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In Nigeria, poor post-harvest handling of agricultural products contributes to increasing spoilage of oranges; hence, the need for the present strategy to enhance its shelf-life. The study evaluates, the physicochemical and microbiological features of peeled and unpeeled oranges, treated with different concentrations of citric acid and stored under room (hawking) and refrigeration temperatures for 16 days. Citric acid treatment of oranges showed significant effect (P≤0.05) on the acidity and enterobacterial count while the nature of samples significantly affected the pH, brix, total bacterial, yeasts and enterobacterial counts. Furthermore, the storage temperature significantly affected all the parameters. The spoilage organisms were identified as Aspergillus nigerMacrophomina species, Bacillus subtilis and Chryseomonas luteola. The citric acid improved the shelf-life of oranges sold in Nigerian open markets, from 10 to 15 days (unpeeled) and from 2 to 3 days (peeled) at hawking temperature. Two strains of Aspergillus niger and one species of Macrophomina were isolated from spoilt oranges and both demonstrated ability to produce pectinase, but the A. niger strains were better. The optimal temperature of pectinases from the A. niger strains was 50oC and optimum pH range of 4-5, while that from Macrophomina species was 40oC and pH 9 respectively. The crude pectinases from the Aspergillus niger strains and Macrophomina species were activated by Ag3+ and Na+, whereas Fe3+ inhibited the enzymes from all three fungal sources. A 2-minute infusion of oranges in citric acid solution is recommended for shelf life elongation of oranges hawked at ambient temperature in open markets. Moreover, based on their optimal pH, pectinases from A. niger will be a good raw material in the industrial production of wine, vegetables, purees and pastes, while the alkaline pectinases from Macrophomina sp. will be useful in waste treatment.

Citric acid, keeping quality, spoilage organisms, oranges, storage temperature.

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1. Piccinelli AL, Mesa MG, Armenteros DM, Alfonso MA, Arevalo AC, Rastrelli L. HPLC-PDA-MS and NMR characterization of C-Glycosyl flavones in a hydro-alcoholic extract of citrus aurantifolia leaves with antiplatelet activity. J Agric Food Chem. 2008;56:1574-1581.
2. Terol J, Conesa A, Colmenero JM, Cercos M, Tadeo F, Agusti J, Alos E, Andres F, Soler G, Brumos J, Iglesias DJ, Gotz S, Legaz F, Argout X, Couitois B, Ollitrault P, Dossat C, Wincker P, Morillon R, Talon M. Analysis of 13000 unique citrus clusters associated with fruits quality, production and salinity tolerance. BMC Genomics. 2007;8:31.
3. Onuorah S, Obika I, Okafor U. Filamentous fungi associated with the spoilage of Post-Harvest sweet orange fruits (Citrus sinensis) sold in Awka major markets, Nigeria. Bioeng Biosci. 2015;3:44-49.
4. Oyegun M. Citrus Cultivation and Processing. Raw Materials Update. 2002;3:32-33.
5. Majo DD, Giammanco M, Guardia M, Tripoli E, Giammanco S, Finotti E. Flavones in citrus fruit: structure antioxidant activity relationship. Food Res Inter. 2005;38:1161-1166.
6. Bukar A, Mukhtar MD, Adamu S. Isolation and identification of postharvest spoilage fungi associated with sweet oranges (Citrus sinensis) traded in Kano metropolis. Bayero J Pure Appl Sci. 2009;2:122-124.
7. Akinmusire OO. Fungal species associated with the spoilage of some edible fruits in Maiduguri Northern Eastern Nigeria. Adv Environ Biol. 2011;5:157-161.
8. Baiyewu RA, Amusa NA, Ayoola OA, Babalola OO. Survey of the postharvest diseases and aflatoxin contamination of marketed pawpaw fruit (Carica papaya L.) in South Western Nigeria. Afr J Agric Res. 2007; 2:178-181.
9. Ojo OA, Olaniran OA, Odelade KA. Survey of Postharvest Diseases and Aflatoxin contamination of marketed orange fruit (Citrus sp.) in major cities in Oyo State, Nigeria. Inter J Appl Plant Pathol. 2013;10:110-117.
10. Akintobi AO, Okonko IO, Agunbiade SO, Akano OR, Onianwa O. Isolation and identification of fungi associated with the spoilage of some selected fruits in Ibadan, South Western, Nigeria. Academia Arena. 2011;3:1-10.
11. Mohammed DSS, Niranjan KD, Damisa, D, Bala E, Muhammed II, Muhammed GR, Yunusa A. Fungi associated with decayed sweet oranges (Citrus sinensis) collected from Lapai, Niger State, Nigeria. Indian J Life Sci. 2013;2:123-131.
