food testing Flashcards
What is the main use of iodine in biochemical tests?
Iodine is primarily used to test for the presence of starch.
True or False: The Biuret reagent is used to detect proteins.
True
What color change occurs when iodine reacts with starch?
The solution turns blue-black.
Fill in the blank: The Biuret test turns _______ in the presence of proteins.
purple
What is the role of ethanol in biochemical tests?
Ethanol is used as a solvent to precipitate lipids.
Multiple choice: Which of the following indicates a positive Biuret test? A) Blue, B) Green, C) Purple, D) Yellow
C) Purple
what colour would iodine stay as if there is no starch present
yellow/brown
what reagent is used to test for fats
ethanol
Fill in the blank: The presence of proteins can be confirmed by the Biuret test through the formation of a _______ color.
purple
Multiple choice: Which reagent is used to test for the presence of starch? A) Biuret, B) Iodine, C) Ethanol, D) Benedict’s
B) Iodine
What does a negative result in the Biuret test indicate?
It indicates the absence of proteins.
True or False: Ethanol can be used to test for sugars.
False
What is the purpose of adding iodine to a sample in a starch test?
To visually confirm the presence of starch.
Fill in the blank: The color of a positive iodine test is _______.
blue-black
What is Benedict’s reagent primarily used for?
to test for the presence of reducing sugars.
What colour change indicates a positive result when using Benedict’s reagent
The solution changes from blue to red
How is the Benedict’s test performed?
The test is performed by mixing the sample with Benedict’s reagent and heating it in a water bath.
What is the original color of Benedict’s reagent?
The original color of Benedict’s reagent is blue.
whats the end colour of benedict reagent
brick red
What is iodine reagent commonly used for?
Iodine reagent is commonly used to test for the presence of starch.
True or False: Iodine reagent turns blue-black in the presence of starch.
True
What color change occurs when iodine reagent is added to a solution containing starch?
The solution turns blue-black.
Which type of carbohydrate does iodine reagent specifically react with?
Starch
True or False: Iodine reagent can be used to test for proteins.
False
Short Answer: What is the appearance of iodine reagent before it is mixed with starch?
Brown or yellow-brown
whats biurets initial colour and what is it end results is results are positive
blue; lilac/purple
What is the primary use of biuret reagent
To detect the presence of proteins.
whats ethanol initial colour and what is it end results is results are positive
colourless to white emulsion
what does ethanol test for
lipids aka fats
what are fats made up of and its function
fatty acids and glycerol its function js a energy source and storage
what are proteins made up of
made of amino acids
what are carbohyrates made up of
simple compounds— glucose and lactose
complex —- cellulose starch and glycogen
whats the carbohyrates function
for energy and storage
