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Monday, June 11, 2018

Understanding Lactose

In "Bluff the Listener" segment of the most recent episode of the popular NPR show, Wait Wait, Don't Tell Me, guest Bim Adewunmi tells a story of an "extremely lactose intolerant" man becoming the spokesperson for a major ice cream company. Which would be funnier, if it didn't reveal just how much the population still doesn't understand about lactose. Let's break it down:

  1. Lactose is not milk. It's a sugar component of almost all milk (well, the real stuff from mammals, not the extracts from plants often called plant milks). 
  2. It's a disaccharide - two simple sugars connected together. It's not a complex protein, as Bim mistakenly calls it on the podcast. 
  3. An enzyme called lactase breaks this bond, creating the two simple sugars again. Lactase is produced by most mammals as infants (that includes humans), but upon maturation, most humans stop producing lactase. Thus, most people (in the world) actually can't digest lactose as adults - this is normal (the statistical definition). 
  4. Through a quirk of evolution, some humans retained the ability to produce lactase through adulthood - mostly through a founding population in Europe (documented human evolution, for realz). In fact, lactase persistence is the odd case, but it's diagnostic of how medicine is so Eurocentric. 
  5. Processed and fermented milk products usually don't have lactose because the microbes used will usually digest it already (think yogurt or long aged cheeses). And yes, you can make ice cream with lactose free milk. 
Hey, contestant, knowing basic milk chemistry should've been a big giveaway on Bim's story. 

Wednesday, June 7, 2017

Houston poké jumps the shark

Poké was all the rage in Southern California, and the wave hit Houston this year, with a large number of poké shops opening in a very short time span. Even the California-based North Shore Poke Company opened an outpost in Houston. What is poké? Basically, it's a raw fish "salad", consisting of diced fish marinated in various seasonings (the name, after all, derives from the Hawaiian word for dicing). More modern interpretations serve this atop rice and include other vegetables. 

Well, the mainstreaming hits when it is now available prepackaged in a supermarket. Behold, the HEB poké bowl:

A note on the pricing: at around $10, it's pretty close in price to an a la carte restaurant prepared poké bowl ( a regular bowl in the pioneering Ono Poke is $10.50). But this version is designed to be sitting around for a while:

This isn't so much poké but literally a regular salad with raw fish thrown in. Not really paying heed to Hawaiian traditions, the dish is edible but lacks any real character. The dressing has that insipid sweetness akin to most packaged dressings, and completely misses out on the synergy marinating the raw fish produces. 

In summary - save your money, and patronize the regular joints. I tried this for science - you shouldn't have to. 

Thursday, October 27, 2016

"Natural Yeast"

So I was listening to the Good Food podcast on KCRW - a pretty well produced podcast, by the way - but it does tend to veer into the various wading pools of pseudoscience that pervades food enthusiast culture. On this particular episode, they were airing an interview with a bread baker, who proudly declares the the bread didn't contain any yeast, just a sour dough starter.

Now, I hear this a lot, as if commercial yeast were somehow inferior to wild "natural" yeast that the baker procured by chance. Some may even say it reflects the mystic "terroir" of the area. And in the same circles, "inferior" is often rounded down to "wrong". And such sourdough loaves can somehow be tolerated by the gluten intolerant (even though gluten is still there - it's again some kind of magical property that the mystic yeast imbues to the bread).

This kind of worship of the unknown somehow lends comfort to the hegemony of the kitchen. What industrially produced yeast has is predictability. We know exactly how long it will take to leaven the loaf, and it's been bred not to carry unexpected flavors. It does not obviate the inclusion of non-standardized microbial cultures, but certainly no reason to demonize the servile commercial yeast we can rely upon.

Thursday, May 12, 2016

Oliver Twisting

Multiple friends and acquaintances promptly sent this pretty good piece John Oliver did "exposing" the media exploitation of scientific studies. Whilst entertaining, the irony is that to do this piece, Oliver's team had to cherry pick the data itself. For example, how frequently did media outlets report the studies accurately as opposed to exploit it for the benefit of the story?

And let's not forget Oliver's own fast and loose interpretation of science (and "scientists") to forward the requisite controversy in a story.

Wednesday, May 11, 2016

Softer, whiter, more predictable

Selection of delicious doughnuts from Morningstar
On 10 May 2016, Houston welcomed the "next generation" of doughnut and coffee shop, Morningstar (probably best to follow the Instagram account - gorgeous). In covering the opening, HoustonPress mentioned that Morningstar uses "...unbromated and unbleached wheat flour (potassium bromate is often added to flour to create stronger, whiter dough, and is classified as a carcinogen

An interesting parenthetical clause. After all, much handwringing and high value is given to using "unbleached" and "unbromated" flour already exists, but what is the basis for mentioning potassium bromate directly?

Before we go into the chemistry of flour bleaching, I tried to find out just how often potassium bromate is added to flour. By law, it has to be listed among the ingredients, and it's quite difficult to source specifically bromated flour. In fact, I get the impression that using bromate in flour has fallen out of favor given the concern that less that fully cooked bread can retain trace amounts of it - and there are multiple alternative oxidizing agents available. I'd welcome comments as to the commonality of bromated flour in restaurant and home applications.

So why is bread bromated and or bleached? Freshly milled flour actually doesn't bake very well, and usually has a yellowish cast. Aging the flour while exposed to air results in oxidation of the proteins and carotenoids, resulting in a paler color, and better baking performance. However, aging is notoriously poorly reproducible, and slow. But we do know that what we are looking for is oxidation - so we can add oxidizing agents in trace amounts to not only speed the process but also make it more reproducible. So, bleaching agents (i.e., benzoyl peroxide) serve to whiten the flour, while maturing agents help develop the gluten. Potassium bromate is a maturing agent - so it doesn't serve to create "whiter dough". Note, however, that there are multiple possible bleaching and maturing agents. In most small batch situations, there really is negligible difference between using unbleached and bleached flour - arguably when scaled up to industrial levels, the differences in reproducibility can be dramatic. But at least in the case of cake flour, bleached (matured) flour is definitely superior in angel food cake

Search results for potassium bromate on Google will be dominated by multiple articles calling it out as a carcinogen - notably the IARC classification of carcinogen Category 2B. However, this classification is so broad, it includes things like coffee, pickled vegetables, and talcum powder. Being a powerful oxidizing agent, doses of potassium bromate is undoubtedly toxic, but I don't see any concern about it with regards to flour. Adding an emotionally charged and factually dubious clause to the report tends to fuel the misunderstandings about flour processing. I do think preference for unbleached flour is certainly any cook's prerogative, but scientifically, that declaration does not add significant value. 

Hat tip to Stella Parks of for her article in Serious Eats. And to Sam Vance (@samvance on Twitter) for vigilant reading of food science, and for sending Stella's article my way.