Ramya Iyer

Response surface optimization of the cultivation conditions and medium components for the production of folate by Streptococcus thermophilus.

Optimization of the cultivation conditions and medium components for folate production by the highest folate producing Streptococcus thermophilus strain RD102 was carried out using a 23 central composite design and surface modelling method of response surface methodology. As folate production was observed to be growth-associated, hence the desired responses selected for the optimization were both folate production and growth. The selected factors based on preliminary investigations were incubation period, concentrations of p-amino benzoic acid (PABA) the growth precursor, and lactose as carbon source. The optimum concentrations of PABA and lactose were found to be 300 micropm and 3% respectively at 72 h incubation. The optimized conditions resulted in an increase in folate production by 26% compared with control conditions (0% PABA and lactose at 37 degrees C). Using the method of experimental factorial design and response surface analysis, it was possible to determine optimal operating conditions to obtain a higher folate production by Strep. thermophilus. Therefore, this study constitutes a step in developing strategies to modulate the folate level to a higher level.

Dietary effect of folate-rich fermented milk produced by Streptococcus thermophilus strains on hemoglobin level.

OBJECTIVE Folate, a water-soluble vitamin, functions as a carbon carrier in the formation of heme, the iron-containing non-protein portion of hemoglobin. Therefore, its deficiency leads to anemia. The objective of this study was to determine the dietary effects of folate-rich fermented milk produced by high-folate-producing Streptococcus thermophilus strains (RD 102 and RD 104) on hemoglobin level using a murine model. METHODS Thirty-two albino mice 30 ± 10 d old were assigned to ingest a basal diet (i.e., a synthetic anemic diet, n = 8, group I, control 1), a basal diet with skim milk (n = 8, group II, control 2), a basal diet with fermented skim milk produced by folate plus RD 102 (n = 8, group III, test 1), and a basal diet with fermented skim milk produced by folate plus RD 104 (n = 8, group IV, test 2) in a 6-wk, double-blind, placebo-controlled study. Hemoglobin concentrations were estimated by the Drabkin-Austin cyanmethemoglobin method during the prefeeding (10 d), feeding (20 d), and postfeeding (10 d) trials, respectively. RESULTS The results showed that the test groups (III and IV) receiving folate-rich fermented milks prepared using high-folate producing S. thermophilus strains showed a significant increase in hemoglobin level compared with the control groups (I and II). CONCLUSION Folate-rich fermented milks have the potential to significantly increase the hemoglobin level of blood. Hence, high-folate-producing S. thermophilus strains offer a novel natural approach to fortify dairy products with folate.

Determination of folate/folic acid level in milk by microbiological assay, immuno assay and high performance liquid chromatography

A concurrent determination of folate versus folic acid in milk by microbiological assay (MA) with Lactobacillus rhamnosus as the assay organism, Enzyme Linked Immuno Sorbent Assay (ELISA) by competitive binding rapid ELISA kit (RIDASCREEN®) and high-pressure-liquid chromatography (HPLC) was done for detection of the folate form and its level. MA gave total folate content as Lb. rhamnosus showed similar response to most folate isomers formed by the tri-enzyme treatment in comparison with the other two methods which specifically estimated the folic acid. In case of ELISA, specificity was apparently limited to folic acid and dihydro folic acid and thereby showed a lower response for other folate derivatives. Estimation by HPLC with UV detector was highly specific and hence only folic acid could be detected without any cross reactivity. Among the different methods HPLC was observed to be the most sensitive method for determination of folic acid and hence can efficiently determine the folic acid fortification level while MA remained highly efficient, sensitive and reproducible method for estimation of total folate indicating its potential use for dietary folate estimation.