Fermentation

what are the four microorganisms involved in fermented foods

LAB, other bacteria (Propionibacterium, Brevibacterium), fungi, yeast

how does natural fermentation occur and what are ex

relies on indiginous organisms-wines, saurkraut, kimchi, soy suace

what is backslopping and what are ex

relies on use of previous batch-sausge, sour dough, beer, keifer

what is the yeast in bakers yeast

saccharomyces cervisiae

what are thermophilic cultures (3)

streptococcus thermophilus and lactobacillus helvecticus or lactobaccilus delbruekii subsp: bulgaricus

the ecological phenomenon that occurs in fermented foods when one group of organisms creates an environment that promotes another group is called?

succession

what do we study to understand biochemical phenotype (3)

sugar fermentation patterns; catalase, oxidase, urease; metabolic end products

what aromas and flavors do the cultures in smear cheeses give off

sulfury

why is taxonomy important in fermentation microbiology (2)

tells us what organisms performed the fermentation and what organisms can be added to enhance the product

what does the successful manufacture of fermented foods ultimately rely on

the performance of the microorganisms

what is a challenge for brewing

the substrates (cereal grains) contain little or no sugars, but lots of starch so the starch must be converted to fermentable sugar

what is the culture in swiss cheese (2)

thermophilic lactic acid bacteria and propionibacterium freudenreuchuu subsp. shermanii

what type of cultures must be used in hard-grating cheeses and why

thermophilic since high cooking temperature

why do we add water to washed cheese curds

to dilute out lactose, resulting in less acid formed during fermentation

why are hard cheeses cooked to a high temperature

to drive our moisture

what is the purpose of malting

to provide a stable source of enzymes and substrates

what products contain tetragenococcus

veg

what are examples of cultured dairy products

yogurt, buttermilk, sour cream, kefir

what are the two fermentative pathways for lactose

homofermentative, heterofermentative

what is the specialized flavor in cultured dairy (2)

1. acetaldehyde (tart apple flavor in yogurt) 2. diacetyl (buttery) in buttermilk and sour cream

what are the 3 basic steps to dairy fermentation

1. acidification 2. enzymatic 3. heat +acid

what are the 4 steps of malting

1. barley 2. steeping and germination 3. drying and kilning 4. malt

what are the steps of post-fermentation (4)

1. beer 2. clarification and filtration 3. packaging and pasteruization 4. beer

what are the 4 current issues in the starter culture industry

1. biomass, stability, viability 2. biopreservation 3. customized properties (flavor, texture) 4. phage-viruses that infect bacteria

what are the 2 types of cultures

1. bulk cultures (lyophilized or frozen) 2. direct-to-vat cultures (lyophilized or frozen)

what are washed curd cheeses (4)

1. colby 2. monterey jack 3. havarti 4. dutch cheeses (gouda, edam)

what are the general properties of fermented foods (6)

1. enhanced preservation 2. enhanced nutritional value 3. enhanced functionality 4. enhanced organoleptic properties 5. unique 6. increased economic value

what is required in swiss cheese to get perfect eye formation (3)

1. exact texture (soft and elastic) 2. 35% moisture 3. pH 2.5

what are the general functions of LAB in fermented foods (5)

1. ferment sugars and reduce pH 2. sythesis of flavor compounds 3. texture changes 4. out-compete other microbes 5. production of antimicrobial substances

what are the desirable properties of bakers yeast (7)

1. gassing power 2. flavor development 3. ethanol tolerant 4. cryotolerant 5. stable to drying 6. stable to storage 7. easy to dispense

why do we not like backslopping and natural fermentations in sausage (5)

1. inconsistent quality 2. unreliable fermentation 3. long fermentation times 4. risky for food safety 5. difficult to control

what are the 4 principles of cultured dairy

1. isoelectric precipitation 2. no whey removal 3. minimize syneresis (whey removal) 4. specialized flavor department

what are the steps of wort preparation (9)

1. malt 2. milling 3. add water and adjuncts 4. mashing 5. lautering 6. kettle boil 7. add hops 8. whirlpool 9. wort

what are the four steps of beer fermentation

1. malting 2. wort preparation 3. fermentation 4. post-fermentation

what are the 3 ways to initiate sausage fermentation

1. natural fermentation 2. backslopping 3. starter culture

what are the three ways to initiate fermentation

1. natural fermentation 2. backslopping 3. starter cultures

what are the prinicples of fermented vegetables (5)

1. natural fermentation-no culture necessary 2. relies on autocthonous organisms 3. requires selection for LAB and against everything else 4. microbes grow in succession 5. leave raw or heat-treat finish product

what are 5 methods to prevent phage problems

1. plant design 2. sanitation 3. phage inhibitory media 4. culture rotation 5. phage resistant cultures

what are four functional properties of sour dough cultures

1. preservation 2. production of anti-fungal agents 3. flavor 4. reduced staling rate

what are the functions of starter cultures in sausage fermentation (6)

1. produce lactic acid and lower the pH 2. flavor 3. out-compete pathogens 4. growth depends on added carbs 5. culture growth lowers Eh 6. for european style sausages nitrate is used instead of nitrite and non-LAB are needed to redice it to nitirite-producing flavor and color

what are the 4 principles of cheese

1. remove water 2. flavor and texture development 3. concentrate protein and fat 4. long shelf-life

what are the 4 nutritional requirements of LAB

1. sugars for energy 2. pre-formed amino acids 3. complex nutrients (some strains) 4. anaerobics (some strains)

why do we need starter cultures (5)

