- Who We Are|
- Green Juice Vs Green Smoothies|
- Fast Juicers Vs Slow Juicers|
- Lab Tests
Testing performed by Australian Government National Measurement Institute, Dec 2013. See 'Lab Tests' section on site for full results.
Results may vary when using a different combination of ingredients, or different models of juicers and blenders.
Not all models are available in all markets.
We have worked in the Product Development Team for Sage, a food thinking kitchen appliance company, for the last 12 years. We have overseen the design of numerous kitchen appliances, and you could say we are also Sage's resident experts on Juicing and Blending.
Juicing Science is filled with what we believe are critical yet missing ingredients in the world of juicing and blending… facts! From the different vitamin contents of green juices and green smoothies, to the precise temperature transfer of slow juiced carrots versus fast juiced carrots, this site shares findings from over a decade of laboratory tests, clinical trials, nutritional data and expert advice.
Believe it or not this is a juicing and blending website that’s really not trying to sell you something. This site is about real science. We want to empower people to make better nutritional choices.
Why? We have been touched by family and friends struggling with illnesses such as heart disease, and cancer. We looked on, then helped, as they studied what they should eat to get well and remain well. We noticed how difficult it was for them to make sense of all the information available. Experts often seemed to contradict each other. While there was a lot of discussion about juicing and blending foods and impact on health, much of it was at complete odds with our personal experience in the product development kitchen.
The further we looked into juicing, blending and available nutritional information, we noticed a lack of scientific studies. So we commissioned seven lab tests and studies1 with two more on the way. We talked to hundreds of chefs, doctors and nutritionists around the world. And we learnt as much as we could. We have been shocked by false nutritional claims and seeing countless consumers, including our own families and friends, accept juicing and blending myths we know to be untrue. We came to the conclusion that something ought to be done. So over the next six months we will regularly update this site. We want to bring you better information to help you make better choices. We are determined to separate pulp fiction from pulp fact.
We Have NO Vested Interest.
We love our products almost as much as we do our children, but unlike most juicing and blending sites, we represent the whole range - fast juicers, slow juicers, citrus presses, and blenders. Our company makes one or more of each of them. They each have hundreds of 5 star consumer reviews2. Most are ranked No. 1 in performance by several independent test labs3. They are all very good sellers. So we don't have a vested interest in whether you buy a blender, fast juicer or slow juicer. We want this site to educate and empower you on your nutritional journey.
Please note not all models are available in all markets42. In the United Kingdom BRG Appliances Ltd trades under the name Sage by Heston Blumenthal. Sage juicer models sold in the UK are very similar to those used in the studies by the Australian Government. Not all models are currently sold in the UK.
Confused? The above comments, both from respected figures could not be more contradictory. One claims blenders kill up to 90% of the nutrition. The other claims that they can actually turn ordinary foods into ‘super foods'. Dr. Brian Clement, runs a medical clinic focused on using high nutrition diets to treat illness. He claims that his statistics are backed by data, tests, and field trials conducted at his institution, as well as MIT and other leading universities. He says he drinks a quart and a half of green juice every day because juicing is much more nutritious than blending.
David Wolfe is a successful author of several books about health and nutrition. He has not provided evidence or a link to studies to support his particular claim about how blending foods enhances their nutrition in any public forum as far as we are aware, but proclaims that blending is the best way to realise the nutrition from food.
So, how can two respected figures support theories that are so radically opposed? We were perplexed by the same question. So we commissioned laboratory tests in December 2013 from the Australian Government National Measurement Institute in Melbourne, Australia.
The testing revealed that green juice made in a juice extractor contains up to twice the concentration of key nutrients (Vitamin C, Beta Carotene) than the same ingredients blended together in the leading commercial blender. This data supports Dr.Clement's findings. It also revealed that different types of blenders performed better at protecting nutrients than others. Dr. Clement believes that the better the blender, the worse they are for nutrition. As a general trend this may be true, but we found that it was also possible to achieve significantly improved nutrient retention in a high performance blender by circulating the ingredients more aggressively to share the processing load more evenly.
