Artichoke industry by-products up-cycling for food fortification

The upcycling of food by-products as functional ingredients for food fortification, particularly those derived from fruit and vegetables, represents a promising solution to the issue of food wastage. This thesis focuses on the transformation of the globe artichoke by-products (stems, bracts and leaves) derived from the Sardinian ecotype "Spinoso sardo", into upcycled ingredients (as extracts and powders), to enhance the quality, sustainability, and economic value of staple savory baked goods, particularly breadsticks. The work is developed into three case studies. The first case study aimed to produce edible and sustainable extracts suitable for use as food antioxidants. Two extraction techniques (maceration and ultrasound-assisted) were optimized, using the response surface methodology, to maximize the recovery of polyphenols from artichoke by-products. The maximum yields were maintained at the shortest extraction time (10 minutes for sonication and 60 minutes for maceration), except for sonicated bracts (41 minutes). Additionally, intermediate ethanol percentages (42%–64%) were identified as optimal for both techniques, except for sonicated leaves (20%). The extracts of leaves, bracts, and stems obtained through the optimized extraction methods, which facilitated the maximum recovery of antioxidant compounds while simultaneously reducing time and cost, were utilized in the second case study to enhance the stability to lipid oxidation of breadsticks. Two concentrations (1000 ppm and 2000 ppm) of each by-product extract were incorporated into a conventional formulation, resulting in an increased antioxidant capacity and oxidative stability without affecting the dough's workability. Although a slight deterioration in texture was observed, the shelf-life of breadsticks was significantly extended, particularly at the highest levels of addition of stem extract, without any visible alteration in their appearance. The third case study assessed the impact of incorporating powders (3 and 5%) derived from artichoke stems and outer bracts, on the conventional breadsticks’ nutritional, bioactive, textural, aromatic and organoleptic properties. All fortified samples exhibited an augmented nutritional and volatile profile, particularly at elevated addition levels. The fortification resulted in an improvement in the brittleness of the breadsticks, without a perceptible alteration in their final color. Consumers perceived fortified samples as more bitter, astringent, and herbaceous, yet also as healthier and more sustainable. It can be concluded that the use of upcycled ingredients obtained from artichoke by-products represents a successful strategy for pursuing a circular economy, enhancing the competitiveness of the artichoke supply chain and benefiting snack manufacturers, who would be able to offer a novel and more durable functional product in a growing market.