Free amino residues react with α-dicarbonyl compounds (DCs) contributing to the formation of advanced glycation end-products (AGEs). Phenolic compounds can scavenge DCs thus controlling dietary carbonyl load. This study showed that high molecular weight cocoa (HMW-COM), bread (HMW-BM) and especially coffee (HMW-CM) melanoidins are effective DCs scavengers. HMW-CM (1 mg/mL) scavenged more than 40% DCs within 2 h under simulated physiological conditions, suggesting some physiological relevance. Partial acid hydrolysis of HMW-CM decreased dicarbonyl trapping capacity demonstrating that the ability to react with glyoxal, methylglyoxal and diacetyl was mainly due to polyphenols bound to macromolecules. Caffeic acid and 3-caffeoylquinic acid showed a DC-scavenging kinetic profile similar to HMW-CM, while mass spectrometry data confirmed that hydroxyalkylation and aromatic substitution reactions led to the formation of a stable adduct between caffeic acid and methylglyoxal. These findings corroborated the idea that antioxidant-rich indigestible materials could limit carbonyl stress and AGEs formation across the gastrointestinal tract.

This study investigated the effect of different types of commercial oils (rice bran oil, shortening oil, high-oleic rapeseed oil, low-erucic acid rapeseed oil, blend oil A and blend oil B) and frying cycles on acrylamide formation during the preparation of French fries by deep-frying. Frying was carried out in intermittent mode (two batches each for 12 min without any time lag) and repeated for 600 frying cycles. Results indicated that the French fries that were fried in oils having lower heat transfer coefficients contained lower acrylamide concentrations (913 µg kg^–1), whereas those fried with oils having higher heat transfer coefficients contained higher acrylamide concentrations (1219 µg kg^–1). Unlike the peroxide value, acrylamide levels in French fries did not change significantly with an increase in the number of frying cycles when tested for 600 frying cycles for every type of oil. This study clearly indicates that the contribution of frying oils to the formation of acrylamide should not be neglected due to their different heat transfer coefficients. On the other hand, continuous use of frying oil does not lead to a higher acrylamide concentration in French fries.