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Flashcards in Energetics 2 Deck (19):
1

How is fat content analysed?

Rapid Soxhlet Extraction

2

How is protein content analysed?

Thermo scientific flash/protein analyser

3

How is salt content analysed?

Digital salt meter

4

How is sugar content analysed?

Digital meter

5

How are energy values measured?

Bomb calorimetry

6

Bomb calorimetry procedure (3)

Measures heat of combustion of a particular reaction
Determines the heat of combustion
Or calorific value of materials which are burned as fuels

7

Bomb calorimetry measures _____ energy

Gross

8

Why isn't all gross energy available to the body?(2)

Not all food eaten is absorbed from digestive tract
Not all energy in protein is released

9

Define metabolisable energy (2)

Proportion of energy available to the body
After urine and faeces loss from gross energy

10

Problems with ME (6)

Assume that all macronutrients are equal
Some forms of starch are indigestible
Assumes he 6.25g of protein contains 1g of nitrogen
Different FAs have different digestibility
Animal and plant protein have different ME
Assumes fibre does not contribute to ME

11

Direct calorimetry (2)

Measures heat generated by the body over a given period of time
Performed in live in chambers

12

Disadvantages of direct calorimetry (3)

Has to be made over long periods of time
Not applicable for sports or occupational activities
Corrections required for all heat entering and leaving chamber

13

Indirect calorimetry (3)

Method of estimating energy expenditure by measuring respiratory gases
Measures the consumption of oxygen and production of carbon dioxide
When foods are oxidised in the body oxygen is used and carbon dioxide is produced

14

Respiratory quotient (2)

The ratio of carbon dioxide produced to the oxygen used on oxidation of a given amount of the nutrient at the cellular level

15

Respiratory exchange ratio (2)

The ratio of carbon dioxide produced to the oxygen used on oxidation of a given amount of the nutrient measured from expired air

16

Doubly labelled water (3)

Consumption of water labelled with two isotopes
Uses rate of CO2 production to estimate EE
Also measures the disappearance rate of 2H2 and 18O

17

How is water content analysed?

Drying oven

18

Doubly labelled water advantages (2)

Can be used in wide range of situations
Closest measurements if free living EE

19

Doubly labelled water disadvantages (2)

Expensive isotopes
Expertise needed