Carbohydrate Analysis

Question 1

Carbohydrates contribute to

Answer 1

bulk, body, viscosity, stability to emulsions and forms, water holding capacity, browning, flavors, aromas, etc

Question 2

Ingested carbohydrates come from

Answer 2

plant origins with milk lactose being an exception

Question 3

The only carbohydrate that can be absorbed in the small intestine

Answer 3

Monosaccharides

Question 4

Humans can only digest

Answer 4

+ Sucrose

+ Lactose

+ Maltooligosaccharides/maltodextrins

+ Starch

Question 5

Dietary fibers regulate

Answer 5

normal bowel function,
reduce the postprandial hyperglycemic response, and may lower serum cholesterol

Question 6

Qualitative analysis ensures

Answer 6

that ingredient labels present accurate compositional information

Question 7

Quantitative analysis ensures

Answer 7

added components are listed in the proper order ingredient labels and that amounts of specific components

Question 8

For labeling purposes sugars are defined as

Answer 8

the sum of all free monosaccharides and diasaccharides

Question 9

Examples of sugar alcohols

Answer 9

Sorbitol and xylitol

Question 10

Sample Preparation

Answer 10

1) Drying
2) Grinding
3) Extraction (lipids)

Question 11

Extraction is done with

Answer 11

hot 80% ethanol

Question 12

Reducing sugars are

Answer 12

those mono- and oligosaccharides that contain a free carbonyl

Question 13

Methods for Total Carbohydrate

Answer 13

Phenol-Sulfuric Acid Method

Question 14

Phenol-Sulfuric Acid Method reagents are

Answer 14

inexpensive
readily available
stable

Question 15

Phenol-Sulfuric Acid Method: Absorbance is measure at

Answer 15

490 nm

Question 16

Method for Total Reducing Sugar

Answer 16

Somogyi-Nelson Method

Question 17

Oxidation of the aldehyde group produces

Answer 17

carboxylic acid group

Question 18

The Somogyi-Nelson method is based on the

Answer 18

reduction of Cu (II) to Cu (I) ion by reducing sugars

Question 19

The Somogyi-Nelson method: Absorbance is measured at

Answer 19

520 nm

Question 20

Dinitrosalicylic acid method will measure

Answer 20

reducing sugars naturally occurring in foods or released by enzymes

Question 21

Munson-Walker Method

Answer 21

Oxidation can determined gravimetrically, titration with sodium thiosulfate or potassium permanganate or in the presence of methylene blue

Question 22

Other methods for total reducing sugars

Answer 22

+ Dinitrosalicylic acid method

+ Munson-Walker

+ Lane-Eynon

+ Electrolytically

Question 23

Keto groups cannot be _____ thus ketoses are not ________

Answer 23

Oxidized; reducing sugars

Question 24

Under alkaline conditions ketoses are

Answer 24

isomerized to aldoses

Question 25

Method for specific analysis of mono and oligosaccharides

Answer 25

High-Performance Liquid Chromatography (HPLC)

Question 26

HPLC give both

Answer 26

qualitative analysis and quantitative analysis

Question 27

HPLC analysis is

Answer 27

rapid, can tolerate a wide range of concen. and provides high accuracy and precision

Question 28

HPLC does not require

Answer 28

prior derivatization of carbohydrates

Question 29

HPLC does require

Answer 29

micron-filter filtration prior to injection

Question 30

Important parameters/principles of HPLC

Answer 30

the stationary phase the mobile phase the detector

Question 31

Stationary Phases (HPLC)

Answer 31

1) Anion-exchange chromatography 2) Normal-phase chromatography 3) Cation-exchange chromatography 4) Reversed-phase chromatography

Question 32

Detectors

Answer 32

1) Refractive index detection 2) Electrochemical detection 3) Postcolumn derivatization 4) Precolumn derivatization

Question 33

Gas Chromatography (GC) gas-liquid chromatography GLC provides both

Answer 33

qualitative and quantitative analysis of carbohydrates

Question 34

A flame ionization detector is detector of choice for

Answer 34

peracetylated carbohydrate derivatives.

Question 35

Two preparation steps for gas chromatography

Answer 35

1) reduction of aldehyde groups to primary alcohol groups 2) conversion of the reduced sugar into a volatile ester

Question 36

The basic principles/important parameters (GC)

Answer 36

1) Stationary phase 2) Temperature programming 3) Detection

Question 37

Method of choice for determination of starch employs a combination of

Answer 37

enzymes in sequential enzyme-catalyzed reactions

Question 38

Sample preparation for enzyme method

Answer 38

Carrez treatment 1) breaks emulsions 2) precipitates proteins 3) absorbs some color

Question 39

Resistant Starch

Answer 39

Composed of starch and starch-degradation products that escape digestion in the small intestine

Question 40

Hydrocolloids/Food Gums

Answer 40

Added polysaccharides along with the protein gelatin (Nonstarch polysaccharides)

Question 41

Physical Method

Answer 41

1) Microscopy 2) Mass and NIR Transmittance Spectrometry 3) Specific Gravity 4) Refractive Index

Question 42

Major components of dietary fiber

Answer 42

1) Cellulose 2) Hemicelluloses 3) Lignin 4) Other nonstarch plant polysaccharides

Question 43

Dietary Fiber

Answer 43

the sum of the nondigestible components of a foodstuff or food product