Posts Tagged food

One-factor-at-a-time (OFAT) food experiments not very nourishing

Knowing of my interest in experiment design,my son-in-law (a newly minted PhD chemist) showed me his book on Cooking for Geeks. It offers a lot of fun detail on chemistry for a fellow like him. As a chemical engineer by profession, I like that too. Furthermore, I am all for the author’s enthusiasm for experimentation. However, his methodology, quoted below, lacks any sophistication or statistical power.

Make a recipe twice, changing just one thing (cookies: melt the butter or not?), and see what changes (if anything). If you’re not sure which way to do something, try both and see what happens. You’re guaranteed to learn something—possibly something the recipe writer didn’t even understand.

– Jeff Potter, author of Cooking for Geeks

Potter is not alone in remaining mired in OFAT and sample sizes of one (n1). This is also the methodology of the prestigious Cooks Illustrated as seen by this experiment on roasting ribs. Chris Kimball who launched this magazine, and, until recently, hosted “Americas Test Kitchen” on PBS, contacted me soon after Forbes recommended Stat-Ease software for multivariable testing (MVT) in March of 1996 (“The New Mantra: MVT”. I gave him a briefing on multifactor (as I prefer to deem it) design of experiments. However, Chris told me that his cooks were artists, not scientists, and they would not take to anything other than n1 OFAT. That works only when you make gross changes, such as roasting at 250 versus 450 degrees F. Even then, I’d like to see at least 4 of each level done in a randomized plan, and, better yet, a multifactor experiment.

The one nice thing about these poorly executed food experiments is that you can re-do them yourself. I might take on the question of roasting ribs, for example. Yum!

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Beware–eating like a king is not healthy

With Tthe-seven-pillars-of-statistical-wisdomhanksgiving coming up I am looking forward to a feast beyond all others throughout the year.  Therefore, I did not want to know that eating like a king has been demonstrated to be unhealthy.  I learned of this while reading The Seven Pillars of Statistical Wisdom by Stephen M. Stigler, one of the world’s foremost experts on the history of statistics.  In his chapter on the pillar of Design, he relates (p. 150) a story from the Old Testament of how Daniel eschewed a rich diet of meat and wine offered by King Nebuchadnezzar.  Daniel proposed what may be the earliest clinical trial—he and his three companions eating only pulse* and water for 10 days.  Meanwhile several followers of the King enjoyed his fare for the same period.  In the end Daniel and his friends fared better, at least on the basis of health.

The lesson here is to polish off the bounty of Thanksgiving before 10 days are up, in other words, do not lay off those lovely leftovers!  Then eat like Daniel for a few weeks in preparation for the year-end holiday feasts.  That will keep you healthy by my interpretation of Daniel’s pioneering study on diet. ; )

*Dried beans and peas (yuk!) as seen here.

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For count of calories it is nary the area of the Oreo but the thickness

In a new twist on sandwich cookies, the manufacturer of Oreo brand cookies, Chicago-area based Mondelez International, now offers a thin version with a 12.5% reduction in calories per serving.  (From what I gather off the internet a “serving” seems to vary from 2 to 4 cookies, depending on the thickness, I suppose.  For example, I would not advise eating four Mega Stuf Oreos in one sitting.)

The Detroit Free Press gives the 7.5 mm thick Oreo Thins two thumbs up in this July 6 review.  Unfortunately the reduction in filling from the 12.5 mm thick regular cookie closes out as a practical matter the option for splitting them apart, which normally about half of Oreo cookie-eaters do, according to Mondelez.

These thin confections are likened by the Oreo maker to crepes, perhaps to be eaten only at fancy teas in the mid-afternoon by proper ladies and gentlemen.  To me that is a deal breaker.  I plan to eschew the Thins in favor of the Mega Stuf, which according to this “implusive” blogger who will eat “anything edible no matter how strange” contains 52.5% more filling than Double Stuf.

Come to think of it, the food scientists at Mondelez really out to come up with an Oreo that is comprised only of the crème filling—saving us the trouble of having to twist them apart.

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Believe it or not–sweet statistics prove that you can lose weight by eating chocolate

Keep calm and carry on eating chocolateA very happy lady munching on a huge candy bar caught my eye in The Times of India on Friday, May 25.  Not the lady—the chocolate.

After tasting a variety of delectable darks from a chocolatier in Belgium many years ago, I became hooked.  However, I never imagined this addiction would provide a side benefit of weight loss.  It turns out that a clinical trial set up by journalist John Bohannon and two colleagues came up with this finding and showed it to be statistically significant.  This made headlines worldwide.

Unfortunately, at least so far as I’m concerned, the whole study was a hoax based on deliberate application of junk science done to expose phony claims made by the diet industry.

