African Journal of
Food Science

  • Abbreviation: Afr. J. Food Sci.
  • Language: English
  • ISSN: 1996-0794
  • DOI: 10.5897/AJFS
  • Start Year: 2007
  • Published Articles: 819

Full Length Research Paper

Effect of coagulants on the physicochemical properties of fresh tofu

Ezeama, C. F.
  • Ezeama, C. F.
  • Department of Food Science and Technology, College of Applied Sciences and Tourism, Micheal Opara University of Agriculture, Umudike, Abia State, Nigeria.
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Dobson, G. N.
  • Dobson, G. N.
  • Department of Food Science and Technology, College of Applied Sciences and Tourism, Micheal Opara University of Agriculture, Umudike, Abia State, Nigeria.
  • Google Scholar


  •  Received: 31 May 2019
  •  Accepted: 16 October 2019
  •  Published: 31 December 2019

Abstract

Soy flour from soybean was processed to produce fresh tofu using three coagulants namely lime, Epson salt and tamarind. The results obtained showed that the pH of the samples were 7.20 for Epson salt, 5.00 for lime and 5.50 for tamarind. There were significant differences (p< 0.05) in the weight increase of all the samples with Epson salt (46.62 kg) as the highest. Epson salt had the least coagulation time of 6 min. The result of the proximate analysis shows that there were significant differences (p< 0.05) in protein, carbohydrate and moisture content in the three samples with the value of protein in Epson salt (12.40) as the highest. Further analysis revealed that there were significant differences (p<0.05) in emulsifying capacity, oil absorption capacity and swelling index in all the samples. The value of the water absorption capacity of Epson salt (4.70 g/ml) was significantly different (p< 0.05) from lime (3.80 g/ml) and tamarind (3.70 g/ml).  In the mineral composition there were significant differences (p< 0.05) in Ca, Mg, K, P, Na and Fe in all the samples though K had the lowest value. There were significant differences (p<0.05) in the total fungal and viable counts. The total fungal count was least in Epson salt (2.00 x 103 CFU/g) while the total viable count was also least in Epson salt (2.6 x 103 CFU/g) after 6 days of ambient storage; however, it was highest in tamarind coagulated tofu. Epson salt coagulated fresh tofu was highly appreciated for ranking highest in protein, Ca, Mg and lowest in total fungal and viable count.

 

Key words: Tofu, coagulants, physical characteristics, functional properties, proximate and mineral composition, microbial.