Polydimethylsiloxane Droplets Exhibit Extraordinarily High Antioxidative Effects in Deep-Frying

Area of Science:

• Food Science and Technology
• Material Science
• Chemical Engineering

Background:

• Polydimethylsiloxane (PDMS) is widely believed to provide antioxidative effects in oils.
• The mechanism of PDMS antioxidative action, particularly during high-temperature applications like deep-frying, requires clarification.
• Previous assumptions attributed PDMS's benefits to a surface layer, but this study investigates alternative mechanisms.

Purpose of the Study:

• To investigate the conditions under which polydimethylsiloxane (PDMS) exhibits antioxidative effects in oils during deep-frying.
• To determine the role of PDMS physical state (layer vs. droplets) in its antioxidative efficacy.
• To elucidate the mechanism behind PDMS's suppression of oil oxidation and volatile compound formation.

Main Methods:

• Comparative analysis of PDMS antioxidative effects in canola oil under different conditions: surface layer vs. suspended droplets.
• Evaluation of oil-soluble methylphenylsiloxane (PMPS) and PDMS in PDMS-soluble canola oil fatty acid ester.
• Assessment of PDMS droplet zeta potential and interaction with low molecular weight compounds and volatile substances.

Main Results:

• A PDMS surface layer on canola oil showed no antioxidative effect during simulated deep-frying.
• PDMS exhibited significant antioxidative effects only when present as insoluble droplets within the oil.
• PDMS droplets, due to high negative zeta potential, attracted oxygen and volatile compounds, thereby inhibiting oil oxidation and reducing odor.

Conclusions:

• The antioxidative efficacy of PDMS in oils during deep-frying is contingent on its formation of insoluble droplets, not a surface layer.
• PDMS droplets suppress oxidation by physically interfering with oxygen molecules and attracting detrimental compounds.
• The addition of PDMS to oil can effectively reduce the formation of undesirable volatile compounds during heating.