Monitoring of the Maillard Reaction Based on the Reduction of Tetrazolium Salt XTT.

Abstract

The reduction of tetrazolium XTT with the Maillard reaction system containing various sugars or aldehydes and glycine was monitored and compared with the conventional indices of the Maillard reaction such as nitroblue tetrazolium (NBT) and dichlorophenolindophenol (DPI) reducibility, free hydroxymethylfurfural and browning. The change in XTT reducibility against the monosaccharide-glycine system showed a similar behavior as that of NBT and DPI reducibility, indicating that the Alnadori product and reductones formed in the Maillard reaction may be involved in the reduction of XTT. In contrast, the XTT reducibility aga consisting of lactose, Iactulose or cellobiose showed a different behavior from those indices. In the system, the reduction of XTT was caused by the substances which have a low reducibility of NBT. Such a property was recognized in some model systems, including the condensation reaction of D-glucosamine, that can form nitrogen-containing heterocyclic compounds such as pyrazinium and pyridinium. The condensation product of D-glucosamine rapidly lost the XTT reducibility with the addition of Cu2+. The phenomenon was also observed in the UHT-treated milk, and the decrease in the XTT reducibility during the storage was suggested to be due to the presence of Cu2+ in milk.

Relationship between the XTT Reducibility and Aminoreductone Formed during the Maillard Reaction of Lactose: the Detection of Aminoreductone by HPLC

“…The retention time in which the XTT reducibility was recognized was identical to that of aminoreductone. In a previous paper, we reported that the XTT reducibility was lost by the addition of Cu 2 ϩ which accelerates the oxidation of the XTTreducing substance (Ukeda et al , 1998). Based on the finding reported previously, Cu 2 ϩ was added to the heated model solution and the effect was examined.…”

“…We proposed an assay method for determining the ability of UHT-treated milk to reduce XTT (3¢-[1-(phenylamino)-carbonyl]-3,4-tetrazolium)-bis(4-methoxy-6-nitro)benzenesulfonic acid hydrate) as a method for evaluating the extent of the Maillard reaction (Ukeda et al, 1995(Ukeda et al, , 1996(Ukeda et al, and 1998. Compared with the conventional methods, the XTT assay is more rapid and convenient and is found to be applicable for estimating not only the extent of thermal treatment but also the storage conditions.…”

Maillard Reaction in Milk - Effect of Heat Treatment

“…In fact, the aminoreductone extracted from the heated model solution of lactose and butylamine was rapidly oxidized by the addition of Cu 2+ , and simultaneously the XTT reducibility was also lost. On the other hand, in our previous work, it was revealed that the commercially available UHT milk contains Cu 2+ at the concentration of 30 μg/L [18]. Thus, it was easily presumed that the aminoreductone formed by the heating process was gradually oxidized by endogenous Cu 2+ in milk during storage period.…”

“…As described above, during the course of elucidation of the XTT-reducing substance, Cu 2+ was used as the oxidizing agent (Figure 10), because we empirically knew that it was easily decomposed by the addition of Cu 2+ [18]. In fact, the aminoreductone extracted from the heated model solution of lactose and butylamine was rapidly oxidized by the addition of Cu 2+ , and simultaneously the XTT reducibility was also lost.…”

Protective effect of aminoreductone on photo-degradation of riboflavin

“…The Maillard reaction in milk leads to the formation of aminoreductone (AR), which can be used to evaluate the extent of the Maillard reaction based on its ability to reduce XTT (2,3-bis[2-methoxy-4-nitro-5-sulphophenyl]-2H-tetrezolium-5-carboxanilide) (Shimamura, Ukeda, & Sawamura, 2000;Ukeda, Shimamura, Hosakawa, Goto, & Sawamura, 1998). As for the other Maillard reaction products, AR shows antioxidant activity (Pischetsrieder et al, 1998).…”