Study of chemical stability of lemon oil components in sodium caseinate–lactose glycoconjugate-stabilized oil-in-water emulsions using solid-phase microextraction-gas chromatography

Abstract

A headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC/MS) method was developed to quantify lemon oil components and their degradation products in oil-in-water (O/W) emulsions prepared with sodium caseinate-heated-lactose (NaC-T + Lact) glycoconjugates as wall materials at two pH values (3.0 and 6.8). NaC-T + Lact conjugates had a significantly lower solubility at both pHs. Hydrolysis prior to glycation enhanced the solubility of glycoconjugates. Glycation with lactose did not improve the emulsion activity of NaC, while caseinate glycoconjugates showed much stronger antioxidant activity than the NaC-control sample. This might be due to the presence of melanoidins formed between the sugar and amino acid compounds as supported by the increase in browning intensity. Among the SPME-fibres tested, carboxen/polydimethylsiloxane (CAR/PDMS) provided better results in terms of sensitivity and selectivity for oil lemon components and their degradation products. Storage studies of these emulsions demonstrated that glycated NaC-T + Lact showed protection against peroxidation compared to the control. However, acidic pH conditions altered their stability over storage time. The major off-flavor components (α-terpineol and carvone) were inhibited in emulsions stabilized with glycated NaC, particularly at pH 6.8. The use of NaC-T + Lact conjugates showed improved encapsulation efficiency and stability and could be used as potential food ingredient-emulsifiers for stabilising citrus oils against oxidative degradation in food and beverage applications.

Improved Physicochemical Properties of Curcumin-Loaded Solid Lipid Nanoparticles Stabilized by Sodium Caseinate-Lactose Maillard Conjugate

“…For all dispersions, no precipitation was observed, indicating the absence of Cur expulsion from SLNs. The higher EE, smaller PDI, better clarity, and better storage stability of Cur-SLNs prepared with NaCas-Lac than NaCas can be attributed to the improved emulsifying activity and capacity of NaCas after glycation . SLNs with Cur loading at 2.5% of lipid mass were used in the rest of this study.…”

“…NaCas-Lac conjugates were prepared according to previously reported literature with slight modification. 26 Briefly, NaCas (120 g) and Lac (44.85 g) were dissolved in Milli-Q water to give a protein concentration of 8% (w/v). Then the dispersion pH was adjusted to 7.5 using 0.1 N NaOH, followed by freeze-drying in 48 h. The freezedried powder was incubated for 3, 6, 12, and 24 h at 50 °C and relative humidity of 65%.…”

“…NaCas-Lac conjugates were prepared according to previously reported literature with slight modification . Briefly, NaCas (120 g) and Lac (44.85 g) were dissolved in Milli-Q water to give a protein concentration of 8% (w/v).…”

Complexed Biopolymer of Whey Protein and Carboxymethyl Cellulose to Enhance the Chemical Stability of Lemon Oil-in-Water Emulsions

“…Degradation pathways of d -limonene and citral (Adapted with permission from refs and . Copyright 2014 Royal Society of Chemistry and Copyright 2005 Springer-Verlag).…”

“…More recently, engineered interfaces with proteins combined with polysaccharides have been explored to control chemical degradation in citral, limonene, and lemon oil emulsions. Maillard conjugates of sodium caseinate and lactose partially inhibited off-flavor formation from lemon oil emulsions compared to those stabilized with the single protein, while soy protein–polysaccharide Maillard conjugates improved the physical stability of citral emulsions during prolonged storage . Furthermore, interfacial stabilization using the layer-by-layer technique, in which oppositely charged polymers, such as proteins and polysaccharides are adsorbed onto the droplet surface to create a bilayered interfacial membrane, has produced stable emulsions with better control of lemon oil degradation.…”