1. volume/density 2. convenience 3. timeliness 4. consistency 5. novel traits

what are the steps of fermentation (6)

1. wort 2. cool 3. add pitch 4. fermentation 5. conditioning and maturation 6. beer

what are the requirements for the bacteria and yeasts for sour dough fermentation (3)

1. yeast must be acid tolerant 2. bacteria must be ethanol tolerant 3. must not compete for the same sugars

what percent of probiotic products contain Lactobacillus

>80%

what are molecular approaches for identification that are good at the species level (3)

DNA-DNA hybridization, 16s rRNA sequencing, whole genome sequencing

what are common characteristics of LAB

G+ rods and cocci, non-spore forming, catalase negative, non-motile, fermentative, facultative anaerobes, acid-tolerant

what are molecular approaches for distinguishing between strains (4)

Random amplification of polymorphic DNA (RAPD), multilocus sequence typing (MLST), pulsed field gel electrophoresis (PFGE), amplified fragment length polymorphism (AFLP)

what is acidification

adding casein, the main milk protein precipitates or coagulates at pH 4.6-4.7

what does blue cheese require for interior mold growth

aeration

what causes the amylose and amylopectin reaction

alpha-amylase

what is the enzymatic step in dairy products

casein also coagulates after treatment with the enzyme chymosin

what is the heat + acid step in dairy fermentation

casein precipitates at high temperatures

what does malt affect

color, body, flavor

What is a starter culture?

concentrated and preserved source of selected microbes that are added to raw or pasteurized substrates to overwhelm the resident organisms and perform the desired fermentation on a reliable, predictable, consistent basis

how can phage resistant cultures prevent phage problems

construct starter culture cells that will grow and perform well even in presence of phage

what is cheese ripening

controlled spoilage

what is malting

conversion of barely to malt

what products is lactococcus found in

dairy

what products is streptococcus found in

dairy

what products are lactobacillaceae found in (most important to know)

dairy, meat, veg, fruit/wine

what products is leuconostoc found in

dairy, veg, fruit/wine

what are starter cultures and what are example products

defined strains in concentrated form-cheese, yogurt, sausage, wine, beer, bread

how are starches converted to sugars

enzymatically, using enzymes synthesized in the barley, acting on substrates in the barley

what does cheese ripening cause changes in (4)

flavor, texture, appearance, rheology

what products is Oenococcus found in

fruit/wine

what do we study to understand morphology (3)

gram reaction, motility, spore formation

what does brie require on the surface

growth by mold

what do we study to understand physiology and ecoloy (3)

growth temperature, pH range, aerobic or anaerobic

what do the cultures in smear cheeses cause on the surface

growth with orange-red pigment

what fermentation path is sour dough

heterofermentative

what are the 2 fermentative pathways in lactic acid bacteria and generation of flavor compounds

homofermentative and heterofermentative

what is mashing

hydrolysis of starch and protein

what are other methods of analysis

immonogenic, cell wall structure, membrane lipids

why will changing a name for a major genus have a major impact on the probiotic and starter culture industry

it will improve sequence-based identification and avoid misidentification/miscommunication and provides a basis for connecting functions to specific species or groups

why do we need to ID strains

just in case another company steals your strain

how can plant design prevent phage problems

keep phage out of production area and prevent cross contamination

how can sanitation prevent phage problems

kill phage in plant environment

what 2 genera of lactic acid are used for meat starter cultures

lacotbacilliacea (favored at high temps) and pediococcus (favored at low temps)

what are the products are homofermentative

lactate

what is the product of the homofermentative pathway

lactate

what are the products of heterofermentative

lactate, acetate, CO2, ethanol

what is the products of the heterofermentative pathway

lactate, acetate, CO2, ethanol

what bacteria are used in brie (2)

lactococcus lactis and penicillium camemberti

what bacteria are used in blue cheese (2)

lactococcus lactis and penicillium roqueforti

what are mesophilic cultures (2)

lactococcus lactis subsp: lactis and/or lactococcus lactis subsp: cremoris

what are citrate-fermenting cultures

leuconostoc mesenteroides subsp. cremoris

what does the flavor in blue cheese come from (3)

lipolysis, fatty acid metabolism, and formation of methyl ketones

what does fermentation do to milk

makes a coagulated milk gel

what is the difference between spoilage and fermentation

matter of control-in fermentation conditions are controlled such that selected microbes grow

what products is pediococcus found in

meat, veg

what type of cultures do munster and other smear cheeses use

mesophilic

what type of cultures do washed curd cheeses use

mesophilic

what are the four traditional methods of analysis

morphology, biochemical phenotype, physiology and ecology, other

what is fermentation controlled by (7)

pH, mositure, substrate availability, temperature, salt, competition

what are examples of hard grating cheeses

parmesan, grana, asiago, romano

how can phage inhibitory media prevent phage problems

prevent phage from attaching to and infection culture cells

how can culture rotation prevent phage problems

prevent proliferation of phage by limiting access to suitable hosts

what is the flavor from in brie (2)

protein and fat metabolism (NH3)