Assessment of pH variations during extended period of fermentation of cow milk with different lactic acid bacterial cultures

Abstract

Lactic acid bacteria (LAB), the Gram positive, catalase negative bacteria are widely used as dairy starter cultures due to their ability to efficiently utilize milk constituents, principally the lactose and caseins. Due to their ability to produce lactic acid, typical flavour compounds, desirable textural attributes and to inhibit the spoilage microflora they play a significant role in dairy fermentations. In this study, eleven different LAB cultures were assessed for their acidification pattern in terms of changes in pH, the major indicator of progress of fermentation processes. The study revealed remarkable differences in between the cultures in terms of the time taken for coagulation (tc) and for attaining a pH of 4.5(tpH4.5). Tc varied in the range of four hours for S. thermophilus DMM1 to fifteen hours for five out of the eleven cultures tested. ΔpH noted at different stages of fermentation revealed culture specific variations in the extent of pH reduction. Marked decrease in pH was observed after 24 h of extended incubation of cultures at their optimum temperature. Highest ΔpH24 was exhibited by Lb. delbrueckii304 (4.07) and lowest ΔpH24 was exhibited by Lb. acidophilus 307 (2.37). Considering the remarkable regional, individual and use specific variations reported in consumer preferences with respect to acidity, a major quality attribute of fermented milk products, observations of the current study could effectively made use while selecting the starter cultures for the preparation fermented milk products meeting the acidity preferences of the consumers. Data obtained in the current study would also help in categorizing LAB cultures to low and high post acidifying cultures

References

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Author information

Authors and Affiliations

¹Verghese Kurien Institute of Dairy and Food Technology, Mannuthy, Thrissur-680651, Kerala Veterinary and Animal Sciences University, Kerala, India

²College of Dairy Science and Technology, Thiruvananthapuram, Kerala Veterinary and Animal Sciences University, Kerala, India

*Corresponding author.

Correspondence to lijimoljames@kvasu.ac.in

Editor Information

Editors and Affiliations

Department of Academics and Human Resource Development

National Institute of Food Technology, Entrepreneurship and Management, Thanjavur (NIFTEM-T)

(An Institute of National Importance)

Ministry of Food Processing Industries (MoFPI), Govt. of India

Thanjavur, Tamil Nadu, India. Pin Code – 613005

Dr. S. Vignesh

Dr. N. Baskaran

Dr. V. Eyarkai Nambi

Dr. M. Loganathan

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