Drying is a technique that involves removal of
moisture using heat energy. This heat affects the protein components in foods
especially the thiosulphide groups, which causes hydrophobic bond break that
has been attributed greatly to denaturation during drying. Safe moisture
content (SMC) is the extent to which moisture can be withdrawn from food crops
during drying that such crops can be considered safe for storage with minimal
loss of nutritional qualities. Several reported minimum moisture contents, and
bulk nutrients’ levels of crops were
collected for the purpose of this review, and scattered plot graph was employed
to determine the levels of bond interaction between moisture content and each
bulk nutrients in the various dried food categories. The moisture contents in
grains, root and tuber crops, fruits and vegetables, and cash crops formed a SMC threshold boundary within the 6% - 14%; 0% - 10%; 0% - 22%; and 0% - 30% respectively.
Crude fibre and most especially the ash content played the most crucial role by
providing the strongest bond interaction with migrating moisture during drying
of all the food crops’ categories, and are of
utmost important in the determination of SMC.
IITA (2007) Southern Sudan, Equatoria Region, Cassava Baseline Survey Technical Report. 1st Edition,Ibadan (Nigeria): Eastern Africa Root Crops Research Network (EARRNET), International Institute of Tropical Agriculture (IITA), Kampala (Uganda); International Institute of Tropical Agriculture (II TA)/Natural Resource Institute (NRI), Dar-es-Salaam (Tanzania); Agricultural Research Corporation (ARC)/Ministry of Agriculture and Forestry (MAF)-Southern Sudan; Catholic Relief Services (CRS), East Africa Regional Office, Nairobi.
Reeb, J. and Milota, M. (1999) Moisture Content by the Oven-Dry Method for Industrial Testing. Western Dry Kiln Association. http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/5190/Moisture_Content_ocr.pdf; jsessionid=94D8904F4F4A6429E1547C222FF28DDA?sequence=1
Troftgruben, J. and Keith, M. (1984) Food Dryer. University of Illinois at Urbana-Champaign, College of Agriculture, Cooperative Extension Service. http://www.aces.uiuc.edu/vista/html_pubs/DRYING/dryfood.html.
Gatea, A.A. (2011) Design and Construction of a Solar Drying System, a Cylindrical Section and Analysis of the Performance of the Thermal Drying System. African Journal of Agricultural Research, 6, 343-351.
Mnkeni, A.P., Soundy, P. and Brutsch, M.O. (2013) Solar Drying of Fruit and Vegetables. Department of Agriculture and the Directorate Communication, University of Fort Hare, South Africa. http://www.nda.agric.za/docs/solar/solardrying.htm
Weiss, W. and Buchinger, J. (2003) Solar Drying: Establishment of a Production, Sales and Consulting Infrastructure for Solar Thermal Plants in Zimbabwe. Arbeitsgemeinschaft Erneuerbare Energie (AEE) of the Institute for Sustainable Technologies, Austria.
Prasad, K.N., Azlan, A. and Yusof, B.N.M. (2013) Nutraceutical Properties of Dried Tropical Fruits: Guava and Papayas. In: Alasalvar, C. and Shahidi, F., Eds., Dried Fruits: Phytochemicals and Health Effects, 1st Edition, WileyBlackwell, John Wiley & Sons Inc., Oxford, 444-456. http://dx.doi.org/10.1002/9781118464663.ch24
Lavoie, V. (2006) Drying under Vacuum. Technology Profile: Value to Wood Research Program. Forintek Canada Corp., Natural Resources Canada, Ressources Naturelles. http://www.valuetowood.ca/imports/pdf/en/tech_profiles/TP-06-01E_VLavoie_Drying_English.pdf
Sattho, T. and Yamsaengsung, R. (2005) Vacuum Drying of Rubberwood. In PSU-UNS International Conference on Engineering and Environment (ICEE-2005), T11-3.4, 1-5. University of Novi Sad, Faculty of Technical Sciences, Trg D. Obradovica 6, 21000 Novi Sad, University of Novi Sad, 1-5.
Puschner, H.A. (2013) Microwave Vacuum Drying for Advanced Process Technology: Rapid and Gentle Vacuum Drying for Thermo Sensitive Products with Low Thermal Conductivity. Puschner and Mlkrowellen Energietechnik Incorporation, Bremen, 7 p.
