How Does Heat and Oxidation Affect Juice Quality?

by Jim

There are three issues concerning juice quality:

One issue centers on too much heat being introduced into the juice by the juicer due to friction which in turn kills the live enzymes in the juice.
The second issue is oxidation created from fast spinning juicer blades.
The third issue involved in juice quality covers the actual mechanical process of separating the nutrients from the pulp.

1. Heat kills live enzymes in juice.

Many people feel that the heat created by certain juicers due to friction and the mechanical nature of these juicers kills the live enzymes. These enzymes are most beneficial and for most people the main reason they want to make fresh live juice.

The fast spinning grating basket of a centrifugal juicer like the one on the left in the picture above is said to generate more heat and thereby damage the juice. The single slow turning auger like on the one on the right supposedly creates less heat.

(You can read about enzymes someplace else but let’s just say here that they are good for you and you want them. And you will not get them out of store bought juices because those are pasteurized thereby killing all the enzymes. Pasteurized juices may gain you a few vitamins but to me they seem like a waste to drink. They are mostly added calories with little benefit.)

Heat does kill enzymes. However, the temperature has to be around 118 to 120 degrees Fahrenheit in order for that to happen. Centrifugal juicers and other juicers in most cases will not heat juice that much. The produce doesn’t come in contact with the cutting blades for long enough to raise the temperature much. Plus, common sense tells us if you start with cold or refrigerated produce, it’s not going to rise in temperature significantly. While all juicers will raise the temperature a little bit because there is friction involved as the juicer crunches, mashes, chops or shreds the produce, it won’t raise it enough to create a serious problem in my opinion.

(I have noticed that certain produce types like wheatgrass and carrots and other dense vegetables can cause juicers blades, augers or gears to get warmer. These are harder to juice so the friction is greater. Still the warmth doesn’t seem to feel like enough to be concerned. I will add that the Champion juicer I have heats the juice the most so far. You can definitely feel the difference in the pulp. I also put a regular thermometer in the pulp and the pulp’s temperature was too high to register on the regular human thermometer which only go up to about 107 degrees.)

To me this heating the juice thing is a bit over the top. It’s got to be a marketing ploy against centrifugal juicers and other fast spinning blade juicers. I’ve decided I’m not buying into the idea. If people wish to be super fanatical about this, that’s fine. It’s like splitting the atom to me. Bottom line is any fresh vegetable or fruit juice made from a juicer of any kind is going to be better than the crap you buy in the store in plastic bottles.
2. Juice Oxidation.

The second juice quality issue is oxidation and it’s a little more serious. Oxidation is what happens to apples when you take a bite out of one and leave it on the counter for a while. The apple will start to turn brown. This is oxidation. The apple is starting to break down or decompose. When you juice anything, if you whip too much oxygen into it and let it sit, the juice will break down quicker. That’s why juicers that create more foam such as the centrifugal or fast masticating models are frowned on in some circles. These juicers expose the vegetable and fruit cells to more oxygen molecules which actually being to burn the cells. I feel you are going to get a little oxidation happening from any juicer. The very nature by which juice extractors operate will tend to cause this.

Centrifugal juice Single auger juice
Juice on the left is from an inexpensive centrifugal juicer. Picture on right depicts juice from a single auger juicer. There is less oxygen injected into the juice on the right. Note the lack of foam and bubbles.

I feel the oxidation issue is a very valid concern. Especially for people with serious health concerns. If you are having serious health issues, the need for the highest quality juice may be much greater. Spare no expense and buy a Green Star GS2000 twin gear extractor or another twin gear type of juicer. That will give you the lowest heat and oxidation levels next to a $2000 Norwalk press. Or you can get something like a Champion juicer to process the vegetables and then run the pulp through a Welles press. This method is also recommended by the Gerson Institute which offers a treatment seriously ill people. It’s more work but you’ll get maybe a little edge in juice quality. Whether it will make a true difference is anyone’s guess but at least you’ll have of peace of mind knowing you are doing what you can to get the best quality juice. Most people will be better off drinking fresh juice from any juicer rather than drinking store bought juice or soda.
3. Harsh mechanical juice extraction.

The third issue in juice quality has to do with the mechanical process of juice extraction. It is said that the gentler process of extracting juice via the twin gear or single auger method delivers a higher quality juice because more of the nutrients are squeezed from the pulp. This is also why the Norwalk press is said to have such high quality juice. The juice is slowly pressured from the pulp as opposed to ripped and torn from the pulp as one would imagine a centrifugal juicer might do.

I look at this issue using common sense and you can tell that more juice is left in the pulp from a centrifugal juicer than in a single auger. The pulp is wetter from a centrifugal juicer and therefore this issue makes sense if you are concerned about getting the highest yield and nutrition from your produce. It is why in the end I chose the Omega 8003 juicer as my main general purpose juicer.

In my quest for a juicer none of these issues seemed end all deal breakers. However, the most important thing I felt I learned was this:
Drink the juice immediately after you make it!

Don’t put it in the fridge and store it. I know many people think it’s a hassle to juice one or two glasses at a time. And maybe it is. I still occasionally store orange juice for a couple days. Everyone kind of does it once and a while. However, the whole point to juicing is to get the freshest nutrition into your body before the juice starts breaking down. So do yourself a favor and don’t store the juice very often. Drink it as you make it more than making it in bulk and storing it. Your health will thank you.

As I said earlier a Green Star juice extractor GS-1000 machine or the GS-2000 or GS-3000 models as well as most other twin gear juicers make juice with the least amount of oxidation to them. The Norwalk press also does but it is expensive. It’s physically big and involves more of a commitment due to the different stages of cutting, pressing and then cleaning in order to get a glass of juice. If you are really concerned about these issues buy a Green Star at a quarter of the price of a Norwalk juicer. You’ll be very happy because they are great machines. If you want to spend a little less, go with an Omega 8003 juicer like I did. This juicer delivers higher quality juice, is easy to clean, comes with a 10 year warranty, and it will change your life.

{ 0 comments… add one now }

Leave a Comment

Previous post:

Next post: