. Heat treatment and enzymatic hydrolysis have been in production of hypoallergenic infant formulas. However, modulation of allergenic epitopes depends on the extent of heat treatment applied, which consequently may also reduce a nutritional value of these proteins. In addition, enzymatic hydrolysis may not target allergenic epitopes thus allergenicity may persist; however released peptides may have detrimental impact on taste and functional properties of final products. Modulation of allergenicity of milk proteins appears to require a concerted effort to minimize detrimental effects as clinical studies conducted on commercial hypoallergenic formulas demonstrated persistence of allergic symptoms. This article covers traditional and novel processing methods and their impact on reduction of cow's milk allergenicity in milk-based infant formulas.
In this study, complexation between β-lactoglobulin (BLG) and Angum gum (Ang) was investigated using spectrophotometric, particle size measurement, and microscopic observation. Also, BLG-Ang complexes were added to O/W systems. Seven pHdelimited zones were determined that including: 1)pH after mixing ; 2)pH opt ; 3, 4, 5, 6)pH between pH after mixing and pH c ; pH c and pH Φ1 ; pH Φ1 and pH opt ; pH opt and pH Φ2 ; 7)pHpH>pH Φ1 . Mean particle diameter at pH opt for BLG:Ang (2:1) was lower (27.00±0.41 µm) than other two ratios (39.54±5.8, 66.47±0.19 µm for 1:1 and 1:2, respectively). Striking microstructure was identified such as cluster-like and vacuoles. Emulsions containing BLG-Ang complexes at pH after mixing >pH>pH c and pH c >pH>pH Φ1 in all ratios, and pH
In this study, emulsifying properties of Angum gum were improved by covalent bonding with β-lactoglobulin (BLG). Angum gum is a natural gum exudate from mountain almond trees (Amygdalus scoparia Spach). Covalent linkage of β-lactoglobulin-Angum gum conjugate was confirmed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Emulsifying properties of emulsions containing β-lactoglobulin:Angum gum (1:1) conjugates were studied with the advancement of Maillard reaction. Dry-heating time showed no significant (p > 0.05) effect on the emulsion activity index; however, emulsion stability index were significantly increased over time and emulsion stability index of two weeks incubated β-lactoglobulin-Angum gum conjugate was significantly different (p < 0.05) from others (β-lactoglobulin-Angum gum mixture, 0, 2, 6 days, and 2 weeks). Moreover, the creaming index decreased with advancement of Maillard-type conjugation of β-lactoglobulin:Angum gum (1:1). β-lactoglobulin-Angum gum conjugates (1:1, 1:2, and 2:1) exhibited much better emulsification performance than Angum gum and gum Arabic alone at the same emulsifier/oil ratio (1.5 wt. % total biopolymer/ 40% v/v oil). In addition, assessing droplet size distribution during storage and freeze-thaw treatment revealed that β-lactoglobulin:Angum gum (1:1) conjugate had finer droplet size compared to other β-lactoglobulin/Angum gum mixing ratios (1:2 and 2:1), Angum gum and gum Arabic.
The current study compares the emulsifying properties of Persian gum (PG) and gum Arabic (GA) in emulsions. The effects of concentration (0.5-3% w/v PG, 2.5-15% w/v PG), pH (2-7), ionic strength [NaCl, CaCl 2 (0-300 mM)], and temperature (40-90°C) were investigated. The surface-volume mean diameter (D 32 ) of the emulsions showed that the minimum values were 9.89 ± 0.68 and 4.52 ± 0.03 µm for emulsions containing 1.5% w/v PG and 15% w/v GA, respectively. In addition, the zeta potential of PG and GA emulsion changed from −23.5 to −39.5 and −30.5 to −46.0 mV, respectively. The interfacial tensions of PG and GA emulsions were varied in the ranges of 34.0-15.0 and 29.0-9.0 mN/m, respectively. Changes in the D 32 value of GA emulsions showed were not significantly different (p > 0.05) with respect to the effects of pH, NaCl, CaCl 2, and temperature. The NaCl concentration had no significant effect on D 32 ; but its value decreased from 13.11 to 5.70 µm as the CaCl 2 concentration increased. The interfacial tension of PG significantly increased with decreasing pH 7-2 and increasing 0-300 mM salts. After heating (25-90°C), the D 32 values of PG and GA emulsions changed to 11.04-14.54 and 4.21-4.21 μm, respectively. The results of this study can be useful for the application of PG as an emulsifier in beverage emulsions.
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