Effect of Storage Temperature on Lactulose and 5-hydroxymethyl-furfural Formation in UHT Milk

Abstract

The amounts of two heating-induced products were studied (lactulose and 5-hydroxymethyl-furfural) in UHT milk samples, directly and indirectly heat-treated, during a period of 90 d storage at five different temperatures. The results indicate an increase in 5-hydroxymethyl-furfural, as well as lactulose, taking place in the range of temperatures between 40–50°C.

Heat-induced and other chemical changes in commercial UHT milks

“…In addition, Nangpal & Reuter (1990a) found that lactulose increased during storage at 20 8C as well as at elevated temperatures. However, contrasting these findings, a number of previous studies found the level of lactulose to be largely stable during storage at y20-25 8C (Andrews, 1984(Andrews, , 1985Moberg & Hegg, 1985;Corzo et al 1988 ;Akalin & Gö nç, 1997;Elliott et al 2003) or only shows an increase with storage time when stored above this temperature (Jiménez-Pérez et al 1992;Akalin & Gönç, 1997). The conflicting reports arise because, during storage, lactulose continues to be formed, but at the same time is also degraded (Andrews, 1989).…”

Use of reconstituted concentrated nonfat milk for the production of UHT milk: physical and chemical effects and stability

“…These results agree with those obtained by Fink and Kessler (1986), who reported higher HMF values in processed UHT milk stored at 35°C, as compared to those of the same milk stored at 20°C. Jimenez‐Pérez et al . (1992) also reported that, as the storage temperature increased, the HMF content values also increased, these increases being significantly greater at temperatures above 30°C.…”

Non-Enzymatic Degradation Pathways of Lactose and Their Significance in Dairy Products

“…The formation of furfural, HMF and furfuryl alcohol is an order of magnitude less than that of lactulose and galactose. Although HMF is an important product in heated milk, the concentration of lactulose can be more than 20 times that of HMF in UHT milk (75 d storage at 508C) (Jimenez-Perez et al, 1992). However, the concentrations of HMF and lactulose in UHT milk change differently with time.…”

“…However, the concentrations of HMF and lactulose in UHT milk change differently with time. Jimenez-Perez et al (1992) reported that while the concentration of lactulose decreased after 75 d storage at either 40 or 508C for all of the commercial lots studied, HMF content increased steadily over the 90 d storage period. In UHT milks, the levels of furfural formed may be more than 20 times lower than those of HMF.…”