Nε-(carboxymethyl)lysine, Available Lysine, and Volatile Compound Profile of Biscuits Enriched with Grape by-Product During Storage

We investigated the changes in N epsilon-(carboxymethyl)lysine (CML) and available lysine content, antioxidant properties, volatiles, and oxidation products of biscuits enriched with grape by-product (GP), stored for six months under a modified atmosphere of 0%/30%/70% O-2/CO2/N-2 and in air. Fresh GP-formulated biscuits showed lower concentrations of CML (89%), available lysine (40%), and pyrazines (75%), but higher antioxidant capacities (similar to sixfold), furans (12-fold), and lipid-derived compounds (three-fold) than the control. Although similar to 15% higher losses of Maillard-type volatiles were identified in the air atmosphere during storage, lipid oxidation was similar to 30% less pronounced in the modified atmosphere. A significant correlation of 0.994 between the reduction in CML and the available lysine suggest further CML reactions with the epsilon-NH2 group of amino acids. Significant correlations (of -0.550 to -0.980) between oxidation products, antioxidant capacities, and changes in CML content during storage suggest that these parameters might be involved in the CML elimination mechanism.

Automated summary

This study investigated the effects of adding grape by-product on the quality of biscuits and found that incorporating grape by-product led to improved antioxidant properties, flavor, and reduced lipid oxidation. Biscuits stored in a modified atmosphere also showed better lipid oxidation resistance.