Carotenoid composition of cooked green vegetables from restaurants

It is generally recognised that databases should be in terms of the food as eaten, but data on cooked foods are lacking. In this work, β-carotene, lutein, violaxanthin and neoxanthin in cooked green vegetables from restaurants were determined by HPLC. In general, there was no statistical difference in the carotenoid concentrations of vegetables taken from different restaurants. This result is surprising at first glance because of the many factors that can cause variation in the raw materials, aside from those brought about by the cooking conditions. However, the interplay of many factors might have masked individual effects. Moreover, taking the analytical sample from a large restaurant batch might have compensated the individual variations, giving more representative average concentrations. Between-lot variations of samples from the same restaurant were sometimes appreciable. Violaxanthin was the carotenoid most affected by cooking.