Tatiane J\u00e9ssica Siebeneichler, Eduarda Caetano Peixoto, Jessica Fernanda Hoffmann, Cesar Valmor Rombaldi, Alvaro Renato Guerra Dias<\/p>\n
The global production of pecan nuts (Carya illinoinensis<\/em>) is expanding, generating growing interest in the valorization of their by-products, particularly the shell, a promising source of bioactive compounds and natural antioxidants. To support its use in food, nutraceutical, and pharmaceutical applications, optimizing extraction conditions is essential. In this study, pecan shells were dried, ground, and sieved into three particle sizes: coarse (250-150 \u00b5m), medium (150-100 \u00b5m), and fine (\u2264100 \u00b5m). Phenolic compounds were extracted using an ultrasonic bath, and total phenolics were quantified by the Folin-Ciocalteu method. Reducing power and the ability of the extracts to scavenge DPPH and ABTS radicals were also assessed. LC-MS\/MS was used to characterize the most efficient extract. Fine particles produced higher extract yields, while medium and fine particles resulted in greater total phenolic content. Twelve phenolic compounds were identified, including the flavonoids gallocatechin 3-O-gallate, catechin, gallocatechin, procyanidin C1, procyanidin B1, isorhamnetin 3-glucuronide, and taxifolin 3-O-rhamnoside, as well as methyl chlorogenate, gallic acid 3-O-gallate, and 3-caffeoylquinic acid. Antioxidant activity increased with particle size reduction down to 100 \u00b5m, but smaller sizes reduced this activity. Extracts obtained from medium particles showed the highest phenolic content (20.52 \u00b1 0.08 mg GAE\/g) and antioxidant activity (58.81 \u00b1 0.80% for DPPH and 79.00 \u00b1 0.96% for ABTS). These findings provide valuable insights into optimizing phenolic extraction from pecan shells for applications in food and health-related industries.<\/p>\n