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63 Cards in this Set
- Front
- Back
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Early days means of preserving foods
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-milk curdled
-cabbage -fruit juices became alcoholic |
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Now a days fermentation....
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-controlled process
-specific microbes involved -specific end products desired in proper concentration |
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Biochemical/physiological fermentation
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breakdown of carbohydrates under anerobic conditions. True biochemical reaction
ex) sreptococcus lactis: ferments lactose anaerobically to get lactic acid |
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common fermentation
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-breakdown of carbs under anaerobic conditions
-more interested in end products, not biochemical rxn -ex) acetobacter aceti- converts ethyl alcohol into acetic acid. Technically an oxidation reaction |
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functions of fermentation
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-preservations
-break down complex foods into simpler foods -enzymatic splitting of cellulose/hemicellulose into simple sugars |
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Breakdowns
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-complex carbohydrates into mono, di and dextrins
-proteins may be broken down into polypeptides, peptides, amino acids |
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Biological form of energy
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ATP
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l. delbrueckii ss bulgaricus
(yogurt) |
-rod shaped
-heat tolerant -growth stimulated by decreased pH and CO2 -has cell wall bound proteases -homofermenter -breakdown casein to make free amino acids |
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streptococcus thermophilus
(yogurt) |
-coccus shaped
-heat tolerant -does not contain cell wall bound proteases -heterofermenter- produces CO2 and acids |
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Mesophilic LAB
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(25-30C)
-Lactococcus lactic ssp lactis -lactococcus lactic ssp cremoris -streptococcus diacetylactis- sour cream -leuconostic mesenteroides ssp cremoris |
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Thermophilic LAB
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40-45C
-streptococcus thermophilus -lactobacillus delbruccii ssp bulgaris -lactobacillus helveticus |
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Lactobacillus Acidophilus
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-probiotic
-homofermenter -adjunct to yogurt. 10^6 cfu/ml |
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Lactobacillus Bulgaricus
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-yogurt culture
-homofermenter -cell wall proteases -grows better in pH below 6 |
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LACTIS
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-work horse of cheese industry
-often used in conjunction with l.lactis ss cremoris -homofermenter -converts 1 lactose to 4 lactic acid molecules |
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CREMORIS
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homofermenter
used in conjunction with l. lactis ss lactis |
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Diacetylactis
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-heterofrementer
-used in production of sour cream -primary fxn is convert lactose--> lactic acid -concerts citric acid to diacetyl molecule and CO2 |
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leuconostoc mesenteroides ss cremoris
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-heterofrementor
-used to make gouda -always in conjunction with homofermentor -major fxn is not LA production but production of flavor compounds |
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Proprionibacterium shermanii
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-does not make lactic acid
-poor stand alone fermentor -heterofermentor -lactose--> lactic acid, increase proprionic acid and acetic acid -swiss cheese |
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Streptococcus Thermophilus
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-heterofermentor
-does not contain cell wall proteases -produces alot of malic acid -heat tolerant -conjunction w/ l. bulgaricus to make yogurt -italian cheese |
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Brevibacterium Linens
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-bacteria
0surface ripened cheese -produce cartenoids -utilized for flavor -proteases and peptides -end products are sulfur containing amino acids -lipases produce stinky buteric acid |
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pennicillium caseicolum
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-white mold
-exterior mold -brie -use LA into neutral compounds -Highly proteolytic |
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penicillium roqueforti
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-blue veined cheese
-interior molds -mold spores added -highly proteolytic and lipolytic -pastey texture |
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goals of malts and grains
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cut up to make simple sugar and alcohols
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adjuncts in beer making
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fruit
corn rice |
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General yeast differences
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1. Alcohol tolerance
2. End products 3. attentuation 4. flocculation |
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yeast fermentation
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acidic with simple sugars
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Lactic Acid Bacteria Fermentation
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plant with neutral pH
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Plant Structure
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Hull- B vitamins
Endosperm- Proteins, strachy Embryo- fat, rancid, enzyme active |
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proteins in beer
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flavor
aroma head formation |
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flocculation
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ability to attach and form large masses
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% malt weight of glucose
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1-2%
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incomplete milling
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molds may break down indigestible coatings
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malting grains
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the process of converting starch to sugar and proteins to smaller polypeptides and even amino acids and then roasting the grain to stop the process
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Malting Process
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1. Soak grain in water and drain
2. spread on floor 3. germinate in 5 days 4. stir regularly 5. When sprouts are 3/4 of seed length, grain is baked in the oven 6. wet kiln process |
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End result of Malting Grains
