Improving the freeze–thaw stability of emulsions via combining phosphatidylcholine and modified starch: A combined experimental and computational study

Abstract

Summary Phosphatidylcholine (PC)‐coated emulsion was unstable during the freezing process. This study aimed to investigate the influences of octenyl succinic anhydride modified starch (OSAS) to PC weight ratios on the properties of the OSAS–PC complex and freeze–thaw stability of oil‐in‐water (O/W) emulsions. The results of molecular dynamics (MD) simulation indicated that electrostatic interaction was dominant in the complex. When OSAS/PC weight ratios were 5:5, 6:4, and 3:7, the complex showed a relatively low interfacial tension, high interfacial layer thickness, and high apparent viscosity at low shear rate. Z‐average diameter in emulsions increased from 175.8 to 270.0 nm and zeta‐potential increased from –49.2 to –29.7 mV, when OSAS/PC weight ratio varied from 0:10 to 7:3. OSAS–PC complex in weight ratios of 3:7 and 5:5 remarkably improved the freeze–thaw stability of emulsions (no creaming and aggregates), which may be related to a thick and dense interfacial layer. These findings indicated that the freeze–thaw stability of PC‐stabilised emulsions could be improved by OSAS with low levels.

Starch-Based Polysaccharide Systems with Bioactive Substances: Physicochemical and Wettability Characteristics

“…During gelatinization, the presence of a large amount of water is forming, and then the layered structure of the starch grains disappears and turns into bubbles. As a result of water entering the vesicles, amylose is completely dissolved, amylopectin swells more strongly, and peptization occurs [18][19][20][21][22][23][24][25]. These changes can also be seen in the example of measurements of size diameter and values of electrokinetic potential.…”

“…The binding energy of the starch-PC complex was significantly lower than that of PC molecules, suggesting that the complex was relatively stable, and their changes were consistent with changes in electrostatic energy, indicating that such energy played a major role in the formation of the starch-PC complex. There were intermolecular hydrogen bonds and hydrophobic interactions in the starch-PC complex, while only hydrophobic interactions existed in the PC molecules [24].…”

“…It is well known that changes to temperature involved in food processing and products can also influence emulsion stability. For example, this type of research has been carried out for phospholipids, and the authors [24] have investigated the effect of the combination of starch and PC on the freeze-thaw stability of an O/W emulsion. The adsorption behavior, rheological properties, and mechanism of the improved stability of the starch-PC complex at the oil-water interface were discussed.…”

“…Therefore, the structural rearrangement of the PC molecules on the starch surface can occur, and the highest increase in the polarity of the starch surface after PC modification is observed. Wang and co-workers proved that the starch-PC complex at weight ratios of 3:7 and 5:5 remarkably improved the freeze-thaw stability of emulsions (no creaming process and creation of aggregates) and stated that it may be related to a thick and dense interfacial layer [24].…”

“…Regarding the above aspects, the physicochemical characterization of dispersion systems was aimed at determining the effect of starch modification and temperature of starch preparation, as well as checking the wettability parameters of starch-coated glass plates before and after modification [22][23][24][25]. Changes in effective diameter, multimodal size distribution, and electrokinetic potential (zeta) as a function of time were analyzed using the dynamic light scattering and microelectrophoresis technique, as well as the advancing and receding contact angle (and angle hysteresis), by the sessile drop method [26][27][28][29].…”