USDA Sponsored Study Shows Oryzatein® May Improve Shelf Life of Emulsion-based Food or Cosmetic Products

Published Online 16 MAR 2017 – European Journal of Lipid Science and Technology

Objective:

Lipid oxidation can be a major issue in emulsion-based products and lead to off-flavors, rancidity and decreased shelf life. While antioxidants are a popular choice to help offset lipid oxidation, options have become limited due to the increasing demand from consumers for more natural products. This study was designed to determine the antioxidant activity of two rice protein concentrates (RPC) in bulk oil and oil-in-water emulsions.

Methods:

Part 1: Bulk oils were mixed with Oryzatein® 70 (RPC1) or Oryzatein® SG-B/N (RPC2) and heated to 180 degrees Celsius. Total polar compounds and triacylglycerol polymerization were measured to determine lipid oxidation compared to control.

Part 2: Oil-in-water emulsions were mixed with RPC1 or RPC2 at 0.5% and 1.0% by weight and subjected to accelerated oxidation for 8 days at 50 degrees Celsius. Lipid oxidation was measured via peroxide values, headspace oxygen levels, headspace volatile oxidation products and fatty acid analysis and then compared to control.

Results:

In bulk oils: RPC 1 showed minor protection against oxidation but not significantly different from the control.

In emulsions: RPC2 showed consistent ability to suppress lipid oxidation

  • RPC2 at 1.0% showed consistent lower peroxide values than all other treatments and control.
  • RPC2 at both 0.5% and 1.0% showed consistently lower levels of headspace volatile oxidation products compared to control.
  • Fatty acids decreased in all samples, except the samples incorporating 1.0% RPC2 which decreased to a lesser extent.

Implications:

Oryzatein® SG-B/N (RPC2) holds promise as an antioxidant ingredient and may aid in the shelf life extension of emulsified food and cosmetic products (e.g. sauces, gravies, dressings, lip stains, etc.).

Conclusion/Discussion:

Adding Oryzatein® SG-B/N at 1.0% by weight appears to help suppress lipid oxidation in emulsions. In an era where consumers are less willing to accept artificial or synthetic ingredients, rice protein may provide a natural alternative to ingredients such as EDTA or BHT and thus a cleaner label.

See study abstract here. 
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