Resumen de Valorización de co-productos de la industria del dátil (phoenix dactylifera l.): caracterización y aplicación en alimentos
Fresh date co-products from the Spanish Elche grove can account more than 90% of the produce, which implies a considerable disposal problem considering the environmental aspects, but it also entails a great loss of valuable materials. These date co-products present very variable properties since they come from different cultivars (Medjool and Confitera) and ripening stages. For their valorization, these co-products were used blanched and/or unblanched, being peeled, pitted and homogenized to be transformed into intermediate food products (IFPs). Then, they were characterized chemically, physicochemically and technologically. IFPs from immature stages presented a lower sugars level, but higher levels of phenolic compounds (up to 1429 mg gallic acid equivalents/100 g) and dietary fibre (up to 22% of total dietary fibre), including a considerable soluble dietary fibre content (up to 5%). Most IFPs also showed high antioxidant activity and good technological properties such as water and oil holding capacities and emulsion stability. Nevertheless, for most IFPs a previous blanching treatment would be advisable, since it helps to stabilize colour, to avoid browning and to increase the retention of some phytochemicals. The remaining skins from the preparation of the IFPs were also evaluated to assess if they could also be of interest. They were good sources of dietary fibre (up to 43%), with up to 8% of soluble fibre; and they also presented considerable amounts of sugars and phytochemicals. Whilst IFPs were richer in phenols, tannins and flavonoids, and they presented higher antioxidant activity, the studied pigments (anthocyanins and carotenoids) were more concentrated in the skins.
Confitera IFPs presented lower sugar content than those from Medjool dates at unripe stages; but also, had higher content of fibre, bioactive compounds and a better antioxidant capacity. Hence, a blanched unripe Confitera IFP was selected to be assayed in different meat products (cooked and dry-cured). Incorporation of high concentrations (10%) of this IFP into a campagne pork liver pâté, despite improved oxidative stability, caused important colour changes. As a result, a spreadable type pâté was studied instead, but with addition of an annatto extract as colourant. Combination of both ingredients resulted in good quality pâtés without important colour changes, which made possible the incorporation of the IFP into this product. Additionally, the IFP aided to improve emulsion quality. Likewise, a good quality "Sobrasada" was obtained adding 5% of the IFP, which provoked minimal changes in the characteristics of the product. Then, IFPs prepared from fresh date co-products could be used as ingredients in the meat industry.