We estimate the nutrient destruction of the most damaging high powered blender tested was between 23% - 63% for Vitamin C, Calcium and Potassium4 (and less again for some minerals) with another high powered blender causing less nutritional damage. So the nutrient destruction was not the 90% as described by Dr. Clement. Our tests involved blending the ingredients for 60 seconds, not 2 minutes like Dr. Clement suggests. We used a 60 second blend time as most green smoothie recipes in high performance blenders require about 60 to 70 seconds to achieve a lump free texture, and we think at-home users blend until they achieve this consistency. We don’t think blending for two minutes is representative of normal at home use.
Here's what happens to the nutrient concentration in a green juice vs. a green smoothie for each of Calcium, Magnesium, Potassium, Vitamin C and Vitamin A (as measured using Alpha and Beta Carotene RAE).
The green juice, made in the best performing fast juicer (Breville BJE410 Juicer42) had a concentration of 142% more Vitamin C, 73% more Alpha Carotene, 109% more Beta Carotene and 54% more Potassium than a green smoothie blended for 60 seconds in the leading commercial blender (Vitamix 5200 Blender). Each of the green drinks was made from the same ingredients (kale, oranges, celery, carrots and apples) however water was added to the blender to allow the ingredients to combine.
To perform the test using a blender it’s usually necessary to add water so the ingredients will combine into a drinkable result. Virtually all green smoothie recipes require added liquid for this reason. But while the end result consists of about 21% added water, the vitamin and mineral concentration is reduced by a much greater amount, indicating that the act of blending is reducing the nutrient yield. Even when compensating for the added water, juice from the juice extractor still has almost double the Vitamin C and significantly more of some of the other nutrients than its blended alternative, as can be seen in the adjusted chart removing the dilution impact shown below.
It’s important to point out that the smoothie does equally as well with Magnesium, and actually has a slightly higher Calcium concentration than the green juice, even before adjusting for added water. Unfortunately though, while leafy greens are high in Calcium, not enough of the Calcium is retained by either juicing or blending to get close to the Recommended Daily Intake (RDI)5. A 100g piece of low fat mozzarella for example, contains about 10 times more Calcium than a 250g green smoothie6.
Based on Dr. Clement’s findings on blenders versus the Australian Government National Measurement Institute, it seems that the length of the processing time may be a big factor in nutrient destruction. Dr. Clement claims that blending for 2 minutes destroys 90% of the nutrients. Based on the Australian Government National Measurement Institute test results, we believe that blending for 1 minute destroyed about 23% - 63% of the available Vitamin C, Carotenes, Calcium and Potassium4, but less of other minerals. Our test results support Dr Clement's observations that blending damages some of the vitamins and minerals. The results suggest that the length of processing is quite important. So what happens to the vitamins and minerals?
Vitamins and minerals are volatile.
The moment you remove a fruit or vegetable from the ground or tree, it begins to lose nutrients. As it sits on the supermarket shelf, it loses nutrients. When you cut it into smaller pieces, it loses nutrients. When you cook it, it loses nutrients. And when you juice it, or blend it, it also loses nutrients40.
A blender creates more heat than a juicer, but even so blenders only get up to a maximum of about 28 degrees C, not enough to cause significant vitamin or enzyme damage7. So, Dr. Clement’s opinion that oxidation (air pushing into the cells) is what causes most nutrient damage when blending, makes sense to us based on our research and the findings of our laboratory tests41.
The best fast juicers8, process ingredients for about one tenth of a second from the moment the food cells first hit the cutting surface, until their juice has passed through the filter9. One tenth of a second of total processing time is roughly 600 times less than a blender and about 20 to 30 times less than a slow juicer10. We estimate that both fast juicers and slow juicers (which are roughly equivalent from a nutritional yield perspective), average vitamin and mineral concentrations of between 75% and 85% of what exists in the whole fruit or vegetable11, but, like blending, this differs enormously from ingredient to ingredient and nutrient to nutrient.
