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Buffering Capacity of Dairy Powders and Their Effect on Yoghurt Quality
Korean J. Food Sci. An. 2018;38:273-281
Published online April 30, 2018
© 2018 Korean Society for Food Science of Animal Resources

Miji Kim1, Sejong Oh2, and Jee-Young Imm1,*

1Department of Foods and Nutrition, Kookmin University, Seoul 02707, Korea
2Division of Animal Science, Chonnam National University, Gwangju 61186, Korea
Correspondence to: Jee-Young Imm
Department of Foods and Nutrition, Kookmin University, Seoul 02707, Korea
Tel: +82-2-910-4772 Fax: +82-2-910-5249 E-mail: jyimm@kookmin.ac.kr
Received January 22, 2018; Revised February 13, 2018; Accepted February 13, 2018.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Preheating conditions (low-, medium-, and high heat-) did not significantly affect the buffering capacity (BC) of skim milk powder (SMP), whereas the level of demineralization significantly affected the BC of whey powders (WP). Heat treatment (85℃ for 30 min) of both SMP and WP (90% demineralized) mixtures (88:12, 76:24, 64:36 and 52:48; SMP:WP) resulted in a reduced BC, and the extent of this reduction increased with the proportion of WP increased in the samples. High-buffering milk prepared by the addition of phosphate salts (40 mM NaH2PO4 and 60 mM Na2HPO4) delayed the rate of pH decline during yoghurt fermentation. The high-buffering yoghurt showed a significantly higher water holding capacity (WHC) than that of control yoghurt (p<0.05), as well as a more uniform and interconnected microstructure with small pore sizes than those of control yoghurt. No significant differences were found between high-buffering and control yoghurt regarding the viable bacterial counts of starter. The manipulation BC can potentially improve the quality characteristics of yoghurts, such as WHC and texture.
Keywords : buffering capacity, skim milk powder, whey powder, quality characteristics, yoghurt


April 2018, 38 (2)