Exploring the Untapped Potential of Pine Nut Skin By-Products: A Holistic Characterization and Recycling Approach
Agata Nolasco,
Jonathan Squillante,
Salvatore Velotto,
Giovanni D’Auria,
Pasquale Ferranti,
Gianfranco Mamone,
Maria Emanuela Errico,
Roberto Avolio,
Rachele Castaldo,
Lucia De Luca,
Raffaele Romano,
Francesco Esposito,
Teresa Cirillo
Affiliations
Agata Nolasco
Department of Agricultural Sciences, University of Naples “Federico II”, Via Università, 100, 100-80055 Portici, NA, Italy
Jonathan Squillante
Department of Agricultural Sciences, University of Naples “Federico II”, Via Università, 100, 100-80055 Portici, NA, Italy
Salvatore Velotto
Department of Promotion of Human Sciences and the Quality of Life, University of Study of Roma “San Raffaele”, Via di Val Cannuta, 247-00166 Roma, Italy
Giovanni D’Auria
Department of Agricultural Sciences, University of Naples “Federico II”, Via Università, 100, 100-80055 Portici, NA, Italy
Pasquale Ferranti
Department of Agricultural Sciences, University of Naples “Federico II”, Via Università, 100, 100-80055 Portici, NA, Italy
Gianfranco Mamone
Institute of Food Science, National Research Council, 83100 Avellino, Italy
Maria Emanuela Errico
Institute for Polymers Composites and Biomaterials-National Research Council of Italy (IPCB-CNR), Via Campi Flegrei 34, 80078 Pozzuoli, NA, Italy
Roberto Avolio
Institute for Polymers Composites and Biomaterials-National Research Council of Italy (IPCB-CNR), Via Campi Flegrei 34, 80078 Pozzuoli, NA, Italy
Rachele Castaldo
Institute for Polymers Composites and Biomaterials-National Research Council of Italy (IPCB-CNR), Via Campi Flegrei 34, 80078 Pozzuoli, NA, Italy
Lucia De Luca
Department of Agricultural Sciences, University of Naples “Federico II”, Via Università, 100, 100-80055 Portici, NA, Italy
Raffaele Romano
Department of Agricultural Sciences, University of Naples “Federico II”, Via Università, 100, 100-80055 Portici, NA, Italy
Francesco Esposito
Department of Agricultural Sciences, University of Naples “Federico II”, Via Università, 100, 100-80055 Portici, NA, Italy
Teresa Cirillo
Department of Agricultural Sciences, University of Naples “Federico II”, Via Università, 100, 100-80055 Portici, NA, Italy
The increasing population, food demand, waste management concerns, and the search for sustainable alternatives to plastic polymers have led researchers to explore the potential of waste materials. This study focused on a waste of pine nut processing referred to in this paper as pine nut skin. For the first time, its nutritional profile, potential bioactive peptide, contaminants, and morphological structure were assessed. Pine nut skin was composed mainly of carbohydrates (56.2%) and fiber (27.5%). The fat (9.8%) was about 45%, 35%, and 20% saturated, monounsaturated, and polyunsaturated fatty acid, respectively, and Omega-9,-6, and -3 were detected. Notably, oleic acid, known for its health benefits, was found in significant quantities, resembling its presence in pine nut oil. The presence of bioactive compounds such as eicosapentaenoic acid (EPA) and phytosterols further adds to its nutritional value. Some essential elements were reported, whereas most of the contaminants such as heavy metals, polycyclic aromatic hydrocarbons, rare earth elements, and pesticides were below the limit of quantification. Furthermore, the in silico analysis showed the occurrence of potential precursor peptides of bioactive compounds, indicating health-promoting attributes. Lastly, the morphological structural characterization of the pine nut skin was followed by Fourier Transform Infrared and solid-state NMR spectroscopy to identify the major components, such as lignin, cellulose, and hemicellulose. The thermostability of the pine nut skin was monitored via thermogravimetric analysis, and the surface of the integument was analyzed via scanning electron microscopy and volumetric nitrogen adsorption. This information provides a more comprehensive view of the potential uses of pine nut skin as a filler material for biocomposite materials. A full characterization of the by-products of the food chain is essential for their more appropriate reuse.
