DOUBLE ROLE OF CORCHORUS OLITORIUS (L.) CULTIVATED IN FLOATING SYSTEM: New leafy vegetable for “ready to eat” industry or active food for developing country

C. olitorius is a traditional African leafy vegetable (ALV). It has interesting nutraceutical properties and is widely consumed among the African and South-East Asia populations. It is commonly cultivated through a conventional way: in the open field. Hydroponic cultivation systems optimize production inputs (water - fertilizer), but they also foster the production and the quality yield. Moreover, hydroponic systems improve shelf life and thus reduce food waste. For this thesis, a floating system cultivation method has been investigated to grow C. olitorius, commercially known as “baby leaf”. The study has focused on two aspects, namely nutrient supply efficiency and shelf life qualities, in order to accelerate the commercialization of C. olitorius within Europe’s leafy vegetable industry. However, both of those improvements were also essential for improving production and quality levels in developing countries. Moreover, the communities which traditionally consumed C. olitorius in their native countries have been increasing in Europe. Likewise, public interest about nutritional and healthy food is rapidly rising worldwide, so promoting the discovery of new, nutritionally valuable food plants such as C. olitorius could be an interesting step forward. For all these reasons, understanding the nutritional shelf-life of vegetables was a crucial claim for meeting customer needs and for boosting innovation in the food industry. In these previous studies (Chapter 3-4) an Egyptian ecotype of C. olitorius has been used as a gold standard. Two different nutrient solutions have been tested to optimize nutrient need during a one year cultivation cycle: a standard solution nutrient in full, then a second one halved to test differences in the growth and qualities response. The harvested biomass has been evaluated as baby leaf at the fresh-cut industry stage. Several quality parameters have been estimated: sugars (total, reducing and sucrose), nitrate, chlorophyll, carotenoids, polyphenols and anthocyanins (Chapter 4). Plant production was similar to other common leafy vegetables cultivated in floating systems in Europe. Analytical determinations displayed good levels of antioxidant compounds and sugars. Mineral content was relevant for Ca, Mg, and Iron in comparison with other common leafy vegetables (Corn salad, rocket and lettuce). Moreover, C. olitorius, when cultivated using traditional growing systems in literature, showed less nutrient content than C. olitorius cultivated with the floating method, which was an interesting result for bio-fortification in developing countries. Results showed that the plant had healthy characteristics for human nutrition, especially for females and children. High levels of Ca, Mg and Fe, in fact, are very important during pregnancy and childhood. Results obtained from yields and nitrates indicate that this species can be grown with a lower mineral concentration in the nutrient solution without decreasing production and quality. The level of sugars measured was higher than in other traditional leafy vegetables which are usually cultivated via floating systems such as rocket, lettuce and 5 spinach. Higher sugar content could have a positive effect on post-harvest storage and could be an important contribution to the human diet. C. olitorius may hence represent a product innovation in the fresh-cut industry in the near future. Moreover, in this thesis, biochemical and physiological differences of several ecotypes of C. olitorius worldwide and their growing behavior were studied. These elements were priority aspects for the food industry in order to introduce the best genotype adapted for growing in a Southern European environment (Chapter 5). However, considering the difficulties involved with introducing a new leafy vegetable, it is important to consider not only agronomic and physiological aspects but also the consumer’s point of view. These days, the European population is interested in the prevention of chronic disease through food consumption. For this reason, the final part of this thesis planned to test the fresh crude extracts of C. olitorius in order investigate phenolic and terpene composition. Results confirmed the relevant presence of many active compounds such as quercetin, coumarin, vitamin E and terpenes inside C. olitorius leaves (Chapter 6).