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-small amount of breakdown in sugars and proteins
-packets of enzymes -color formation from heating |
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Wort
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sugary solution with maltose and glucose. Breakdown proteins present. Happens after mashing of malted grains
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Beer production
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-shake cool wart
-add yeast -airlock and keep at appropriate temperature -fermentation occurs -rack off traub -secondary fermentation -ferment added sugars chill and consume |
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LAGER
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sacchaomyces carlsbergensis
-bottom fermenter -like colder temps (less than 55f) -an ferment raffinose (a 3 sugar unit CHO) -low ester formation |
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ALE
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saccharomyces cerevisiae
-top fermenter -does not like cold temperatures -can not ferment raffinose -can produce lots of esters (fruity aroma) |
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attentuation
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ability to ferment the sugars in the wort
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Lambic
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-style of beer
-wild fermentation -end result: sour fruity beer |
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hard cider
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sanitize the cider
add pectinase and sugar honey or rasins add yeast nutrients tannin acid mix pitch yeast and ferment be careful of acetobacter secondary ferment |
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make sauerkraut
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1. wash cabbage
2. slice cabbage 3. add salt (2.25%) 4. exclude O2 5. incubate @ 21 C 6. allow fermentation until desired end point reached (1.5% LA) 7, package:heat treat 200-210F 8. cool and store at room temp |
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Whats happening when making sauerkraut
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-growth curve
-changing environment -successive populations |
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Leuconstoc mesenteroidses
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-cocci shaped
-21C -2.5% salt -short life span -rapid grower -heterofermenter -dies off around 0.7-1.0% acid -1-3 days increase acid level to 0.1-1.0 -drops pH |
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lactobacillus plantarium
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-rod shaped
-like increased temperatures (greater than 21C) -produce large amount of acid -homofermenter -increase acid level: 2% acid -drops pH even more -leads to growth of l. pentaceticus |
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L. Pentaceticus
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-rod shaped
-heterotfermenter: LA and small amt of CO2 -increase acid level to around 2-2.5% -final pH around 3.1-3.7 |
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soft kraut
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-initial growth is l.plantarium and l.pentaceticus
-textural changes arise -lack of good flavor development l.mesenteroides is the flavor maker |
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slimy kraut
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-temperature too high
-promotes l. cucumeris and l.plantarium -textural changes can occur |
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rotted kraut
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surface growth of yeast, bacteria and molds
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pink kraut
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caused by species of tonia yeast
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Spoilage issue w/ sauerkraut
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-surface growth of mold
-low pH= good for molds -drive pH up= keeps bacteria in check |
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MEAT
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-mix meat, fat, salt, sugar, cure and spices
-stuff into casing -put in warm place to ferment -may or may not be smoked |
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meat preservation
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-acid produced from sugars and CHO which reduce growth of pathogens and spoilage microbes
-"cure" contains nitrite and prevents growth of cl. botch -heating/smoking is lethal -drying: may hang for long periods of time which drops water activity |
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meat starter cultures
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-must be USDA approved
- added at around 10^6 CFU/g -can be frozen or freeze dried -typically slightly salt tolerant -typically produces lactic acid which aids in color and flavor and texture -exert effect by dropping pH and preventing growth of contaminents |
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Pediococcus
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major player in meat fermentation
-produces lots of lactic acid -homofermenter -species of interest: cerevisiae, acidilacticii -all used in sausage production -grow well at 32-49C -commercially available |
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L. Plantarum
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-heterofermenter
-can be used to protect both summer and semi dry sausages -predominant organism in naturally fermenting meats |
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molds in meat
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-italian dried salami
-impart flavors -typically penicillum or aspergilli -initially >95% yeast , within 2 weeks its about 50/50 yeast/mold, 4-8 weeks 955 molds |
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dry italian style
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30-40% moisture, not smoked, eaten unprocessed
-make process 1.grind and cure meat 2. place in casing 3.incubate at 80-95F 4. place in drying room doe 10-100 days 5. pH usually about 4.5-5.2 |
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Semi Dry
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"starter" pedicoccus cervisiae
combine ingredients, cool for 3-4 days and process composition: 30% f 20% p 3% minerals 47-50% water |
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semi dry meat make process
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1. mix meat salt, glucose, cure, starter mix
2. stuff into casing 3. ferment @ 85-110F 4. incubate until pH drops 4.6-5.2 for 8-12 hours in a smokehouse 5. cook 140 F 6. cool <50F 7. store below 50F 8. Get pH low before s. aureus can grow to high levels |
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Country Ham
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1. rub sugar cure on flesh side/hock end of butchered hog
2. let set a bit 3. wrap in paper and place in cotton fabric bag 4. lie flat several days 32-40c 5. hang shank end down for 6 weeks 6. may be smoked 7. mold may impart some flavors but is big in preventing outgrowth of pathogens |
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Proscuitto
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italian style country cured ham
-salt is only cure -hand rubbed kept at 60% humidity -cure 1-3 months -wash and dry -hang in drying rooms -finally into ripening rooms 3-5 months -may be over 100 days before ready |