12. Bali RV, Gopireddy BM, Chenga RV, Gurava RK Chandrasekhar RM. Post harvest fungal spoilage in sweet orange (Citrus sinensis) and acid lime (Citrus aurentifolia swingla) at different stages of marketing. Agric Sci Digest. 2008;28:265-267.
13. Bevilacqua A, Corbo MR, Campaniello D. Shelf life prolongation of fruit juices through essential oils and homogenization: A review. Science against Microbial Pathogens. Commun Curr Res Technol Adv. 2011;1156–1166.
14. Anisha SK, Ashwini S, Girish K. Isolation and screening of Aspergillus spp. For pectinolytic activity. Elect J Biotech. 2013;9(2):37-41.
15. Famotemi AC, Lawal AK, Dike EN, Olatope SOA, Shittu KA, Itoandon EE, Kehinde MO, Orji FA, Elemo GN. Production of pectinase from strains of Aspergillus niger using corn pomace by solid state fermentation (SSF). Inter J Adv Res Biol Sci. 2015;2(5):93–99.
16. Morais AMMB, Kirby R, Brochado, CM, Rocha AMCN. Shelf life of chilled cut orange determined by sensory quality. Food Control. 1995;6:317-322.
17. Pao S, Petracek PD. Shelf life extension of peeled oranges by citric acid treatment. Food Microbiol. 1997;14:485- 491.
18. Balali GR, Naete SM, Scott ES, Whisson DL, Wicks TJ. Anastomosis group and pathogenicity of isolates of Rhizoctonia solani from potato crops in South Australia. Plant Pathol. 1995;44:1050-1057.
19. Aruwa CE, Olatope SOA. Characteristization of Bacillus species from convenience foods with conventional and API Kit Method: A Comparative Analysis. J Appl Life Sci Inter. 2015;3:42- 48.
20. Chessbrough M. District laboratory practice in tropical countries (part 2). Cambridge University Press Briton. 2006;180-185.
21. Olutiola PO, Famurewa O, Sonntag HG. Biochemical reaction of microorganisms. In: An introduction to general microbiology: A practical approach. Bolabay Publications. 2001;157-177.
22. Yogesh K, Vamsi KK, Amol B, Nikhil G, Soham T, Prasad P, Girish G, Mayank G, Amol J, Adarsh M, Joshi B, Mishra D. Study of pectinase production in submerged fermentation using different strains of Aspergillus niger. Inter J Microbiol Res. 2009;1(2):13-17.
23. Venkata Naga raju E, Divakar G. Production of pectinase by using Bacillus circulans isolated from dump yards of vegetable wastes. Inter J Pharm Sci Res. 2013;4(7):2615-2622.
24. Akinola SO, Ayanleye TA. The use of fungal glucoamylase enzyme for the production of glucose syrup from cassava starch. Acta Satech: J Life Phy Sci. 2004;1(2):138-141.
25. Pao S, Petracek PD, Brown GE. Effect of infusion method on peel removal and storage quality of citrus fruit. Hort Technol. 1996;6: 409-413.
26. Lafuente MT, Zacarias JM, Sala, MT, Sachez-ballesta MT, Gosalbes JF, Marcos L, Candelas G (2005). Understanding the basis of chilling injury in citrus fruit. Acta Hortic 682: 831-842.
27. Hobbs G. Ecology of food microorganism. Microbiol Ecol. 1986;12:15-30.
28. Morais AMMB, Kirby R, Brochado, CM, Rocha AMCN. Shelf life of chilled cut orange determined by sensory quality. Food Control. 1995;6:317-322.
29. Mbogo GP, Mubofu EB, Othman CC. Post-harvest changes in physicochemical properties and levels of some inorganic elements in off vine ripened orange (Citrus sinensis) fruits (Navel and Valencia) of Tanzania. Afr J Biotechnol. 2010;9:1809-1815.
30. Kibrom K, Lijalem T. Effect of ripening on the overall quality of orange juice. J Nat Sci Res. 2015;5:31-33.
31. Schmid H, Weber D, Rossmann A, Werner R. The potential of intermolecular and intramolecular isotopic correlations for authenticity control. In Flavor Chemistry: 30 Years of Progress; Teranishi, R.; Wick, E.; Hornstein, I. Kluwer Academic/Plenum: New York. 1999;55-57.
32. Penniston KL, Nakada SY, Holmes RP, Assimos DG. Quantitative assessment of citric acid in lemon juice, lime juice and commercially-available fruit juice products. J Endourol. 2008;22:567-570.