The green smoothie results are particularly interesting when you examine the nutrition from a typical serving size (250g)6 and what that means in terms of the required daily intake (RDI)5 for some key nutrients. The green juice delivered between 83% and 85% of the RDI5 of Vitamin C and Carotenes (Vitamin A equivalent), more than double that of the smoothie. Multiple studies link increased fruit and vegetable intake to a significantly longer life expectancy and lower rates of heart disease, stroke and cancer14. Based on the green juice nutrient concentrations versus the published vitamin and mineral RDIs, there is certainly a strong case to be made for green juice becoming part of everybody’s daily routine.
One obvious omission from the data on green smoothies versus green juice in this section is fibre. Blended drinks contain about 1.5% fibre by weight15, approximately three to four times more than juice (but a very small amount of the recommended daily intake).
Because of the controversy surrounding the role of fibre in juice and smoothies we discuss fibre in far more detail in another section of this site.
"Sage's NutriDisc spins extremely fast ... However, on average it only raises the temperature 1.2 deg F (0.7 deg C) from fruits & veggies to juice…. This means that the vital enzymes and micronutrients won't degrade from heat when you use our (fast) juicers."
Food Thinkers (by Sage) copy from editorial "Won't Heat Up" 2011 – 2014
"in centrifugal juicers .. fast spinning blades create heat above 50 degrees Celsius (and) kill all nutrients and enzymes found in fruits and vegetables ... juice must be drunk immediately as the enzymes and nutrients have been destroyed ... it is simply dead"
Quote from video 'Why is a Cold Press Juicer better?' www.vitality4life.com.au July 2nd, 2013
As evidenced in the quotes shown above, some marketers have formed radically opposing views on the health and nutritional benefits of the different types of juicers. Luckily, this area has been well researched and the answer is all but beyond repute. And that is... the nutritional difference between the best fast juicer8 and the best slow juicer16 is virtually nothing at all. Really? Yes, really! Because fast juicers process ingredients for such a short time, the faster spinning speed makes no noticeable difference to the nutrition of the juice versus using a slow juicer. Slow juicer advocates have not been able to show higher temperature transfer from the best performing fast juicer8 versus the best performing slow juicer16, nor demonstrate any damage to enzymes by fast juicers in any study we've been able to find.
Slow juice being healthier than fast juice is well and truly an incorrect urban myth. Yet some slow juice advocates have recently taken advantage of this to help sell more juicers. Some slow juicer manufacturers even claim they have supporting lab test results. If they do they either don’t name the fast (centrifugal) juicer they’ve tested against or if they do name them the nominated fast juicer is a relatively obscure one17. Our company sells both types of juicers (not all products are available in all markets42). We believe we can say with minimal bias that there is no clear overall difference in the health benefits of either when you use the best performing fast and best performing slow juicers. To clarify, there are substantial differences between the best performing fast juicer and the worst performing fast juicer18, but it is not the juicing system itself that causes the difference, but rather the overall quality and design of the product. To validate the differences between quality fast and slow juicers, we have made the full, nutritional test results between the fast and slow juicers we’ve had tested, available for review on this site.
Of course it's not as simple as saying that all nutrient concentrations from fast and slow juicers are always exactly the same. When juicing some ingredients, some nutrients show variations between the two types of juicers. We've seen test results for example, where the Sage (fast) Nutri Juicers have yielded an average Iron concentration 78% higher than that of a leading slow juicer from spinach leaves19. Yet the same slow juicer that yielded a significantly lower concentration of Iron19, yielded a 60% higher concentration of Vitamin B1 from the same ingredient. But these are rare and unusual examples and not indicative of what happens for the majority of nutrients with the majority of ingredients. For example, while fast juicers produced a lower Vitamin B1 concentration from spinach, they produced higher Vitamin B1 concentration than the slow juicer from apples, carrots and tomatoes. And while slow juicers produced lower iron concentrations from spinach and apples, they yielded higher Iron concentrations than the fast juicers from celery, carrots and tomatoes.
