clarifying juice

[chef koo]

if i boil fruit juice, like orange, with egg white, will it go clear?

[tim]

if i boil fruit juice, like orange, with egg white, will it go clear?

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Chef,

In making a consomme, egg whites bind with the albumin, proteins and fats in a stock. Since those ingredients are not clouding your orange juice, I don't think that method will work.

You might want to look at the technique of adding gelatin to the juice, freezing the juice solid and then straining. The result should be an orange flavored water.

I am no expert on this technique but know there is another discussion.

Tim

[nickrey]

Egg white can be used to clarify juices but is most successful with juices such as red grape. It has been used traditionally by many makers in France to clarify wines, which are in essence fermented grape juice.

Orange juice is not particularly stable and much of the flavour resides in the pulp so I'd suspect it would not be a good candidate for this process. That is, it would go clear but may lose much of its orange flavour.

[slkinsey]

Enzymatic clarification is the way you want to go.

[chef koo]

Enzymatic clarification is the way you want to go.

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intersting. that seems promising. i'll try it... if i can find it

[TheSwede]

I've read about traditional raft clarification beeing applied to a tomato consommé (in Gordon Ramsey *** Chef perhaps?), ie mix finely diced vegetables with egg white and simmer slowly, ladle off the clear consomme.

Gelatine/agar clarification should work too, search for the thread here. As noted in the link above, it won't be as efficient as enzymatic clarification but on the other hand you probably already have the ingredients.

[slkinsey]

It appears to me that chef koo is seeking to clarify fresh fruit juices, and not "juices" or other liquids that are either typically cooked or are not significantly altered for the worse by cooking. I don't think anyone wants orange juice that has been boiled with egg whites.

Gelatin or agar syneresis would seem to be the method that can be accomplished with easily available ingredients, but the yield isn't as good.

[TheSwede]

No, I don't think you want to boil your orange juice (although the egg white probably is harmless once it coagulates). But I though it interesting that traditional clarification evidently works on a very similar substance, a vegetable juice with a lot of pulp.

[mickm]

The only problem with the enzyme is it cannot tolerate extremely low pH, such as sour orange juice.

Just noticed that from the enzymatic clarification link you posted slkinsey. Do you think using a modifier to adjust the pH would remedy this?

[danwalk]

Perhaps a centrifuge would help. From the French Culinary Institute's Cooking Issues:

What is a centrifuge and why would we want one?

A centrifuge is a device that spins at high speed to separate products into parts based on density. The faster you spin it, the more separation power you get. This separation power is usually described in “g’s” (also called RCF)—the number of times the force of gravity the product is feeling.

In the kitchen we could use one to clarify juice by spinning the hell out of the juice and making all the cloudy parts slam into the bottom of the container forming what’s called a “pellet.” We could also take an emulsion, spin it, and demulsify it to remove the fat, etc.

According to the post, this is the first installment of a primer on centrifuges in the kitchen.

Happy spinning!

[slkinsey]

The only problem with the enzyme is it cannot tolerate extremely low pH, such as sour orange juice.

Just noticed that from the enzymatic clarification link you posted slkinsey. Do you think using a modifier to adjust the pH would remedy this?

I don't know why you would want to do this, since the sourness is what makes sour orange juice interesting.

It's hard to tell from this line whether they are referring to regular orange juice which they deem to be a tart juice, or regular orange juice that is especially tart, or juice from sour oranges.

[mickm]

The only problem with the enzyme is it cannot tolerate extremely low pH, such as sour orange juice.

Just noticed that from the enzymatic clarification link you posted slkinsey. Do you think using a modifier to adjust the pH would remedy this?

I don't know why you would want to do this, since the sourness is what makes sour orange juice interesting.

It's hard to tell from this line whether they are referring to regular orange juice which they deem to be a tart juice, or regular orange juice that is especially tart, or juice from sour oranges.

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That is a very good point. I'd love to find a source for the Pectinex to try it out myself, so far no luck.

[jk1002]

I attended a demo last year where they showed the pectin smash trick. They did fiddle with the acids afterwards, but have forgotten why.

