“Dairy products curdled with vegetal rennet and enriched by natural antioxidants”

The present work, part of a GAL-START Project, funded by Tuscany Region (acronyme LOCIV), concerns the creation of a new line of dairy products, obtained with vegetal rennet and enriched by natural antioxidants. The new production line is planned to be linked to a specific geographical area and cultural traditions, in particular San Cresci (Borgo San Lorenzo, Mugello). The vegetal rennet, employed for design and manufacture of the dairy products, is obtained from thistle (Cynara cardunculus L.) by water extraction of the enzymes present in the flowers [1, 2]. Plant extracts from helichrysum, artichoke, nettle, vine, olive and saffron, standardized in polyphenolic content, were added to different cheeses (pecorino, ricotta, raveggiolo and yogurt). These extracts were evaluated by both HPLC/DAD/MS analysis and the spectrophotometric Folin-Ciocalteu method (results expressed as GAE, Gallic Acid Equivalents). The analysis performed on olive leaf extract, showed a value of 76.73 mg/g of polyphenols concentration (72.53% of oleuropein); vine leaf extract 2.86 mg/g of polyphenols (62.2% of quercetin 3-O-glucoronide); nettle leaf extract 2.79 mg/g of polyphenols (88.50% of chlorogenic acid). Contemporaneously, GAE values were 48.21 and 15.71 mg of polyphenols per gram of olive and vine leaf extracts, respectively, and, finally, for the nettle’s extract, 17.67 mg per gram of dried leaves. The presence of such molecules gives the final product peculiar organoleptic characteristics, antioxidant and radical scavenging properties. The evaluation of such polar secondary metabolites is more complex in the dairy products that, predominantly, consist of fats and proteins. However, the total polyphenols content were also evaluated in cheese, obtaining the following GAE results: 0.357 mg/g (cheese) in the sample added of nettle extract, and 0.295 mg/g (cheese) in the sample added of vine extract. The characterization and the knowledge of the procedures, concerning the supply chain of these innovative products, can help to lay the groundwork for the creation of the suitable documentation for territorial brands and certified products, as an example the Kosher brand.