So, if someone's goal is to sell a slow juicer by any means possible, they could point to the isolated result of Vitamin B1 content in spinach as evidence that slow juicers produce healthier juice. And fast juicer manufacturers could point to iron content in apple or spinach juice as evidence of their juice being better for you. But, in both cases, this messaging is misleading, as all the test results we've reviewed suggest this is not all representative of what typically happens across a variety of fruits and vegetables. Looking at one vitamin in isolation of all others does not fairly take into consideration how different compounds and enzymes in fruits and vegetables work together to enrich our cells and immune systems.
For those keen to drill down into the detail, we've included the full test results of the 2012 nutritional study completed by the Australian Government Laboratories National Measurement Institute on this site (Click here to view). Below is a summary of the findings in relation to temperature, yield and nutritional concentration averaging all five of the tested ingredients (apples, carrots, celery, tomatoes and spinach);
The above table shows the average temperature and nutrient content of the whole ingredients before they are juiced, as well as the temperature, juice yield and nutrient content of the ingredients after they are juiced in both a fast and slow juicer. The differential between the fast and slow juicer is also shown in the bottom row with the best performing product highlighted in green. Savvy analysts will note that the concentration of iron from the fast juicer, and the concentration of carotenes from both juicers are higher in the juice than in the whole ingredients. This is not unusual. Carotene content in carrots is enhanced through processing20. We believe the increase in iron which is much less significant, is probably due to a slightly higher ratio of iron in the juice versus the discarded pulp.
Perhaps a simpler and more interesting way to look at the nutritional yields is to compare the nutrient concentrations within a whole fruit or vegetable, with the nutrient concentrations of its juice. This helps illustrate how each juicing system acts to damage (or enhance) the vitamins and minerals found in the whole ingredients during the juicing process. When looking at the average concentration of the vitamins and minerals in the juice as a percentage of the concentration of the whole fruits and vegetables, this is what happens;
As can be seen above, Calcium, Vitamin C and Vitamin B1 undergo the largest reduction in concentration in going from whole ingredient to juice. Even so, between 44% and 80% of their original concentration is maintained in the juice. Alpha and Beta Carotene are both significantly enhanced in concentration through processing (as they are through cooking12) and in some cases, Iron and Magnesium concentrations have increased in concentration slightly also.
The average concentration versus the whole ingredient for the eight vitamins and minerals tested was 109% for fast juicers and 98% for slow juicers. This number is somewhat distorted by the enhancement of the Alpha and Beta Carotene concentrations. In the last column, the averages are shown excluding the Carotenes and are 82% and 83% respectively. So, on average, excluding Carotenes, the nutrient concentrations were reduced by less than 20% in going from whole ingredient to juice, with a 1% difference between the two juicing systems.
It’s also possible to look at these averages for each fruit or vegetable. Below shows the average concentrations for all vitamins and minerals (excluding Carotenes) in the juice as a percentage of their concentration within the whole ingredient, for each of the five fruits and vegetables tested:
As can be shown above, the differences between fast and slow juicers, even when looked at by individual ingredients, is minimal. Sometimes the average slightly favours fast juicers and sometimes it slightly favours slow juicers. But overall, it is virtually impossible to say that one produced a more nutritious juice than the other, nor does either do a noticeably better job at protecting the key vitamins and minerals than the other. What’s also interesting is that, apart from apples, all of the average concentrations of the juices were a minimum of 75% of the nutrient concentrations of the whole ingredient. We think drinking the freshly juiced juice from the fruit or vegetable is a positive alternative to the whole fruit or vegetable and can provide a nutritious and delicious way to consume nutrients.
Here’s a summary of what typically happens to juice yield, temperature, nutrients and oxygen in fast vs. slow juicers across a variety of fruits and vegetables.
