Biotechnological production of natural sweeteners and preservatives on tomato paste

There is a growing interest in healthier foods and cleaner labels. In particular, foods containing a lower sugar concentration but with the same organoleptic properties and the same shelf life are becoming a new challenge. To this end, we performed a first set of experimentations on two simple broths (LFM1 and LFM2), which differed in their glucose concentration (250 g/L and 200 g/L, respectively), and a second set of fermentations on two diluted tomato pastes (TP1 and TP2), with the same glucose concentration but different in the presence (TP2) or absence (TP1) of yeast extract. These substrates were fermented by Yarrowia lipolytica ATCC 8661 at 30°C for 192 hr, to understand its ability in simultaneous production of erythritol and citric acid. Although the process should be optimized, in all the cases tested we obtained the erythritol and the citric acid production. Practical application: The aim of the present study was the simultaneous production of erythritol and citric acid on a food matrix. This is a preliminary study to obtain, directly by fermentation, a natural sweetener able to give the food product, in particular tomato paste, a sweet taste without adding artificial sweeteners. At the same time, we tried to produce citric acid as a natural preservative to improve shelf life. In this way, we wish to obtain, through several experimentations, semifinished products for the production of vegetal soups and sauces.