International Journal of Agricultural Science Research Vol. 2(5), pp. 124-130, May 2013 ISSN 2327-3321 ©2013 Academe Research Journals

Full Length Research Paper

Effect of preservatives on microbiological qualities of kunu zaki

J. A. Ayo*, V. A. Ayo, B. Yelmi, G. Onuoha and M. O. Ikani

*Department of Food Science and Technology, The Federal University, Wukari. Nigeria

Department of Food Science and Technology, Federal Polytechnic, P.M.B O231, Bauchi, Nigeria.

*Corresponding author. E-mail: jeromeayo@yahoo.com.

Accepted 31 January, 2013

Abstract

“Kunun-zaki” was prepared using millet, with varied levels (0.01-0.05%) of chemical preservatives (sodium benzoate and metabisulphite). The effects of the chemical preservatives on the physico-chemical (total soluble solids, total solids, moisture, ash, and protein), sensory (colour, mouth feel, flavour and general acceptability), and microbial qualities were evaluated. Total soluble solid decreased from 11.0 to 4.2, 11 to 5.3, 11.0 to 10, 11.0 to 9, 11.0 to 9.0, 11.0 to 7.5, 11.0 to 10, and 11.0 to 9.0%; total solids decreased from 21.20 to 20.8, 21.0 to 20.9, 21.2 to 21.0, 21.8 to 21.1, 21.8 to 21.7, 21.0 to 20.9, 21.5 to 20.9, and 21.9 to 21.7 g/100g, while protein increased from 3.27 to 4.31, 3.57 to 3.59, 3.4 to 3.44, 3.48 to 3.49, 3.22 to 3.29, 3.29 to 3.32, 3.19 to 3.23, and 3.22 to 3.29%, total titratable acidity increased from 0.28 to 2.1, 0.12 to 0.91, 0.13 to 0.42, 0.2 to 0.61, 0.18 to 0.83, 0.19 to 0.34, 0.18 to 0.32, and 0.17 to 0.3 g/100ml, total microbial count increased from 1.8 × 10⁴ to TNTC, 4.0 × 10³ to 8.7 × 10⁴, 2.5 × 10³ to 7.4 × 10⁴, 0 to 5.4 × 104, 0 to 3.85 × 10⁴, 2.0 × 10³ to 6.9 × 10⁴, 1.0 × 10³ to 6.45 × 10⁴ and 0 to 4.9 × 10⁴ cfu/ml for UPK, PK, P (0.01) NaBZ, P (0.03) NaBZ, P (0.05) NaBZ, P (0.01) MBS, P (0.03) MBS, and P (0.05) MBS respectively with increase in the storage duration (0-7 days). The samples preserved with metabisulphite had the lowest mean scores for colour. The pasteurized samples chemically preserved with 0.03% sodium benzoate product had the least microbial count, and was most accepted in terms of assessed sensory attributes.

Key words: Effects, chemical preservatives, pasteurization, shelf-life, kunun-zaki.