A Second Useful Life of Coffee Silver Skin

Coffee silver skin (CSS) is the unique by-product discarded in a coffee manufacturing plant [1]. The study presents the properties of CSS as functional additive in food and non-food matrices. Safety and nutritional aspects are assessed by means of microbial, toxicological, chemical, physical and sensory analyses [2-5]. All parameters and characteristics are useful to assess the potential advantages of CSS applications in the investigated fields. CSS used for our experiments was a blend (1:1) of Coffea arabica and C. canephora varieties; while mycotoxins were absent, a content of 720 ± 110 μg/kg of acrylamide was found [2], higher than the 489 μg/kg reported for coffee silver skin from arabica only [3]. High-methoxyl pectin functionalized with phenolic compounds extracted from CSS, improves antioxidant and sensory properties of chicken meatballs during refrigerated storage, and cooking does not affect these benefits [4]. In cooked chicken burgers, CSS at 3% counteracted the emergence of hexanal (-55%) and other markers of lipid oxidation, provided a source of fibre and micronutrients (Zn), and reduced weight losses after cooking (50% lower than the control) [5]. Our other studies initiated the evaluation of the most appropriate use of CSS as platform for food edible coatings; results showed that CSS increased the consistency and significantly enhanced the antioxidant activity of edible coatings based on alginate or locust bean gum. Applications of CSS in food provide models for circular economy practices and resource efficiency, contributing to the development of useful strategies with a one health approach. Moreover, further in-depth studies will be carried out on new CSS-based biomaterials adopting a green approach.