Yogurt
YOGURT
INTRODUCTION
There are thousands of microorganisms present at almost every surface. Some of them are pathogenic which causes diseases but most of them are useful especially in the food industry (Lasztity, n.d.). Microorganisms have been used for preparing food products such as cheese, bread, yogurt, etc, for a long period of time without even knowing that the process involves fermentation of the starting material (Pai, 2003). Fermentation is the process of utilizing nutrients anaerobically (D 'Souza & Killedar, 2006).
Yogurt is a product of fermentation brought by adding Streptococcus thermophilus and Lactobacillus bulgaricus to ferment the milk and turn it into a thickened acidic food ( Lee & Lucey, 2010). These bacteria partially digest milk and produce lactic acids which makes it edible even to people who cannot tolerate milk (Cascio & Dinstel 2011). The lactic acid decreases the pH of the milk and coagulates the milk proteins, giving it a semi-solid consistency and the ability to inhibit the growth of other microorganisms (Kahl, 2011).
The primary goal of the study is to demonstrate the use of microorganisms in the food industry using yogurt as an example. Secondary to that, the study also aims to present a simple instruction on how to make a homemade yogurt using cultured bacteria found in commercial yogurt.
METHODOLOGY
Heat treatment → Cooling to Incubation Temperature → Inoculation → Fermentation → Cooling → Packaging
Figure 1: General steps in the yogurt production.
Figure 1 summarizes the procedure in the production of yogurt. Heat treatment was done for 30 min at 85 C to ensure that the milk was free from unwanted microbes. After heating, the milk was cooled to temperature suitable for the growth of the starter bacteria which was around 40C – 45C. Commercialized unflavored yogurt was used to serve as a starting culture. The milk was placed in an air-tight jar and was left undisturbed for at least 10 hours and the
INTRODUCTION
There are thousands of microorganisms present at almost every surface. Some of them are pathogenic which causes diseases but most of them are useful especially in the food industry (Lasztity, n.d.). Microorganisms have been used for preparing food products such as cheese, bread, yogurt, etc, for a long period of time without even knowing that the process involves fermentation of the starting material (Pai, 2003). Fermentation is the process of utilizing nutrients anaerobically (D 'Souza & Killedar, 2006).
Yogurt is a product of fermentation brought by adding Streptococcus thermophilus and Lactobacillus bulgaricus to ferment the milk and turn it into a thickened acidic food ( Lee & Lucey, 2010). These bacteria partially digest milk and produce lactic acids which makes it edible even to people who cannot tolerate milk (Cascio & Dinstel 2011). The lactic acid decreases the pH of the milk and coagulates the milk proteins, giving it a semi-solid consistency and the ability to inhibit the growth of other microorganisms (Kahl, 2011).
The primary goal of the study is to demonstrate the use of microorganisms in the food industry using yogurt as an example. Secondary to that, the study also aims to present a simple instruction on how to make a homemade yogurt using cultured bacteria found in commercial yogurt.
METHODOLOGY
Heat treatment → Cooling to Incubation Temperature → Inoculation → Fermentation → Cooling → Packaging
Figure 1: General steps in the yogurt production.
Figure 1 summarizes the procedure in the production of yogurt. Heat treatment was done for 30 min at 85 C to ensure that the milk was free from unwanted microbes. After heating, the milk was cooled to temperature suitable for the growth of the starter bacteria which was around 40C – 45C. Commercialized unflavored yogurt was used to serve as a starting culture. The milk was placed in an air-tight jar and was left undisturbed for at least 10 hours and the
References: Lasztity, R. (n.d). Micro-organisms important in food Microbiology. Retrieved March 6, 2013 at http://www.eolss.net/Sample-Chapters/C10/E5-08-06-01.pdf Pai, J. S. (2003). Applications of microorganisms in food biotechnology. Indian Journal of Biotechnology, 2, p382-386. D 'Souza, J. & Killedar, S. (2006). Biotechnology and fermentation process. Pune: Rachana Enterprises. Lee, W. J. & Lucey, J. A. (2010). Formation and Physical Properties of Yogurt. Retrieved March 6, 2013 at http://www.ajas.info/pdf/23-149.pdf Cascio, J. & Dinstel, R.R. (2011). Making yogurt at home. Retrieved March 6, 2013 at http://www.uaf.edu/files/ces/publications-db/catalog/hec/FNH-00062.pdf Kahl, A. (2011). Yogurt production. Retrieved March 6, 2013 at http://bioweb.uwlax.edu/bio203/s2007/kahl_ambe/yogurt_production.htm Anonymous (n.d.) An introduction to lactic acid bacteria. Retrieved March 6, 2013 at http://inst.bact.wisc.edu/inst/index.php?module=book&type=user&func=displayarticle&art_id=95 Anonymous (2009). Yogurt everyday.Making yogurt &real food changes. Retrieved March 6, 2013 at http://yogurt-everyday.com/yogurt-making-troubleshooting.html