Arrowroot ( Maranta arundinacea ) Extract Increases the Survival of Probiotic Lactobacillus acidophilus

Probiotics are live microorganisms that benefit a host by sustaining healthy micro flora in the gut. However several factors including pH, metabolites and dissolved oxygen limit the growth and survival of probiotic organisms. Prebiotics are selectively fermented ingredients that may increase the survival and activity of probiotics. Arrowroot is rich in prebiotics and may increase the biomass of probiotics. This study was aimed at determining the prebiotic potential of water extractable carbohydrates of local yam arrowroot. Arrowroot carbohydrates were extracted by wet milling and recovery was 14.32% (w/w). The results of the proximate analysis revealed that the percentages of moisture, ash, protein and fat were 10.15%, 4.91%, 0.13% and 0.32% respectively. The contents of starch and low molecular weight carbohydrates were 79.65% and 1.93% respectively. No reducing sugars were detected. 12% (w/v) of arrowroot carbohydrates were incorporated into 12% skim milk and distilled water along with an inoculum of 109 colony forming units (CFU)/g of Lactobacillus acidophilus in order to test the growth performances. 12% skim milk was used as a control. Treatments were incubated at 37°C anaerobically for 12 h followed by storage at 4°C for 14 days. The pH, titrable acidity and colony counts of L. acidophilus were determined throughout the storage period. Media added with arrowroot gave a significantly (p<0.05) higher pH compared to the control although there was no significant difference (p>0.05) among the two media where arrowroot was added. Similar results were observed for titrable acidity as well. Results showed that arrowroot carbohydrates significantly (p<0.05) increased the CFU (log 10)/g of L. acidophilus compared to the control (6.71) in both distilled water (9.34) and skim milk (9.01) media. It was revealed that water extractable arrowroot carbohydrates shows significant prebiotic effect by maintaining a higher viability of probiotics.