Field of Science

Chips worth their salt

This from the WSJ caught my eye today:
"PepsiCo Develops 'Designer Salt' to Chip Away at Sodium Intake"

Later this month, at a pilot manufacturing plant here, PepsiCo Inc. plans to start churning out batches of a secret new ingredient to make its Lay's potato chips healthier.

The ingredient is a new "designer salt" whose crystals are shaped and sized in a way that reduces the amount of sodium consumers ingest when they munch. PepsiCo hopes the powdery salt, which it is still studying and testing with consumers, will cut sodium levels 25% in its Lay's Classic potato chips. The new salt could help reduce sodium levels even further in seasoned Lay's chips like Sour Cream & Onion, PepsiCo said, and it could be used in other products like Cheetos and Quaker bars...working with scientists at about a dozen academic institutions and companies in Europe and the U.S., PepsiCo studied different shapes of salt crystals to try to find one that would dissolve more efficiently on the tongue. Normally, only about 20% of the salt on a chip actually dissolves on the tongue before the chip is chewed and swallowed, and the remaining 80% is swallowed without contributing to the taste, said Dr. Khan, who oversees PepsiCo's long-term research.

PepsiCo wanted a salt that would replicate the traditional "salt curve," delivering an initial spike of saltiness, then a body of flavor and lingering sensation, said Dr. Yep, who joined the company in June 2009 from Swiss flavor company Givaudan SA.

"We have to think of the whole eating experience—not just the physical product, but what's actually happening when the consumer eats the product," Dr. Yep explained.

The result was a slightly powdery ingredient that tastes like regular salt.
"Secret new ingredient"?! Perhaps not. The first thing that popped into my mind after reading this was "polymorph". People in drug discovery face the polymorph beast all the time. Polymorphs are different crystal packing arrangements of a molecule that can have dramatically different dissolution rates. Often a drug which otherwise has impeccable properties crystallizes in a form that renders it as "brick dust" which is unable to dissolve. Polymorphs also serve as a way to get around patents; you can actually patent a different polymorph of an existing drug. And of course, due to their unpredictable nature (computational prediction of crystal packing is still in a rather primitive stage) polymorphs cause extremely serious problems; the HIV protease inhibitor Ritonavir had to actually be withdrawn from the market because of the appearance of an unexpected polymorph.

To me it sounds like PepsiCo has hit on the right polymorph for common salt that has enhanced dissolution rates. I hope they have done adequate stability studies on it, because polymorphs can actually interconvert into each other based on environmental conditions. But it's a neat idea that can potentially be used for other food ingredients.


  1. Interesting idea they've got - the 80/20 swallowed/tasted ratio is pretty worrying.

    BTW I don't think it's going to be strictly a different polymorph - NaCl is very unlikely to crystallise in any other structure than the one we all know and love.

    I guess it's just the size of the salt crystals - smaller ones will have more surface area (relative to volume) and dissolve more quickly.

  2. Good point, maybe they are just making the crystals smaller. I wonder how anyone did not accomplish that before though. The 80-20 fact is one that I was not aware of before and is disconcerting.

  3. Thanks for pointing out this article. Leatherhead Food International has been experimenting with freeze-drying to make smaller salt crystals. I neglected to ask the company about polymorphs at the time.

  4. You're welcome. Nice C&EN writeup. The molecular mechanism of salt-sensing seems fascinating.


Markup Key:
- <b>bold</b> = bold
- <i>italic</i> = italic
- <a href="">FoS</a> = FoS