Group : I 3 -8. Fermented Foods are foods which processed through the activities of microorganisms...

Group : I3-8

Fermented Foods are foods which processed through the activities of microorganisms but in which the weight of the microorganisms in the food is usually small.

Ex: Bread, Cheese, Fish sauce, coffee, Tea, Cocoa….

Fermented Food

The benefits of Fermented foods are:1. Preserving Foods in low cost manner2. Improvement of organoleptic

properties3. Removing unwanted(harmful)

properties in raw material.4. Improvement of nutritive content of

food.5. Reducing the cooking time

Fermented foods are mainly influenced by :1) Nature of the substrate 2) Microorganism involved in the

fermentation3) The length of the fermentation 4) The treatment of the food during

processing.

Basic ingredients are flour, water, salt, and yeasts.

Other components and additive are: sugar, milk, eggs, shortening(fat) emusifiers, anti-fungal agents, anti-oxidants, enzyme, flavoring, and enriching ingredients.

Fermented Food from Wheat (Bread)

Flour is the chief ingredient of bread and is produced by milling of grains of wheat.

Yeast: used for baking are Saccharomyces Cerevisiae.

SugarShortening (Fat): increased loaf size; a more tender crumb; enhanced slicing.

Emulsifiers (Surfactants)

Milk: to make the bread more nutritious, to help improve the crust color.

SaltWaterEnzymesMold-inhibitors (antimycotics)

Enriching additives

• Pre-fermentation (sponge mixing)• Dough mixing• Cutting and rounding• First (intermediate) proofing• Molding • Second proofing• Baking • Cooling, Slicing and wrapping

Baking process:

The principle role of Yeast is to create leavening.

Methods of leavening is the increase in the size of the dough induced by gases during bread-making.

Role of Yeasts in Bread-making:

oDuring bread making, yeasts ferment hexose sugars mainly into CO2 and other alcohols. CO2 in the gaseous state become bubbles in dough which causes the dough to rise or leaven.

o The total time taken for the yeast to act upon the dough varies from 2-6h or longer.

Process of Leavening:

oThe nature of the sugar availableoOsmotic pressureoEffect of nitrogen and other nutrients

oEffect of fungal inhibitorsoYeast concentration

Factors which effect the leavening action of yeasts:

Difference of process of baking to cause the aroma of fermentation also different.

The flavor compound found in bread are organic acids, esters, alcohols, aldehydes and other carbonyl compounds.

Flavor development:

o Bread is baked at a temperature of about 215-225oC for 17-23mn. Various events occur during baking process as below:• At about 45oC alpha-amylase yielding

fermentable sugars.

• Between 50 and 60oC the yeast is killed.

Baking:

• At about 65oC the beta-amylase is thermally inactivated.

• At about 87oC the cereal alpha-amylase is inactivated.

• Finally, the gluten is denatured and coagulates, stabilizing the shape and the size of the loaf.

Fermented Food from Milk

Cheese YoghurtYoghurt

CheesesoCheese is a highly proteinaceous food made from the milk of some herbivores.

oCheese made from the milk of goat and sheep has a much stronger flavor than that made from cow’s milk.

Standardization of milkInoculation of pure cultures of lactic

acid bacteria as starter culturesAdding of rennet for coagulum

formationShrinkage of the curdSalting of curd and pressing into

shapeCheese ripening

Stages in the manufacture of Cheeses

Yoghurt is a dairy product produced by bacterial fermentation of milk

In the manufacture of yoghurt, two kinds of lactic acid bacteria,Lactococcus spp, (Lactococcus salivarius and thermophilus,)

Lactobacillus spp, (Lacto. acidophilus, bulgaricus and bifidus.)

Yoghurt

The bacteria produce lactic acid causing pH to drop to about 4-5 from about 7.0

This drop in pH causes the milk to coagulate.

The lactic acid give yoghurt its sour taste and limits the growth of spoilage bacteria.

To sump up, after the presentation, we hope that you all gain more knowledge related to the production of Bread and Cheeses.

Conclusion