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Egg yolk powder is a widely used functional food ingredient due to its beneficial physicochemical and nutritional properties. However, its utilization in food can be limited due to its relatively high lipid content and low water-solubility. To address this issue, a two-step processing method utilizing enzymatic treatment combined with subcritical fluid extraction was investigated in this study. This method effectively reduced lipid content and improved water-solubility of egg yolk powder. An alcalase enzyme concentration of 500 U/g, extraction temperature of 313.15 K, extraction time of 120 min and a solid-liquid ratio of 1:9 (g:mL) produced powder with 20% lipid content and 71% water-solubility. Enzymatic hydrolysis clearly enhanced subcritical fluid extraction efficiency. This was attributed to hydrolysis disrupting the structure of egg yolk particles and facilitating the release of enclosed lipid molecules and was confirmed by scanning electron microscopy and laser confocal microscopy.

Non-meat proteins are widely used in the meat processing, and the final product is greatly affected by salt. This study presented the combined use of soybean protein isolate (SPI) and egg white (EW) on the gelation of chicken myofibrillar protein (MP) with or with NaCl. Gel properties were determined with the use of texture profile analysis, cooking loss, intermolecular forces, rheological properties, scanning electron microscopy and low field nuclear magnetic resonance (LF-NMR) measurements. Non-meat proteins improved the MP gel quality when it was without NaCl, except for the increased cooking loss caused by 1.2% SPI. The effect of non-meat proteins on MP gel quality was more obvious at 0.3 mol/L NaCl, including the improvement of gel hardness by SPI and the reduction of cooking loss by EW. When the added non-meat proteins changed from 1.2% SPI to 0.3% EW-0.9% SPI, the gel hardness significantly decreased (P

The purpose of this study was to evaluate the physicochemical stability and potential gastrointestinal fate of the lutein-enriched high internal phase emulsions (LE-HIPE) stabilized by egg yolk-modified starch complex. Results showed that the physical stability and lutein retention of the LF-HIPE stabilized by egg yolk-hydroxypropyl distarch phosphate (EY-HPDSP) or egg yolk-octenyl succinic anhydride starch (EY-OSA) complex were both significantly improved at 4 °C. However, the LE-HIPE stabilized by EY-HPDSP complex showed better physical stability, lower lipid oxidation and higher lutein retention during storage at 37 °C than that stabilized by EY-OSA complex, which was related with the results of smaller droplets, more restricted water and oil protons for the former. In vitro digestion results showed that high level of HPDSP in LE-HIPE was beneficial to the improvement of the bioaccessibility of lutein. These results could be useful in the development of nutrient delivery system based on egg yolk-modified starch complex stabilized HIPE.

The effects of sodium tripolyphosphate and sugar on cold-set gel properties of egg yolk/κ-carrageenan/xanthan gum mixed dispersions were investigated by zeta potential, rheological measurements, gel textural analysis and low-field nuclear magnetic resonance (LF-NMR). As the yolk content increased to the 5 g/100 mL in aqueous systems, phase separation of mixed gel could be observed, due to the relatively rough gel appearance. Furthermore, the addition of phosphate could significantly improve the phase separation of mixed gels by elevating the pH and reducing zeta potential. The increase in the content of yolk and sugar brought an enhancement in gel storage modulus, while the addition of phosphate induced a dramatic decrease in the gelation rate of mixed gels. Textural analysis confirmed that hydrogen bonding interaction was the important force, which determined gel strength of the ternary composite cold-set gelation system. The result of LF-NMR revealed that there was a negative correlation between the decrease of proton mobility of immobilization water and the increase of gel strength in different sample series.