Fast juicers yielded an average of 63% of the weight of the whole fruits and vegetables and the slow juicer averaged 65% of the original weight before straining excess pulp. To put this in perspective, a normal sized glass (250ml)6 of slow juiced juice from these five ingredients would contain about two teaspoons more juice than the juice from a fast juicer which would take a trained eye to tell the difference. The results varied from ingredient to ingredient with the fast juicer yielding 22% more juice from carrots, and the slow juicer yielding 14% more juice from spinach. Both types of juicers can juice the same ingredients (they can both do leafy greens, grasses, soft and hard fruits13) and overall the differences across a variety of fruits and vegetables are minimal13.
Fast juicers averaged 0.85 degrees C temperature transfer, and slow juicers averaged 1.1 degrees C temperature transfer, a difference of a quarter of a degree Celsius. The fast juicer transferred slightly less heat on carrots, celery and tomatoes and the slow juicer transferred slightly less on apples and spinach. Neither produced heat transfer of any significance7 on any fruit or vegetable and overall, contrary to popular belief, fast juicers transferred less heat.
Fast juicers produced 11% higher concentrations of Alpha Carotene, 10% higher concentrations of Beta Carotene, and 47% higher concentrations of Iron than the slow juicer on average. The slow juicer produced 16% higher concentrations of Vitamin C, 34% higher concentrations of Vitamin B1, 13% higher concentrations of Calcium and 10% higher concentrations of Magnesium. They both yielded the same concentrations of Potassium on average. While fast juicers produced higher Alpha Carotene, Beta Carotene and Iron levels on average, slow juicers had higher levels of Iron on 3 of the 5 ingredients tested. And while slow juicers had higher Vitamin C, B1, Calcium and Magnesium levels on average, fast juicers had higher Vitamin C levels than slow juicers from apples, celery and tomatoes, higher Vitamin B1 levels than slow juicers from apples, carrots and tomatoes, higher Calcium levels than slow juicers from spinach, and higher Magnesium levels than slow juicers from tomatoes and celery. Potassium levels while the same also deviated from ingredient to ingredient. The only vitamins where one juicer always had an advantage over the other were Alpha and Beta Carotene where the fast juicer always produced a higher concentration, but even then the differences were not significant. Overall, it is difficult to separate the two from a nutritional perspective.
Results for nutrient loss over time were conducted in another study (two studies in total) and are also published on this site under Green Juice vs. Green Smoothies. Results varied from fruit to fruit and vitamin to vitamin but the rate of deterioration was very similar between fast and slow juicers, if anything indicating a longer life for some nutrients in juice from a fast juicer. We have seen no evidence that suggests that juice made in a slow juicer is safer or healthier to store for a longer period than a fast juicer. Both types of juicers maintain nutrients for approximately the same period of time. Juice from leafy greens loses nutrients much faster than other types of juice. Citrus fruits tend to lose nutrients at a much slower rate. But most nutrients in all types of juice we've tested deteriorate at a similar rate regardless of whether a fast or slow juicer is used. Some slow juicer advocates point to juice separation (the coloured pigments of the juice sitting on top of the clearer liquid to form a visible layer in the glass) that happens faster in fast juiced juice than slow juiced juice as proof that the juice is of poorer quality. This is not correct and separated juice can easily be recombined by gently stirring.
Results for dissolved oxygen testing date back to 2003, so we will likely repeat these again soon. These tests measured oxygen trapped inside the juice as well as froth on top of the juice, as it is the oxygen trapped inside the juice that causes the most oxidation. Only apples and carrots were tested. Both types of juicers had the same dissolved oxygen content on apple juice but slow juicers had up to four times the dissolved oxygen in carrot juice, even though the fast juiced carrot juice produced more froth on top of the juice21. In the 2012 study, fast juicers produced more froth on average, but slow juicers produced 33% more froth than fast juicers when making spinach juice. It is not accurate to say one always creates more froth than the other, nor can you correlate froth to nutritional yield or juice preservation.
As shown in table 1, slow juicers produce more heat on average, yield lower concentrations of some vitamins and minerals, and higher concentrations of others. Any inference that juice from a slow juicer is either “cold pressed” (which is a totally different commercial process for making juice unrelated to slow juicing) or “healthier”, is at best an uneducated guess, or at worst, a deliberate attempt to mislead.
