The Effect of Grape Seed Extract on Lipid Oxidation, Color Change, and Microbial Growth in a Beef–Pork Sausage Model System

The effect of various natural antioxidants-grape seed extract (GSE), ascorbic acid (AA), α-tocopherol (TP), a combination of GSE and AA, and a combination of GSE and TP-on pH, water activity, color change, lipid oxidation, antioxidant capacity, total bacterial count, protein content and free fatty acids was studied in sausages during the drying process. The model sausage system was prepared according to a traditional Bulgarian recipe for "lukanka". AA and KNO₃ were used in the recipe as antioxidants and preservatives, respectively. The results obtained with natural antioxidants were compared with the results of samples prepared according to the traditional recipe and with a synthetic antioxidant, butylated hydroxytoluene. The samples with a combination of GSE and AA showed the highest antilipid potential, the lowest malondialdehyde values (0.41 mg/kg MDA), the highest antimicrobial capacity (TBC 78.50 × 10³ cfu/g), the lowest color change, and the lowest change in antioxidant activity (17.74%), through the sausage drying process. There was an obviously synergistic effect between GSE and AA, and their antioxidant activity was highly effective. The sample with 0.05% GSE ranked second. The samples with a synthetic antioxidant and a combination of KNO₃ and AA gave similar results, but KNO₃ had a toxic effect. The samples with α-tocopherol had lower results. It was found that grape seed extracts and the combination of GSE and AA were the most effective and could successfully replace synthetic antioxidants, improve the quality of sausages, and provide healthier foods to consumers.