Inhibition of the Maillard reaction by ohmic heating in a glucose–lysine model system

BACKGROUND: Ohmic heating is a methodology with rapid and uniform thermal processing, thereby minimizing the risk of excessive heat exposure. Unexpectedly, ohmic heating is less prone to browning than retort heating. The present study aimed to examine the impact of ohmic heating on preventing browning and determine whether this effect was related to the inhibition of the Maillard reaction. RESULTS: Solutions containing glucose, lysine and sodium chloride were exposed to either ohmic or retort heating at 120 °C for 10, 20 or 30 min, by matching the temperature histories from the start of heating to the end of cooling. Ohmic-heated samples exhibited reduced browning compared to retort-heated samples, although slight differences were observed in the molecular weight distribution. Furthermore, ohmic heating resulted in lower consumption of reducing sugars and free amino groups, and decreased production of melanoidins, low-molecular-weight colored compounds, 3-deoxyglucosone, methylglyoxal, diacetyl, furosine and pyrraline. CONCLUSION: Ohmic heating causes less browning than retort heating, and browning suppression is attributed to the overall suppression of the Maillard reaction.