Tomato seed oil for biodiesel production

Abstract

The use of vegetable oil for biodiesel production as a renewable energy source can have five main goals: the reduction of dependence on fossil energy, the reduction of wastes, the increase of the economic value of fruits, the increase of the economic value of vegetable oils, and the reduction of total CO2 emissions. Tomato seeds could be used for biodiesel production. The influence of the hot break and cold break treatments together with the harvest year effect on the physicochemical properties of the tomato seed oil were studied. Relative density was within 928 ± 0.33, acid value ranged from 0.48 ± 0.07 to 2.50 ± 0.03. The oil stability index measured at 110°C was always above 6 h. Kinematic viscosity decreased with the increase of the temperature from 30 to 50°C, being similar to the value indicated by the DIN 51605 for rapeseed oil at 40°C (35.17 ± 020–41.35 ± 0.56 mm2/s). Eleven fatty acid were detected: myristic acid, palmitic acid, palmitoleic acid, margaric acid, margaroleic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidic acid, and eicosenoic acid. Linoleic acid prevailed on all fatty acid methyl esters (mono‐alkyl esters) (49.61–57.89%) followed by oleic acid (18.79–21.82%). In the large part of cases, the iodine value was within the maximum of DIN 51605. Cetane number, calcium, and magnesium were out of the limit. International standards for biodiesel and vegetable oil quality standard were discussed.Practical applications: This study is related to the possibility of using an unusual vegetable oil as a source for biodiesel production. In this way, one can monetize a waste product (tomato seeds) and at the same time obtain a vegetable oil useful for biodiesel production. It is noteworthy that, at present, tomato seed oil is not used in the food industry so its use for biodiesel will not increase its price.In the tomato seed oil, the sum C18:1 + C18:2 is similar to an olive oil. All biodiesels produced by the studied TSOs have a CN well above 51.0 and 47.0 stated by the European and USA regulations for a biodiesel.