33. Wills RBW, McGlasson WB, Graham D, Lee T, Halle G. Postharvest: An introduction to the physiology and handling of fruit and vegetables. Van Nostrands Renhold, New York. 1989;17-52.
34. Hussain I, Asif M, Ahmed M, Khan M, Shahur I. Effect of uni-packaging on the post-harvest behavior of citrus fruits in Khyber pakhtinkjwa. Pakistan J Nutr. 2004;3:336-339.
35. Perviamen MT, Nyysonen K. Ascorbic acid. In: APD Leenler, NE LAmbart, H Nelis (Eds.) Modern chromatographic analysis of vitamins. New York: Marcel Dekker Inc; 1992.
36. Lee SK, Kader AA. Preharvest and postharvest factors influencing vitamin C content of horticultural crops. Postharvest Biol Technol. 2000;20:207-220.
37. Davey MW, Van Montagu M, Inze D, Sanmartin M, Kanellis A, Smirnoff N. Plant L-ascorbic acid: Chemistry, function, metabolism, bioavailability and effects of processing. J Sci Food Agric. 2000;80:825- 860.
38. Sanusi RA, Ogunro Y, Nwozoh S. Effect of storage time on ascorbic acid content of some selected “made in Nigeria” fruit Preserves. Pakistan J Nutr. 2008;7:730-732.
39. Ihekoronge AI, Ngodoly PO. Integrated Food Science and Technilogy for the Tropics Macmillian publishing company limited London. 1985;165–301.
40. Micambi SR, Rajagopal MU. Vitamin C content of some fruits grown in Eastern Nigeria. J Food Technol. 1997;12:189-199.
41. Fischer P, Bender A. Value of food. Second Ed Oxford University Press. 1975;37-50.
42. Padayatty SJ, Katz A, Wang Y, Eck P, Kwon O, et al. Vitamin C as an antioxidant: Evaluation of its role in disease prevention. J Am Coll Nutr. 2003;22:18 -35.
43. Benwart GJ. Basic Food Microbiology, 2nd Edition. New York. Van Nostrand Reinhold. 1989;603-604.
44. Beuchat LR, Golden DA. Antimicrobials occurring naturally in foods. Food Technol. 1989;43:134-142.
45. Korf HJG, Schutte GC, Kotxe JM. The effect of packhouse procedures on the viability of Phyllosticta citricarpa, anamorph of the citrus black spot pathogen. Afr Plant Prot. 2001;7: 103-109.
46. Plotto A, Narciso JA, Baldwin EA. Flavor and other quality factors of enzyme-peeled oranges treated with citric acid. HortScience. 2007;42: 1644-1650.
47. Abbey SD, Heaton E.K, Golden DA, Beuchat L. Microbiological and sensory quality changes in unwrapped and wrapped sliced watermelon. J Food Prot. 1988;51:531-533.
48. Brackett RE. Microbiological spoilage and pathogens in minimally processed refrigerated fruits and vegetables, (ed. RC Wiley). New York. Chapman and Hall. 1994;269-312.
49. ICMSF. Soft drinks, fruit juices, concentrates and food preserves,” in Microorganisms in Foods 6: Microbial Ecology of Food Commodity, Kluwer Academic; 2005.
50. Hitha PK, Girija D. Isolation and screening of native microbial isolates for pectinase activity. Inter J Sci Res. 2012;3:632-634.
51. Akintobi AO, Okonko IO, Agunbiade SO, Akano OR, Onianwa O. Isolation and identification of fungi associated with the spoilage of some selected fruits in Ibadan, South Western, Nigeria. Academia Arena. 2011;3:1-10.
52. Tafinta IY, Shehu K, Abdulgannijyu H, Rabe AM, Usman A. Isolation and identification of fungi associated with the spoilage of sweet orange (Citrus sinensis) fruits in Sokoto State, Nigeria. J Basic Appl Sci. 2013;21:193-196.
53. Jay JM. Microbial Spoilage of Food. Modern Food Microbiology (4th ed.). Chapman and Hall Incorporated, New York. 2003;187-195.
54. Silva EG, Borges MF, Medina C, Piccoli RH, Schwan RF. Pectinolytic enzymes secreted by yeast from tropical fruits. Fed Eur Microbiol Soc Yeast Res. 2005;5:859–865.
