Aprovechamiento de los subproductos del brócoli como fuente de compuestos bioactivos

Résumé

The agri-food industry is currently one of the main engines of economic development in the world, with the Region de Murcia being a power in the production of fruit and vegetables. The processing of these products generates a huge number of by-products that, in most cases, have no application in the production of new foods or products, and are discarded, creating an environmental problem. Nowadays, there are numerous references about the potential of by-products from the agri-food industry as an important source of bioactive compounds, but this potential has hardly been specifically explored in broccoli by-products. For this reason, the main goal of this Doctoral Thesis is focused on developing a sustainable production system of bioactive ingredients, promoting the revalorization of broccoli by-products generated in large quantities by the company Agrícola Santa Eulalia S.L, through the use of environmental friendly extraction technologies, for its incorporation into the manufacture of new products with cosmetic and nutraceutical applications. Thus, once the broccoli by-product was crushed and dehydrated, an experimental design based on the response surface model was developed to optimize and validate the extraction procedures of bioactive compounds using supercritical fluids (SFE) and pressurized fluids (PLE). The identification and quantification of the bioactive compounds was carried out by HPLC-DAD, HPLC-MS, GC-MS and spectrophotometer, determining, also, the antioxidant capacity of the extracts obtained by the ABTS method. SFE-based extraction optimization showed that temperature, pressure, time, flow rate and ethanol percentage significantly influenced the extraction resulting in an extract richer in total bioactive compounds (β-carotene, total phenolic compounds, chlorophylls, phytosterols and α-tocopherol) than conventional extracts, which in turn was correlated with higher antioxidant activity. On the other hand, the optimization of glucosinolates extraction based on PLE was carried out, demonstrating the efficiency of PLE as an environmentally sustainable alternative to extract glucosinolates from broccoli by-products. Once the bioactive compounds present in the SFE and PLE extracts were characterized, in vitro bioactivity was performed to assess whether the pretreatment with the SFE and PLE extracts from broccoli by-products could reduce oxidative stress caused by exposure to UV-B light in a non-tumorigenic keratinocyte cell line (HaCaT) as well as a protection system against intestinal inflammation induced by lipopolysaccharide (LPS) in a healthy colonic myofibroblast cell line (CCD-18Co). For this, the transcription profiles of genes involved in the inflammatory response were determined using qRT-PCR. The results showed that the SFE extract exhibited a cytoprotective effect on keratinocytes exposed to UV-B light by effectively reducing the intracellular ROS accumulation and significantly reversing the increase in proinflammatory cytokines induced by UV-B radiation. On the other hand, the extract enriched in glucosinolates obtained by PLE showed anti-inflammatory properties in CCD-18Co cells stimulated with LPS, and showed potential capacity to attenuate the production of some proinflammatory markers and to reverse the intracellular accumulation of ROS. Furthermore, both extracts were found to be effective as potential therapeutic agents for skin wound repair. These results demonstrate that extracts from broccoli by-products have potential utility as additives to cosmetic and nutraceutical products. In addition, it will allow the company Agrícola Santa Eulalia to make a qualitative leap in its range of products, while revaluing a by-product derived from its own production process.