The effect of inulin, inoculum's level and different temperatures on the growth and metabolism of Lactobacillus acidophilus La5 in milk
Subject Areas : Food Science and Technology
1 - Department of Food Hygiene, Faculty of veterivary medicine, Sanandaj branch, Islamic Azad University, Sanandaj, Iran
Keywords: growth, metabolism, temperature, Lactobacillus acidophilus, Inulin,
Abstract :
The biological activity of probiotics is affected by various environmental factors which can influence the performance as well as the growth of probiotics for increasing the health of the consumers. This study aims to investigate the effect of inulin, concentrate 0.5, 1, 1.5 and 2% of the primary culture and temperature of 35, 38, 41 and 44°C on the growth and metabolism of L. acidophilus La5 in UHT milk. In order to achieve this, the milk fermented with L. acidophilus La5 (as the culture ferment) was used for incubating the milk sample; incubation at 35, 38, 41 and 44°C were used in order to find the optimum temperature for the growth of microorganisms. The acidity and the pH of the milk samples were measured during 0, 2, 4 and 8 h and lactobacillus counts were performed at 0.4 and 8 h after the incubation period. In order to measure the effect of inulin, 0.5% (w/v) was added to the milk samples, and the resulted samples together with the control sample, were kept at 41°C. Then the acidity, pH and the total number of L. acidophilus of milk samples were determined during the above mentioned periods. Every of above operations were replicate ten times; then , utilizing statistical tests, the average of acidity, pH and enumeration of L. acidophilus were compared with one another during the above mentioned periods. The findings of the study indicat that, lactobacillus count and the amount of acidity in the incubated milk samples at 41 and 44°C were significantly greater than the other temperatures (P<0.05). The growth rate of the bacterium in samples containing 2% of starter culture during the fourth h of incubation was significantly greater than the other samples (P<0.05). However, this difference in 8 h after the incubation was not significant (P>0.05). Concerning the use of prebiotic inulin, the number of L. acidophilus and the acidity of milk samples containing inulin was significantly greater than the number of the bacterium in control sample (P<0.05). It is concluded from this study that, the best alternative temperature for this purpose is an incubation temperature ranging from 41 to 44°C. Addition of inulin enhance significantly the growth of L. acidophilus La5.
Akin, M.B. and kirmaci, Z. ( 2007). Effects of inulin and sugar levels on the viability of yogurt and probiotic bacteria and the physical and sensory characteristics in probiotic ice – cream. Food Chemistery, 104 : 93 – 99.
Dave, R. and Shah, N. ( 1997). Viability of yoghurt and probiotic bacteria in yoghurts made from commercial starter cultures. International Dairy Journal, 7: 707 – 715.
Fuller, R. (1989). Probiotics in man and animals. Journal of Applied Bacteriology, 66: 365–378.
Gibson G.R., Beatty E.R., Wang X., Cummings J.H. (1995). Selective stimulation of bifidobacteria in the human colon by oligofructose and inulin. Amer. Gastroent. Assoc, 108: 975-982.
Hild, M.O. and Heland, M.H. ( 2003). Growth and metabolism of select strains of probiotic bacteria in milk.International Journal Food microbiology, 87: 66 – 72.
Huebner, J. and Wehling, R.L. (2007). Function activity of commercial prebiotics. International Dairy Journal, 17: 770 – 775.
James, M.J. (1998). Modern food microbiology. Translated by Mortazavi Ali and et al.1rd.Vol.2. FerdousiUniversity Press, pp: 484. [In Farsi]
Karim, G. (2002). Microbiological examination of foods. TehranUniversity Press, PP: 63-87. [In Farsi]
Kurmann, J. A. (1998). Starters for fermented milks, Bulletin of International Dairy Fedrationو 277: 41-55.
Malekzadeh, F. (2003). Micribiology. 2nd Edn, TehranUniversity Publication Pressو pp: 507-508. [In Farsi]
Merete H.H. and Wicklund, T. (2004). Growth and metabolism of selected strains of probiotic bacteria in milk and water – based cereal puddings. International Dairy Journal, 14: 957 – 965.
Mirzaei, H. (2004). Probiotics and introduction to their role in human health. 1rd. Islamic AzadUniversity Press, pp: 1-2. [In Farsi]
Mirzaei, H., Karim, G. and Soodi, M. (2006). Study on the effect of dextrose, valine, glycine, thiamine and different tempratures on growth rate of Lactobacillus casei in milk. J. Iranian Food Science, 2: 51-59. [In Farsi]
Mutlu, B. and Guler, A. (2007). Effect of cysteine and different incubation temperature on the microflora , chemical composition and sensory characteristics of bio – yogurt made from goat milk. Food chemistery, 100: 788-793.
Ostlie , H.M. and Treimo, A. ( 2005). Effect of temperature on growth and metabolism of probiotic bacteria in milk. International Dairy Journal, 5:989 – 997.
Ostlie, H. M., Treimo, J., Narvhus, J. A. (2005). Effect of temperature on growth and metabolism of probiotic bacteria in milk. International Dairy Journal, 15: 989–997.
Ping, S., Anders, H. and Hazel, M. (2007). Selected prebiotics support the growth of probiotic mono-cultures in vitro, Food Microbiology, 13: 134-139.
Razavilar, V (2002): Pathogenic Microorganisms in food and epidemiology of foodborne intoxications. 2rd. TehranUniversity Press, pp: 84-95. [In Farsi]
Roller, M., Pietro Femia, A., Caderni, G., Rechkemmer, G. And Weizel, B. (2004). Intestinal immunity of rats with colon cancer is modulated oligofrutose- enriched inuline combined with Lactobacillus rhamnosus and Bifidobacterium lactis. Gr J. Nutr, 92: 931-938.
Sarela, M., Mogensen, G.,Fonden, R., Matto,j., Mattila-sand-holm, T (2000) . Probiotic bacteria: safety, functional and technological properties .j. Biotechnol, 84: 197-215.
Tamime, A. (2005). Probiotic Dairy Products, 1st ed Black Well Publication Press, pp: 121- 135.
Vinderola, C, G., Bailo, N. and Reinheimer, J.A. (2000). Survival of probiotic microflora in Argentinean Yoghurts during refrigerated Storage. Food Res. Int, 33: 97 – 102.