55. Priya V, Sashi V. Pectinase Enzyme Producing Microorganisms. Inter J Sci Res Pub. 2014;4 (3):1-4.
56. Blanco P, Sieiro C, Villa TG. Villa production of pectin enzymes in yeasts. FEMS Lett. 1999;175:1-9.
57. Roussos S, de los Angeles Aquiahuati M, del Refugio Trejo-Hernandez M, Gaime Perraud I, Favela E, Ramakrishna M, Raimbault M, Viniegra-Gonzalez G. Biotechnological management of coffee pulp – isolation, screening, characterization, selection of caffeine-degrading fungi and natural microflora present in coffee pulp and husk. Appl Microbiol Biotechnol . 1995;42:756-762.
58. Rolz C, De Leon R, De Arricola MC. Biotechnology in washed coffee processing. Process Biochem. 2011;16:8-11.
59. Geetha M, Saranraj P, Mahalakshimi S, Reetha D. Screening of pectinase producing bacteria and fungi for its pectinolytic activity using fruit wastes. Inter J Biochem Biotechnol Sci. 2012;1:30-42.
60. Mrudula S, Anitharaj R. Pectinase production in solid state fermentation by Aspergillus niger Using orange peel as substrate. Global J Biotechnol Biochem. 2011;6(2):64-71.
61. Ramesh MV, Lonsane BK. Solid waste fermentation for production of alpha amylase by Bacillus magaterum 16M. Biotechnol Lett. 1987;9:323-328.
62. Freicetes PM, Martin N, Silva D, Silva R, Gomes E. Production and partial characterization of polygalcturonase production by thermophilic Monaseus sp N8 and by thermotolerant Aspergillus sp N12 on solid state fermentation. Braz J Microbiol. 2006;37:302-306.
63. Chellegatti MASC, Fonseca MJV, Said S. Purification and parfial characterization of exopolygalacturonase from Penicillum frequentans. Microbiol Res. 2002;157:19- 24.
64. Esquivel JCC, Voget CE. Purification and partial characterization of an acid polygalacturonase from Aspergillus kawachii. J Biotechnol. 2004;110:21-28
65. Saad N, Briand M, Gardarin C, Briand Y, Michaud PH. Production, purification and characterization of an endopolygalacturonase from Mucor rouxii NRRL 1894. Enzym Microbiol Technol. 2007;41:800-805.
66. Khalil TA. Effect of fungal pectinases and gelatin on apple juice clarification. Mesopotamia J Agric. 2013;4:313–317.
67. Diaz JV, Anthon GE, Barrett DM. Nonenzymatic degradation of citrus pectin and pectate during prolonged heating: Effects of pH, temperature and degree of methyl esterification. J Agric Food Chem. 2007;55: 5131- 5136.
68. Stresh PV, Chandrasekaran M. Impact of process Parameters on chitinase production by an alkalophilic marine Beativeira bassiana in solid state fermentation. Process Biochem. 1999;34:257-267.
69. Torres EF, Sepulveda TV, Gonzalez GV. Production of hydrolytic depolymerising pectinases. Food Technol Biotechnol. 2006;44: 221-227.
70. Ramanujam PK, Saritha N, Subramanian P. Production of pectinase by solid-state fermentation of sugarcane bagasse using Aspergillus niger. Adv Biotechnol. 2008;30-33.
71. Zhang CH, Li ZM, Peng XW, Jia Y, Zhang HX, Bai ZH. Separation, purification and characterization of three endo-polygaladuronase, from a newly isolated Penicillium oxalicum. China J Process Eng. 2009;9:242-249.
72. Silva D, Martins ES, Silva R, Gomes E. Pectinase Production from Pencillium viridicatum RFC3 by solid-state fermentation using agriculture residues and agro-industrial by products. Braz J Microbiol. 2002;33:318-324.
73. Carmona EC, Pedrolli DB, Monterio AC, Gomes E. Pectin and pectinases: Production, chracterization and industrial application of microbial pectinolytic enzymes. The Open Biotechnol J. 2009;3:9-18.
74. Kashyap DR, Chandra S, Kaul A, Tewari R. Production, purification and characterization of pectinase from Bacillus spp. DT7. World J Microbiol Biotechnol. 2000;16:277–282.
75. Kapoor M, Begbhushan QKB, Smgh K, Dadhich KS, Hoondal GS. Application of an alkaline and thermostable polygalacturonase from Bacillus sp. MG-cp-2 in degumming of ramie (Boehmeria nirea) and sunn hemp (Crotalana juncea) bast fibers. Process Biochem. 2001;36:803- 807.
76. Hoondal GS, Tiwari RP, Tewari R, Dahiya N, Beg QK. Microbial alkaline pectinases and their industrial application: A review. Appl Microbiol Biotechnol. 2002;59:409–418.