Effect of Different Processing Conditions on Proximate and Bioactive Contents of Solanum aethiopicum (Shum) Powders, and Acceptability for Cottage Scale Production

Akanyijuka Sam¹, Acham Hedwig^1, , Tumuhimbise Gaston¹, Agnes Namutebi¹, Michael Masanza², John N. Jagwe³, Kasharu Apolo⁴, Kizito B. Elizabeth² and Deborah Rees⁴

¹Department of Food Technology and Nutrition, Makerere University College of Agriculture and Environmental Sciences,P.O.Box 7062, Kampala-Uganda

²Department of Agricultural and Biological Sciences, Uganda Christian University (UCU), P.O.Box 4, Mukono, Uganda

³Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Chatham, Kent ME4 4TB, UK

⁴5Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Chatham, Kent ME4 4TB, UK

Cite this paper:
Akanyijuka Sam, Acham Hedwig, Tumuhimbise Gaston, Agnes Namutebi, Michael Masanza, John N. Jagwe, Kasharu Apolo, Kizito B. Elizabeth and Deborah Rees. Effect of Different Processing Conditions on Proximate and Bioactive Contents of Solanum aethiopicum (Shum) Powders, and Acceptability for Cottage Scale Production. American Journal of Food and Nutrition. 2018; 6(2):46-54. doi: 10.12691/ajfn-6-2-3

Abstract

The purpose of this study was to investigate the effects of different processing conditions for production of dried Solanum aethiopicum (S.) leaf powder by comparing solar drying and cabinet drying processing techniques. Four (4) pre-treatments were done on S. aethiopicum leaves to inhibit enzyme action and prolong storage life. Treatments included dipping in; 10% saline solution, 10% vinegar solution, water (as the control), and steam blanching; done for both whole and sliced S. aethiopicum leaves. Each of the resultant samples were dried in both solar and cabinet dryers for a period of 24 hours. The dried leaf samples were grounded into powder using a coffee grinder and subjected to different laboratory analyses including; catalase activity, moisture content, vitamin C retention capacity and phytate content analyses. The results obtained were analysed using MINITAB version 16.0 at 5% significance level. The results showed that there was a reduction in catalase activity after pre-treatment and drying from 5.0±0.0 cm³ for the fresh un-treated leaves to a range of 4.5±0.7 – 3.0±0.0 cm³ for whole solar dried; 4.5±0.7-4.0±0.0 cm³ for sliced solar dried; 4.0±0.0 - 3.0±0.0 cm³ for whole cabinet dried and 3.5±0.7-2.3±0.7 cm³ for sliced cabinet dried leaf powder. Solar dried S. aethiopicum leaf powder contained significantly high moisture content than hot air cabinet dried one (24.9±0.5 % for saline treated sliced leaves to 8.9±0.8 % for blanched sliced leaves, than hot air cabinet dried one with 9.3±0.0 % for sliced plain water treated leaves to 7.0±0.2 % for sliced vinegar treated leaves; respectively). Cabinet dried S. aethiopicum contained significantly more vitamin C content (1.1±0.2 mg for whole blanched leaves compared to 0.6±0.1 mg for sliced vinegar treated leaves) than the solar dried one (1.0±0.2 mg for sliced plain water treated leaves to 0.6±0.1 mg for sliced vinegar treated leaves). There was no significant difference in phytate content between the hot air cabinet dried and solar dried i.e. 0.7±0.1 - 0.2±0.1 mg for solar and 0.7±0.1 - 0.3±0.3 mg for cabinet dried. Solar dried S. aethiopicum powder contained significantly higher catalase than the hot air cabinet dried one (4.5±0.7 - 3.0±0.0 and 4.0±0.0 - 2.5±0.7 cm³; respectively). However, in terms of acceptability, there was high preference for saline treated leaf powder soups compared to other soups. It can be concluded that High activity of catalase, moisture retention and high loss of Vit.C occurs in the solar drier than in cabinet drier. Whole leaf saline pretreated leaf powder soup is rated high compared to other dried soups. Therefore, the best method for production of dried S. aethiopicum powder is by slicing, dipping it in plain water and drying using a cabinet dryer. Under circumstances where cabinet drying is not achievable, solar drying is recommended using whole leaf, pretreated with saline water to promote preservation and consumption of the vegetable.

Keywords:
Solanum aethiopicum powder pre-treatments solar cabinet drying

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References:

