UV-B radiation application had a positive effect in the antioxidant characteristics of green and red lettuce at baby leaf stage

Lettuce (Lactuca sativa L.) is one of the most consumed vegetables in the world, that is the reason why it is very important to fill the consumer?s requirements using smoothy leaves, different shapes and colours, and assuring the safety of them. To carry out that task, it can be linked to different farming techniques as hydroponic and baby leaf production. Furthermore, it is necessary to have a highly functional product; that is to say a product that gives appropriate nutritional characteristics with beneficial compounds for human being; that is why recently it has been researched UV-B radiation (280-320 nm), which has the capacity to increase the phenolic compounds, linked directly with higher antioxidant activity of the plant. The objective of this research was to evaluate the increase in the antioxidant capacity of hydroponic baby leaf lettuce cvs. 'Kristine RZ' (green) and 'Versai RZ' (red), with UV-B radiation treatments at pre-harvest. For this, it has been applied three intensities of UV-B radiation treatments, as well as, control treatment for 10 days to lettuces in their fifth true leaves. After this period, external lettuce?s leaves were harvested keeping two central leaves for the second application period, during which were replicated the management already said. In each harvest different parameters were measured, evaluating leaf area, biomass, leaf pigments and phenolic compounds. The main result of this research was the increased of total phenolic compounds at the second harvest as a response of UV-B application at ?Kristine RZ? cultivar from 122 to 169 ?g EAG?g-1, while ?Versa? RZ? cultivar increased from 544 to 589 ?g EAG?g-1. Moreover, it was observed antioxidant capacity increase of the leaves because of the UV-B radiation at ?Kristine RZ? cultivar from 298 to 332 ?g ET?g-1, while at ?Versa? RZ? cultivar increased from 1117 to 1522 ?g ET?g-1. These results show that the UV-B radiation application had a positive effect in the antioxidant characteristics of the vegetal product measured after the first harvest. SourceTRATAMIENTOS PRECOSECHA DE RADIACI?N ULTRAVIOLETA-B PARA AUMENTAR LA CALIDAD FUNCIONAL DE LECHUGAS (Lactuca sativa L.) ?BABY? HIDROP?NICASLuis Arturo Rivera Marchant1; Mar?a Luisa Tapia1; Luis Luchsinger1; Silvia Rodr?guez2; V?ctor Escalona1 1Centro de Estudios Postcosceha (CEPOC), Facultad de Ciencias Agron?micas, Universidad de Chile. Casilla 1004, Santiago (Chile)Correo electr?nico:?vescalona@uchile.cl: Sitio web:?www.hortyfresco.cl; www.cepoc.cl 2Centro de Investigaciones y Transferencia de Santiago del Estero (CITSE-CONICET), Universidad Nacional de Santiago del Estero (Argentina)?