04 August 2010


Last week, my computer crashed and I was face with the daunting tasking of filling up my time, prairie style. Luckily, I haven't touched any of my Christmas books since they were given to me due to the lure of the Internet and so I had 3 brand new books batting their eyelashes at me.
Since I'd been spending most of my computer time either being a professional lesbian or a a future professional housewife (this is only sort-of true, I also spend a lot of time researching linguistics programs and making myself panic about grad school so that I don't end up on Wisteria Lane), I pulled out this 844-page baby. So far, I've learned that mead is fermented honey-water (yum), that fruits and vegetables don't have to turn brown when you cut them, and that Henry David Thoreau had nice things to say about popcorn.

"I have been popping corn to-night, which is only a more rapid blossoming of the seed under a great than July heat. The popped corn is a perfect winter flower, hinting of anemones and houstonians...By my warm heath sprang these cerealious blossoms, here was the bank where they grew"

But let's go back to keeping green vegetables green. Guacamole is my passion. I had it for the first time last summer (I know. I had sushi for the first time a month ago and tried my first soup--gazpacho--last week.) and never looked back. It's easy to make; cheap (holla 10/$10); and, regardless of how much you want to tell me that avocados are mostly fat, it's a green vegetable. Sometimes when I go home to visit my family, I spend time telling my grandparents new foods that I've eaten. "Red peppers!" I'll tell them, "Broccoli!" "Peaches!" "Crab!" and they're very proud. Despite having traveled all over the world, though, they insist on calling tortillas "tor-til-lee-yahs" and guacamole "guac-a-mol." They also exclusively call each other "dear" and my grandpa introduces my grandma as "my wife" instead of her name so much that once her friend addressed her birthday card "to my wife." This is a completely digression that I'm only including to point out that I used to think that the arcade game whack-a-mole had something to do with chips and dip.

Like any warm-blooded man, I like to come home from work to find dinner ready on the table. Just kidding, my girlfriend lives in Canada and I don't have a table. So I like to come home and have snacks waiting patiently in my fridge. Unfortunately, guacamole has a tendency to turn blackish-brown after a few hours and, while the taste doesn't change so much, the texture isn't quite the same and the color can be hard to get past. But guys, Harold McGee has all the answers and I'm about to break it down for you.

Q: Where did the avocado get its name?
A: "The name comes from the Nahuatl word ahuacatl, which was apparently inspired by the fruit's pear-like shape and irregular surface; it means 'testicle.'" (page 337)

Q: The avocados at the grocery store are never ripe but I want guacamole NOW. What do I do?
A: "Ripening can be accelerated by enclosing the fruit in a paper bag with an ethylene-emitting banana. If these warm-climate fruits are refrigerated while unripe, their cellular machinery is damaged and they will never ripen; once ripe, however, they can be refrigerated for several days and retain their quality" (page 337)

Q: What makes guacamole turn brown?
A: Guacamole is a puree. "We make purees by applying enough physical force to rush the tissue, break apart and open its cells, and mix cell innards with fragments of the cell's walls." "Many fruits and vegetables...quickly develop a brown, red, or gray discoloration wen cut or bruised. This discoloration is caused by three chemical ingredients: 1- and 2-ring phenolic compounds, certain plant enzymes, and oxygen. In the intact fruit or vegetable, the phenolic compounds are kept in the storage vacuole, the enzymes in the surrounding cytoplasm. When the cell structure is damaged and the phenolics are mixed with enzymes and oxygen, the enzymes oxidize the phenolics, forming molecules that eventually react with each other and bond together into light-absorbing clusters. This system is one of the plant's chemical defenses: when insects or microbes damage its cells, the plant releases phenolics that attack the invaders' own enzymes and membranes." (page 269)

Translation: Cells are basically little bags of stuff with bags of other stuff inside them. You know those glow sticks that you crack and they start glowing because the chemicals start mixing together? Cells are tiny versions of that. Only instead of glowing, they just turn a gross color and try to attack your mouth.

Q: How can you prevent it from changing color?
A: Mr. McGee and I don't agree on this one. Here's what he says: "Avocado flesh is well known for browning rapidly once cut or mashed, a problem that can be remedied by adding an acidic ingredient (often lime juice) or by airtight wrapping with a plastic film that blocks oxygen effectively" (page 337)

But you know what else he says? "The enemy of green: acids," (page 279) then goes how to explain how acids remove tails from chlorophyll a and turn it into chlorophyll b which is an olive brownish color. Acids like lemon or lime juice should be added at the last minute and he advises us to "consider protecting them first with a thin layer of oil" (page 280) Avocados are about 30% oil, so I guess that's helpful.

He recommends blanching green vegetables as "boiling temperatures will destroy the enzyme [that reacts and turns vegetables brown], so cooking will eliminate the problem," and quickly submerging them in a bath of icy water to stop cooking since "high temperatures can encourage phonolic oxidation in the absence of enzymes."

This all sounds great and very good stuff for modern jackass so rather than try to figure out what might work, I went ahead and did it. I split my avocado in two, blanched one half, added the same ingredients to both bowls, and came home to see what they looked like, with a couple of taste tests along the way.

On the left is the unblanched avocado. On the right is the blanched one. I lost a few flecks of avocado to the boiling water, but it's looking mighty green. Mr. Food said that vegetables appear to turn a brighter green after a few seconds in boiling water because of a "sudden explansion and escape of gasses trapped in the spaces between cells. Ordinarily, these microscopic air pockets cloud the color of the chloroplasts. When they collapse, we can see the pigments much more directly." (page 279) We're going to be breaking cells open in a minute so it shouldn't matter, but it's nice to look at for the moment, isn't it?

They look pretty much the same at this point. I like to add onions, garlic, salt, lime, tomatoes if I have then, and cilantro to my guacamole but I'm down for new ideas. Even after putting the boiled avocado in an ice bath, it didn't cool down completely so the guacamole was weirdly warm and slightly more bland.

After 7 hours at work, this is what I came home to find in my fridge. I thought the blanched guacamole tasted slightly fresher but that might have just been wishful thinking. The verdict: If you're making a vat of guacamole to serve later and want it to last and stay in the salad days of youth until then, you might want to consider boiling your avocados before mashing them. If you're looking for a quick snack, it's definitely not worth the extra time.


stef said...

thank you laura! this was very informative.

Nirja Desai said...

You write so well!!!!

Jonathan said...

Awesome popcorn pic! We need to meet up pronto. You bring the guacamole, I'll bring the popcorn. We'll meet in an Indian restaurant for nan.

saint modesto said...

don't worry baby, i'll still put the meat on your counter.

wonderful post!

ps. word verif = seversis .. snape?

laura said...

+stef: oh thanks!
+nirja: you're too kind.
jonathon: i leave in a few weeks so let's get out popcorn and naan on asap.
+saintmodesto: i hope it's steak.