[1]	Dai, Q., Borenstein, A.R., Wu, Y., Jackson, J.C., & Larson, E.B., 2006. Fruit and vegetable juices and Alzheimer’s disease: the Kame project. Am. J. Med. 119 (9), 751e759
[2]	Schippers, R.R. 2000. African Indigenous Vegetables: An overview of the cultivated species. University of Greenwich, Natural Resources Institute: London, UK, 2000.
[3]	Santos, P.H.S., & Silva, M.A. (2008). Retention of vitamin C in drying processes of fruits and vegetables-A review. Drying Technology, 26, 1421-1437.
[4]	Naggayi, G. 2016. Vegetable Consumption and selected Micronutrient retention of Prepared and Cooked Solanum aethiopicum (L.). A case for Rubaga Division, Kampala. A dissertation submitted to the College of Agricultural and Environmental Sciences, Makerere University.
[5]	Uusiku, N.P., Oelofse, A., Duodu, K.G., Bester, M.J., & Faber, M. 2010. Nutritional value of leafy vegetables of sub-Saharan Africa and their potential contribution to human health Review. Journal of Food Composition and Analysis, 23(6), 499-509.
[6]	Food and Agriculture Organisation & International Life Sciences Institute. Preventing Micronutrient malnutrition: A guide to Food-based Approaches, A manual for policy makers and programme planners. International Life Sciences Institute, Washington, USA.1997.
[7]	Nwatarali, P.O., Acham, H., & Nakimbugwe, D. 2017. Acceptability, Nutritional Quality and Contribution of Vegetable-Enriched Products to Nutrient and Energy Requirements of School Children Aged 5 to 13 Years. Food and Nutrition Sciences, 2017, 8, 242-266.
[8]	Argyropoulos, D., Heindl, A., & Muller, J., 2011. Assessment of convection, hot-air combined with microwave-vacuum and freeze-drying methods for mushrooms with regard to product quality. Int. J. Food Sci. Technol. 46 (2), 333e342.
[9]	Karam, M.C., Petit J., Zimmer, D., Djantou, E.B., & Scher, J. (2016). Effects of drying and grinding in production of fruit and vegetable powders. Journal of Food Engineering 188 (2016) 32-49.
[10]	Rubaihayo, E.B., 1996. The diversity and potential use of local vegetables in Uganda [1996] (Kawanda Agricultural Research Institute, Kampala (Uganda).
[11]	Kiremire, B.T., 2010. Effects of vegetable drying techniques on nutrient content: a case study of south-western Uganda. African Journal of Food, Agriculture, Nutrition and Development AJFAND, Vol. 10: 5, 2010.
[12]	Camire, M.E., Dougherty, M.P., & Briggs, J.L., 2007. Functionality of fruit powders in extruded corn breakfast cereals. Food Chem. 101 (2), 765e770.
[13]	Wang, C.L., Chen, Z.X., Chan, A.K.K. & Zheng, Z.C. 2000. The influence of hedonic values on Consumer behaviours. Journal of Global Marketing 14 (1): 169-186.
[14]	Agona, J. A., Nabawanuka, J. & Kalunda, P.A. 2002. Market overview of the dried fruit sector in Uganda. National Post Harvest Programme/KARI. 1-5, 8-9
[15]	Che Man, Y.B. & Sin, K.k., 1997. Processing and consumer acceptance of fruit leather from unfertilised floral parts of jackfruit. Journal of Food Science and Agriculture 75, 102-108.
[16]	Dat, J.F., Pellinen R, Beeckman T, Van De Cotte B, Langebartels C, Kangasjarvi, Inze D, & Van Breusegem F. 2003. Changes in hydrogen peroxide homeostasis trigger an active cell death process in tobacco. Plant J. 2003 Feb; 33 (4): 621-32.
[17]	AOAC, 1999. Official Methods of Analysis. 16th edn. Association of Official Analytical Chemists Washington USA.
[18]	Rahman, M.M., Mohammad, M.R.K., & Mohammad, M.H. 2007. Analysis of Vitamin C (ascorbic acid) contents in Various Fruits and Vegetables by UV-spectrophotometry. Bandladesh Journal of Scientific and Industrial Research, 42 (4) (2007), pp. 417-424.
[19]	Harland, B.F. D., & Oberleas, D. 1986. Anion-exchange method for determination of phytate in foods: collaborative study. J Association of Official Analytical Chemists 1986; 69: 667-70.
[20]	Bisamaza, M., & Banadda, N., 2017. Solar drying and sun drying as processing techniques to enhance the availability of selected African indigenous vegetables, Solanum aethiopicum and Amaranthus lividus for nutrition and food security in Uganda. Food Technology and Nutrition Department, Agricultural and Biosystems Engineering Department Makerere University.
[21]	Bruhn, C., M., & Uestice, R.F., 2006. Consumer acceptance and marketing of irradiated foods. In: SommersCH, FanX, editors. Food irradiation research and technology. Ames, Iowa: Blackwell. P. 63-83.
[22]	UBOS 2011. Uganda Demographic and Health Survey 2011. Measure DHS, ICF International, Calverton, Maryland USA.
[23]	Apolot, M.G. 2018. Profile and estimates of postharvest losses that occur along value chains of Solanum aethiopicum shum (nakati) and Amaranthus lividus (bugga) leafy vegetables. MSc. Thesis. Makerere University 2018 (unpublished).
[24]	Byaruhanga,Y.B., Kaaya, A.N., Bambona, A. & Mutyaba, C. (2001). Processing and Preservation of Fruits and Vegetables using Solar Drying Technology. Training Manual Development Net for Staff of the East African Energy Technology Network (EAETDN) p. 2-20.
[25]	Ossamulu, I.F., Akanya, H.O., Jigam, A.A. & Egwim, E.C. 2014. Nutrient and phytochemical constituents of four eggplant varieties. Elixir Food Science, 73 (2014), 26424-26428.
[26]	Grubben, G.J.H. & Denton O.A. (2004) Eds. Plant Resources of Tropical Africa 2: Vegetables. Prota Foundation, Wageningen, Netherlands/Backluys Publishers, Leidin, Netherlands/CTA Wageningen
[27]	Osborne, D.R., & Voogt, P. 1978. The analysis of nutrients in foods. Academic Press Inc. (London) Ltd., 24/28 Oval Road, London NW1 7DX.
[28]	Abdel-Haleem A.M.H., & Omran, A.A. 2014. Preparation of dried vegetarian soup supplemented with some legumes. Food and Nutrition science, 2014; 5, 2274-2285.
[29]	Barrett, D.M., Beaulieu, J.C., & Shewfel, T.R. 2010. Color, Flavor, Texture, and Nutritional Quality of Fresh-Cut Fruits and Vegetables: Desirable Levels, Instrumental and Sensory Measurement, and the Effects of Processing. Critical Reviews in Food Science and Nutrition, 50: 369-389.