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NU FS 374 > Plant Proteins > Flashcards

Plant Proteins Flashcards

1
Q

What are the two proteins in the processing industry?

A
  • concentrate: >50% protein
  • isolate: >80% protein
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2
Q

Benefits of plant proteins to replace animal meat

A
  • healthy (sometimes)
  • sustainable and ensure long term food stability
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3
Q

Comparing protein content of the different grains

A
  • Cereals (wheat 8-15% and oat 13%)
  • Oilseeds (soybean 40% and flax 25%)
  • Pulse grains (25-30%)
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4
Q

Amino acid composition and sequence

A
  • The amino acid composition determines the nutritional quality
  • sequence determines the physiochemical property of the protein.
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5
Q

nine essential AAs

A
  • phenylalanine
  • valine
  • threonine
  • ryptophan
  • isoleucine
  • methionine
  • leucine
  • histidine
  • lysine
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6
Q

AAs additionally required by infants and growing children.

A
  • Cysteine (or sulphur-containing amino acids),
  • tyrosine (or aromatic amino acids)
  • histidine
  • arginine
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7
Q

conditionally essential AAs

A

not normally required in the diet, but must be supplied exogenously to specific populations that do not synthesize it in adequate amounts.
* arginine
* cysteine
* glycine
* glutamine
* histidine
* proline
* serine
* tyrosine

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8
Q

Functional groups in proteins:

A
  • OH
  • COOH
  • NH2
  • SH
  • Alkyl groups
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9
Q

Major bonds in the protein tertiary structures.

A
  • Hydrogen bond, (OH and OH; OH and COOH)
  • Ionic interaction (NH3+ and COO-)
  • Hydrophobic interaction (between alkyl groups)
  • Di-sulfide bond (SH and SH)
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10
Q

Major bond in wheat protein

A

Di-sulfide bond (SH and SH) between cysteines
* helps produce gluten network in brad making

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11
Q

Major bond in tofu protein

A

ionic interactions (CaCl2)

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12
Q

What composes gluten in wheat?

A
  • gliadin: intramolecular
  • glutenin: networking
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13
Q

How does the gluten network form?

A

gentle kneeding (water +dough) causing interchain interaction between the glutenin molecules (quaternary)

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14
Q

AA acid profile of cereal proteins

A
  • Lack in nutritionally important amino acids such as lysine, tryptophane, methionine.
  • Generally high in aspartic acid, glutamic acid, proline, alanine and leucine.
  • Lysine is high in oat and rye than any other cereals
  • High lysine corn is available; high feed value.
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15
Q

AA profiel of oilseed proteins

A
  • When compared to cereals, oilseeds are high in lysine (3-4%).
  • Generally very high in aspartic acid, glutamic acid and arginine.
  • Generally high in serine, proline, glycine, alanine and leucine.
  • Low in tryptophane.
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16
Q

What lowers plant protein bioavailability?

A

Cross linked with phytic acid, tannins, lignins etc. making digestion and bioavailability lower

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17
Q

DIAAS

A

digestible indispensable amino acid score
* egg is golden standar
* ratio of the digestible amino acid content in the food (mg/g of protein) to the same amino acid in a reference pattern taken from age-specific amino acid requirements.

18
Q

PDCAAS

A

protein digested corrected amino acid score
* evaluates a food’s protein quality. It compares amino acid composition to what our bodies require.

19
Q

Protein classifications

A

basis of their extraction and solubility in water
* Albumin: water soluble, coagulated by heat.
* Globulin: water insoluble, soluble in dilute salt (0.5 M NaCl)
* Prolamin: soluble in 70% ethyl alcohol
* Glutelin: soluble in dilute acid (0.5 M acetic acid) or alkali

20
Q

What belongs to albumins and globulins?

A
  • Enzymes belong to this fraction
  • Storage proteins of pulses, oilseeds, etc
  • Concentrated in the aleurone cells, bran and germ/cotyledon
  • Relatively high in lycine, methionine and tryptophan
21
Q

What belongs to prolamins and glutelins?

A
  • Storage proteins in cereals
  • Limited to endosperm
  • Lack in nutritionally important amino acids such as lysine, tryptophan, methionine (low feed/food quality).
22
Q

Gliadin in wheat protein gluten

A

Do not contribute to elongation but are a part of stabilization and trapping CO2 (yeast using sugars) in compartments, holding it in, sealing it and preventing CO2 from leaking out.
* ~66%, w/w
* viscous
* sinlge unit with intra molecular disulfide bonds

23
Q

glutenins in wheat protein

A

Joins glutenin chains by disulfide bonds forming network as it is kneaded; usually ~ 5 min is optimal kneading time for everything; chain extension occurs with the disulfide bonds which helps to form the network.
* ~33%, w/w
* elastic
* has subunits connected with inter molecular disulfide bonds
* multi-peptide unit

24
Q

glutathione

A

Naturally present in wheat - small chain and takes place of high moelcular weight glutenin and can
terminate the chain extension. So interferes with network for ation in gluten
* Has cysteine unit and sulfide group

25
Q

Protein secondary structures of glutenin

A

beta sheets and alpha helix do it can coil with sheet in the middle; giving it a spring action. When they elongate with the disulfide bonds this makes dough highly elastic in nature.

26
Q

Development of glutenin network during dough kneading

A

Disuflide break and reform to creat the network, so network forms in many different dimensions; network give stability to bread as well

27
Q

Basic ingredients of bread making

A
  • flour
  • sugar
  • fat
  • water
  • salt
  • yeast
28
Q

Function of salt

A

1-2% Taste

29
Q

function of shortening

A

up to 4% - Incorporate air during mixing

30
Q

function of yeast

A

up to 3% - Leavening agent

31
Q

function of sugar

A

up to 3% - Yeast food, taste

32
Q

function of flour starch

A

(65-70%)
* Absorb water, swell, gelatinize
* Stabilize crumb structure through retrogradation

33
Q

function of flour protein

A

(13-14%)
* Aids in crumb grain formation
* Hold gas

34
Q

Bread making steps

A
35
Q

Purpose of punching/ knocking in bread making

A

During initial stages the yeast will grow in numbers within clusters but to get uniform crumb need to redistribute because they will produce CO2 and in cluster will make it regionally (big wholes seen in bread) so punch back redistributes the yeast more evenly and then CO2 forms more evenly and more even crumb.
* To redistribute yeast cells.
* Yeast cells do not have mobility in the dough; remixing will bring the fermentable sugars closer to yeast.
* Subdivide the air cells to produce many more smaller cells.

36
Q

Purpose of yeast in breadmaking

A

used in bread making as a leavening agent; causes the rising of dough. When added and mixed into the dough, Yeast grows in number by aerobic fermentation.
* Consume simple sugars & oxygen.
* Depletion of oxygen will trigger anaerobic fermentation.

37
Q

name for bakers yeast

A

Saccharomyces cerevisiae
* compressed yeast (70% water; stored at T < 5 C)
* Active dry or instant yeast (< 5% moisture stored under room temp.)

38
Q

problem with commercial yeast

A

Always contaminated with bacteria, mainly Lactobacilli spp. Causes mellowing or softening of dough / proteins swell

39
Q

Yeast fermentation

A
40
Q

Yeast Fermentable Sugars

A
  • Glucose, Fructose
  • Sucrose, Maltose, Maltotriose (converted)
41
Q

Active dry yeast

A
  • Prepared from special strains of bakers yeast which can stand drying
  • Less active than the strains used to make compressed yeast
42
Q

What Happens During Bread Making

A

NU FS 374 (8 decks)

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