Fruits • Cereals • Leaf and root vegitable • Legumes • Oilseeds These are all used for the production of fermented foods.
Why fermentation? • Improve digestibility • Nutritional value • Texture • Flavour
Detailed Discussion • Bread • Sauerkraut Production • Soya Bean Fermentation • Coffee • Cocoa • Tea
Bread Production • A History of 4000 Years • Yeast • Purpose: • Generate Carbon dioxide • Add flavor, alcohol, acid, chemical modified Gluten to promote the expansion of dough.
Wheat and several related cereal grains are used. • Contain Gluten protein. • Gluten Function • Final flavor of the bread • Dough making • Elastic properties to the dough • Dough trap CO2 and rise in volume • Baking • Bread protein is denatured and along with starch it forms the open crumb texture.
Bread dough contains more than 20% rye flour which must be acidified to produce acceptable bread. • Amylase Activity stops (Acidification). • Acidification can be done by adding citric acid or by sour dough fermentation.
Sauerkraut Production • Wilted shredded Cabbage • Mix with 2-3% salt to reduce the activity of water • Inhibition of Gram negative bacteria. • Starter culture of lactic cid bacteria are added (Lactobacillus plantarum, Lactobacillus brevis, Leuconostocmesenteroids). • Fermentation occurs and lasts for 20-30 days at 18-20 C. • Final lactic acid levels reach 1.5% v/v.
Modern commercial fermentation • Fiber glass or concrete tanks are used • Capacity 100 tones. • Traditional process • Natural Micro flora is used. • E.g. Sauerkraut
Soya Bean Fermentation • Substituted for dairy fermented products in South east Asia. • Different products like • Miso • Tempeh • Soya sauces
Involves the fermentation of cooked whole or dehulled soya beans by Rhizopus species. • soy sauce are used as colouring agents and flavouring as well. • Manufacturing involves three different stages. • Koji • it is solid substrate, aerobic fermentation of cooked soya beans. • It is also made by steamed defatted soya flakes, with addition of rice and wheat flour.
The temperature is 25-30 Celsius and it is processed in 2-3 days. • Moromi • It involves the fermentation of the liquid slurry and it is anaerobic fermentation that results from the fermentation of brine to koji. • The activity of microbe acidify and prevent spoilage.. • Along with this they perform alcoholic fermentation and produce additional flavour compounds. • The product is traditionally made in 6-9 months.
Coffee, Cocoa and tea fermentation Coffee • Bean is either obtain by dry or wet process. • Wet gives better beans. • It involves better action of indigenous bacteria and filamentous fungi. • The pulpy material that surrounds the bean is removed by the action of enzymes. • Then it is subjected to lactic acid fermentation.
cocoa • Has same microbial activity as coffee. • But this is more important comparatively. • At first we observe alcoholic fermentation. • Followed by activity of lactic acid bacteria. • Finally acetic acid bacteria does its duty and converts it into alcohol and acetic acid.
Tea • No action of micro organisms is there. • Action of enzymes are involved. • Breaks the leaves and eliminate moisture content. • To give a dry product that we refer to as tea.