It turns out to be very easy to generate false positive results that favor a dietary supplement.  Simply measure a large number of things on a small group of people.  Something surely will emerge that out of this context tests significantly significant.  What this will be, whether a reduction in blood pressure, or loss in weight, etc., is completely random.

Read the whole amazing story here.

My thinking is while Bohannan’s study did not prove that eating chocolate leads to weight loss, the subjects did in fact shed pounds faster than the controls.  That is good enough for me.  Any other studies showing just the opposite results have become irrelevant now—I will pay no attention to them.

Now, having returned from my travel to India, I am going back to dip into my horde of dark chocolate.

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Glass-shattering interaction of factors

Last week (12/21) the Today Show broadcasted an alarming demonstration of Pyrex glass exploding after being subjected to certain combinations of conditions.  See NBC News’ detailing here .  As reported in this American Ceramic Society Bulletin , some scientists believe that changes to the material (replacing borosilicate with soda lime silicate) weakened the glass.  However, makers of Pyrex disagree vehemently with these conclusions—see their side of the story here.

It turns out that hot Pyrex pans set directly on a wet or cool surface, such as a granite counter-top, undergo a sudden temperature change that produces some risk of it shattering.  That strikes close to home for me, having re-done our kitchen (as is the style nowadays) with granite.  Fortunately, being accustomed to plastic (Formica) countertops, I always put down cloth potholders before setting down the hot Pyrex pan.  The take-home message is being careful not to subject Pyrex to rapid increases or decreases in temperature.  See this site for safety instructions.

PS. On a lighter note (literally: too much sun) regarding heat and silica (main constituent of sand) see this New York Times news making it official that the hottest temperature ever recorded is 134 degrees F in Death Valley.  They are pyre Rex.

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Pigging out in Italy – a 30-meter pork roast

We are gathering quantities of food for a Thanksgiving feast at the Anderson home this Thursday.  As my stomach rumbles* in anticipation, my thoughts turn to another great feast that I saw prepared last summer in Bergamo, Italy.**  There they prepared pork (or porchetta, as they say), rather than the turkey we prefer in the New World.  What made this Bergamo barbecue so singular was the way the cooked their pigs – sewn together into a 30 meter roast!  See the results in this video I took (produced by my daughter Emily).

A meter or two of this porchetta would be the perfect warm up for our Thanksgiving banquet.  I wonder what these Italians would do to dress up a turkey.  They sure know how to create a spectacle!

*In medical terms known as “borborygmi” – a normal symptom of hunger.

**See this report

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Brain-bending thoughts on a coffee experiment

The Stat-Ease training center here at our world headquarters in Minneapolis features a wonderful single-cup brewing system that you can see demoed here.  When we are not holding a workshop, I sometimes sneak in to steal a cup late in the day.  By then I am reaching my limit, so I brew a “half-calf” at the half-cup setting.  Being a chemical engineer, I calculate that, in this case, half of half makes a whole, that is, coffee with the normal concentration of caffeine.  Does that make sense?

Making a tasty and effective cup of coffee is a huge deal for knowledge workers who need to keep their heads in gear from start to finish of every single day.  One of our workshop students, a PhD, has been picking my brain about testing coffee blends on her staff of scientists.  She proposes to do a mixture design such as I did on varying types of beers (see Mixture Design Brews Up New Beer Cocktail—Black & Blue Moon).

Obviously overall liking on a sensory basis should be first and foremost for such an experiment on coffee – a 5 to 9-point scale works well for this.*  However, the tricky part is assessing the impact of coffee for accelerating information processing and general problem-solving, which I hypothesize depends on level of caffeine.  I wonder if an online “brain training” service, such as this one developed by neuroscientists at Stanford and UCSF, might provide a valid measure.

The down side of doing a proper test on whether coffee improves cognitive skills will be the necessity of reverting to the base line, that is, every morning getting up and trying to function without the first cup.

“A mathematician is a machine for turning coffee into theorems.”

— Alfréd Rényi

*Turn your volume down (to not hear the advert) and see this primer on sensory evaluation by S-Cool– a UK educational site for teenagers.

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PB&J please, but hold the jelly (and margarine) and put it on toast – a mixture design combined with a categorical factor

My colleague Pat Whitcomb just completed the first teach of Advanced Formulations: Combining Mixture & Process Variables.  It inspired me to develop a virtual experiment for optimizing my perfect peanut butter and jelly (PB&J) sandwich.  This was a staple for me and my six siblings when we were growing up.  Unfortunately, so far as I was concerned, my mother generously slathered margarine on the bread (always white in those days – no whole grains) and then thick layers of peanut butter and jelly (always grape).  As you see* in the response surfaces for overall liking [ 🙁 1-9 🙂 ], I prefer that none of the mixture ingredients (A: Peanut butter, B: Margarine, C: Jelly) be mixed, and I like the bread toasted.  This analysis was produced using the Combined design tab from Design-Expert® software version 8 released by Stat-Ease earlier this year.  I’d be happy to provide the data set, especially for anyone that may be hosting me for a PB&J dinner party. 😉

*Click to enlarge the plots so you can see the legend, etc.

