Wednesday, October 24, 2012

Looks like Fruit & Veg!

But don't worry, we'll also do breads in a couple weeks.

On the fruit & veg side of things... We'll very likely do some tasting in the coming week or so. Are there any fruits or vegetables that you have never tried that you're curious about? Some vegetables that might be a bit less common (but I know I can get pretty easily...) might be some of the root vegetables (rutabaga, parsnip, turnip), or some different varieties of potato, or some different types of greens... On the fruit side, some of the less-typical citrus fruits, or unique berries...
Basically, if there's a fruit or vegetable (broadly defined) that you've always wondered about, let me know, we might use that as part of an in-class tasting, and you can have a new and exciting experience.

Tuesday, October 23, 2012

Next topics...

Fruits and Vegetables are winning in the early returns, but the polls are still open in the rural areas. Vote early, and in this case you can even vote often.

Sunday, October 21, 2012

Exam #2 Practice Problems

#.     What is cheese? – Milk that has been curdled by acid and rennet that has had most of the water removed

#.     What is the primary role of salt in cheese? – Preservative

#.     Some enzymes used in cheesemaking hydrolyse fats and proteins during the aging process. How does this affect the final cheese? – Hydrolyzed fats and proteins usually lead to smaller molecules that contribute flavor and aroma. They can also tweak the texture.

#.     Why is it important to get chymosin (rennet) from young calves rather than adult cows? – Cows only produce chymosin while they are feeding on milk, once they’re off the milk, chymosin production drops off very quickly

#.     How was rennet “discovered? – It was a happy accident. When calf stomachs were used as waterproof bags for milk storage and transportation, the rennet curdled the milk into cheese

#.     What specific protein does chymosin (rennet) react with during cheesemaking? – Chymosin reacts with the kappa-casein proteins that coat casein micelles… This lets the “gooey” inner caseins to stick together and form a network of casein micelle chains

#.     When chymosin (rennet) reacts with protein during cheesemaking, what happens on a molecular level? – Rennet “shaves” some of the kappa-casein off the outside of the casein micelles and they stick together

#.     When acid reacts with protein during cheesemaking, what happens on a molecular level? – Acid denatures the casein proteins much more completely, allowing the individual casein protein strings to interact

#.     What are the main roles of propionibacteria in cheesemaking? – This is the hole-making bacteria

#.     Brevibacterium linens mainly contributes what to cheese? – This is the “stinky cheese” bacteria

#.     What are the properties of Penicillium roqueforti and other “blue molds” used in cheesemaking? – Can survive low oxygen, found inside the cheese, digests fats, contributes sharp/peppery flavor

#.     How are the “white molds” used in cheesemaking different from the blue molds? – Surface molds, digest proteins, make creamy texture

#.     When slowly adding heat to try and melt cheese, what component (food molecule) is affected first? Second? – Fats melt first, proteins denature next, water starts to boil/evaporate off, fat/protein start to brown/burn, things start on fire, chaos ensues

#.     In dishes that contain melted cheese, what causes “stringiness”? – Too many protein-protein interactions, lots of stirring

#.     Where is most of the fat found in eggs? - Yolks

#.     What does the color of the shell of a chicken egg tell you? – It can indicate the breed of chicken, but not much more

#.     What does amylase (an enzyme found in egg yolks) do? – We talked about this one in the food molecules section, amylase digests (hydrolyzes) amylose, that’s starch

#.     After water, what is the largest component (food molecule) of egg white? – Albumen proteins

#.     What happens on a molecular level when eggs are cooked “hard”? – Proteins denature and get all tangled up

#.     Describe the molecular changes that take place when egg whites are whipped. – Mechanical shearing/denaturing  of proteins, proteins stretch and tangle, capture air bubbles

#.     What role does cream of tartar serve in whipped egg whites? – It’s an acid, it prevents the formation of too many disulfide bonds

#.     Why are very strong interactions, like disulfide bonds, unfavorable in whipped egg whites? – Very strong interactions tend to squeeze water out and limit the ability of the protein chains to slide by each other while the meringue is forming/building

