Lecture 6 Flashcards
Why are salads a good thing?!
Provides opportunity to increase fruit and veg intake
Contain variety of vitamins and minerals
What are salad dressing made of ?
Usually contain an acid ingredient like vinagar, lemon, fruit juices
and
Thickener Agent
-xanthan gum, alginate, cellulose gum, locust bena gum, modified starch
What are thickening agents a substitute for?
Fat replacement
Produce an emulsion
What are the properties of thickening agents?
Hydrophilic–> holds lots of water which increases thickness
Where do the following thickeners come from/what do they do? Xanthan gum Alginate Cwllulose gum locust bean gum modefied starch
Xanthan gum: Used in gluten free baked goods, give batter more stickiness
Alginate: From brown algae, forma a gum when hydrated
Cellulose gum: Stabilize and thickens
Locust bean gum: Thicken and Stabilize
Modified starch: Chemically or naturally altered improves thickness
What are potential sources of contamination for salads?
Fields where grown Cooling facilities Packing houses Processors Transportation Food Establishments
What are some sanitary food handling practices you can take when dealing with salads?
Hand washing
Cutting board and other prep surfaces
Avoid cross contaminationi
What temp do salads need to be stored at?
4C or below
Minimizer time at room temperature during preparation or service
What kind of salad would require more strict food handling?
High protein
Neutral pH
High moisture
What are some food safety technologies that help keep salads safe?
Industrial scale washing procedures Lettuce treatments Bagging material Sanitizing leafy greens before processing Controlling atmospheric condiitons
How is vainer made?
2 step fermentation process involving yeast and acetic bacteria (minimum 4%). Can be done form any fermentable carb
- Yeast> Carb> alcohol
- Alcohol> Acetic acid `
What is a mother of vinegar?
non toxic thick slimy firm layer of cellulose formed by acetic acid bacteria during fermentation.
-acts as a starter culture to make more of the vinegar
Why do people like apple cider vinegar?
Supposed to interfere with fat deposition
Research has only been done on animals so far
Bad for teeth and esophagus
Can you eat olive directly from the tree?
No
-they have to be processed to remove the bitter water soluble phenolic components
How do you remove the phenolic components from olives?
Involves a lye (sodium hydroxide) or salt or brine treatment followed by water rinsing to remove bitter components
What is the process of removing the phenolic components?
Fermentation of sugar> lactic and acetic acid
-breaks bond between bitter oleuropein and sugar which allows the bitter components to be exerted out
Does the removal of phenolic compounds happen mechanically or naturally?
Can occur naturally but takes longer because it is just fermenting on yeast
Most olive oil production is mechanical
What are the 4 ways of processing olives?
- brine cured olives
- Dry salt cured olives
- Lye cured olives (most common method for commercial olives)
- Lye-cured Fermented Olives
What happens in the Brine cured olive process?
Salt solution, acts as a preservative
What happens in the dry salt cured olives?
Salty and more bitter as less oleuropein is removed, dry and shrivelled in appearance
What happens in the lye cured olives?
No fermentation step, rapid curing method using lye
Natural phobic compounds in the olives react with air to crease black colour
-Fe salts sometimes added to fix the black colour
What happens in the lye cured fermented olives?
Undergo initial lye treatment and then fermented in brine
Lactic acid starter culture is usually added
what is the diffrence between Virgin, extra virgin, lite and pure/classic?
Extra virgin: More expensive, top grade, low acidity, less processed, higher amount of natural compounds such as vitamins and minerals
Virgin: Slightly lower quality, from first pressing of the olive
Lite: Lacks the olive flavour
Pure/Classic: Mix of extra virgin and virgin, less expensive and less flavourful
What are the 3 main types of dispersion systems in food?
Emulsions (liquid in liquid)
Sols (solid in liquid)
Gels (liquid trapped in solid)
How do you classify emulsions?
Based on dispersed phase
- oiling water: oil droplets dispersed in water
- Water in oil: water droplets dispersed in oil
What are the 2 kinds of emulsions
Temporary
-Emulsioin formed upon shaking but separated upon standing
Permanent
-Require emulsifying agent
What are the emulsifying agents?
Amphiphilic: attracted to both fat and water
- more attracted to water=oil in water
- more attracted to fat= water in oil
Hyprophilic lipophilic balance (HLB) scale 1-20
- less than 6 = water in oil
- greater than 8= oil in water
What is the purpose of emulsifying agents?
Stabilize continuous phase by increase viscosity (thicker is better)
Impact droplet size (smaller is better)
Distribute colour in food
What are examples of emulsifying agents?
Lecithin in egg yolks Mono and diglycerides Isolated milk protein casein Whey protein Isolated soy protein Gelatin Vegetable gums
How does an emulsion break?
Is dispersed particles coalesce and separate
–coalesce to come together to forma mass/whole
What are casques for an emulsion to break?
Oil is added too rapidly
Too high of a ratio of oil to emulsifier
Inefficient method o agitation
What are sols?
Sol is in a liquid pourable condiiton
-may be transformed into a gel under the right conditions of temp, pH and concentration
What are gels?
Composed of fluid but behave like solids
-contain polymers cross linked to trap liquid
What are gels impacted by?
Temp
Syneresis
pH
Which polymers form cells?
Amylose
Egg protein
Pectin
Gelatin
How do you get gelatine?
Obtained by hydrolyzing collagen which is sound ind animal:
- hide
- skin
- bone
Is gelatin a good source of protein?
It has low biological value of protein
What is the manufacturing process of gelatin?
- Separate the collagen from other components
- Purified collagen is converted into gelatine
- Gelatine is purified, refined and recovered in dry form
Does gelatine need to be refrigerated when combined with water?
Yes, because moisture and animal products have a higher chance of bacterial growth
What are food products you can find gelatin in?
Foams: as stabilizer
Pudding/Pie: Thickener
Candy: Marshmallows
ice Cream: control crystal size
What is gelation?
Gel formation or stiffening of a gelation
-is a gradual process caused by linking of gelation molecules to form a structure that is typical of gels
What does dry gelation do in water?
Swells
- in hot water particles dissolve
- hot only preferred when [high gelation] is desired
What inhibits gelation swelling?
Sugar
-some salts
What speeds up swelling?
Salts
When does dispersion of gelatin occur?
greater than 35C
-cooling starts at less than 35C
How do you prepare unflavoured gelation?
- Soak in cold water to hydrate gelation
- Elevate temp to 35C or higher by adding hot liquid/suspending over hot water
- Remaining liquid is added cold
- Add fruit acids/sugar/salts
How do you prepare flavoured gelation?
Add hot water to disperse and dissolve geltain
-no soaking required
What are the condition impacting gelation solutions?
Temp [ ] pH Sugar Salt enzymes
What temp is required for solidifying gelation solution?
10-16C
-gel weakens at greater than 40C
Whats the difference between rapid and slower cooling of gelatins?
Rapid: sets gel more quickly results in a softer gel
Slower cooling: sets gel more slowly results in a firmer gel
How does concentration of gelation effect solidification?
- usually 1.5-2% gelatin
- when beaten to a foam the gel is less firm
How does pH effect solidification?
High acid prevents gelation and softens gel
Lemon juice and vinegar have pronounced effect on gelation than foods that are less acidic
-tender and stiff gel
What do enzymes do to gelatine solidification?
Bromelein from pineapple can hydrolyse gelatin proteins
-proteinases in kiwis and papayas do the same thing
What kind of salads/desserts can gelatin be found in?
Fruit, veggie, meat and fish jellies Aspics Foam and Sponges Bavarian and Spanish Creams Unmolding getlatin gels
