The Chemistry Behind Biological Properties of Agro-industrial Portuguese By-Products

As the global population grows, food production and processing generate significant by-products that cause environmental issues. These by-products contain bioactive compounds, including phenolic compounds, which have beneficial biological properties. Extracting these compounds and incorporating them into various products, can promote circular economy. This study examined the correlation between the chemical composition and biological properties of phenolic-rich extracts from chestnut shells, grape seeds, onion peels, and passion fruit peels. Using HPLC-DAD, the primary compounds were identified and quantified. The study analysed their antioxidant, and antibacterial properties, sun protection factor, and alpha-amylase inhibitory capacity. Catechin was found in all four extracts, with the grapeseed extract having higher levels. Chestnut shell extract revealed the best antioxidant properties, with a total phenolic content of 497.5 mgGAE/g. On the other hand, onion peel extract exhibited the best antibacterial capacity, as well as the highest sun protection factor value (4.8). Concerning the ability to inhibit the alpha-amylase enzyme, all the extracts displayed the ability to inhibit more than 70% of this enzyme. Overall, the presented extracts had varying phenolic compositions and biological properties. It is crucial to evaluate the chemical composition of extracts to comprehend their biochemical properties and define their potential applications.