Week8-Course2 Flashcards
Define one calorie
amount of heat required to increase the temperature of 1gram of H2O by 1°C (from 14.5 to 15.5 ° C).
1 cal = ___ joules
4.184
Why would determining energy content of a food not be reliable if it only done by the bomb calorimeter
doesn’t take into account digestibility
How can you estimate the energy content of food if you are not using the bomb calorimeter?
You use analytical chemistry to estimate the content of food and you multiply the content by the standard values.
T or F : for fat 9kcal/g is an average value of the energy content but it varies
T
T or F : sugar alcohol are non-nutritive sweetners
False, they are nutritive sweetners because they provide 1.5-3kcal/g
T or F : artificial sweetners can interact with water like real sugar so they can be used for baking
F, the sugar alcohol can be used for baking because they bind water but not the artificial sweetners
Why sugar alcohol can be used for baking?
because they can bin with water by making hydrogen bonds and they provide most of the functional properties of sugars
What a.a. contain aspartame? How are they bounded?
methyl ester of a dipeptide (phenylalanine +
aspartic acid
What is the alternative really similar to aspartame that phenylketonuria patients can consume? Why?
Neonatame, because it is the same molecule as aspartame but with a neohexyl attached so the peptidic bound can’t be broken so the phenylalannine is not released
What is the sweetning power of neonatame?
7000-13000
What is the sweetning power of aspartame?
200
What is the sweetning power of acesulfame-K
200
What is the molecule of sucralose?
sucrose molecule with three chlorine instead of the hydroxyl groups
What is the sweetning power of sucralose
600
Name two fat replacers
olestra
simplesse
What is simplesse?
fat replacer made of microparticulated milk and/or egg-white proteins
Why is simplesse not suitable for frying?
Because made of egg-white proteins and they are going to denature
T or F : sugar alcohol behave exactly the same as sugars?
False, they have most of the functional propoerties of sugars but do not behave the same as sugars
What is olestra?
Fat replacer, sucrose molecule with 6-8 hydroxyl groups are esterified with fatty acids
What are the kind of fat replacers really used in industries right now
carbohydrates based fat replacers because they act as fat in food products
T or F: Carbohydrates: both sugars and starch assist the body in utilizing fats
more efficiently by producing organic acids that are required to
convert fats fully to CO2 and water
T, the carbohydrates are necessary for the conversion of glucose to pyruvate (organic acid) that is necessary for the conversion of acetyl coa to CO2 and energy in the TCA cycle
T or F :proteins are the main source of nitrogen and amino acids
for the body’s synthesis of tissue and other protein- or nitrogencontaining
constituents
T
What determine the biological value or nutritional quality of protein?
The presence of essential amino acids and their balance and the digestibility
What essential amino acid is lacking in cereals
lysine
What essential amino acid is lacking in legumes
methionine
Why are animal used in the evaluation of a protein’s quality?
Because the balance of amino acid (composition of the protein) is not enough to evaluate the quality, the protein digestibility needs to be taken into account
Why is the plant based protein of low quality?
Because of the poor essential amino acid profil content (lacking either methionine or lysine) and the low digestibility
T or F : if you only consume gelatine as a source of protein you will loose weight
True, because low essential amino acid content will make your body catabolise body’s protein content
What is the PER?
Protein efficiency ratio (PER) : a measure of the animal’s weight gain per gram of a certain protein consummed.
Higher is the PER, higher is the _______
protein quality
What is the BV?
Biological value, it measure the protein quality using the nitrogen retention by measuring the protein consummed - the nitrogen excreted
What is the NPU ?
Net protein utilization, it is the biological value (BV) times the digestibility factor
What is the NPV
it is the net protein value (NPV) times the % protein in food
T or F : Many food processing operations reduce the vitamin content or
availability in foods
T
What are the fat soluble vitamins?
A Retinol
D calciferol
E alpha-tocopherol
K Phylloquinone
What are the water soluble vitamins?
C ascorbic acid
B vitamins (1,2,3,5,6,7,9,12)
and choline
T or F : hydrosoluble vitamins are more stable than liposoluble so they are less affected by oxidation
False it is the inverse that is true
T or F : Dramatically reduced fat intake can lead to a shortage of fat-soluble
vitamins
True
T or F : vitamin A is only found in animal derived products
True, but the precursor (or pro-vitamin) beta-carotene is found in plant
What are the roles of retinol, retinal and retinoic acid?
Retinol: Strengthens mucous membranes; keeps skin flexible
Retinal: Plays a fundamental role in vision: vitamin A deficiency affects night vision
Retinoic acid: Regulates gene expression/protein production in cell nucleus
Retinol is a
alchohol
Retinal is a
aldehyde
Retinoid acid is a
acid
Cleaving one molecule of the beta-carotene gives to molecules of ____
retinol
Complete : vitamin D is synthesized from
____ upon exposure to ____ specifically ___
cholesterol and other sterols
to sunlight
UVB
Complete : vitamin D is involved in the absorption of ____ and ___ from the
calcium and phosphorus from the kidneys
T or F : Raw milk is a rich source of vitamin D
FALSE, vitamin D is added to milk in the processing.
What are good food sources of vitamin D?
fish, liver, dairy products (added) and eggs
T or F : Vitamin E is present in most unprocessed vegetable oils but may be
lost during processing and refining.
True
What is specific molecule in the tocopherol family that has the highest antioxidant funciton
delta-tocopherol
T or F : Vitamin K is also synthesized by microorganisms in the intestinal
tract.
True
T or F : it is very rare to notice the deficiency of vitamin K because it is produced by the microorganism in the colon by fermenting fiber
True
T or F : protein quality can be evaluated on the basis of amino acid composition.
F, it need to take into account the digestibility of the protein source so animal studies are necessary.
