What does High Hydrostatic Pressure do to My Juice?

Freshly squeezed juices have become increasingly popular with Americans.  Americans have been drinking more and more fresh juice as a way to improve their health and daily nutrition.  While the trend is growing quickly, one of the biggest barriers to wide mainstream adoption is also what makes juice great.  The short shelf life makes traditional big distribution channels inappropriate.  Currently, most people either use a home juicer or purchase juice at local juice stores as fresh squeezed juice will lose most of its vitamins, mineral, and enzymes within 72 hours and even worse will become a petri dish for pathogenic microorganisms.

One possible solution to this is HHP or High Hydrostatic Pressure but this method is also controversial.  HHP is based on the Le Chatelier principle which assumes increasing the net volume will retard (or kill) potential microorganisms.

Benefits of HHP:

  • Increases shelf life from 3 days to 10 – 14 days
  • The look, taste, and texture of the juice is unchanged
  • Juice nutrition is preserved (Controversial claim)

The High Hydrostatic Pressure Process:

  • Industrial size batches of fresh cold press juice is produced in a factory
  • The juice is placed in highly pressurized tanks and subjected to pressure of up to 100,000 PSI.  To put that into perspective, the PSI at sea level is just 14.7 so this would be over 5,000 times greater.
  • The juice is bottled and transported nationally for sale in large retail stores. 

As this is a new process, it is also still controversial, let’s look at the evidence of maintaining the fresh juice nutrition beyond 72 hours.

Does HHP destroy the vitamins along with the microorganisms?

  • A study by Ferrari in 2010 tested the polyphenols in pomegranate juice before and after pressurization.  Polyphenols is good proxy as it’s the powerful antioxidant that is linked to pomegranate’s anti-cancer benefit.  Ferrari’s study showed that between 75% & 80% of the polyphenols remained after HHP.
  • Ferrari’s results were later replicated by Lui et al in 2013 using watermelon juice.  In fact, the watermelon juice maintained over 95% of its polyphenols.

Does HHP treated juices really preserve the nutritional value of juice?

  • Researchers evaluated fresh squeezed blueberry juice in 2012.  Half the blueberry juice was HHP treated and the other half wasn’t.  After 14 days, the HHP maintained 88% of the vitamin C while the untreated fell to below 70%.

What does that mean to juicers?

HHP is another option which makes pressed juice more conveniently available to the masses.  However, this convenience comes with a bit of a price.  With more research necessary to replicate these finding across more juice types and vitamins, it appears that HHP juice may still lose 20 to 30% of the nutritional value prior to a customer drinking it.

If you are looking to enjoy the maximum benefit of fresh juice, you should still purchase non-HHP juice with local distribution or invest in a cold press home juicer. For myself, I will continue to skip the added convenience of HHP and make my own fresh juice at home.  If you are interested in home juicing, I welcome you to check out my juicer reviews.  These reviews are based on hours of personal research which helped me decide.

Sources:

Ferrari et al. The application of high hydrostatic pressure for the stabilization of functional foods: Pomegranate juice. Journal of Food Engineering 100 (2010) 245-253

Barba et al. Evaluation of quality changes of blueberry juice during refrigerated storage after high pressure and pulsed electric fields processing. Innovative food science and emerging technologies 14 (2012) 18-24.

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