ABSTRACT
This study evaluated the nutritional value of aerial yam potato fermented with different methods and other food processing. Aerial potato was subjected to different treatments (peeled, unpeeled, peeled and blanched, unpeeled and blanched, peeled and boiled, unpeeled and boiled) before fermentation with different methods like submerged fermentation and back slope (BS) fermentation. The proximate and mineral compositions were monitored using standard methods. Crude Protein (%) of the peeled aerial potato significantly increased from 4.12 ±0.13 at the initial to 10.11±0.85 at the end of the fermentation while unpeeled aerial potato slightly increased from 3.66a±0.04 at the initial to 4.19±0.03 at the end of the fermentation. Peeled and blanched; unpeeled and blanched as well as the unpeeled and boiled samples had the highest iron (0.143±0.01 ppm), magnesium (6.40±0.02 ppm) and calcium (6.32±0.03 ppm) contents in fermented aerial potato sample. Generally, the different of methods of fermentation employed improved the nutrient contents of fermented aerial potato.
ABSTRACT
Aim: To determine the antibiotic reaction and adhesion pattern of antimicrobial homofermenting LAB strains in the fermenting slurries of kunu zaki. Study Design: ANOVA. Inhibition of indicator lawn used ≥10mm inhibition as antibiotic susceptible. Adhesion was measured by staining and quantifying recorded as percentage and index values. Place and Duration of Study: Department of Microbiology, Federal University of Technology Akure and Biotechnology Unit, Federal Institute of Industrial Research, Oshodi, Nigeria between June, 2012 and December, 2012. Methodology: Kunu-zaki drinks were produced using spontaneously fermenting cereal grains of Digitaria exilis (acha), Sorghum bicolour (sorghum) and Pennisetum americanum (millet) in composite and non-composite proportions. LAB isolates were obtained on MRS agar. Homo-fermenting isolates were identified to species level using the API 50 CHL test kit. Antibiotic sensitivity testing on the identified isolates followed the modified standard Kirby-Bauer procedure on MRS agar (pH 7.4) using the disc diffusion technique with selected antibiotics. For quality control of the antibiotics, sensitive reference strains S. aureus ATCC 25923 and E. coli ATCC 25922 obtained from the Nigeria Institute of Medical Research were used. Adhesion and antimicrobial properties were determined using standard method. Results: Antimicrobial substances produced by the eight LAB isolates inhibited the growth of four selected human pathogens in vitro. All eight LAB isolates were resistant to amoxicillin, gentamycin and ciprofloxacin. L. plantarum126, L. paracasei subsp paracasei339 and Pediococcus damnosus32 were resistant to erythromycin whilst all others were susceptible. L. plantarum126 and L. paracasei subsp paracasei339 were resistant to all antibiotics tested. All LAB isolates demonstrated high in-vitro intestinal epithelial cell adhesion potential. Conclusion: LAB antimicrobial activity may not be affected if kunu zaki is consumed simultaneously with these antibiotic therapies. However, if these LAB strains are intended for use as kunu-zaki starter cultures, it is important that they should be further carefully examined for inability to transfer antibiotic resistance genes to food pathogens.
ABSTRACT
Aims: The research was carried out to study the purification, characterization and application of polygalacturonase from Aspergillus niger CSTRF. Methodology and Results: The polygalacturonase (PG) from the fungus was purified by ammonium sulphate precipitation and dialysed. The resulting fraction of the enzyme was further separated by molecular exclusion and ion exchange chromatography. The enzyme was purified 28.19 fold with a yield of approximately 69 % following purification with SP C-50. It has a relative molecular weight of 79,430 daltons and markedly influenced by temperature, pH and substrate concentrations of reactions with optimum activity at 35 °C, pH 4.0 and 8 mg/mL respectively. The PG was heat stable over a broad range of temperatures. Line weaver-Burk plot for the apparent hydrolysis of pectin showed approximately Km value of 2.7 mg/mL. The activity of the enzyme was enhanced by Na+, Ca2+, Mg2+ and Zn2+, while EDTA, PbCl2, HgCl2 and IAA were inhibitory. The ability of the purified enzyme to clarify fruit juice was also investigated. Conclusion, significance and impact of the study: This study revealed that polygalacturonase possesses properties for clarification of fruit juice and by extension bioprocessing applications.