CARATTERIZZAZIONE DEI SOTTOPRODOTTI DELLA FILIERA DEL POMODORO PER UN POTENZIALE SVILUPPO INDUSTRIALE

The processing industry of crops generates significant quantities of vegetable waste of various kinds. In tomato processing waste generated by industrial processing, mainly skin and seeds, are an additional cost for manufacturing companies that generate them because process of disposal. Currently are used as animal feed or as fertilizer for agriculture. However, several studies also highlight their value and potential that could lead to a reassessment of them from waste to byproduct. Searches conducted on tomato’s skins fractions have shown that they have high levels of total phenols, lycopene, ascorbic acid and antioxidant activity compared with fractions of seeds and pulp. It was shown that skins and seeds contribute to 53% of total phenols, 52% of total flavonoids, 48% of total lycopene, 43% of ascorbic acid and 52% of the total antioxidants found in tomatoes. These results show that the removal of skins and seeds during cooking or industrial processing involving a significant loss of all major antioxidants. This work is part of a project in collaboration with industry Conserve Italia Soc. Agr., San Lazzaro di Savena (BO) and provides for study, research and characterization of healthy and nutritional components with higher added value derivable from one or more waste products obtained from the various stages of processing tomato and eligible as raw materials or semi-finished products for food industries, pharmaceutical and cosmetics industries that require innovative products, with the simultaneous valorisation of a by-product of processing tomato. The characterization of raw material is a prerequisite to prepare a correct plan of study and work. Studies completed during the first year of PhD led to the development of selective methods of extraction with regard to functional components of the tomato; in particular attention was paid to the evaluation of antioxidants because of the growing development of experimental evidence about the beneficial properties of these compounds. It was shown that it’s possible the identification of varieties and soil conditions suitable for obtaining a functional food quality. While it is possible to improve the quality of raw material, going ahead of the industrial process, it’s also possible to identify other components with high added value in waste materials from the tomato processing for a potential recovery and reintegration into industrial process to obtain products enriched in functional components. After a brief investigation on commercial products, the search is continued with the characterization of waste materials from industrial processing of tomato taken directly from the processing line. Were first conducted analysis for dry matter, proteins, mineral fraction, lipids and metals and these have highlighted how the skins and seeds are a rich source of minerals potentially recoverable and used in the manufacture of food supplements. The characterization continued with the study of the antioxidant properties of extracts from the seeds. These extracts showed a high content of total phenols and a good antioxidant capacity. To continue characterization of the lipid fraction it has been studied the fatty acid profile by gas chromatography of the oil isolated from tomato seeds. It show a significant antioxidant capacity and also contain high percentages of unsaturated fatty acids especially linoleic acid, an essential fatty acid. These properties make feasible a recovery or a use of tomato seed oil as functional food and/or dietetic food. A major factor in the preservation of lipids is the presence of a fair amount of natural antioxidants in food, which prevents the formation of oxidation products. While natural antioxidants act significantly to delay or prevent the oxidation of a substrate oxidation, represented not only by lipids, improving the shelf-life of the food and maintaining the nutritional and organoleptic quality over time, they also have a protective effect in the organism that consumes these foods. For this reason, during the period of research conducted in the Department of Nutrition and Bromatology at University of Granada (Spain), the focus has been towards the development of methods for measuring antioxidant activity in food matrices. The level of individual antioxidants in food matrices do not necessarily reflect their total antioxidant capacity, but there are interactions of synergism and antagonism between different molecules, which is why an integrated assessment of antioxidant potential may be more important than the concentration of individual antioxidants. The methods developed in this research are all based on the transfer of a single electron by measuring the capacity reduction of a radical species generated. Samples analyzed using DPPH method showed an antioxidant capacity, in absolute terms, compared with those measured by the FRAP method and Photochem®, regardless of protocol. The antioxidant capacity of samples analyzed by DMPD method lies in a range of values higher and more comparable with those obtained by the ABTS method. This leads us to suppose the presence in this tomato’s extracts compounds more reactive toward ABTS˙ and DMPD˙ radicals than radicals involved in the other assays. It was finally estimated the total phenols content in the same samples. Statistical processing of results showed a good correlation between different methods for measuring antioxidant capacity and the method for the determination of total phenols content. Finally, it was developed an HPLC method for the quantification of lycopene, the carotenoid antioxidant even more present in this food and quality marker for tomato. This method has also permitted to identify β-carotene, allowing the simultaneous quantification. The method has proved simple and rapid and it has demonstrated a good repeatability intradia and interdia. High recovery confirm the efficiency and selectivity of the extraction method used to isolate these carotenoids. The relative simplicity and effectiveness of the developed method allows rapid quantification of lycopene content and potentially it’s applicable to both raw material to finished products and waste. In this work, the extraction method was optimized.