Shevtsova, V.I., Gurley, T. and Gorobets, N.Y. (2006) Drying: Microwaves Will Guarantee Macro-Results. International Business Journal of the EuroAsian Chemical Market (Evraziyskiy khimicheskiy rynok) (Revised Edition of Article in Russian). In: Yu, V.A., Lopatina, V.V. and Shishkin, O.V., Eds., Eurasian Chemical Market International Magazine, Simferopol. http://www.chemmarket.info/
Swasdisevi, T., Devahastin, S., Ngamchum, R. and Soponronnarit, S. (2007) Optimization of a Drying Process Using Infrared-Vacuum Drying of Cavendish Banana Slices. Songklanakarin Journal of Science and Technology, 29, 809-816.
Orak, H.H., Aktas, T., Yagar, H., Isbilir, S.S., Ekinci, N. and Sahin, F.H. (2011) Antioxidant Activity, Some Nutritional and Colour Properties of Vacuum Dried Strawberry Tree (Arbutus unedo L.) Fruit. Acta Scientiarum Polonorum, 10, 327-338.
Clary, C.D., Mejia-Meza, E., Wang, S. and Petrucci, V.E. (2007) Improving Grape Quality Using Microwave Vacuum Drying Associated with Temperature Control. Journal of Food Science, 72, E23-E28. http://dx.doi.org/10.1111/j.1750-3841.2006.00234.x
Practical Action. (2012) Drying of Foods. The Schumacher Center for Technology and Development. http://practicalaction.org/practicalanswers/product_info.php?products_id=88 http://www.appropedia.org /Drying_of_foods_(Practical_Action_Brief)
Borques, R., Espinoza, Z. and Ormeno, R. (1994) Effect of Storage Time and Chemical Preservatives on the Total Volatile Basic Nitrogen Content in Chilean Mackerel Prior to Fish Meal Production. Journal of Science of Food and Agriculture, 66, 181-186. http://dx.doi.org/10.1002/jsfa.2740660211
Raghunath, M.R., Sankar, T.V., Ammu, K. and Devadasan, K. (1995) Biochemical and Nutritional Changes in Fish Proteins during Drying. Journal of the Science of Food and Agriculture, 67, 197-204. http://dx.doi.org/10.1002/jsfa.2740670209
Ojo, O.I. and Ojo, J.O. (2009) A Comparative Study of Effects of Storage on Basic Nutritional Composition of Two Major Edible Dioscorea dumentorum Varieties. Global Journal of Pure and Applied Sciences, 15, 353-355.
Chukwu, G.O., Ezenwa, M.I.S., Osunde, A., Asiedu, R. and Ogbogu, N.J. (2007) Qualities of Yam Tubers Grown on Typic Paleudults: Hybrid Yam and Fertilizer Effects. Scientific Research and Essay, 2, 508-511.
Adebowale, A.A. and Sanni, L.O. (2011) Cereals and Tuber Technology Lecture Note of the Department of Food Science and Technology, University of Agriculture, Abeokuta. http://www.unaab.edu.ng/attachments/455_FST%20501%20lecture%20note-DR%20ADEBOWALE.pdf.
Etudaiye, H.A., Nwabueze, T.U. and Sanni, L.O. (2009) Pasting and Functional Properties of Fufu Processed from Cassava Mosaic Disease-Resistant Varieties Cultivated in a High Rainfall Zone. Nigeria Food Journal, 27, 185-193. http://dx.doi.org/10.4314/nifoj.v27i2.47489
Oloyede, O.B. and Afolabi, I.S. (2002) The Preservative Efficacy of Nspri Multipurpose Dryer on Ascorbic Acid and Polyphenol Content of Lycopersicum esculentum (Tomato). Bioscience Research Communication, 14, 8-15.
Appiah, F., Kumah, P. and Idun, I. (2011) Effect of Ripening Stage on Composition, Sensory Qualities and Acceptability of Keitt Mango (Mangifera indica L.) Chips. African Journal of Food and Nutritional Development, 11, 5096-5109.
Afolabi, I.S., Williams, J.O., Babarinsa, F.A. and Otitodun, O.G. (2006) Physicochemical Properties of Mango Cultivars (Mangifera indica L.) Dried with a Hybrid Dryer. Nigerian Drying Symposium, 2, 93-96.
Unuigbe, O.M. and Ozekhome, M.C. (2009) Comparative Quality Assessment of Flour from Sun-Dried and Heated Air-Dried Green Banana (Musa sapientum) and Plantain (Musa paradisiaca). Nigeria Food Journal, 27, 114-118.
