Evaluation on oxidative stability of walnut beverage emulsions

Area of Science:

• Food Science
• Emulsion Technology
• Nutritional Chemistry

Background:

• Walnut beverages are susceptible to physical instability and lipid oxidation.
• Food antioxidants are crucial for preserving emulsion quality and extending shelf life.

Purpose of the Study:

• To investigate the impact of various food antioxidants on the physical stability and lipid oxidation of walnut beverage emulsions.
• To evaluate the efficacy of tea polyphenols, vitamin E, BHT, enzymatically modified isoquercitrin, and natural antioxidant extracts.

Main Methods:

• Preparation of walnut beverage emulsions using walnut kernels, nonionic emulsifiers, and xanthan gum.
• Assessment of physical stability under thermal storage (62 ± 1 °C).
• Measurement of lipid oxidation levels influenced by thermal and UV light exposure.

Main Results:

• Tea polyphenols increased droplet size and enhanced emulsion physical stability during thermal storage.
• Vitamin E and enzymatically modified isoquercitrin decreased physical stability.
• Tea polyphenols and Butylated hydroxytoluene (BHT) significantly retarded lipid oxidation under thermal and UV light.
• Vitamin E showed prooxidant effects during thermal storage but antioxidant effects under UV light.

Conclusions:

• Tea polyphenols are effective in improving the physical stability and oxidative resistance of walnut beverage emulsions.
• The choice of antioxidant is critical, as some can negatively impact emulsion stability and oxidative status.
• Further research into synergistic antioxidant combinations may optimize walnut beverage quality.