PDA

View Full Version : Food tests


mysterious_nad
Oct 4, 2008, 04:00 AM
Hi, I've been doing experiments at scool, and I need help to answer this question, would anyone be able to tell me any other types of food test we might come across such as Benedict's food tests

Clough
Oct 4, 2008, 04:08 AM
Hi, mysterious_nad!

I think that it would help those who come along to address your question is you would list the experiments that you've already performed.

Thanks!

mysterious_nad
Oct 4, 2008, 04:18 AM
OK the experiments I did at scool, were testing for reducing and non-reducing sugar. The experiments were, cellulose, lignin, lipids. I don't know if that helps

Unknown008
Oct 5, 2008, 09:01 PM
I know for some, namely reducing sugars and starch concerning carbohydrates.

Ok, here we go, for reducing sugars.

You have your sample, in solution, in a test tube. Add some drops of Benedict's solution and warm. If reducing sugars were present, then, the mixture will change colour. From blue, to green, then yellow, then orange and finally red. Sometimes, it may stop at orange.

For starch.

Add a few drops of iodine solution onto your sample. The iodine will turn blue black in the presence of starch.

For proteins.

Add some drops of copper(II) sulphate solution and dilute sodium hydroxide to your sample, then warm. The solution will turn purple if proteins were present.

For fats

Add some alcohol and shake. Add some water, then shake again. You shold see and emulsion if fats were present.

You can also place a drop on filter paper, if fats are present, then the paper will be transluscent, provided the fats is in the form of an oil.

That's all that I know concerning food tests. Hope it helped:).

mysterious_nad
Oct 10, 2008, 09:22 AM
I know for some, namely reducing sugars and starch concerning carbohydrates.

Ok, here we go, for reducing sugars.

You have your sample, in solution, in a test tube. Add some drops of Benedict's solution and warm. If reducing sugars were present, then, the mixture will change colour. From blue, to green, then yellow, then orange and finally red. Sometimes, it may stop at orange.

For starch.

Add a few drops of iodine solution onto your sample. The iodine will turn blue black in the presence of starch.

For proteins.

Add some drops of copper(II) sulphate solution and dilute sodium hydroxide to your sample, then warm. The solution will turn purple if proteins were present.

For fats

Add some alcohol and shake. Add some water, then shake again. You shold see and emulsion if fats were present.

You can also place a drop on filter paper, if fats are present, then the paper will be transluscent, provided the fats is in the form of an oil.

That's all that i know concerning food tests. Hope it helped:).

Thank you that has really helped with my experiment at scool. How do you know so much?

Unknown008
Oct 11, 2008, 02:18 AM
I did these at school a year ago, and am required to know them for my upcoming exams... in 2 weeks :eek:! ;)

mysterious_nad
Oct 11, 2008, 07:45 AM
I did these at school a year ago, and am required to know them for my upcoming exams... in 2 weeks :eek:! ;)

Good luck for your exams!! I think you would do really well seen as though you know so much. What exams are you taking? :) Nadia

Unknown008
Oct 11, 2008, 10:18 PM
Cambridge Syndicate exams. Well, I'm blushed, but this is a small chapter compared to the whole book. A 'rate this answer' form you would be most welcomed, if you don't mind. And I'm longing for more questions from you, it'll be a revision form me too!;)

I don't know if you know what exams I am taking, but it is from england.:)

mysterious_nad
Oct 12, 2008, 08:39 AM
Cambridge Syndicate exams. Well, i'm blushed, but this is a small chapter compared to the whole book. A 'rate this answer' form you would be most welcomed, if you don't mind. And i'm longing for more questions from you, it'll be a revision form me too!;)

I don't know if you know what exams i am taking, but it is from england.:)

Don't worry I have loads more questions to ask, but not just yet.:) I'm not familiar with the exams your taking, and its probably because I'm still doing my A levels. Are you over in england just for your studies? :)

Unknown008
Oct 14, 2008, 07:35 AM
Uh... no, they sent the test papers in Mauritius, then, the answered papers and sent over to england for correction, well, most of them. Maths I think are corrected locally. I'm supposed to be doing 'O'-level!!

mysterious_nad
Oct 16, 2008, 11:33 AM
I didn't think that still existed! My teacher told me they did o-levels back in the olden days when A-levels didn't exist :)

Unknown008
Oct 18, 2008, 02:35 AM
Huh? After my 'O' level, I'll have to do my 'A' level, there's nothing that I can do to escape that. But I'll only do Chemistry and Physics, along with Maths, no more Biology for me as from next year. Well, see you later, perhaps!:)

mysterious_nad
Oct 18, 2008, 12:52 PM
Huh? After my 'O' level, i'll have to do my 'A' level, there's nothing that i can do to escape that. But i'll only do Chemistry and Physics, along with Maths, no more Biology for me as from next year. Well, see you later, perhaps!:)

Yeah maybe. I can't believe your going to do maths! That's my worst subject, although I did enjoy it during my GCSEs last year, surprisingly! That's mainly because my teacher made it enjoyable I guess. But chemistry and physics are interesting to study, well for me anyway :)

Unknown008
Oct 19, 2008, 08:10 PM
So you're taking Physics, Chemistry and Biology main?? That seems too much for me. Well, I like maths... can help you with it if you like, but if you do not do it in the mains. Anyway, I like to try things, and solve problems, which I find plenty in maths, and the other sciences. And yes, chemistry and Physics are interesting! For me too anyway;)!

mysterious_nad
Oct 20, 2008, 12:15 PM
So you're taking Physics, Chemistry and Biology main??? That seems too much for me. Well, i like maths... can help you with it if you like, but if you do not do it in the mains. Anyways, I like to try things, and solve problems, which i find plenty in maths, and the other sciences. And yes, chemistry and Physics are interesting! For me too anyway;)!

