"Nata", a glycidic food obtained by surface fermentation with Acetobacter xylinum, is well-known in some Asiatic countries, mainly the Philippines. Coconut milk or water, low economical value by-products of coconut processing, are employed as culture media; the literature on the subject indicates that other agricultural residues such as milk whey and even fruit juices may also be used. To evaluate the production of "nata" aiming further studies concerning alternative culture media, a synthetic medium was employed, what enabled the determination of the conditions concerning pH, inoculum and incubation, as well as the observation of the influence of the presence of sucrose and acids on the process. To optimize the process, it was designed a set of experiments with acetic acid and glucose as variables. The defined conditions were pH correction to 4, the addition of 10% (v/v) of inoculum to the medium and incubation at 28°C for 10 days. The optimum initial concentrations of the considered nutrients were 0,65 moles/l of acetic acid and 67,4 g/l of glucose in which were produced 7,107 g of "nata"/250 ml of medium.
"Nata"; surface fermentation; optimization; Acetobacter xylinum
