• AKUBOR PI Department of Food Science and Technology, Federal University Wukari, Taraba State, Nigeria.
  • THOMAS SL Department of Food Science and Technology, Federal University Wukari, Taraba State, Nigeria.




Microwave drying, Biscuit, Orange peel, phytochemical composition, Sensory quality


Objective: The broad objective of the study was to determine the effects of microwave and sun drying on the chemical composition, functional, and biscuit making properties of sweet orange peel flour.

Methods: Peels were prepared from sweet orange fruits and cut into thin pieces. The peel pieces were dried in a domestic microwave oven at power outputs of 200, 400, 600, and 800 W. Flour samples were prepared from the dried peel pieces, evaluated for chemical composition and functional properties, and compared with of the sun dried sweet orange peel flour. Each of the flours was used to substitute 10% wheat flour in biscuits, which were assessed for the chemical composition, physical, and sensory properties.

Results: The microwave oven dried sweet orange peel flour contained higher amounts of ash, fat, fiber, and carbohydrate than the sun dried peel flour. The microwave drying decreased the total phenol content of the flour from 2.04 to 0.78 mg/g and the flavonoids content from 1.17 to 0.71 mg/g. The water absorption capacity, oil absorption capacity, and swelling capacity increased with the intensity of the microwave drying. The ash, crude fat, carbohydrate, fiber, and total phenol and flavonoids contents of the biscuits containing microwave dried peel flour were slightly (p>0.0.5) higher than those of the biscuits containing sundried peel flour. The diameter and height of the biscuits were not significantly (p>0.05) affected by the microwave oven drying. The spread ratio of the biscuit containing sun dried peel flour was 9.15 and decreased to a range of 7.530–5.595 for the biscuits containing microwave oven dried flour. The break strength and the weight of the biscuits increased with the power output of the microwave oven. The scores for flavor, texture, and overall acceptability of the biscuits containing sweet orange peel flour dried at 200 and 800 W were not significantly different (p>0.05). However, the scores for color and taste were higher for the biscuit containing the peel dried at higher power out puts (600 and 800 W) than the biscuits containing the peels dried at low power outputs (200 and 400 W).

Conclusion: It is concluded that microwave oven drying at 200 W improved the proximate composition and phytochemical contents but decreased the functional properties of the sweet orange flour. The biscuit containing sweet orange peel flour dried at 200 W was preferred to the others for the chemical composition, physical, and sensory properties.

Author Biography

AKUBOR PI, Department of Food Science and Technology, Federal University Wukari, Taraba State, Nigeria.

Department of Food Scinece and Technology. Associate Professor.


Padharipande S, Makode H. Separation of oil and pectin from orange peel and study on effect of pH of extracting medium on the yield of pectin. J Eng Res Stud 2012;3:1-4.

Food and Agriculture Organization. Citrus Fruit Statistics. Rome, Italy: Food and Agriculture Organization of United Nation; 2016.

Ali AH, Hassan A. Study on some macronutrient composition in peels of different citrus fruits grown in Pakistan. J Chem 2010;32:83-6.

Akubor PI. Functional properties of sweet orange peel and pulp flours, wheat flour and their blends. FUW J Agric Life Sci 2019;3:213-30.

Goulas V, Manganaris GA. Exploring the phytochemical content and the antioxidant potential of Citrus fruits grown in Cyprus. Food Chem 2012;131:39-47.

Barros H, Ferreira RD, Genovese MI. Antioxidant capacity and mineral content of pulp and peel from commercial cultivars of Citrus from Brazil. Food Chem 2012;134:1892-8.

Hasler CM. Regulation of Functional Foods and Nutraceuticals. A Global Perspective. Iowa, USA: IFT Press and Blackwell Publisher; 2003. p. 24-34.

Ramful D, Bahorunb T, Bourdonc E, Tarnusc E, Aruoma OI. Bioactive phenolics and antioxidant propensity of flavedo extracts of Mauritian Citrus fruits: Potential prophylactic ingredients for functional foods application. Toxicology 2011;278:75-87.

Youssel KM, Mokhtar SM. Effect of drying methods on the antioxidant capacity, color and phytochemicals of Potulaca oleracea L leaves J Nutr Food Sci 2014;4:2-6.

Yi T, Fang Y, Wang K, Huang X. Influence of drying methods on the functional properties of dietary fiber. J Chem Pharm Res 2014;6:2887-94.

Arslan D, Ozcan MM. Study the effect of sun, oven and microwave drying on quality of onion slices. LWT Food Sci Technol 2010;43:1121-227.

Krokida MK, Maroulis ZB. Effect of microwave drying on some quality properties of dehydrated products. Drying Technol 1999;17:449-66.

Maskan M. Microwave/air and microwave finish drying of banana. J Food Eng 2000;44:1-10.

Agu HO, Ezeh GC, Jideani AI. Quality assessment of acha-based biscuit improved with Bambara nut and unripe plantain. Afr J Food Sci 2014;8:278-9.

Akubor PI. Chemical composition, physical and sensory properties of biscuits supplemented with cashew pomace flour. NSUK J Sci Technol 2016;6:138-41.

