Using egg yolk power to stabilise paprika oleoresin

Paprika oleoresin (PO) is an oil-soluble extract from the fruits of Capsicum annuum or Capsicum frutescens, and is primarily used as a colouring and/or flavouring in food products, such as sausages or burgers.

PO is often introduced for its colour-giving effect but it also has antioxidant and anti-inflammatory properties thanks to its carotenoid content. However, its lipophilic nature and sensitivity to factors like oxygen, heat and light restrict its use in water-based foods. In meat products, the colour isn’t stable so over time it can start to fade, especially if there are high temperatures in storage facilities.

While previous approaches, including emulsions and liposomes, have aimed to improve PO’s stability, the results have been limited. These persistent challenges underscore the need for new stabilisation methods for PO.

New research has now used high-pressure homogenisation (HPH) to restructure low-density lipoprotein (LDL) from egg yolk, producing a stable aqueous PO solution. By examining microstructure, particle size, encapsulation efficiency, and stability under various conditions, the study confirmed that HPH enhances PO’s solubility and stability, offering a method of using LDL as a bioactive carrier.

The researchers found that HPH at 100 MPa for 10 cycles decreased the average particle size of the LDL-PO complex by 37.2% and improved encapsulation efficiency by 9.2%. Stability assessments showed notable enhancements in storage, thermal, and UV irradiation resistance, with stability rates increasing from 30.83% to 62.90%, 64.42% to 76.97%, and 77.56% to 92.98%, respectively. Structural analysis revealed that HPH promotes better interaction between LDL and PO, optimising the dispersion and stability of PO in water without compromising the lipoprotein’s structure.

“The innovative use of HPH to remodel LDL represents a significant advance in the stabilisation of natural pigments like PO,” stated Dr Jinqiu Wang, the study’s lead researcher. “This technique not only boosts LDL’s role as an effective carrier but also broadens the potential uses of natural colourants in various food products, marking a greener and safer approach to food processing.”

The study, led by scientists from Chengdu University and Huazhong Agricultural University, was published in the journal Food Science of Animal Products.

The study’s findings suggest that HPH could be extended to stabilise other fat-soluble bioactive compounds, enhancing their application in the food industry. This method offers a promising pathway toward more sustainable and efficient food production, leveraging LDL’s versatility as a carrier for diverse nutrients and active ingredients in aqueous solutions.

Image credit: iStock.com/Stanislav Sablin