No! I'm not taking physics and chemistry, although I help my friend who's taking it, when she wants a partner for revsion session. I will have to agree with you that would be too much!:( but I am taking Biology, Sociology, English lit as my main subjects. I think they're a grt range of subjects, so it gives me plenty of time to decide what I want to study at Uni! How about u? Only maths and science ar you studying:)

Unknown008
Oct 21, 2008, 04:12 AM
Yup! I can't stand sociology or economics, lol, though I can with accounts. I'll do Chemistry, Physics and French as main, with English and Maths as compulsory. I'm not so good at languages I guess... but as English is comlpulsory... but only one english, no litterature, I'll be stumped flat, LOL:p!

mysterious_nad
Oct 21, 2008, 10:12 AM
Yup! I can't stand sociology or economics, lol, though i can with accounts. I'll do Chemistry, Physics and French as main, with English and Maths as compulsory. I'm not so good at languages I guess... but as English is comlpulsory... but only one english, no litterature, i'll be stumped flat, LOL:p!

No, don't say that! Sociology isn't as bad as you make it out to be. I actually enjoy the subject, and find it very interesting.:) but yeah got to agee with u, econmics woukld put me to sleep! I'd love to do french, and learn the language, but I didn't do it for GCSEs so can't do it now:( I know really that I'm terrible at learning languages, reason not to do them. But I definitely find English lit intreaging, so much info is to be gained out of this subject! :)

Unknown008
Oct 24, 2008, 02:14 AM
Ok, I had my Chemistry ATP, Biology ATP and French Translation and Essay tests recently, all is going on well up to now.:)

Is sociology as I used to know it the same? I mean, with things about culture, values, family things like segregation? I know, I don't know much... the teacher was so boring!! :eek:Could you tell me the really interesting things? If you don't mind of course.

mysterious_nad
Oct 25, 2008, 07:23 AM
Ok, i had my Chemistry ATP, Biology ATP and French Translation and Essay tests recently, all is going on well up to now.:)

Is sociology as I used to know it the same? I mean, with things about culture, values, family things like segregation? I know, i don't know much... the teacher was so boring!!! :eek:Could you tell me the really interesting things? If you don't mind of course.


wow that's a whole load of exams to be doing. Good to know that it went well, hope you did as well as you come across to be. Don't worry I don't mind explaining the things you don't know. I enjoy sociology, that's mainly because I'm learning something new everyday, and it really gets me thinking about society we live in, but the teacher I have is a great laugh, he's not one of those bring kinds! Sociology is the study of society and of people and their behaviour.we learn about families and households, education, societies norms and values and at the moment were studying how marriage remains a patriarchal institution. :)

Unknown008
Oct 29, 2008, 01:42 AM
Ok, that gets as far as that? I'm starting to like it too, lol!! :p You lucky! Fortunately, the teachers I work with now are all a bit humourous, bringing some laugh to the class once in a while, I like them all! I guess I don't need to wish you good luck, you are already interested in the subject, meaning you won't easily forget it. Btw, you'll have your exams soon?

For me, just had my Biology papers 1 and 2 today. I don't know yet if I did as well in the Paper 2.

One question in specific; 'Put a large X on the point where evaporation occurs', given the transverse section of a leaf... I put it in a region where there were no cells, just above the stomata...

Some friends put it near the xylem, confusing me more, sigh. Paper 1 was much easier thank God.

Ok, looking forward to tomorrow... Physics ATP and French Paper 2(comprehension).

mysterious_nad
Oct 31, 2008, 08:54 AM
Ok, that gets as far as that? I'm starting to like it too, lol!!!:p You lucky! Fortunately, the teachers I work with now are all a bit humourous, bringing some laugh to the class once in a while, I like them all!! I guess I don't need to wish you good luck, you are already interested in the subject, meaning you won't easily forget it. Btw, you'll have your exams soon?

For me, just had my Biology papers 1 and 2 today. I don't know yet if I did as well in the Paper 2.

One question in specific; 'Put a large X on the point where evaporation occurs', given the transverse section of a leaf... I put it in a region where there were no cells, just above the stomata...

Some friends put it near the xylem, confusing me more, sigh. Paper 1 was much easier thank God.

Ok, looking forward to tomorrow... Physics ATP and French Paper 2(comprehension).

No it actually goes on further, because I'm going to have a class test when on Monday about childhood, we have started and finished this topic in a matter of 3 lessons! I agree I don't think I'll be forgetting it that essily, although its so much to learn in a matter of short time!

I'll be having my first exams in January, both Biology and Sociology. So I'm starting revision now, seen as though I'm going to be tested on all of unit 1! I hope you have done well on both papers! You come across as though you know your stuff, so I don't think you have anything to worry about :) I'm glad you found paper one easier, don't think I can say the same for myself when it comes eventually! Good luck on physics and french!! :)

Unknown008
Nov 1, 2008, 01:19 AM
Yay! Both Physics and French actually went on well. Except the Physics, I did the last number worth 3 marks, wrong. I hope I'll get at least 2 marks for the theory I put in it.

Ok... January, good luck then! :) I consider those food tests really basic, so if you understood it well, you shouldn't have any problem to do advanced problems on them.

Btw, I think it's not too good to have this thread carried on like that. It may seem chatting to people. I suggest you meet me and a whole bunch of friends in another thread. There you will be able to talk about anything you like :p! We are a really crazy bunch there. The thread is the (around) 7th of its kind. Here's the link:

https://www.askmehelpdesk.com/lounge/haunted-castle-274953.html