EXTRA CREDIT ASSIGNMENT

Hey guys, I put up two experiments for you to do for extra credit.  Also, do not worry, the second experiment video has additonal experiments for you to do but you do not have to do all of them.  You can just choose one experiment which you would like to do.  I also put up an experiment report form that you can use to write down all your findings.  You can submit anytime before Christmas break.  Have fun. 

Experiment Report Form

Date:


Names of participants :




Title of Experiment:




Hypothesis:



 


Process:








Result:














Conclusion:

Experiment 2- A Fun Yeast Experiment

Experiment 1 - How to Make Yogurt

Make yogurt at home from milk to guarantee quality, to power-pack your diet with nutrition, and to save a little cash.

You Will Need

• 1 qt. milk
• 1/4 c. yogurt starter
• Raisins or fruit
• Candy thermometer
• Clean containers
• Incubator

Step 1: Measure milk

Measure and pour the milk into a large pot. Using a candy thermometer, make sure the milk is heated to 185 degrees; then allow it to cool to 110 degrees.

Use any type of milk you prefer to make the yogurt including cow, goat, horse, sheep, yak, or even water buffalo milk.

Step 2: Add yogurt culture

Add unflavored active yogurt culture as a starter to the milk and stir well with a spoon.

Yogurt starter cultures may be purchased at a natural foods store, or use a commercial plain cultured yogurt from the grocer as a starter.

Step 3: Pour into containers

Pour the milk into clean containers for incubating.

Step 4: Incubate the milk

Incubate the milk. This can be done in a number of ways; you can incubate the milk in a covered thermos, place filled containers in a 110-degree Fahrenheit oven, set filled containers on a heating pad and cover with towels, or place in a commercial incubator.

Step 5: Wait

Wait for up to 12 hours for the yogurt to firm, keeping in mind that the longer the incubation period, the more tart your yogurt will taste.

Step 6: Refrigerate

Refrigerate the yogurt until you are ready to serve, then present plain, sweetened with raisins or fruit, added to smoothies. Watch your yogurt become a family favorite.

              < Retrived from http://www.howcast.com/videos/396528-How-To-Make-Yogurt>

Foods that contain Yeast

Beer

Breads

Kimchi

Wine

Yogurt

What is yeast and how is it made?

Yeasts consist of one cell, and belong to the taxonomic group called fungi, which also contains moulds.

There are many species of yeasts. The most common yeast known is Saccharomyces cerevisiae, which is used in the baking- and brewing industry. Yeasts also play an important role in the production of wine, kefir and some other products.

                                                      <Yeast cell>


Yeasts need sugar to grow. They produce alcohol and carbon dioxide from sugar. This reaction makes yeast so important for the food industry. Yeasts also produce pleasant aroma components. These aroma compounds play a very important role for the flavour of the end product. In beer the yeast is needed to produce the alcohol and the carbon dioxide for the brim. In the bread industry, both alcohol and carbon dioxide are formed; the alcohol evaporates during baking.

Yeasts can be found everywhere in nature, especially on plants and fruits. After fruits fall off the tree, fruits become rotten through the activity of moulds, which form alcohol and carbon dioxide from the sugars in it. Sometimes drunk animals appear in the news because they have eaten these spoiled fruits.

Yeasts are grown in the industry in big tanks with sugary water in the presence of oxygen. When the desired amount of yeast is reached the liquid is pumped out, and the yeast is then dried. Nothing else is added in the production of yeast.

                                         < retrived from http://www.food-info.net/uk/qa/qa-wi8.htm>