For your problem, try 1 to 2 gram gelatin-powder per liter juice. Mix it properly, freeze it and let it thaw through a filter, maybe a "super bag" or coffee filter or something like that.

Cheers

JK

[mickm]

How effective is the gelatin/agar-agar method at removing color?

[dougal]

...

That is a very good point. I'd love to find a source for the Pectinex to try it out myself, so far no luck.

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The source for pectinase/pectolase (pectin-haze-removing-enzyme) would be a home winemaking supplies store.

In the UK, it can be found in Wilkinson's supermarkets (one of the few high street winemaking supplies retailers).

But such stuff is nowadays easier to find online.

Wilkinsons: http://www.wilkinsonplus.com/invt/0022653 ~ $1

The alternative would be to use a flocculant (which I believe is the winemaking use of eggwhite, cold and very dilute). I suspect that some VERY dilute gum solution might speed up the dropping of the suspension. This seems likely to be what is happening with agar and gelatine.

However, neither of these methods are 'instant'. The juices are likely to lose 'freshness'.

Hence the interest in centrifuges...

[Tri2Cook]

How effective is the gelatin/agar-agar method at removing color?

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It doesn't really remove color that is inherent to the liquid. If the particulates that are removed by the filtering process are what is providing the visible color then the liquid will be clear after filtering. Below are a couple of examples. The first is from a stock of water, peach juice, pickled peaches and their juice and some spices. Most of the color of the unfiltered stock was from the peach solids and it disappeared after filtering. The other was from a strawberry stock and, although I don't know the scientific explanation, something besides the strawberry solids provide the color. Maybe pigments that require a higher level of filtration to remove than is possible with the syneresis process.

[jk1002]

http://www.moreintelligentlife.com/story/t...0-gin-and-tonic

This explains what they (Dave & Nils) did with the acids after "clarification".

Besides this, entertaining and interesting article.

[chef koo]

i couldn't find any enzymes for clarification (although i didn't try very hard) but jsut out of curiosity i tried it with egg white.

this is the orange juice. i put a red mug behind it as a way of identifying the difference between the 2.

this is after clarifying with just egg white. i whisked 3 egg whites to 1.5 litres of orange juice completely cold. i slowly simmered it until it clarified. i strained it through a coffee filter. i then took the juice and brought it to a rolling boil to foam up any left over protein.

the taste is just as slkinsey predicted. no sourness at all. in fact i'd describe the taste as orange zest. it was kind of sweet. the flavor of orange is synonymous with sour so after tasting is a differnt expirience. but with a bit of citric acid and sugar it almost works... but not quite.

Edited June 3, 2009 by chef koo (log)

[nickrey]

the taste is just as slkinsey predicted. no sourness at all. in fact i'd describe the taste as orange zest. it was kind of sweet. the flavor of orange is synonymous with sour so after tasting is a differnt expirience. but with a bit of citric acid and sugar it almost works... but not quite.

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The problem is the complexity of what you are trying to reproduce.

There are nine acids in fruit juices (oxalic, citric, malic, quinic, galacturonic, ascorbic, succinic, and fumaric acid) and three sugars (sucrose, glucose and fructose) [Chinnici et al (2005) Optimization of the determination of organic acids and sugars in fruit juices by ion-exclusion liquid chromatography. Journal of Food Composition and Analysis, Vol 18, pp. 121-130].

To get the sourness and sweetness balance right for a true citric flavour you'd need to add these in appropriate proportions. The absence of any of these components through filtering, etc will lead to people tasting it saying that it seems like orange juice but that it's not quite right.

[TheSwede]

Definitely try the gelatine filtration: Gently heat some of the liquid, add 0.5% gelatine (by weight of the total liquid), add the rest of the liquid when gelatine is dissolved.

Freeze overnight, then place in a chinoise in the fridge and let the clear liquid slowly strain out over the next two days.

I don't know how it will affect the acids, but you won't get any "ccoked" taste.

[thayes1c]

Let me just revive this thread to ask, has anyone tried the rapid agar clarification from the Cooking Issues team? It's fast, easy and I think it works great. No more freezing!

http://cookingissues.wordpress.com/2009/07/14/agar-clarification-made-stupid-simple-best-technique-yet/