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kunal 1.ppt

Jun 02, 2018

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Anshuman Singh
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    Fermented products are:

    Fermented products are those whose

    production involves the action of

    microorganisms or enzymes which

    cause desirable biochemical changes

    and significant modification to the

    food.

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    Fermentation processes:

    Lactic acidAlcoholic

    Acetic acid

    Propionic acid

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    Fermented foods

    Beverages

    Dairy products

    Cereals

    Meat and fishFruits and vegetables

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    Beverages

    Beer

    WineSake

    Cider

    spirits

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    Dairy products

    Cheese

    Yoghurt

    Kefir

    Kurut

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    Cereals

    Breads

    Rolls

    dosa, idli, adai, vada (cereals& legumes)

    lao-chao, kenkey, ogi

    injera

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    Meat and Fish

    Jerky, country ham, salami, pepperoni

    pickled meat

    fish sauce, paak, bagoong

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    Fruits & vegetables

    Pickled fruits & vegetables

    olivessauerkraut

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    Contribution of the fermented

    foods:

    Enrichment of the human dietary

    preservation of substantial amounts of food

    enrichment of nutritional value of food (vitamins,proteins, essential amino acids etc]

    detoxification of food (flatulence-causing

    sugars, lectins, phytates etc] a decrease the cooking time and fuel

    requirements

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    Preservation principle:

    To hinder (delay) the growth of

    food spoilage microorganisms

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    Alcoholic fermentation:

    Simple sugars yeasts > ethanol

    Saccharomyces cerevisiae

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    Yeasts involve in fermentation

    should possess:

    Rapid and relevant carbohydrate

    fermentation ability;

    appropriate flocculation and

    sedimentation characteristics;

    genetic stability;

    osmotolerance

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    Yeasts involve in fermentation

    should possess:

    ethanol tolerance

    ability to produce elevated concentration

    of ethanol;

    high cell viability for recycling;

    temperature tolerance.

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    Alcoholic fermentation is

    affected by:

    Oxygen supply

    sugar content

    alcohol content

    temperature

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    Alcoholic fermentation:

    Unlimited oxygen supply - cell

    growth

    Limited oxygen supply - alcohol

    production

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    Beer

    A diluted solution of ethanol with a

    characteristic flavour arising from theuse of malt as predominant source of

    carbohydrates and other yeast

    nutrients and hops as a source of bittercomponents.

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    Kinds of beer

    Lager - produced by bottom fermen-

    ting yeasts ( Saccharomyces uvarum) .

    Ale - produced by top fermenting

    yeasts ( Saccharomyces cerevisiae)

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    Production of beer:

    Malting

    Mashing

    Boiling of wort with hops

    FermentationStorage

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    Malting (preparation of malt):

    Soaking barley grains in water at

    10-15 0C

    Germination of barley grains at

    16-21 0C for 5-7 days

    Separation germs and sproutsCrushing the malt

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    Mashing (preparation of wort)

    Mixing malt with water at 38-50 0C

    (protein hydrolysis)

    Saccharafication of malt at 65-70 0C

    (hydrolysis of starches to simple

    sugars)Inactivation of enzymes at 75 0C

    Separation of insoluble materials.

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    Boiling of wort with hops is done to:

    concentrate it

    sterilize itinactivate enzymes

    extract soluble substances from hops

    coagulate and precipitate proteins

    contribute antiseptic resins:

    humulone, cohumulone, adhumulone.

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    Fermentation of beer

    Pitching (inoculation)- 1lbs of yeasts per

    barrel of wort

    Lager beer is fermented at 7-15 0C

    Ale beer is fermented at 18-22 0C

    Fermentation - 9 days

    At the end of fermentation yeasts are

    skimmed (top-fermenting) or are cropped

    (bottom-fermenting).

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    Storage and packaging

    after fermentation beer is stored (lagered)

    at 0 C (several weeks to several months)

    clarified or filtered

    pasteurized at 60 C shortly

    carbonated to CO2

    content 0.45-0.52%

    packaged to cans or bottles.

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    Beer defects (off flavour) may be

    due to:

    butyric (Clostridiumsp.) or lactic acid

    fermentation during mashing process.

    Inoculum contaminated with wild yeasts or

    lactic acid bacteria.

    - Yeasts may produce off flavor.

    -Bacteria may produce sour taste and/orsilky turbitidy.

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    WINES

    Products obtained by alcoholic

    fermentation of grapes, grapejuices, fruit juices, berries,

    rhubarb, honey etc by yeasts.