Nwosu AN, Akubor PI. Health promoting potentials of biscuits produced with orange peel and pulp flours. J Nutr Ecol Food Res 2016;3:43-8.

Adedeji OE, Ezekiel OO, Akubor PI. Effect of alkali and microwave pretreatments on the functional properties of orange and plantain peel flours. FUW J Agric Life Sci 2017;1:1-12.

Onimawo IA, Akubor PI. Food Chemistry (Integrated Approach with Biochemical Background). 2nd ed. Agbowo, Ibadan, Nigeria: Joytal Printing Press; 2012.

Adebowale YA, Adeyemi IA, Oshodi AA. Functional and physicochemical properties of flours of six Mucunu species. Afr J Botechnol 2005;4:1461-8.

Association of Official of Official Analytical Chemists. Official Methods of Analysis. United States: Association of Official of Official Analytical Chemists; 2010.

Okwu DE. Phytochemical and vitamin contents of indigenous spices of Southeast Nigerian. J Sustain Agric Environ 2004;6:30-7.

Akubor PI, Ukwuru MU. Functional properties and biscuit making potential of soybean and cassava flour blends. Plant Foods Hum Nutr 2003;58:1-12.

Ihekoronye AI, Ngoddy PO. Integrated Food Science and Technology for the Tropics. London: Macmillan Press Publisher; 1985. p. 193-234.

SPSS. Statistical Package for Social Sciences (SPSS) Version 17. Chicago, IL, USA: SPSS Inc.; 2007.

Anderson JW, Baird P, Davis RH. Health benefits of dietary fiber. Nutr Rev 2009;67:188-205.

Weicker MO, Pfeiffer AI. Metabolic effects of dietary fiber consumption and prevention of diabetes. J Nutr 2008;138:439-42.

Adeyemi SB, Ogundele KO, Animasaun MA. Influence of drying methods on the proximate and phytochemical composition of Moringa oelifera Lam. Glob J Med Plant Res 2014;2:15.

Hayat K, Zhang X, Farooq U, Abbas S, Xia S. Effect of microwave treatment on phenolic content and antioxidant activity of citrus mandarin pomace. Food Chem 2010;123:423-9.

Mediani A, Abas F, Tan CP, Khatib A. Effects of drying methods and storage time on free radical scavenging activity and total phenoloic content of Cosmos caudatus. Antioxidants 2014;3:358-70.

Amarowicz R, Carle R, Dongwoski G, Durrazk A, Galensa R, Kammera D, et al. Influence of post harvest processing and storage on the content of phenolic acids and flavonoids in foods. Mol Nutr Food Res 2009;53:151-83.

Sawalha SM, Arráez-Román D, Segura-Carretero A, Fernández- Gutiérrez A. Quantification of main phenolic compounds in sweet and bitter orange peel. Food Chem 2009;116:567-74.

Jiang P, Burcynski F, Ctria JA, Campbell C, Pierce G, Austria JA, et al. Rutin and flavonoids contents in the three buckwheat species and their protective effects against lipid peroxidation. Food Res Int 2007;40:356-64.

Niba LL, Bakonga MM, Jackson EL, Schlimme DS, Li BW. Physicochemical properties and starch granule characteristics of flour from various Manihot esculenta (cassava) genotypes. J Food Sci 2001;67:1701-5.

Mallek-Ayadi S, Bahloul N, Kechaou N. Characterization, phenolic compounds and functional properties of Cucumismelo L. peels. Food Chem 2017;221:1691-7.

Guillon F, Champ M. Structural and physical properties of dietary fibres, and consequences of processing on human physiology. Food Res Int 2000;33:233-45.

Bogert JL, Briggs GM, Galloway DH. Nutrition and physical fitness. Int J Food Sci Nutr 1994;45:225-30.

Fowomola MA. Some nutrients and antinutrients contents of mango (Mangifera indica) seeds. Afr J Food Sci 2010;4:472-6.

Wong JM, de Souzu RO, Kendall CW, Emman A, Jenkins DJ. Colonic health: Fermentation and short chain fatty acids. J Clin Gastroenterolo 2006;40:235-43.

Magda RA, Awad AM, Selim KA. Evaluation of mandarin and navel orange peels as natural sources of antioxidants in biscuit. J Food Sci Technol 2008;5:75-82.

Khattack M, Muzaffa AK. Ingredients and chemical composition of biscuit available in Peshawar and Murdan divisions. Sarhad J Agric 2003;19:279-83.

Akubor PI, Nwosu AN. Acceptability and storage stability of biscuits produced with orange peel and pulp flours. J Environ Sci Toxicol Food Technol 2018;12:8-15.



How to Cite

PI, A., & SL, T. (2021). EFFECTS OF MICROWAVE AND SUN DRYING ON THE CHEMICAL COMPOSITION, FUNCTIONAL, AND BISCUIT MAKING PROPERTIES OF SWEET ORANGE PEEL FLOUR. Innovare Journal of Food Sciences, 9(2), 1–6. https://doi.org/10.22159/ijfs.2021.v9i2.41351



Original Article(s)