But why are some of the individual nutrient results on some ingredients so different? Well we can’t say with absolute certainty but after 12 years of testing we believe that raw fruits and vegetables are complex, living ingredients whose behaviour varies from food to food. And looking at Vitamin C content in isolation in a spinach leaf is a gross simplification of the potential health benefits of the food. There can be up to thousands of different phytochemicals23 as well as enzymes, vitamins and minerals that coexist inside a fruit or vegetable. Science is yet to discover which of these ingredients, or which combination of them, is most responsible for lengthening life expectancy or reducing disease risk. We have not and cannot test for all of them. But we believe that the test results we have discussed in these pages are likely to be a good indication of how ‘alive’ the whole juice is and that both fast and slow juice are both likely to be rich in a vast array of enzymes and phytochemicals.
It is little wonder that taking refined vitamin supplement tablets in isolation from the living fruit or vegetable has no impact on improving life expectancy or disease risk12. It is our contention that comparing a spinach leaf with a vitamin supplement is like comparing a human being with a toy doll. One is alive and the other is not. It makes sense that the fresh unprocessed ingredient is going to be better for you. Fresh ingredients can behave unpredictably when processed which is why some vitamins and minerals respond better to a fast juicer than a slow juicer and vice versa. But if you look at the vitamin and mineral concentrations across a variety of fruits and vegetables, there is very little difference nutritionally between the two types of juicers.
Fibre is found naturally in foods, and there are two types: soluble fibre which is soluble in water, and insoluble fibre which is the solid pulpy part of the food. Fibre is a really important part of a healthy, balanced diet. It helps to keep your bowels moving29 and impacts overall digestion making fibre protective to colon cancer and diverticular disease. Soluble fibre also helps to lower blood glucose and blood cholesterol. Most health experts recommend 25 – 30 grams of fibre per day5. And most of us need to eat more.
Juicing removes most of the fibre in foods - about 75% of the fibre is ejected into the pulp container. Blended fruits and vegetables retain the fibre though even with blending the total fibre content is much reduced from the whole fruit or vegetable because of the mechanical process.
Juicing or blending fruits and vegetables, as opposed to eating them whole, results in a missed opportunity to consume more fibre. What’s great about juicing is that it is a fast and palatable way of consuming a significant amount of other vital nutrients. We suggest juicing in conjunction with consuming whole fruits and vegetables and smoothies to ensure the best overall balance.
Although juicing removes the fibre what’s interesting is the fibre content in whole, commonly juiced fruits and vegetables is often much less than people assume it to be anyway. It is best to include other more high fibre sources in your diet to ensure you are getting the recommended amount.
What are the best sources of fibre?
In terms of the fibre content in fruits and vegetables, we surveyed our friends and family about kale. We chose kale as an example of a nutrient packed leafy green. All our respondents thought it contained between 25% and 75% fibre. Before we tell you what it really is, here’s a picture of it. What would you guess it to be?
Kale has become the pin up vegetable of the green juice and smoothie movement over the last few years, as it contains extraordinarily high levels of many vitamins and minerals. One hundred grams of Kale contains more than 100% of your recommended daily intake (RDI) of Vitamin A, Vitamin C and Vitamin K, and more than 10% of your RDI5 of Vitamin B1, B2, B6, Calcium, Iron, Magnesium and Manganese27. Yet, despite its dense, dry appearance, it is made up of only 1.7% fibre27. This means 100 grams of kale contains less than 6% of your RDI of fibre. So smoothies can certainly help, but if you are pursuing a high fibre diet, you’re going to need to get the vast majority of your fibre from sources other than green smoothies or green juices. Here are some of the best fibre sources, many of which make great snacking foods.
As seen above, most commonly juiced fruits and vegetables30 range between 0.4% to 2.8% fibre content. This means it’s best to consume other high fibre whole foods, as well as your smoothies and juices, which provide you with a boost of other essential nutrients.
We find juicing by the 80:20 rule works wells i.e. 80% veg with 20% fruit. And we suspect the commonly juiced are probably the tastiest, though experimenting with a rainbow of vegetables and fruits will provide you with a rainbow of phytochemicals.
