The study, published in LWT - Food Science and Technology, suggests that the L. lactis ssp. cremoris may be of use as a starter culture, to increase the folate bioavailability levels in both fermented skimmed milk and in fruit juices.
The researchers, from the National Institute for Interdisciplinary Science and Technology (NIIST), India, said that the use of a potent folate producing bacterium as a starter culture, may have benefits for the food industry “as a viable alternative in producing functional foods with increased nutritional value.”
“The elevated levels of folate in the present study indicated the significant influence of the starter culture … and cultivation conditions in increasing the folate levels in fermented food products,” said the authors, led by K. Madhavan Nampoothiri from NIIST.
“In addition, the use of natural fermentation media can be used as a replacement for synthetic fermentation media eliminating the need for purifying the folate from the culture,” they added.
Folic acid is an essential vitamin for growth and reproduction in all vertebrates, however humans and other animals are dependent on dietary folate intake as they cannot synthesize it.
The efficiency of DNA replication, repair, and methylation are affected by folate availability; therefore, large amounts of folate are required by rapidly growing cells.
Nampoothiri and colleagues said that recent research on the protective role of folic acid in the reduction of neural tube defects, coronary heart diseases and cancer has renewed interest in folate supplementation to combat deficiency.
They added that further research studies have shown the capacity for vitamin production by certain microorganisms, which has the potential to be exploited to either to replace costly chemical synthesis vitamins for food fortification “or for in situ fortification of fermented foods.”
“The overproduction of vitamin by lactic acid bacteria (LAB) provides a very attractive approach to improve the nutritional composition of fermented foods,” said the authors.
Previous research has reported the ability of L. lactis and Streptococcus thermophilus to synthesize folate, whilst increased folate production in L. lactis and Lb. plantarum by metabolic engineering has been demonstrated.
The new study investigated the fermentative production of folate with its implications for fortification of skim milk and fruit juices (cucumber and water melon) using a newly isolated L. lactis ssp cremoris.
The authors reported the highest production of folate was obtained at 37 °C.
Nampoothiri and colleagues observed that fermentation of the extracts with L. lactis ssp. cremoris elevated the folate levels in the extracts of cucumber and water melon from 10 and 18 nanograms (ng) per ml to 60 and 26 ng/ml respectively.
They added that fermentation with L. lactis ssp. Cremoris also significantly increased folate levels in fermented milk products, noting that supplementation with prebiotics such as mannitol further increased folate production, with production reaching up to 37.2 nanograms (ng) per ml.
The authors said the elevated levels of folate “gives a lead for the development of an important strategy for the development of fermented functional foods.”
However, Nampoothiri and co-workers said that further characterization of the fortified food product “is essential before use.”
Source: LWT - Food Science and Technology
Published online ahead of print, doi:10.1016/j.lwt.2011.05.002
“Folate production using Lactococcus lactis ssp cremoris with implications for fortification of skim milk and fruit juices”
Authors: D. Gangadharan, K.M. Nampoothiri