Fagbohun, E.D., Abegunde, O.K. and David, O.M. (2010) Nutritional and Mycoflora Changes During Storage of Plantain Chips and the Health Implications. Journal of Agricultural Biotechnology and Sustainable Development, 2, 61-65.
Oladele, A.K., Osundahunsi, O.F. and Adebowale, Y.A. (2009) Effect of Processing Techniques on the Nutrients and Antinutrients Contents of Tigernut (Cyperus esculentus L.). Nigeria Food Journal, 27, 210-218. http://dx.doi.org/10.4314/nifoj.v27i2.47492
Essien, E.B., Amaefule, O.I. and Ihenacho, E. (2009) Proximate Analysis and Physico-Chemical Properties of Water Melon (Citrullis lunatus) Seeds. Nigerian Journal of Biochemistry and Molecular Biology, 24, 6-10.
Bankole, S.A., Osho, A., Joda, A.O. and Enikuomehin, O.A. (2005) Effect of Drying Method on the Quality and Storability of ‘Egusi’ Melon Seeds (Colocynthis citrullus L.). African Journal of Biotechnology, 4, 799-803.
FAO (1995) Sorghum and Millets in Human Nutrition. In: Food and Agricultural Organisation of the United Nations, Ed., Agricultural and Consumer Protection of the Food and Agricultural Organisation, Rome. http://www.fao.org/docrep/T0818E/T0818E00.htm
Grausgruber, H., Scheiblauer, J., Schönlechner, R., Ruckenbauer, P. and Berghofer, E. (2004) Variability in Chemical Composition and Biologically Active Constituents of Cereals. In: Vollmann, J., Grausgruber, H. and Ruckenbauer, P., Eds., Genetic Variation for Plant Breeding Proceedings of the 17th EUCARPIA General Congress, 8-11 September, EUCARPIA, Tulln, 23-26.
Almeida-Dominguez, H.D., Serna-Saldivar, S.O., Gomez, M.H. and Rooney, L.W. (1993) Production and Nutritional Value of Weaning Foods from Mixtures of Pearl Millet and Cowpeas. Cereal Chemistry, 70, 14-18.
Mohammed, N.A., Ahmed, I.A.M. and Babiker, E.E. (2011) Nutritional Evaluation of Sorghum Flour (Sorghum bicolor L. Moench) during Processing of Injera. International Journal of Biological and Life Sciences, 7, 35-39.
Amoo, I.A., Adebayo, O.T. and Oyeleye, A.O. (2006) Chemical Evaluation of Winged Beans (Psophocarpus tetragonolobus), Pitanga Cherries (Eugenia uniflora) and Orchid Fruit (Orchid Fruit Myristica). African Journal of Food Agriculture and Development, 6. http://www.bioline.org.br/request?nd06014.
Arawande, J.O. and Borokini, F.B. (2010) Comparative Study on Chemical Composition and Functional Properties of Three Nigerian Legumes (Jack Beans, Pigeon Pea and Cowpea). Journal of Emerging Trends in Engineering and Applied Sciences, 1, 89-95.
Nweke, F.N. (2010) Rate of Water Absorption and Proximate Analysis of Different Varieties of Maize Cultivated in Ikwo Local Government Area of Ebonyi State, Nigeria. African Journal of Biotechnology, 9, 8913-8917.
Odebunmi, E.O., Oluwaniyi, O.O., Awolola, G.V. and Adediji, O.D. (2009) Proximate and Nutritional Composition of Kola Nut (Cola nitida), Bitter Cola (Garcinia cola) and Alligator Pepper (Afromomum melegueta). African Journal of Biotechnology, 8, 308-310.
Afolabi, I.S., Akpokene, O.N., Fashola, D.V. and Famakin, T.C. (2012) Comparative Evaluation of the Nutritional Benefits of Some Underutilised Plants Leaves. Journal of Natural Product and Plants Resource, 2, 261-266.
FAO (1989) Prevention of Post-Harvest Food Losses Fruits, Vegetables and Root Crops a Training Manual. FAO Corporate Document Repository, Edited by Food and Agricultural Organization of the United Nations. Agricultural and consumer protection unit of the Food and Agricultural Organisation, Rome. http://www.fao.org/docrep/T0073E/T0073E00.htm