Experiment 5: Salmon Sushi

Figure 1. Salmon Sushi.

Introduction
Sushi came up in conversation as a potential cooking challenge well before this blog came to be.  It's different, it's relatively exotic, and it's absolutely delicious.  Making sushi involves a process that is unlike anything one would encounter by sticking to typical American cuisine.  Or Italian, or Mexican, or anything else that one's mind easily turns to as a dinner option.  It utilizes only fresh ingredients.  There are no fillers.  Each ingredient serves a specific function without reducing quality or nutrition, and each provides a fresh taste that contributes to the complex flavor of sushi.

Tell your taste buds to get ready for a boost.

Our NFPA ratings:

Prep time: Simmering, slicing, arranging, rolling.  It will take you about an hour 20 if everything goes as planned.  Salmon takes about 20 minutes to cook, but you can do that while the rice is simmering.  Neither should be hot, so leaving them to the end won't do you much good.

Difficulty: We will give this one a solid 6.  Most of those points go to laying out and rolling up the nori with everything in it.  Take your time and roll evenly so that nothing falls out the sides of the roll.

Course: Since sushi is a cold dish, it can serve as of a flavorsome dinner as easily as it can be eaten straight out of the fridge for a next-day lunch.  Or a midnight snack, if your stomach asks for it.  Be careful, though: avocado browns easily, and rice dries out, if the sushi is not wrapped adequately.

Figure 2.  Sticky Rice.  Mmm.....Amylopectin!

Materials

1) Sushi rice - 2 cups
2) Rice wine vinegar - 6 tablespoons
3) Nori (dry seaweed) - 6 sheets
4) Avocado - 1 peeled, pitted, and sliced
5) Cucumber - 1 peeled and sliced
6) Smoked Salmon - 8 ounces, cut into long strips
7) Wasabi paste - 2 tablespoons

8) Bamboo mat

Procedure

1) If you want to use a rice cooker: soak the rice for four hours.  Drain it and cook it in the rice cooker with 2 cups of water.  If you don't want to spend your whole day making rice, just follow the instructions on the bag.  It will most likely involve 20-30 minutes of simmering.

Figure 3. Unlike what's shown here, cutting thin strips

might be best.

2) Immediately after the rice is cooked, mix in the rice wine vinegar.  Spread the rice on a plate until it is completely cool.

3) Place one sheet of nori on a bamboo mat.  Press a thin layer of cool rice on the nori.  Leave 1/2 inch on the top and bottom edges of the nori uncovered (necessary for rolling).  Dot some wasabi on the rice.  Arrange the cucumber, avocado, and smoked salmon on the rice (Figure 4).  Position them about 1 inch away from the bottom of the nori.

5) Slightly wet the top edge of the nori.  Tightly roll from the bottom to the top edge with help from the bamboo mat.  Cut the roll into roughly 8 equal pieces.

Figure 4. a) Lay a sheet of nori flat on rolling device of choice. b) Lay a thin layer of rice on the sheet, leaving a 0.5 inches on both ends. c) Place the ingredients across the width of the sheet (top to bottom: avocado, salmon, cucumber).

Results

Instead of using smoked salmon, we bought fresh salmon and cooked it ourselves.  Why?  To be honest, notice of the word "smoked" did not occur until the typing of the ingredient list for this article.  Who reads directions anyways?  Besides, using fresh salmon is is the more traditional course of action.  However, we decided to cook it so as to avoid potential food poisoning.  All we did was put a thin layer of oil in a frying pan and cook it on both sides for 5-10 minutes each.  Nothing fancy.  We even left the skin on (neither of us are experts with a filet knife, so, again for safety, we decided not to experiment).  You can season it if you want (although not recommended for sushi).  Tip: adding salt before cooking it will cause the fish to dry out, so don't do it.  Using smoked salmon sounds like a good idea, now that it's been realized that the recipe originally called for it.  It probably would have added a bit more flavor.

Figure 5. A freshly rolled roll, before cutting.  So that's 

why they call them rolls.

Despite using wrongly-prepared fish and poorly cut avocado, the sushi not only came out looking amazing, but it tasted fresh and flavorful.  Honestly, we were pretty impressed.  Although we were uncertain about the purpose of the rice wine vinegar, we found that it gave the rice a tang that reminded us of what sushi should taste like, assuring us that we were on the right track.

One important point to mention is that we did not use special bamboo mats to roll the sushi.  Although slightly less efficient, it is completely possible to roll sushi without them.  Maybe the key is having four hands to roll each piece.  It's up to you to figure out how you are going to find four hands.  Perhaps we shouldn't admit that we used a piece of computer paper in place of a bamboo mat.  We are students, and we cook like students.  That includes not buying bamboo mats.

While we deviated greatly from the protocol that was laid out for us, we were reminded that we shouldn't be afraid to change recipes a little, as this may lead to new ideas.  As Isaac Asimov said, "the most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka' but 'that's funny...'"  Or in our case, "The recipe says what?  Too late."

Discussion
Rice is perhaps the most important part of sushi because it holds everything together.  Sticky rice

Figure 6. Chemical structure of a) amylose, an unbranched
starch, and b) amylopectin, a branched starch.  

holds the nori in its rolled conformation, not the other way around.  So what makes this rice stickier than other rice?  Most rices are made of two types of starch: amylose and amylopectin (Levan 2011).  Both of these starches are composed of chains of glucose, but amylose is a straight chain, while amylopectin has a bunch of branches that occur at alpha-1,6-glycosidic bonds (Fig. 6).  Amylopectin is therefore more soluble in water because it has more spots where enzymes can bind and break it down (Green et al. 1975).  Sticky rice is composed mainly of amylopectin, so when you boil water, heating the sticky rice, the amylopectin breaks down and becomes sticky (Levan 2011).



Future Directions
Coming next: Banana Bread!

Additionally, we still have about 4 lbs. of sticky rice left.  So, there might be more sushi in the not-so-distant future.  In other realms of food, we were thinking about making a Lou Malnati's-inspired deep dish pizza.  You better start salivating now.

Figure 7. Dinner time!

Figure 8. Sushi and Pumpkin Cake Pop Timeline

References
1) Levan J.  Aug 2011.  "What Makes Sticky Rice Sticky?"  foodrepublic.com.
2) Green MM, Blankenhorn G, Hart H. 1975. "Which Starch Fraction is Water-Soluble, amylose or amylopectin?" http://pubs.acs.org/doi/pdf/10.1021/ed052p729
3) Wilson, R. Aug 2011. "Saving Calories - Why this doesn't Work." Nutritional Biochemistry.