Effects of postharvestUV‐Ctreatment on carotenoids and phenolic compounds of vine‐ripe tomatoes

Abstract

Summary Light red tomatoes were exposed to different doses of ultraviolet C (UV‐C) irradiation (1.0, 3.0 and 12.2 kJ m−2). After treatment, the tomatoes were stored for 2 days at room temperature, and then analysed to determine the effect of irradiation on the main antioxidants, carotenoids and phenolic compounds and the results compared with the control samples. The lycopene content was found to have increased by 14% with respect to the control samples, while β‐carotene decreased. Cis‐isomers from lycopene also increased when the tomatoes were exposed to irradiation for more than 3 h. UV‐C irradiation also had a positive effect on total phenolic compounds; however, the same effect was not observed in the individually analysed phenolic compounds. While chlorogenic and ferulic acids increased in content, naringenin and rutin contents decreased. These results suggest that UV‐C irradiation of tomatoes could improve the beneficial effect of red tomatoes for human health by increasing the levels of certain bioactive compounds; it could also be used to obtain higher content of bioavailability components, such as cis‐isomers from lycopene.

Evaluation of the chemical composition and colour in long‐life tomatoes (Lycopersicon esculentum Mill) dehydrated by combined drying methods

“…According to Bravo et al . (), from the nutritional point of view, the changes that occur in the carotenoid structures can provide benefits by facilitating absorption when they participate in the human diet.…”

“…The carotene concentration increase can be perceived when it is submitted to heating and also when the fruits are ripened at higher temperatures. According to Bravo et al (2013), from the nutritional point of view, the changes that occur in the carotenoid structures can provide benefits by facilitating absorption when they participate in the human diet.…”

Changes in the composition of tomato powder (Lycopersicon esculentum Mill) resulting from different drying methods

“…The increase in b-carotene in tomato powder dehydrated by heated air flow was higher than in the freezedried powders. According to Anguelova and Warthesen (2000), Bravo et al (2013), and Demiray et al (2013), b-carotene is more stable than lycopene, thus implying only minor changes in terms of degradation increased extraction. The increasing drying temperature from 70 8C to 80 8C increased the reaction rate of lycopene degradation in tomatoes by about 2.4 times (Demiray et al, 2013), and rearrangement of its chemical structure.…”

“…However, DHAA can, in turn, quickly hydrolyze to diketogulonic acid (DKGA), which shows no biological activity (Mertz et al, 2010). Bravo et al (2013) stated that tomato is a very important food item for humans because of the protective effect against cardiovascular diseases and cancer afforded by its bioactive compounds. In fact, Oloyede et al (2012) conducted in vitro studies and demonstrated that antioxidants can offer a protective effect against damage caused by free radicals, reducing the occurrence of such diseases.…”

Irradiance-based treatments of Quillaja brasiliensis leaves (A. St.-Hil. & Tul.) Mart. as means to improve immunoadjuvant saponin yield

“…Considering this latter function, exposure to UV irradiance is well explored in order to increase metabolites of economic interest (Matsuura et al, 2013), such as glycyrrhizin in Glycyrrhiza uralensis, resveratrol in Vitis vinifera, saponins in Q. brasiliensis, essential oil and phenolic compounds in Mentha piperita, and brachycerine in Psychotria brachyceras (Afreen et al, 2005;Berli et al, 2008;De Costa et al, 2013;Dolzhenko et al, 2010;Nascimento et al, 2013). Even during post-harvest, UV-C treatment can promote accumulation of metabolites such as lycopene and phenolics in vine-ripe tomatoes, and resveratrol in red wine grape varieties (Bravo et al, 2013;Cantos et al, 2003).…”