Technical Challenges (5)

Question 1

what are 4 imp factors influencing efficiency of carrageenan gum?

Answer 1

1. acidulants or pH
2. cations
3. temp
4. sugars

Question 2

how does acidulants or pH affect efficiency of carrageenan gum?

Answer 2

at high temp, carrageenan solutions that contain acidulants exhibit some loss in viscosity and potential gel strength

Question 3

how does cations influence efficiency of carrageenan gum?

Answer 3

as conc of cations increases, dispersion improves, gelling T increases, remelting T increases

Question 4

how does temp influence efficiency of carrageenan gum?

Answer 4

gels can be subjected to repeated heat/cool cycles w/ very little effect on gel structure

Question 5

how do sugars influence efficiency of carrageenan gum?

Answer 5

high levels of sugars reduces solubility of carrageenan

Question 6

what are main functionalities of carrageenan gums?

Answer 6

• moisture binding
• stabilizes emulsions
• suspends particles
• controls flow properties
• produces stable gels at room temp

Question 7

describe how carrageenan gum effects emulsification

Answer 7

its thickening and thixotropic properties inhibits oil from coalescing

Question 8

describe how carrageenan gum effects poultry processing

Answer 8

causes problems such as protein denaturation, textural changes, moisture loss, fat oxidation, breakdown of meat texture

Question 9

describe the synergism of carrageenan gums with other gums

Answer 9

interactions increases gel strength, improves moisture binding capabilities and modifies gel texture to be more elastic and resilient

Question 10

describe the synergism of carrageenan gum with starch

what happens when only kappa carrageenan is added?

Answer 10

carrageenan increases viscosity of starch systems by 10 times the viscosity of the starch alone

only kappa carrageenan: no increase

Question 11

describe the effects of adding carrageenan with casein

Answer 11

forms a weak thixotropic gel structure which will suspend cocoa in chocolate milk and form milk gels

Question 12

describe the structure of furcellaran

Answer 12

one sulfate ester with two sugars

Question 13

describe the structure of carrageenan

Answer 13

one sulfate ester with three to four sugars

Question 14

describe the effects of adding ____ to furcellaran

1. potassium ions
2. calcium ions
3. Na ions
4. sugar.

Answer 14

potassium: increases gel strength
calcium: lowers effects

Na ions: prevents gel setting

sugar: forms a brittle to a more elastic texture

Question 15

describe solubility of furcellaran

Answer 15

soluble in water (75 to 77C)

forms elastic gels when cooled to 35-45C

Question 16

describe solubility of alginate gum

Answer 16

very soluble in hot or cold water

Question 17

describe gelling properties of alginate gum

Answer 17

• forms clear gels with polyvalent cations

- increase GG fractions = increases ability to form strong gels

Question 18

how does increasing temp affect viscosity of alginate gum?

Answer 18

temp incr of 1C = viscosity decrease of 2.5%

Question 19

what acid conditions does alginate gum need?

Answer 19

high acid

Question 20

what sugar solids and pH is required for alginate/high methoxy pectin gels to form?

what is required when sodium alginate is included?

Answer 20

alingate/pectin gels: high sugar solids with narrow pH range

with sodium alginate: low solids and below pH 3.8

Question 21

what are the two major fractions of agar gum

Answer 21

a) agarose

b) agaropectin

Question 22

describe the structure of agarose

Answer 22

neutral polymer with repeating alternate units of beta-1,3-D-galactose and alpha-1,4-3,6-anhydro-L-galactose

Question 23

describe the structure of agaropectin

Answer 23

sulfate polymer composed of agarose + glucuronic acid

Question 24

which is non-gelling?

a) agarose
b) agaropectin

Answer 24

agaropectin

Question 25

describe solubility of agar in water

Answer 25

• insoluble in cold water, but swells considerable (absorbs 20x its own weight of water)
• dissolves readily in boiling water, then sets to a firm gel at low concentrations

Question 26

describe the gelling properties of agar gum

Answer 26

• forms weak gels at very low conc (0.2%)
• forms rigid gels at 0.5%
• thermo-reversible gel
• has syneresis and hysteresis
• increased gel strength with increased salt and sucrose conc

Question 27

how does increasing salt and sugar conc affect gelling properties of agar gum

Answer 27

increase salt + sugar = increases gelling

Question 28

what is syneresis

Answer 28

extraction of a liquid from a gel

Question 29

what is hysteresis

Answer 29

when the physical property lags behind changes in effect causing it

Question 30

describe the temperature and acid conditions needed for agar

Answer 30

• sensitive to low pH

- can withstand high temp

Question 31

describe stability of agar gum

Answer 31

stable to retorting

not stable to repeated freezing and thawing

Question 32

what bacterium produces xanthan gum

Answer 32

xanthomonas campestris

Question 33

describe solubility of xanthan gum

Answer 33

soluble in hot or cold water

Question 34

describe viscosity properties of xanthan gum

Answer 34

• forms viscous and non-thixotropic solutions even in small concentrations
• pseudoplastic hydrocolloid
• higher viscosity when mixed with guar or LBG than when used alone

Question 35

compare the viscosity of xanthan gum alone vs when mixed with guar or LBG

Answer 35

higher when mixed with guar or LBG

Question 36

describe emulsifying properties of xanthan gum

Answer 36

high emulsifying properties at low pH

Question 37

describe Konjac (glucomanna) and xanthan gels

Answer 37

very cohesive and elastic