Abstract
Worldwide, there is a growing need to valorize agri-food waste containing bioactive compounds to fit into the circular economy action plan approved in Europe. In this paper, the carotenoids of peel powder of pumpkins (PPP) of five varieties (Hokkaido, Lunga di Napoli, Mantovana, Moscata di Provenza, and Violina rugosa) were characterized by spectrophotometric (antioxidant activity) and chromatographic analyses. PPP from the Hokkaido variety showed high levels of carotenoids (2993.90 μg β-carotene equivalents/g). They were mainly composed of mono- (9065.35 μg zeaxanthin dipalmitate equivalents/g) and di-esterified (1832.74 μg zeaxanthin dipalmitate equivalents/g) xanthophylls. It also showed high antioxidant activity (ABTS 2036.02 μg Trolox equivalents/g). Therefore, it was used as a functional plant ingredient (4%) to prepare chicken burgers (100, 70, and 50% chicken meat). Physical-chemical, microbiological, color, and sensorial analyses of fortified chicken burgers were carried out. The product with 70% chicken meat and 4% PPP obtained the highest overall acceptability score (5.95 ± 0.25). The results confirm that the addition of PPP could represent a valid approach to increasing the health properties and acceptability of burgers, even if a larger assessor size is necessary.