Carbohydrate Analysis Slides

Question 1

What are carbohydrates
Empirical Formula:

Answer 1

Compounds of Carbon, Hydrogen and Oxygen

CnH2nOn

Question 2

Carbohydrates functional role in food

Answer 2

Bulk
Viscosity
Water Holding Capacity

Question 3

Classification of CHOs

Answer 3

1) Monosaccharide
2) Disaccharides
3) Oligosacharides
4) Polysaccharides

Question 4

Examples of monosaccharides

Answer 4

Glucose and Fructose
(easily absorbed)

Question 5

Examples of Disaccharides

Answer 5

Lactose, Sucrose, and Maltose

Question 6

Only polysaccharides digested by humans

Answer 6

Starch

Question 7

Sugars =

Answer 7

sum of all free mono- and disaccharides

Question 8

Sugar Alcohols =

Answer 8

alditols, polyhydroxyalcohols, polyols, sorbitol, and xylitol

Question 9

Other carbohydrate =

Answer 9

total carbohydrate - (dietary fiber + sugar)

Question 10

Total carbohydrate =

Answer 10

100% - (% Moisture + %Ash + %Lipid + %Protein)

Question 11

Test for Hexose or Pentose

Answer 11

Bial Test

Question 12

Test for aldose or ketose

Answer 12

Seliwanoff test

Question 13

Reducing sugars test

Answer 13

+ Benedict’s test

+ Barfoed’s Test

Question 14

Test for starch or glycogen

Answer 14

Iodine test

Question 15

Quantitative chemical methods

Answer 15

Phenol-sulphuric
Somoygi-Nelson
Dinitrosalicyclic method

Question 16

Quantitative chromatography method

Answer 16

HPLC
Gas chromatography
Thin-Layer
Paper

Question 17

Preparation of sample

Answer 17

1) Drying
2) Grinding
3) Extract lipids

Question 18

Bial’s Test Reagents

Answer 18

FeCl3 or HCl

to give blue color: positive of pentoses

Question 19

Dehydrated ketose reacts with resorcinol to produce

Answer 19

cherry red color (Seliwanoff’s Test)

Question 20

Principle of Phenol-Sulfuric Acid Method

Answer 20

Carbohydrate treated with strong acid/heat form furan derivatives

Question 21

Benedict’s Test (reducing sugars)

Answer 21

Alkaline solutions of copper are reduced by sugars having free aldehyde or ketone group

Question 22

Seliwanoff’s Test distinguishes between

Answer 22

Aldose and ketose sugars

Question 23

When heated ketoses dehydrate

Answer 23

more rapidly than aldoses

Question 24

Examples of ketose monosaccharides

Answer 24

Dihydroxyacetone
Erythrulose
Ribulose
Fructose

Question 25

Examples of aldose monosaccharides

Answer 25

Glyceraldehyde Erythrose Ribose Xylose Glucose Mannose Galactose

Question 26

Barfoed's test is used for

Answer 26

detecting the presence of reducing monosaccharides

Question 27

Barfoed's Test is based on the

Answer 27

reduction of copper (II) acetate to copper (I) oxide (Cu2O) (brick red)

Question 28

In got acidic medium starch is _______ and dehydrated to _____

Answer 28

hydrolyzed to glucose; hydroxymethyl furfural

Question 29

Methods for total reducing sugar

Answer 29

Somogyi-Nelson Munson-Walker Lane-Eynon

Question 30

Principle for total reducing sugar

Answer 30

Sugars with aldehyde group act as reducing agents - they reduce Cu2+ to Cu+

Question 31

Starch contain what two polysaccharides

Answer 31

Amylose (linear) and Amylopectin (branched)

Question 32

Most starches contain

Answer 32

15 - 35 % amylose

Question 33

Amylose are linked together by

Answer 33

alpha 1,4 linkage

Question 34

Amylopectin are linked together by

Answer 34

alpha 1,4 and alpha 1,6 linkage

Question 35

Amylose is _____ in water, while amylopectin is ______

Answer 35

soluble; insoluble

Question 36

Amylose gives what reaction in iodine solution vs amylopectin

Answer 36

Blue color vs no reaction

Question 37

Give rise to; Amylose vs Amylopectin

Answer 37

Gel formation vs Thickened preparation

Question 38

Starch usually contain more

Answer 38

amylopectin than amylose

Question 39

Starch Gelatinization: Heat causes

Answer 39

1) Water absorption by amyloplasts 2) Rupturing of the amyloplasts 3) Starch network formed 4) Hydrated network with water pockets 5) Gelatinization

Question 40

Factors influencing gelatinization

Answer 40

+ Types of starch + Water + Temperature + Stirring + Addition of other ingredients

Question 41

Starch Dextrinization

Answer 41

Starch and dry heat

Question 42

Starch --> Dextrin; which provides

Answer 42

flavor, color, and aroma

Question 43

Gel formation: Upon cooling

Answer 43

the realignment of starch molecules with water being squeezed out