Effect of Drying Method on Volatile Nutraceuticals and Microbial Growth in Moringa oleifera

Document Type : Research paper

Authors

1 Department of agricultural sciences, Karatina University, Karatina, Kenya

2 Department of Occupational Safety and Health, Jomo Kenyatta University of Agriculture and Technology, Kenya

Abstract

Fresh Moringa oleifera leaves are very rich in phytonutrients, however the leaves are also highly perishable and require processing for increased shelf-life. The method of processing, specifically  drying affects the nutritional value of the product. The present study therefore, analyzed the nutraceutical value and growth of toxic microbes when the leaves were dried under different conditions i.e. room temperature, greenhouse, 50% shade net, and in the oven at 60 oC for 4 h. The experiments were carried out at the Jomo Kenyatta University of Agriculture and Technology (JKUAT). The treatments were applied in triplicate and arranged on a completely randomized design (CRD). Data on nutritional value of dried Moringa leaves was subjected to analysis of variance (ANOVA) for parameterization and means separated using protected LSD0.05. The study showed that drying Moringa leaves under shade, room and greenhouse conditions significantly (P<0.05) affects the nutritional value of the product. The results showed highest levels of vitamin C, vitamin A, polyphenols and terpenoids when the leaves were dried under 50% shade net and room temperature conditions. In contrast, the glucosinolate content was significantly (P<0.05) higher when the leaves were dried instantly in the oven (9.1%/wt), followed by drying under greenhouse conditions (8.7%/wt) before oven drying. However, drying of Moringa leaves under shade before oven drying resulted in growth of toxic microbial organisms such as staphylococcus, yeast, E. coli and molds that can potentially affect the safety of the product. Finally, the drying conditions also significantly (P<0.05) affected the moisture content of the powder obtained. The results of this study form an important reference for small-holder Moringa growers and processors in the development of an optimal processing regime for high value Moringa powder.

Keywords

References

Abdullah K. 1997. Drying of vanilla pods using a greenhouse effect solar dryer. Dry Technology 15, 685-698.
Aires A, Mota V, Saavedra M, Rosa E, Bennett R. 2009. The antimicrobial effects of glucosinolates and their respective enzymatic hydrolysis products on bacteria isolated from the human intestinal tract. Journal of Applied Microbiology 106(6), 2086-95.
Atawodi E, Atawodi C, Idakwo A, Pfundstein B, Haubner R, Wurtele G, Bartsch H, Owen W. 2010. Evaluation of the polyphenol content and antioxidant properties of methanol extracts of the leaves, stem, and root barks of Moringa oleifera Lam. Journal of Medicinal Food 13 (3), 710–6.
Bargah K. 2015. Preliminary test of phytochemical screening of crude ethanolic and aqueous extract of Moringa pterygosperma Gaertn. Journal of Pharmacognosy and Phytochemistry 4(1), 07-09.
Baruah D, Bhuyan P, Hazarika M. 2012. Impact of moisture loss and temperature on biochemical changes during withering stage of black tea processing on four Toclai released clones. Two and a Bud 59(2), 134-142.
Begum S, Ahmed F, Rahman M. 2009. Effect of cooking temperature and storage period on preservation of water soluble vitamin C content in Citrus macroptera and Moringa oleifera lunk. Asian Journal of Food and Agro-Industry 2(3), 255-261.
Fahey J. 2005. A review of the medicinal evidence for its nutritional therapeutic and prophylactis properties, part I, Tree Life Journal (1)5.
Food and Drug Administration (FDA). 2002. Enumeration of Escherichia coli and the coliform bacteria: Bacteriological Analytical manual.
Food and Drug Administration (FDA). 2011. Quantitative Assessment of Relative Risk to Public Health from Foodborne Listeria monocytogenes Among Selected Categories of Ready-to-Eat Foods. Fish and Fishery Products Hazards and Controls Guidance 4th Edition.  appendix 5: FDA and EPA Safety Levels in Regulations and Guidance.
ISO 21527-1. 2008. Microbiology of food and animal feeding stuffs - horizontal method for the enumeration of yeasts and moulds - part 1:  Colony count technique in products with water activity greater than 0.95.
Jensen S, Liu Y, Eggum B. 1995. The effect of heat treatment on glucosinolates and nutritional value of rapeseed meal in rats. Animal Feed Science and Technology 53 (1), 17-28.
Kasolo J, Bimenya G, Ojok L. 2010. Phytochemicals and uses of Moringa oleifera leaves in Ugandan rural communities. Journal of Medicinal Plants Research 4, 753-7.
Khodaeeyan G. 2008. Classification of bacteria. Food Microbiology 9-11, 138-140.
Negi S, Roy S. 2001. Effect of drying conditions on quality of green leaves
during long term storage. Food Research International 34, 283-287.
Official Methods of Analysis (AOAC). Food Compositions; Additives, Natural. Contaminants, 15th ed; Arlington, VA, 1990, Vol. 2.; Official Method.
Omiadze N, Mchedlishvili J, Rodrigez L, Abutidze T, Sadunishvili A, Pruidze N. 2014. Biochemical processes at the stage of withering during black tea production. Applied Biochemistry and Microbiology 50(4), 394-397.
Olson E. 2010. Moringaceae Martinov; Drumstick Tree Family; In: Flora of North AMERICA, North of Mexico, vol. 7: Magnoliophyta: Dillenniidae, Part 2. Oxford University Press. P. 168.
Sanjay R, Biradar B, Racheric D. 2013. Extraction of secondary metabolites and thin layer chromatography from different parts of Centella asitica L. American Journal of Life Sciences 1(6), 243-247.
Singh G, Sharma S. 2012. Antimicrobial evaluation of Moringa oleifera Lam. International Research Journal of Pharmacy 3, 1-4.
Song L, Thornalley P. 2007. Effect of storage, processing and cooking on glucosinolate content of Brassica vegetables. Food and Chemical Toxicology 45 (2), 216 – 224.
Sreelatha S, Padma P. 2009. Antioxidant activity and total phenolic content of Moringa oleifera leaves in two stages of maturity. Plant Foods for Human Nutrition 64, 303-311.
Yameogo C, Bengaly M, Savadogo A, Nikiema P, Traore S. 2011. Determination of chemical composition and nutritional values of Moringa oleifera leaves. Pakistan Journal of Nutrition10, 264-268.
Yang X, An R. 2011. Determination of Aflatoxins (B1, B2, G1and G2) in Corn and Peanut Butter by HPLC-FLD Using Pre-column Immuno-affinity Cleanup and Post-Column Electrochemical Derivatization.
International Journal of Horticultural Science and Technology
Volume 8, Issue 4
October 2021
Pages 315-322

Files

History

  • Receive Date: 12 November 2020
  • Revise Date: 12 May 2021
  • Accept Date: 18 May 2021

Share

How to cite

Statistics