The generation of a chain-breaking antioxidant capacity has been analyzed in butter cookies, as a function of the cooking time. A kinetics approach was used, by which the antioxidant capacity of aqueous extracts of cookies was measured in terms of equivalence by weight of a reference antioxidant. A diazo compound was used to generate at constant rate peroxyl radicals, and the reporting reaction was the bleaching of crocin in the presence of these radicals. Results indicated that during the first 20−30 min of cooking, when browning takes place, an antioxidant capacity accounting for up to 5 g of Trolox is produced in 100 g of dried aqueous extracts of the cookies. This result supports the concept that functionally relevant antioxidants are generated by Maillard reaction. Keywords: Maillard reaction; lipid oxidation; free radical scavenger; bakery product

Maillard reaction volatile compounds were prepared by heating a glucose-glycine solution. The antioxidant effect of the volatiles was tested in soybean oil (SBO) thermoxidation. Volatile compounds were transferred from the heated Maillard solution to the oil with a gas-tight syringe after removing the same volume of oil headspace (air). Standard accelerated oxidation was performed by heating the SBO at 90°C. Antioxidant activity was evaluated through peroxide value and headspace gas chromatographic analysis of oil volatile compounds. Furthermore, some indices, such as protection factor and oxidation kinetic rate, were used to measure the antioxidant effect. Maillard volatile effectiveness was related to browning level of glucose~glycine solution. The maximum antioxidant effect was obtained with volatiles from 12-18 hr of heating the glucose~glycine solution. This result is related to the quantity of Maillard volatiles transferred into the oil atmosphere and to the reduction power of the browned Maillard solution.

Parmigiano Reggiano (PR) cheese, packed in single 20g portions under vacuum, was stored at three different temperatures (25C, 2C and -25C) to evaluate chemical and physical changes in the product during 120 days of storage. There was no increase in lipid oxidation, even though the presence of pentane in the head space showed that the PR samples were already slightly oxidized following the 18 months of ripening process. Color and water activity determinations led to the hypothesis that the lipid fraction migrated to the sample sugace when stored at 25C. Other changes observed by the authors influenced the modification of the flavor and a decrease in the overall acceptance of the PR samples packed under vacuum and stored at room temperature. However, they did not seem to be related to lipid oxidation.

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