Food and Bioprocess Technology

, Volume 5, Issue 4, pp 1394–1401

Application of Response Surface Methodology to Improve Fermentation Time and Rheological Properties of Probiotic Yogurt Containing Lactobacillus reuteri

  • Mona Sadat Bitaraf
  • Faramarz Khodaiyan
  • Mohammad Amin Mohammadifar
  • Seyed Mohammad Mousavi
Original Paper

DOI: 10.1007/s11947-010-0433-2

Cite this article as:
Bitaraf, M.S., Khodaiyan, F., Mohammadifar, M.A. et al. Food Bioprocess Technol (2012) 5: 1394. doi:10.1007/s11947-010-0433-2

Abstract

Response surface methodology was employed to investigate the combined effects of inulin addition (0–4% w/w), probiotic inoculum level (1–3% v/v), and fermentation temperature (37–45 °C) on fermentation time and rheological properties of nonfat-set yogurt. The rheological characteristics were measured by dynamic oscillatory rheometery. The second-order polynomial model was fitted to the fermentation time (Tf), structure strength (A value), resistance to mechanical force or yield stress (τy), and complex viscosity (ŋ*) of runs as the responses. Analysis of variance revealed that the quadratic models are well adjusted to predict the experimental data. Lack-of-fit tests were not significant and determination coefficients (R2) were higher than 88.6%. The results showed that fermentation time decreased with increasing inulin content, incubation temperature, and probiotic inoculum level. Rheological properties significantly influenced by independent variables. Inulin addition had a softening effect on yogurt. However, the effect of incubation temperature on structure strength was positive. Medium levels of probiotic inoculum resulted in stronger gels.

Keywords

Yogurt Rheological properties Response surface methodology Inulin Probiotic 

Copyright information

© Springer Science + Business Media, LLC 2010

Authors and Affiliations

  • Mona Sadat Bitaraf
    • 1
  • Faramarz Khodaiyan
    • 1
  • Mohammad Amin Mohammadifar
    • 2
  • Seyed Mohammad Mousavi
    • 1
  1. 1.Department of Food Science and Engineering, Faculty of Agricultural Engineering and TechnologyUniversity of TehranTehranIran
  2. 2.Department Food Science and Technology, Faculty of Nutrition and Food ScienceShahid Beheshti Medical UniversityTehranIran

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