Fermentation Ppt 7166

8/10/2019 Fermentation Ppt 7166

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A PRESENTATION ON

FERMENTATI

ONPRCOCESS & FOODPRODUCTS


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FERMENTATION

Fermentation is the process of converting oneorganic substance into another with the help ofmicroorganisms, generally in the absence of oxygen.

Fermentation occurs naturally in many differentfoods given the right conditions, and humans haveintentionally made use of it for many thousands of

years.

For example: Curd, Yakult, Pickles etc.


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In this process, either desirablemicroorganisms are added to the food materialor the activity of indigenous microorganismsare enhanced and the food is allowed to stand

for few hours at a particular temperature.The added microorganisms as pure or

mixed cultures will produce certain enzymeswhich will degrade the available macronutrients

like carbohydrates, proteins and lipids intosimpler substances and further transform theminto specific end products.


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Transformation Of Macronutrients

during fermentation

Conversion of lactose

and other sugars present

In milk, vegetables, fruitsInto pyruvic acid by lactic

acid bacteria.

The accumulation of

lactic acid during ferment-

-ation will bring down the

pH of foods making them

sour in taste.


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Fats and lipids arePresent in foods arebroken down into fatty

acids and glycerol bythe bacteria & fungiand by the enzymelipase produced by

fermenting organisms.


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Yeast Fermentation

What are yeast?

A yeast is a unicellular fungus which reproduces

by budding or division, especially the genus

Saccharomyces which is important in food

fermentations.

The most well known examples of yeast

fermentation are in the production of alcoholic

drinks and the leavening of bread.


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Most yeasts require an abundance of oxygen forgrowth, therefore by controlling the supply of oxygen,their growth can be checked.

Yeasts are active in a very broad temperature range -

from 0 to 50 C, with an optimum temperature rangeof 20 to 30 C.

In terms of water requirements, yeasts areintermediate between bacteria and moulds. Yeasts are

fairly tolerant of high concentrations of sugar andgrow well in solutions containing 40% sugar.


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BACTERIAL FERMENTATION

What are bacteria?

Bacteria are "a large group of unicellular or multi-cellular organisms lacking chlorophyll, with a

simple nucleus, multiplying rapidly by simplefission.

There are several bacterial families present infoods.

1. Lactic Acid Bacteria

2. Acetic Acid Bacteria


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Micro-organisms vary in their optimal pHrequirements for growth. Most bacteria favourconditions with a near neutral pH (7).

Most bacteria have a temperature optimum ofbetween 20 to 30C, and there are some whoprefer higher (50 to 55C) & some prefer colder(15 to 20C).

Water activity- In general, bacteria require afairly high water activity (0.9 or higher) tosurvive.


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Lactic Acid Fermentation[yogurt]

The main method of producing yogurtisthrough the lactic acid fermentation of milkwith harmless bacteria.

These bacteria produce lactic acid in the

milk culture, decreasing its pHandcausing it to congeal. The bacteria alsoproduce compounds that give yogurt itsdistinctive flavor. An additional effect of thelowered pH is the incompatibility of theacidic environment with many other typesof harmful bacteria.
http://en.wikipedia.org/wiki/Yogurthttp://en.wikipedia.org/wiki/Milkhttp://en.wikipedia.org/wiki/PHhttp://en.wikipedia.org/wiki/PHhttp://en.wikipedia.org/wiki/Milkhttp://en.wikipedia.org/wiki/Yogurt


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Acetic acid fermentation

Oxidation of alcohol to acetic acid and water.The oxidation of one mole of ethanol yields one

mole each of acetic acid and water;

C2H5OH + O2 CH3COOH

+

H2O

AlcoholAcetic acid Water


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Fermentation Technology

In Food Scienceo For thousands of years our

ancestors used fermentation to create

foods with nutritional value far superior

to that of the things most modernpeoples eat, and to preserve these

foods without freezing or canning.

o The most useful bacteria for this arethe lactic-acid forming bacteria, with

which we create the lacto-fermented

foods.


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Fermentation is a

Unique process with great potential

It is environment friendly

Consume less energy

Produce less waste

Easy to manage

under house hold conditions of

low income communitiesas well as in industrial scale for

urbanised welfare societies


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Thank you

Fermentation Ppt 7166

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