Characterizing changes in Maillard reaction indicators in whole milk powder and reconstituted low‐temperature pasteurized milk under different preheating conditions

The chemical properties and quality of milk powder and reconstituted milk can be changed by preheating treatment during milk powder processing. The effect of preheating conditions (low-temperature pasteurization [LT], high-temperature pasteurization [HT], extended shelf-life [ESL], ultra-high-temperature [UHT], and in-container sterilization [CS]), on furosine, furfural compounds, and advanced glycation end products were investigated in milk powders and reconstituted milk. The results revealed that Maillard reaction indicators were affected by preheating intensity; contents of furosine, 5-hydroxymethylfurfural (HMF), 2-furfural, Nε-(carboxymethyl)lysine (CML), and Nε-(carboxyethyl)lysine (CEL) increased, whereas lysine and 5-methyl-furfural (MF) decreased in both milk powder and reconstituted milk with an increase in the intensity of preheating. CML and CEL contents in reconstituted milk increased by 1.7- to 2.4-fold and 1.3- to 1.6-fold, respectibely. The content of CML and CEL in high-preheating powders was 11%-34% and 18%-123% higher than that in LT samples, respectively. Compared with milk powder, furosine was reduced by 22%-55% and MF by 57%-69% in reconstituted milk; HMF increased by 12%-52%, CML and CEL increased 1.7-2.4 times and 1.3-1.6 times, respectively. A superposition effect was observed between preheating intensity and heat process times, which increased the content of Maillard reaction products. PRACTICAL APPLICATION: Our findings revealed the promotion effect of higher preheating conditions on Maillard reaction indicators in milk powder and reconstituted low-temperature pasteurized milk. The results will help reduce some of the harmful Maillard reaction indicators (e.g., advanced glycation end products) formed during heat processing and assist customers in selecting dairy products with low amounts of Maillard reaction products.