Abstract:

A series of experiments have been conducted to establish a model system through microwave heating to explore
the formation of 3-chloropropane-1,2-diol (3-MCPD) in edible oil as a function of oil type, NaCl, pH, heating time,
intermittent microwave heating and metal ions. The results showed that 1) microwave heating resulted in formation of over
9 mg/kg 3-MCPD in hot-pressed oils, whereas much less 3-MCPD was formed in cold-pressed oils and commercial oils; 2)
the amount of 3-MCPD esters increased with increasing concentration of sodium chloride solution, and increased firstly and
then decreased with increasing proportion of sodium chloride solution added, reaching maximum value at 20%; 3) acidic
condition could promote the formation of 3-MCPD; 4) the amount of 3-MCPD increased with increasing time up to 10
minutes; 5) compared to continuous microwave heating for an equal time, intermittent microwave heating could inhibit the
production of 3-MCPD; and 6) metal ions could significantly promote the formation of 3-MCPD esters because metal ions
could act as catalysts to promote the formation of intermediates during the formation of 3-MCPD. Therefore, this study can
be regarded as a data support for limiting the formation of 3-MCPD esters during microwave heating of foods.

Key words: microwave, 3-chloropropane-1,2-diol (3-MCPD) esters, NaCl, pH, time, intermittent microwave, metal ions