Descripció del contingut i pla d'activitats:
Aquest treball s'emmarca dins d'un projecte d'investigació, centrat en la valorització de subproductes de l'horta (gènere Brassica), amb capacitat antioxidant, per a la seva introducció a la cadena alimentària. L'objectiu del TFG se centra en la caracterització de la composició nutricional d'aquests subproductes, així com també de les seves propietats antioxidants (contingut total de polifenols, activitat antiradicalària, etc.). Durant el projecte formatiu, la persona involucrada treballarà activament amb la resta d'investigadors del projecte, realitzant diferents tipus d'anàlisis fisicoquímiques, així com també involucrant-se en el disseny d'experiments, anàlisis de dades i avaluació dels resultats obtinguts.
Overview (resum en anglès):
The agri-food industry and crops generate large amounts of by-products that are discarded, and the majority of these are products with high quantities of bioactive compounds and nutritional interest. The aim of this study was to characterize by-products (from broccoli, white cauliflower, artichoke and wheat bran) provided by an agri-food company, as potential functional ingredients for the food and cosmetic industries. First, the most suitable preservation pretreatment of the fresh samples (drying or freeze-drying) was evaluated, aiming to preserve the maximum total polyphenol content present in the fresh product. Subsequently, the nutritional composition (water content, mineral matter, fat, protein, and carbohydrates) and bioactive compound content were determined, such as polyphenol content (Folin-Ciocalteu method, previously optimizing the extraction method) and glucosinolate content (only in Brassica, by spectrophotometry). Additionally, the radical scavenging capacity of the by-products was evaluated (by DPPH, ABTS, and FRAP methods). Regarding wheat bran, the different fractions of polyphenols (free, esterified, and bound) were separated, and the water and oil retention capacity of the sample was determined.
The results showed that the most suitable preservation treatment was drying. The nutrient and bioactive component content of the by-products depended on the type of by-product. In artichoke, the leaf had the highest percentage of minerals, fat, protein, and carbohydrates, while in Brassica, the content of minerals, protein, and carbohydrates depended more on the different tissues of the plant (leaf, floret, stalk, and stem). In general, the radical scavenging capacity values of the leaf, floret, stalk, and stem were proportional to the amount of determined polyphenols, with optimal extraction at a 1:10 (m/v) ratio with a 50% ethanol solution, for 1 hour in agitation and 20 minutes in a centrifuge at room temperature. The radical scavenging capacity varied depending on the characterization method used (DPPH, ABTS, or FRAP), generally being higher in the leaf and floret. Regarding wheat bran, bound polyphenols were the majority fraction.
In conclusion, the by-products of broccoli, white cauliflower, artichoke, and wheat have shown interesting results in terms of bioactive compounds, nutritional composition, and radical scavenging capacity. These could have potential interest as possible ingredients in the food and cosmetic industries, contributing to the valorization of agri-food by-products.
Keywords: food by-products, bioactive compounds, polyphenols, radical scavenging capacity.