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Fermentation. Chapter 17 Page 493. Categories. Bacteria Fungi Yeast Mold . Common Food Bourne Pathogens. Bacteria Salmonella enteriditus Campylobacter jejuni Many, many others Fungi Some are used in food production Other are contaminants or even toxic. Types.
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Fermentation Chapter 17 Page 493
Categories • Bacteria • Fungi • Yeast • Mold
Common Food Bourne Pathogens • Bacteria • Salmonella enteriditus • Campylobacter jejuni • Many, many others • Fungi • Some are used in food production • Other are contaminants or even toxic
Types • Bacteria = Monera kingdom • Yeast & Mold = Fungi kingdom • Proteolytic microbes feed off protein • Lipolytic microbes feed off fats • Halophilic microbes feed off high salt concentrations • All microbes need water, pH, and temperature
Pasteurization • Liquid is heated until pathogens and some spoilage bacteria have been destroyed • Prevent disease, lengthen shelf life, can also affect milk flavor • Louis Pasteur • http://youtu.be/OXdbQ1JkX7c
Bacteria • Bacteria = single celled organism • Rod-shaped bacteria = bacilli • (buh-sil-uh)
Spherical shaped bacteria = cocci • (kok-sahy)
Sprial shaped bacteria = spirilla • (spahy-ril-uh)
Aerobic needs air • Anarobic oxygen-free environment • Gram stain • http://youtu.be/CyyY8h1doJk • http://youtu.be/MY-ad03-f0I • http://www.microbiologybytes.com/video/Gram.html article
Fungus • Aerobic, spore-producing organism that lacks chlorophyll • Not always single celled • Spores = reproductive cells of fungi • Explode when full – sending spores everywhere • “Food Poisoning or Witchcraft?”article pg 497
Microbes and Food • Microbes are added to foods to bring about fermentation • As microbes release their digestive enzymes the enzymes break down the food product. • By-product – carbon dioxide, acetic & lactic acid, and ethanol. • Break down large molecules – absorb smaller molecules for GROWTH AND ENERGY • 3 types we will look at Yeast, Bacterial, and Mold
Yeasts • Fungi with a single-celled structure • Result in the production of alcohol • Creates good sources of edible microbial protein • Microbes add nutritional value • Baking kills yeast, but not nutritive value (protein, vitamins & minerals)
http://youtu.be/FqxkMqsEQI0 Alton Brown • All yeast breads, alcoholic beverages, and vinegars require yeast in the production process • Most common yeast is Saccharomycescerevisiae = warm, moist, where ______ and/or st______ • Too much sugar lower the pH of the liquid and microbes can’t reproduce • Quick rising yeast is a combination of 2 yeast strains • Starters – Make a starter
Yeast Fermentation • Warm liquid 110 degrees Fahrenheit • Gluten, protein, needs to be developed – Kneading • Proofing – Enzymes released • Break down sugar, releasing ethanol (alcohol) & carbon dioxide • Carbon dioxide is trapped in gluten and EXPANDS
Baking • Baking = alcohol evaporates & yeast cells are killed • Carbon dioxide continues to expand during baking • Crust forms and protein sets • If proofed too long – too much carbon dioxide is produced • Gluten is over stretched & bread is heavy or dry • Too much alcohol is produced creating bad taste • http://youtu.be/ZXYZYKfjNBg
BREAD!!! • Let’s make some bread!!!