Resumen de Recuperación de variedades infrautilizadas de frutales y de plantas comestibles silvestres para su uso en la alimentación moderna
Resumen de la tesis: At present, the agrifood industry is suffering changes both regarding profitability and at sociological and ecologic levels. The reinforcement of the paradigm of diversity in all its components, biodiversity, agrodiversity or cultural and food diversity, is needed. Considering this reality, this thesis tries to support the recovery of old species and varieties that are now underutilized or forgotten. Many of these species show high nutritional, dietary and even medicinal values, and they could be employed for the development of innovative products in current gastronomy.
Firstly, a fresh-cut product was developed from underutilized varieties of citrus fruits. A traditional variety of orange (Citrus sinensis L. cv. Cadenera) was selected and the most adequate conditions of enzymatic peeling and storage were optimised in order to obtain a quality product. The results showed that the best condition to obtain Cadenera segments by enzymatic peeling was 1 ml/L of Peelzym II applied at 53 kPa with three vacuum pulses of two minutes and a subsequent period of 30 minutes in the enzymatic solution at atmospheric pressure. The segments were packaged in two films with different permeability and stored during 10 days at 4 ºC. Colour (a/b) increased with the peeling process and it remained without significant changes during the whole storage period for both films. Some parameters, like the weight loss and the antioxidant capacity, slightly decreased after 10 days of storage. The microbial flora decreased after the enzymatic peeling. Both the sensory and the microbiological quality (mesophilic microflora, moulds and yeasts and lactic microflora) were kept in adequate levels for consumption during 7 days. Therefore, a fresh-cut product was developed from an underutilized variety of orange.
Secondly, thirteen species of wild edible plants (WEP) from eleven botanical families that have traditionally employed as food were selected, and different parameters like the antioxidant activity, the content in organic acids, the mineral composition and the sensory characteristics, were analysed. This allows the selection of the species with a higher nutritional or functional interest. Sanguisorba minor, Quercus ballota and Sedum sediforme showed the highest total antioxidant activity (TAA) and the highest content in total phenols. Asparagus acutifolius, Allium ampeloprasum, Foeniculum vulgare and Malva sylvestris showed high levels of potassium. Malva and Asparagus were interesting due to their high content in zinc and, Urtica urens presented high levels of calcium. The sensory analysis indicated that fruits from Q. ballota could be considered very sweet and plants of Crithmum maritimum and Oxalis pes-caprae were very acidic. Moreover, testers highlighted the salty taste of C. maritimum, Mesembryanthemum nodiflorum and Mesembryanthemum cristalinum, the spicy taste of A. ampeloprasum, and the aroma of F. vulgare. Our results indicate that an increased consumption of the investigated plant species could provide health benefits. Moreover, due to their sensorial properties, they could be used as new ingredients to improve the diversity in modern diet and highly creative cuisine.
The most adequate WEP (fruits from R. canina, fruits from Q. ballota and leaves and young stems of S. minor) were added to matrices of fruits and to edible plant oils in order to design new drinks enriched with bioactive ingredients and/or to protect against oxidation. The addition of WEP to orange juice and kiwifruit cremogenate did not affect, and even improved, some parameters of acceptance by consumers. The addition of R. canina and S. minor increased the content of phenolic compounds and the antioxidant capacity in both matrices (orange juice and kiwi cremogenate) in more than 30 %. The three WEP increased the oxidative stability of sunflower oil while the effect of these WEP against the decrease of the lipid peroxidation in olive oil was evident just for the highest concentration. Therefore, these wild edible plants could be employed for designing new drinks combined with juices or plant creams, as well as for enriching edible plant oils with low content in natural antioxidants, like sunflower oil, and for avoiding or reducing the use of synthetic antioxidants.
The results obtained in this work from underutilized plant species could be considered when designing new products for current diets. Likewise, they could be also used for promoting the conservation of local genetic resources that can keep biodiversity.
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