Effect of prickly pear (Opuntia ficus-indica) and algarrobo (Prosopis spp.) pod syrup coatings on the sensory and chemical stability in roasted peanut products

The purpose of this work was to determine the oxidative stability of roasted peanuts coated with prickly pear and algarrobo pod syrups. General composition, total phenolic compounds and radical scavenging activity were determined on prickly pear and algarrobo pod syrups. Chemical (peroxide value) and descriptive analyses were performed on samples of roasted peanuts, roasted peanuts with prickly pear syrup and roasted peanuts with algarrobo pod syrup stored at 23C for 112 days to determine protective effect of the syrup coating on the product stability. Prickly pear syrup showed higher moisture, protein, ash, lipid, phenolic compound content and lower carbohydrate content than algarrobo pod syrup. Prickly pear syrup also showed higher antioxidant activity (diphenyl picryl hydrazyl inhibition). Peroxide value, oxidized and cardboard intensity flavors increased and roasted peanutty intensity attribute decreased across the storage time for all studied products. Therefore, the addition of syrup coating provided protection against lipid oxidation. Peroxide value reached 10 meqO₂/kg after 8.5 days in roasted peanuts, 20.7 days in roasted peanuts coated with prickly pear syrup and 29.5 days in roasted peanuts coated with algarrobo pod syrup at 23C. In consequence, algarrobo pod syrup had the highest protective effect in the roasted peanut product stored at room temperature. The results of this work show advantages for using coatings that improve the stability of peanut products by making it more resistant to lipid oxidation and the development of rancid flavor. In this case, the edible coatings are elaborated using prickly pear and algarrobo pod syrups. These syrups could be applied on other similar food products with high lipid content to increase their shelf life and improve their stability, thus preventing loss of their sensory and nutritional quality.