Aprovechamiento de derivados de tomate como fuente de licopeno en productos cárnicos tradicionales y tratados con radiaciones ionizantes

Abstract

The industrial transformation of tomato has great effect on the Spanish economy due to the extent of its cultivation, but in general terms it generates large quantities of surplus and waste that are rich in bioactive compounds such as lycopene, a compound which possesses great antioxidant potential that has beneficial effects to health. The use of these tomato byproducts as a source of functional ingredients would entail a significant reduction in the expenditure of tomato processing industries and would avoid serious environmental problems. In recent years, great efforts have been made to improve existing meat products and to introduce new ones on the market in which the composition has been modified in some way so that the resulting product is more in line with the new nutritional guidelines. One possible way to carry out this demand would be to enrich meat products in bioactive compounds, turning them into functional foods. These new meat products should be adapted to the demands of the consumer and to the lifestyle of the present society, which would lead to the appearance of products that can be consumed in a short time, practically without culinary treatment, while being nutritious and hygienically safe. These foods are known as Ready to Eat (RTE). Their manufacture implies a manipulation that could be associated with the potential risk of microbiological contamination. For that reason, it is necessary to apply an additional treatment to guarantee the microbiological quality before it reaches the consumer. One of the best options is the use of non-thermal technologies, such as the irradiation treatment which is a safe technology and is endorsed by Food and Agriculture Organization (FAO), World Health Organization (WHO), Food and Drug Administration (FDA), and European Food Safety Authority (EFSA); in addition it entails minimal losses of organoleptic and nutritional value. However, both the application of ionizing radiation and the complex meat matrix could compromise the functional capacity of the added ingredient and its availability in the organism to carry out the function for which it was designed. Therefore, the research has been conducted with a double objective: on the one hand to design new functional meat products (hamburgers and dry fermented sausages) by incorporating tomato derivatives (Dry Tomato Peel, DTP, and Low Serum Tomato Powder, LSTP) as a source of lycopene and to study its viability as a RTE product using Ebeam irradiation; on the other hand to carry out tests aimed to study whether ionizing radiations compromise the antioxidant ability and accessibility of lycopene from tomato derivatives. The methodology used was summarized as follows: Both meat products and tomato derivatives were treated with accelerated electrons in the IONISOS IBÉRICA plant at doses of 2 and 4 kGy. Physical-chemical characteristics, color and texture attributes were determined through instrumental analysis. Sensory properties were studied through hedonic analysis of processed meat products. To study the antioxidant capacity of lycopene contained in tomato derivatives, an in vivo method was used with the RAT-1 cell line; on the one hand the amount of EROs produced by the cells treated with lycopene extracts was directly quantified, and on the other hand the expression of sensible redox proteins such as ERK, JNK, p38, Nox-4, Cox-2 and transcription factor NF-ĸβ. Finally, the accessibility study of lycopene was carried out on both irradiated and non-irradiated meat products by an in vitro method, which simulated the gastrointestinal process. The most relevant results are summarized as following: - The amount of LSTP most suitable for incorporation into meat products technologically and sensorially was 4 and 1.5% for fresh and dry fermented sausages respectively. The amount of DTP was determined in previous works in 4 and 2% respectively. - The incorporation of DTP and LSTP caused changes in the color and texture of the enriched meat products with respect to the control batch. Sensorially, the lowest punctuations corresponded to the batches with the highest tomato derivative concentrations, but their scores were always higher than the general acceptability limit. - The irradiation treatment (2 kGy) did not modify the color or texture of the meat products, but when 4 kGy doses were applied sensorial changes were observed, mainly in smell and taste, although the sensorial quality improved throughout the storage time. The addition of PTS and TDD to meat products could mask some negative sensory characteristics associated with irradiation. - The irradiation treatment extended the shelf-life of hamburgers from 5 to 11 and 28 days at doses of 2 and 4 kGy respectively. The sensory characteristics of sausages were maintained up to 120 days. - The application of E-beam treatment caused losses of the amount of lycopene of meat products with LSTP up to 15%. In the case of the DTP no losses were detected in the irradiated samples. These differences between DTP and LSTP could be related to the resistance and greater thickness of tomato peel cells which makes them less sensitive to irradiation treatment. - Lycopene present in tomato derivatives had an important antioxidant activity, being higher in DTP than in LSTP. This activity was enhanced by the irradiation treatment due to the isomerization of lycopene, which in biological terms supposes a greater antioxidant capacity. - Neither the irradiation nor the type of tomato derivative added influenced the accessibility of lycopene, however the type of meat product did. Dry fermented sausages had higher values of accessibility due to its higher fat content, which stimulates the absorption of lycopene. - The consumption of meat products with tomato derivatives would contribute to increase the daily intake of lycopene. Thus, 100 g of fresh meat products with LSTP would provide between 4.3-11.7 mg of lycopene depending on the amount added; and 100 g of dry fermented sausages with DTP or LSTP would contribute between 1.2-2.1 mg, respectively. As a general conclusion, it could be said that the products designed could be considered a new way to increase the consumption of lycopene in the diet, even when it was presented as RTE. According to Regulation (EU) Nº 1924/2006 developed products could be considered as a source of lycopene, finding us consequently, with new foods suitable to provide this antioxidant in the diet.