Traditional Potato Preparation Reduces Acrylamide


Image Potato StarchMy grandmother's mother-in-law - my great-grandmother - taught my grandmother to soak potatoes overnight  in a brine, prior to simmering, baking, roasting, broiling or frying. 

Whatever her final potato-dish - gratin, latke, mashed, pan-fries, or oven-roasted - she prepped the potatoes, cutting them in halves or quarters, sometimes peeling, sometimes not.

If they were grated or match-stick cuts, she placed them into a tight-weave buttercloth, lowered into the brine to soak.  The cloth made it easy to extract the pieces from the brine, without disturbing the collected potato starch which sat on the bottom of the bowl like a fine, marsh silt.

Potato Starch & Ironing

My grandmother and great-grandmother highly-prized potato starch.  Without it, their shirts pillowcases, sheets, housedresses and aprons would have lacked its soft sheen, luxurious to the touch.

"Starches & Sizes are plant starches, usually corn starch nowadays, but formerly wheat or potato starch were commonly used when ironing cottons. Starches are used to stiffen; add crispness, body and glossiness; promote soil resistance (dirt particles adhere less easily to smooth, starched surfaces); and make ironing easier.  

If you like cottons, cotton blends and linens that have not been resin-treated for wrinkle resistance, you may also enjoy them ironed with a bit of starch."  Home Comforts - The Art & Science of Keeping House

Delicate Matters

My grandmother didn't reveal the other important reason for soaking potatoes, until I was nearly a teen.  It was of a more "delicate in nature" and not discussed in "mixed company".

"The potato is rightly held responsible for flatulence. But what is flatulence to the vigorous organs of peasants and workers?" - Denis Diederot, 18th century

Acrylamide - Grandma Never Knew

Two decades after my grandmother died, I learned about a third benefit of soaking potatoes in a brine.  

In 2002, the European factory-food industry was shaken by the discovery of acrylamide, described as a "a neuro-toxin, genome-affecting, possible carcinogenic compound", created during the baking of gingerbread.  

Over the next few years, other high-starch foods - French fries, chips, pan-fries, latkes, and even some canned black olives - were also found to contain questionable levels of acrylamide.  (Friedman 2003; Dybing and others 2005) 

"Acrylamide is formed by a heat-induced reaction between sugar (glucose, fructose and sucrose) and asparagine. Known as the Maillard reaction, this process is responsible for the brown colour and tasty flavour of baked, fried and toasted foods." Food Quality News

Since then, industrial food scientists have been scrambling - nearly a decade now - researching ways to eliminate or disrupt acrylamide creation.  Most researchers targeted the amino acid - asparagine - experimenting with ways to disable its ability to interact with glucose or fructose.  

Exotic food-additives were created  -  fungal extractsbamboo leaf extracts, and even an FDA-approved bacteria-derived enzyme - none of which were successful.  If any one extract or enzyme had been successful, a multi-billion dollar industry would have sprung up over night based on its success.  Instead, the solution was far more simple, and subsequently, not patentable. 

Grandma Trumps Scientists

My grandmother, and the generations of women before her, were good, intuitive scientists, employing good food-biochemistry practices now being confirmed. 

"The study found that washing raw French fries, soaking them for 30 minutes and soaking them for 2 hours reduced the formation of acrylamide by up to 23%, 38% and 48% respectively but only if they were fried to a lighter colour."  - Science Daily

This was a start! Far better success than bamboo or fungus extracts!  I continued to dig through the latest biochemistry research using methods that were more in-line with my ancestors - that of a longer soaking time in brine, instead of plain water

Image Fermented FriesDiscovery!

Acrylamide Development = Created/Determined by the Glucose or Fructose Content, and NOT the Presence of Asparagine

While most factory-food researchers focused on reducing the amino acids using modern chemicals and unnatural food additives, a few thought inside the traditional-box of food preparation.

