From by-product to natural antioxidant: Incorporation of peanut skin extract in mayonnaise and its effect on physico-chemical and sensory properties

A peanut skin extract (PSE) was tested as a natural preservative for soybean oil mayonnaise during 6 months. Two treatments containing PSE at two different concentrations (1 and 2 mg PSE/g mayonnaise) were compared to two control treatments, one consisting of mayonnaise without any added antioxidant (CON1), and the other (CON2) containing a mixture of two common synthetic additives [butylated hydroxytoluene (BHT) + ethylene diamine tetraacetic acid (EDTA)]. As compared to the control treatments, the addition of PSE increased the overall color intensity but did not affect other sensory and physico-chemical properties tested (pH, a w, adhesiveness, firmness, spreadability, viscosity and droplet size parameters). Data from a storage test (6 month, 25 °C) showed lower rates of increase in primary oxidation indicators (peroxide, conjugated dienes and conjugated trienes) in the PSE treatments compared to the control treatments. Also, at the final storage time, the PSE treatments showed significantly lower values of secondary oxidation products (volatile an non-volatile carbonyl compounds) than the CON1 treatment. Taken together, findings regarding oxidative parameters indicate that the PSE may confer similar or greater stability to that achieved by the BHT + EDTA combination. Overall, the results suggest that the PSE could be suitable for obtaining a soybean oil mayonnaise with acceptable sensory properties and satisfactory shelf-life.