Prebiotic potential of two commercially available purple yam (Dioscorea alata L.) varieties in Laguna, Philippines

Date

4-2014

Degree

Bachelor of Science in Agricultural Biotechnology

College

College of Agriculture and Food Science (CAFS)

Adviser/Committee Chair

Lotis Escobin-Mopera

Abstract

The prebiotic potential of Hinaligi and Magnolia varieties of purple yam was determined using the prebiotic activity assay and prebiotic activity score. Flour was obtained from tubers of purple yam varieties and was analyzed for its physicochemical properties. Pure cultures of Lactobacillus casei, Lactobacillus acidophilus and Lactobacillus plantarum were grown in MRS medium containing 1% (w/v) flour of each purple yam variety. Escherichia coli were grown in M9 minimal medium containing 1% flour of each purple yam variety. Medium without purple yam flour served as the control while medium mixed with 1% yacon flour served as the positive control. Cell densities were obtained at 0 hr and 24 hr incubation. Cell densities were used to calculate for the prebiotic activity score of each flour. Resistant starch (RS) content was higher in Hinaligi flour compared to Magnolia variety. The growth of L. acidophilus on MRS with Hinaligi flour (9.54 log cfu ml-1) was significantly higher (p<0.05) compared to the growth of other microbial cultures on different treatments. On the other hand, E. coli grown in minimal medium with Hinaligi flour had the lowest cell density (8.11 log cfu ml-1). Magnolia variety showed the highest prebiotic activity scores in all Lactobacilli species compared to Hinaligi, however,statistical analyses showed that the score of Magnolia was not significantly different from that of Hinaligi. The prebiotic potential of Magnolia and Hinaligi varieties were partially attributed to their RS content. The prebiotic potential of the two varieties were supported by the significant increase in cell densities of lactobacilli in medium with purple yam flour compared to the control. Also, the purple yam flour was found to limit the growth of E. coli which is a potential pathogenic bacteria.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2014 A127 G66

Document Type

Thesis

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