Celiac disease is an autoimmune disorder for which the only current treatment is a strict
adherence to a gluten-free diet. However, most commercially available gluten-free products tend to have lower nutritional quality, as they are typically low in fiber, antioxidants, and other essential nutrients. This nutritional imbalance can lead to long-term health issues for patients. At the same time, the food industry discards large amounts of plant-based by-products each year, despite their significant nutritional value, resulting in both economic losses and negative environmental impacts.
To address both challenges, this Final Degree Project focuses on the development of functional gluten-free brownies enriched with Mediterranean kiwi peel, an agro-industrial by-product. The goal is to revalorize this by-product while simultaneously creating healthier products for those who suffer from celiac disease. Additionally, the project evaluates the impact of a Pulsed Electric Field (PEF) treatment, a novel non-thermal emerging technology that enhances the extraction and bioavailability of bioactive compounds. For this purpose, five gluten-free brownie formulations were developed using amaranth flour: brownies without any by-product (control), brownies with 5% untreated by-product, brownies with 10% untreated by-product, brownies with 5% PEF-treated by-product, and brownies with 10% PEF-treated by-product. In addition, a commercial brownie was also included as a reference. The samples underwent physicochemical analyses (pH, acidity, and colour) and nutritional assessments (protein, fat, fiber, carbohydrate content, and energy value). Antioxidant capacity was evaluated using FRAP, ABTS, and DPPH assays; total phenolic compounds (TPC), digestible and resistant starch, and mineral content were also measured. Furthermore, in vitro gastrointestinal digestion and a sensory evaluation were carried out. The results showed that the samples that had received the PEF treatment improved their fiber content, resistant starch, and antioxidant capacity. In sensory terms, they were the most highly rated, indicating that the incorporation of this PEF-treated by-product not only enhances the nutritional profile but also its acceptability.