Some of the discussion around the loss of fibre when drinking juice relates to the drinking of pure FRUIT juice. Because we might be drinking the juice of e.g. 4-6 oranges rather than eating that many oranges including the fibre, our blood glucose tends to go up quite quickly. This is true! So we suggest if drinking pure fruit juice, even from our Sage juicer to drink it with a meal or a snack. The addition of food will slow the absorption of the fruit sugars and reduce the rise in glucose in our blood stream. It will also help protect our teeth from acid erosion by the fruit sugars. So we still get to enjoy our fruit juice.
The recent work of course by the Australian Government National Measurement Institute on green juices vs green smoothies highlights the optimum way to get the best out of the Sage juicer. And that is by juicing your greens! Most vegetables are low calorie because they contain virtually no fat or protein; the few calories they contain come from carbohydrates. Juicing larger quantities than we might put on our plate is a great way to boost our nutrient intake without having to eat plates and plates of greens. Naturally we want you to eat the whole vegetables also but in the UK we are well below the 5 a day recommendation which is generally regarded as 2 fruit and 3 veg. Recent research is pointing towards even more veg e.g. 2 fruit and 5 veg being optimum! Many people find it difficult to eat greens because they can taste somewhat bitter. Adding 1 or 2 fruits to your vegetable concoction will likely turn it from just alright to really delicious.
How is fresh juice different?
Juice made in a Sage fast juicer takes about 0.1 of a second from the moment it is first cut by the juicer to the point processing is complete. The fruit hits a cutting disc and the pulp is pushed against a mesh filter separating the pulp from the juice, all in about a tenth of a second9. That is the beginning and the end of the process.
Juice from concentrate goes through a process similar to that of a juicer, plus up to six additional processes; pasteurisation, dehydration, freezing, thawing, dilution and flavour reconstitution.
Pasteurisation involves killing bacteria by heating the juice to at least 75 degrees C (sometimes much higher) usually for a few seconds32. This process kills all of the bacteria, as well as most of the naturally occurring soluble vitamins like Vitamin C, and many B vitamins33. It is also believed to destroy significant amounts of flavonoids and damage proteins such as enzymes.
The second process is dehydration. Dehydration extends shelf life and saves money by lowering the shipping weight of the beverage. Dehydration means holding the juice under partial vacuum and at a high temperature for a long period of time. The water within the juice is boiled or evaporated off. What remains is a paste or syrup that is made up of about 67% sugar. This syrup usually weighs about 15% of what it weighed prior to dehydration. The other 85% is evaporated during the dehydration process35. An incredible 85% of the original juice is now gone forever.
Many, but not all fruit syrups, are then subjected to cold storage. This involves storing the concentrated syrup or paste at approximately minus 12 degrees Celsius36. From pasteurisation to dehydration, to storage, the food cells are subjected to total temperature changes of close to 100 degrees C.
Thawing the frozen paste is the fourth step in the process.
Dilution is next, adding water to the thawed paste to create a drinkable consistency, similar to juice.37. Finally, refined supplements like Vitamin C, Calcium, Vitamin D, Omega-3 fatty acids, as well as citric acid and natural flavours (usually derived from orange peels) are added back into the drink to try and replace what was lost during processing38.
The original fruit juice has been heated, evaporated, frozen, thawed, diluted and finally had nutrients and flavours added to make it taste like juice. Remarkably, the US, Australian and several other governments, allow this diluted syrup to be called 100% fruit juice39.
For further information, we have provided below, links to download the full studies performed by the Australian Government National Measurement Institute under the commission of BRG Appliances Limited.
The juicer and blender models used in the studies are sold in Australia by Sage Pty Ltd, not all these products are available in all markets. In the United Kingdom BRG Appliances Ltd trades under the name Sage by Heston Blumenthal, the Sage juicer models sold in the UK are very similar to those used in the studies by the Australian Government, however, not all models are currently sold in the UK.