"Acrylamide formation in potato tubers is mainly determined by the contents of glucose, fructose and not by the content of the asparagine."  - Amrein

In other words, if you use spontaneous, natural fermentation methods which are efficient at reducing the potatoe's gluose and fructose, acrylamide formation will be disrupted.  When there's insufficient amounts of potato sugar, there's a erduce interaction with the acrylamide-producing amino acid. 

Anaerobic Fermentation is Key! 

Anaerobic fermentatation is the perfect tool for reducing food starches and reducing-sugars.

"Lactic acid bacteria converts reducing sugars (sucrose, fructose, glucose) in vegetables to lactic acid thus lowering pH (Slinde and others 1993; Kaaber and others 1995). 

Previous studies have shown that lactic acid fermentation of potato (Kaaber and others 1995) and carrot slices (Slinde and others 1993; Baardseth and others 1995, 1996) reduces sugar levels, amounts of Maillard products, and the burnt taste of deep-fried chips.Food Chemistry Journal Vol. 71, Nr. 1, 2006

When anaerobic, lactic-acid bacteria break down and digest the potato reducing sugars, the following changes occur:

  • Reduced pH from 5.70 to 4.05 after 3 h
  • Glucose declined from 610.8 mg/100 mL to 7.9 mg/100 mL
  • Fructose declined from 457.8 mg/100 mL to 0.0 mg/100 mL
  • Sucrose declined from 132.0 mg/100 mL to 29.2 mg/100 mL
  • Asparagine content remained largely unaffected between 0 h (1217.5 μmol/100 mL) and 4 h (1175.6 μmol/100 mL) and increased slightly (1470.3 μmol/100 mL) after 5 h fermentation.
  • Levels of several other amino acids involved in Maillard reactions, that is, alanine, arginine, phenylalanine, and serine, decreased during fermentation.
  • They taste amazing with a nice "tang"
Pickl-It is the perfect tool for the anaerobic-fermentation removal of reducing sugars from foods.

Image Caldwell Starter Culture

The Pickl-It anaerobic fermenting chamber locks oxygen out, strengthening the anaerobic lactic acid bacteria to do what they were created to do = consume "reducing sugars" - using those sugars as a food-source for energy in order to create healthy lactic acid as well as carbon dioxide which pushes dissolved oxygen out of the brine. 
Modern potatoes have a higher-starch content (thanks to McDonald's perverting the potato market, demanding high-starch potatoes). Adding Caldwell's Starter Culture - the world's first and best broad-spectrum all-natural vegetable starter -  increases the number of sugar-eating lactic acid bacteria, thereby decreasing acrylamide formation.

A Picture's Worth a Thousands Fries

Acrylamide formation during production of French fries is most effectively lowered by lactic acid fermentation of potato rods before deep-frying or baking.  Here are some side-by-side comparisons from Vol. 71, Nr 1, 2006, in the Journal of Food Science which used blanching, instead of soaking, and fermentation in various combinations.  Reprinted with permission.

Image French Fry

Most acrylamide, darkest color:

A = blanched, unfermented
D = non-banched, unfermented

B = blanched and fermented for 45 minutes
C = blanched and fermented for 120 minutes 

E = nonblanched, fermented for 45 minutes
= nonblanched and fermented for 120 minutes

The research results?

Image French FriesIn terms of the above-study, blanching, and especially fermentation, reduced visually judged browning of the French fries.

There are numerous studies that used soaking instead of blanching, a technique that I find to be a timer-saver over blanching.   The results indicate that soaking is equally as effective as blanching in reducing acrylamide production:

"....soaking process leads to a higher leaching of one  important  acrylamide  precursor,  such  as  glucose,  that finally results in lower acrylamide formation." Franco Pedreschi, Processing Effects on Safety & Quality of Food

One last note - if you decide to try potato starch for ironing, the Pickl-Itwon't be of much help.

Unlike an open-bowl water-only soaking-method which leaves a thick residue of starch in the bottom of the bowl - perfect for ironing, there will be no starch in the Pickl-It.

That's because the Pickl-It environment supports a healthy community of lactic acid bacteria which are very efficient at breaking down reducing-sugars and the starch, leaving only clear brine and not undigested starch-sludge.

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