African Journal of
Food Science

  • Abbreviation: Afr. J. Food Sci.
  • Language: English
  • ISSN: 1996-0794
  • DOI: 10.5897/AJFS
  • Start Year: 2007
  • Published Articles: 899

Full Length Research Paper

Application of wedge fracture test for texture analysis in boiled sweetpotato (Ipomoea batatas)

Linly Banda
  • Linly Banda
  • Department of Molecular Biology and Biotechnology, Pan African University Institute of Basic Science, Technology and Innovation, P. O. Box 62000 00200 Nairobi, Kenya.
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Mukani Moyo
  • Mukani Moyo
  • Food and Nutritional Evaluation Laboratory, International Potato Center, sub-Saharan Regional Office, P. O. Box 25171 00603 Nairobi, Kenya.
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Mariam Nakitto
  • Mariam Nakitto
  • International Potato Center, Ntinda II Road, Plot 47, P. O. Box 22274 Kampala, Uganda.
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Jolien Swanckaert
  • Jolien Swanckaert
  • International Potato Center, Ntinda II Road, Plot 47, P. O. Box 22274 Kampala, Uganda.
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Arnold Onyango
  • Arnold Onyango
  • Department of Food Science, Jomo Kenyatta University of Agriculture and Technology, P. O. Box 62000 00200 Nairobi, Kenya.
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Esther Magiri
  • Esther Magiri
  • Dedan Kimathi University of Technology, Private Bag 10143 Dedan Kimathi, Nyeri, Kenya.
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Gordon McDougall
  • Gordon McDougall
  • Environmental and Biochemical Sciences, James Hutton Institute, Dundee DD2 5DA, Scotland.
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Laurence Ducreux
  • Laurence Ducreux
  • Cell and Molecular Sciences, James Hutton Institute, Dundee DD2 5DA, Scotland.
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Mark Taylor
  • Mark Taylor
  • Cell and Molecular Sciences, James Hutton Institute, Dundee DD2 5DA, Scotland.
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Tawanda Muzhingi
  • Tawanda Muzhingi
  • Food and Nutritional Evaluation Laboratory, International Potato Center, sub-Saharan Regional Office, P. O. Box 25171 00603 Nairobi, Kenya.
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  •  Received: 06 November 2020
  •  Accepted: 22 February 2021
  •  Published: 30 April 2021

Abstract

Several instrumental texture analysis methods have been developed for use in sweetpotato. However, there are very few reports on the use of the wedge fracture test. The purpose of the study was to develop a texture analysis method using a wedge fracture and evaluate its performance against compression test in assessing sweetpotato varieties with different cooking times. The optimal cooking time (OCT) of five sweetpotato varieties was determined by boiling 2.5 cm3 cubes until soft. Samples for texture analysis were prepared under four conditions: 85°C for 10 and 15 min; and 95°C for 5 and 10 min. Peak positive force (firmness) and total work done (toughness) were determined using the wedge fracture texture analysis. The correlation between the OCT and texture measurements was evaluated, and samples incubated at 85°C for 15 min had the highest correlation with OCT (R2 = 0.725). Using this heat treatment, texture measurements from the wedge fracture were compared to those obtained from a compression test. The wedge fracture test gave significant discrimination of sweetpotato varieties (p ≤ 0.05) while the compression test did not. The wedge fracture test is thus recommended for determining the instrumental firmness of boiled sweetpotato varieties with different cooking times.

 

Key words: Texture, wedge fracture test, orange-fleshed sweetpotato, optimal cooking time.