Re: Is it more value for money if purchased condensed powder fruit juice?

Aloha, Lee Hwee Kuan,

     You have asked a series of intersting questions.  I will attempt to 
answer one or two of them, and suggest a way that you can answer the 
others.
     First, yes, there are many ways that fruit juices are available.  Here 
in the U.S., we have mainly fresh-squeezed (refrigerated), concentrate 
(frozen OR packaged in shelf-stable wrap), and canned (heat sterilized).  
We also have some powdered juices/juice drinks.
     The shelf-life depends on the mode of processing.  For example, the 
fresh-squeezed juice is probably the least shelf stable, since it is a 
fresh product, and may not be pasteurized.  If it is not made in a sterile 
process, it can contain harmful bacteria, like E. coli O157H7, that killed 
a number of children here in the U.S.  My suggestion is to use only 
pasteurized, fresh juices, for just that reason.
     The canned juices have 'inifinite' shelf-stability, since they are 
heat treated to kill the microorganisms that can make you sick or that can 
ruin the juice.  They are safe, until you open them...then it depends on 
how you store them, yourself, as to whether or not they remain safe.  Of 
course, they will not taste like the fresh ones.
     The frozen concentrate is safe, as long as it remains frozen.  Once it 
is thawed/diluted, it depends upon the cleanliness of the water used, the 
cleanliness of the container, and how it is stored.  And, this one usually 
tastes quite close to the fresh juice.
     Regarding your question about the relative value of each type of 
juice:  You can calculate this yourself.  You will need to calculate the 
cost for a uniform amount, say an 8-oz glass or about 250 ml and then 
compare them.  The canned juice is simple...just the cost of the can 
divided by the number of 8 oz servings it contains...or the cost of the 
container divided by the number of oz in the container...and then times 8. 
Same for the fresh-squeezed juice.  For the powder, it's the cost of the 
powder needed to make an 8 oz/250 ml glass.  For the frozen, you'll have to 
figure out the amount of frozen concentrate that is in one glass (diluted) 
and use this number to see how much that amount of concentrate costs (out 
of the whole carton).
     Good luck on your calculations.  I'll make a guess that the 
concentrate will be the cheapest...but, that's only an educated guess.