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Pushing the limits on alcohol levels for holiday cheer – higher the better (?)

Just in time for holiday gift-givers to the guy who already owns everything, Boston Beer Company (BBC) — brewer of Sam Adams lager — announced this year that they’d achieved new heights for alcohol content – over 25 percent by volume.  Alcohol levels traditionally have been capped at the 14% level due to natural limits of the yeast that drive fermentation.  However, the beer boffins at BBC applied their wits to the zymurgy and came up with “Utopia,” which can be purchased at $599.99 a mini-kettle via this internet purveyor (warning: it’s banned in 13 states!).   Otherwise you can await the next batch of ten thousand bottles or so of this potent beer to emerge in two years from the 15-year aging cycle.*

Perhaps this holiday season you may restrict yourself to tamer drinks than high-alcohol beer, such as the traditional eggnog — a “sweetened dairy-based beverage made with milk, cream, sugar, beaten eggs (which gives it a frothy texture), and flavored with ground cinnamon” (according to Wikipedia).  However, my plans to pick up our annual eggnog after Thanksgiving were dashed after listening to a recent radio broadcast of NPR’s Science Friday by Ira Flatow.  They warned about people (like me) risking salmonella-induced food poisoning by milking their ‘nog clear through Christmas.  The show posted this video reporting results from microbiologist Vince Fischetti on his challenge tests** in a lab at the Rockefeller University (RU).  I’ve seen these at food clients of Stat-Ease and they gross me out, so I know the end result of dosing up a dairy product with spoilage organisms and pathogens cannot be pretty.  Fischetti compared the results after one month of storing a spiked eggnog made by a traditional RU recipe (equal parts bourbon and rum to a 20 % alcohol level) versus one purchased commercially (no alcohol).  See the outcome by watching the video – it may encourage you to keep a bottle of spirits on hand.  (I’ve got a supply of tequila – just in case.)  Being a devotee of DOE, I must say that Fischetti’s findings appear to be based only on sample-size 1.  But to his credit, he expresses the desire for grant money leading to more definitive studies.

So whether you hoist a beer or a ‘cheered-up’ glass of eggnog to give your seasonal salute to your friends and family, here’s hoping you all a happy holiday!

*Source for news about high-alcohol beer: 11/30/09 article by Russell Contreras of the Associated Press, seen here as published by the Huffington Post.

** For all the gory details see this posting of Microbiological Challenge Testing by the Institute of Food Technologists (IFT).  The “Phoenix” phenomenon is particularly worrying (lethal bugs rising from the ashes of sterilization).

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Running hot and cold in Apalachicola – steaming to cook clams and steaming to make ice

My wife and I are celebrating our 35th anniversary with a Thanksgiving week getaway on the panhandle of Florida.  Later today we will enjoy a southern version of the traditional banquet, this one will featuring all sorts of grits – the chef’s specialty.  I expect some oysters too – mainly harvested just down-beach at Apalachicola.  Also, at the local Piggly-Wiggly I noticed lots of sweet potato pies laid out, along with pecan pies, of course.  If I lay off the grits, maybe I will keep some room for a piece of the pecan pie, preferably with some whipped cream on top.

Earlier this week we stopped by an interesting museum in Apalach’ (as the locals refer to it).  It celebrates the achievements of a local physician, John C. Gorrie, who invented the ice-making machine.  He is also considered to be the father of refrigeration and air conditioning.  Obviously the folks here in Florida hold Dr. Gorrie in high esteem for his dedication to cooling things off.  What interests me, being that I am a chemical engineer, is how steam powered Gorrie’s ice machine.  That seems very counter-intuitive, but the thermodynamics are explained nicely here by the inventor:

“If the air were highly compressed, it would heat up by the energy of compression. If this compressed air were run through metal pipes cooled with water, and if this air cooled to the water temperature was expanded down to atmospheric pressure again, very low temperatures could be obtained, even low enough to freeze water in pans in a refrigerator box.”

For a picture of what he patented in 1851 and historical background, see this Wired magazine article by Randy Alfred.

Getting back to the Thanksgiving feast this afternoon and thinking about the oysters,  I suppose we will be given a choice of raw ones laid out on ice (thanks to the local inventor) or one cooked with steam.  Coming from the middle of our continent, it may be too much of a stretch to eat uncooked shellfish.  In fact, it makes me a bit queasy just thinking of it.  Although I fancy myself an experimentalist, sometimes I must draw a line in the sand.

PS. One thing I find curious is that the oystermen (sorry ladies) still do their harvesting the old-fashioned way with tongs – see this video, for example .

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