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    Kinds of wines

    still wines

    sparkling winesartificially carbonated wines

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    Steps involve in fermentation of

    wine:

    Preparation of must (grape juice, crushed

    grapes, fruit juice].

    inoculation of must with wine yeasts(2-5% ].

    aeration of must to encourage the growth

    of yeasts and to facilitate the extraction ofpigments from a skin (mixing must twice a

    day ].

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    Steps involve in fermentation of

    wine:

    Active fermentation:

    - red wines 24 -27 0C; 3-5 days;

    - white wines 10-210

    C; 7-14 days; separation of fermented juice from residue

    (pomace);

    placing fermented juice under light CO2pressure

    secondary fermentation: 21-29 0C, 7-11 days.

    aging of wines.

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    Problem solving

    Calculate the% [w/w] of EtOH in wine.

    Assume that at fermentation starting

    point 30 kg of must contained 26% of

    sucrose. The fermentation ceased at

    2% concentration of sugar. The yield

    of conversion of sugar to ethanol was

    94%.

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    Calculation steps:

    C6H12O62 C2 H2OH + 2 C02

    1. Calculate the amount of sugar in must.

    M1 = 30 * 0.26 = 7.8 kg

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    Calculation steps:

    2. Calculate the final weight of must (M)

    at the end of fermentation process.

    M = M0 - M2 + M3

    M0 - initial weight of must;M2 - weight of fermented sugar;

    M3- weight of produced alcohol.

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    Calculation steps:

    3. Calculate the weight of sugar in wine.

    M4 = M * 0.02

    4. Calculate the weight of sugar fermen-

    ted to alcohol.M2 = (7.8 - M4 ) * 0.94

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    Calculation steps:

    5. Calculate the weight of produced alcohol.

    C6H12O6 2 C2 H2OH + 2 C02 180 92

    M2 M3

    ---------------------------------M3= 92 * M2 /180 = 92* ( 7.8 - M4)/180 =

    92* ( 7.8 - M * 0.02) * 0.94/180

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    Calculation steps:

    6. Calculate the final weight of wine (M)

    M = M0 - M2 + M3

    M = 30 - (7.8 - 0.02*M)+

    + 92*(7.8 - 0.02*M) *0.94/180

    M = 26.22 kg of wine

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    Calculation steps:

    7. Calculate the weight of produced

    ethanol.

    M3= 92 * (7.8 - 26.22 *0.02) *0.94/180

    M3 = 3.495 kg of ethanol

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    Calculation steps:

    8. Calculate [ % ; w/w) of ethanol in wine.

    [%] = M3/M * 100

    [%] = 3.495/26.22 *100

    [%] = 13.3%

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    Production of ethanol

    Starch pretreatment:

    -gelatinization,-liquefaction,

    -saccharification

    Fermentation

    Distillation

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    Lactic Acid Fermentation

    Lactobacilli

    Streptococci (dairy streptococci)

    Pediococci

    Leuconostocs

    B fit f L ti A id

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    Benefits from Lactic Acid

    Fermentation

    Alteration of flavour, texture, and

    appearance

    enhancement of nutritional value

    retardation of food spoilage and reduction

    of microbial contamination

    probiotic effect- prolongation of life:

    (Metchnikoff 1908) due to lactase,

    metabolism of dietary cholesterol,

    detoxification of potential carcinogens.

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    Sequence in changes in raw milk in

    relation to acid concentration

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    Sequence of acid fermentation in

    sauerkraut manufacture

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    Are fermented foods safer than

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    Are fermented foods safer than

    fresh foods?

    Cases of microbial food-borne infection have

    been reported in association with fresh cheese,

    sausages, fermented fish and fermented cereals. Cases of microbial food intoxications due to

    mycotoxin contaminated raw material,

    production of microbial toxins, production of

    mycotoxins by fungal have been reported.

    Toxic by-products (ethyl carbamate and biogenic

    amines) may be produced.

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    Toxic by-products of fermenta tion:

    Ethyl Carbamate: a carcinogenic and

    mutagenic compound which results from

    the esterification of ethanol with carbamicacid (NH2COOC2H5- also known as urethane)

    Biogenic amines - a mildly toxic

    substances. 100-200 ppm; >1000ppm issupposed to elicit toxicity.

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    Biogenic amines

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    Biogenic amines in fermented foods

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    Major risk enhancing factors:

    Use of contaminated raw materials.

    Lack of pasteurization.

    Poorely controlled natural fermentations.

    Sub-optimal fermentation starters.

    Inadequate storage and maturation

    conditions.

    Consumption without prior cooking

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