The recalcitrance of oxalate, nitrate and nitrites during the controlled lactic fermentation of commonly consumed green leafy vegetables

摘要

Purpose - Green leafy vegetables (GLVs) are important components of a balanced diet especially in developing countries where the major requirements of micronutrients are met. However, GLVs also contain significant amounts of oxalate, nitrate and nitrites, whose role in the human diet is constantly changing. The current study explored the behavior of nitrate, nitrites and oxalate in lactic-fermented GLVs with an intention to develop functional foods based on them.Design/methodology/approach - Selected strains of beneficial lactic acid bacteria were used for the controlled fermentation of GLV, while an identical portion was subjected to spontaneous fermentation. The nitrate and nitrites were monitored spectrophotometrically, while oxalate contents were quantified by both titrimetric and by high-performance liquid chromatography throughout the duration of fermentation.Findings - More than 90 per cent of individual constituents studied remained intact in the GLVs paste after the six-day controlled fermentation period. However, there was significant difference between the controlled and spontaneously fermented samples in terms of oxalate, nitrate and nitrite contents. Originality/value - Controlled lactic fermentation although superior in all other aspects may not be able to lower the anti-nutrients present. The advantages of spontaneous fermentation vis-d-vis controlled fermentation are discussed. The work will bring out the importance of the beneficial effects of GLVs and the effect of lactic fermentation.