#.     How does heat affect an albumen foam (a meringue)? – Heat dehydrates the meringue, also denatures additional proteins (ovalbumen) to form more network connections, if there’s sugar present the heat will also dehydrate and form a bit of a sugar-strand network

#.     What component of an egg preparation has a very high heat capacity? - Water

#.     What component of an egg preparation is an excellent heat insulator? - Air

#.     What component of an egg preparation can melt, solidify or separate depending on temperature? - Fats

#.     What component of an egg preparation affects the structure and texture of the final dish depending upon whether it has been denatured or not? - Proteins

#.     What is “candling” and why is it done? – Shining light through an egg to see the yolk and determine the egg’s grade

#.     Describe the different grades of eggs. – AA = thicker albumen, prominent chalazae; A = less thick, weaker chalazae; B = industrial eggs, yolk swirls around inside the shell

#.     What is specific heat capacity? – The amount of heat/energy required to raise a given amount of a substance by a given temperature. Usually calories per gram-degree-Celcius

#.     If the specific heat capacity of water is 1 calorie per gram-degree-Celcius (1cal/g•°C), adding 100.0 calories of heat to 20.0g of liquid water at 17°C should {increase/decrease} the temperature to _______°C. – This should increase the temperature by 5°C to 22°C. 
(100.0calories) / (1cal/g°C) = 100 g°C
(100 g°C) / (20.0g) = 5°C.

#.     What role does the water bath play when cooking/baking a custard? – Even heating, slows down and evens out the denaturing of proteins in the custard, manages heat transfer

#.     Why is tempering important? – Tempering evens out the denaturing of proteins. If hot and cold were just dumped together all at once, some proteins would denature quickly where the solution was hot and the result would be a clumpy mixture

Saturday, October 20, 2012

Exam 2 Format

Exam 2 (and all of your exams in BCBT 100) will be a multiple choice exam. The practice questions I posted do not have "multiple choice" answers included with them because when you are studying for the exam I want you to be thinking about the substance of the questions and topics, not just picking the correct answer out of a list of 4 or 5 options. Good luck and let me know if you have other questions.

(I'll post answer to the practice questions some time late today or tomorrow, make sure you look at the questions and try to formulate a response BEFORE you check the answers.)

Friday, October 19, 2012

You're the expert!

One of the nice things about a science class based on food and cooking is that in some cases YOU have real first-hand experience with the topics we're discussing. That means that sometimes (maybe even quite often), you will have experience or insight that is beyond what I have. I like that! It means that I can learn something too, and I always try to learn at least 1 new thing every day.
Related to this, someone pointed out a pronunciation I slipped up on in class yesterday... I have a very basic understanding of German, and in reading what was written on my slide while I was talking and thinking about what was coming up, I did a really bad job on the word "kuchen". It is absolutely NOT pronounced "koo-chin"... The typical American English "ch" pronunciation is generated almost entirely in the front of the mouth with the tongue and the teeth (it's a more "dental" sound), whereas the "ch" in "kuchen" is generated in the back of the mouth and throat, almost as if you're pronouncing a "hard c" and an "h" at the same time, a little like the "ch" in "chalazae" or "Bach". When this German "ch" is in the middle of a word, it is often pronounced almost like a "g", but a little farther back in the mouth/throat.
The biomechanics of linguistics is really pretty fascinating, and if you think about just how the sound of different letters and words are produced in the mouth, it's fun to experiment. Most people don't think about the way tongue, teeth, lips, cheeks, throat and lungs interact to do something as "simple" as speaking, if this is something you're really interested in you should check out the Speech, Language, Hearing Sciences department at MSUM.

Practice questions

Exam #2 is coming up on Tuesday... I've posted some practice questions {}, take a look at them. I posted them in a little more open-ended format to encourage you to think about the question a little more rather than just ferret out which answer is correct. I'll post answers some time over the weekend, make sure you look at and think about the questions before you look at the answers. Good luck.

Saturday, October 13, 2012


The word “perfect” has a lot to live up to, and although the truly “perfect” spatula may not exist, I think there are a few that come close. The criteria I use to evaluate spatulas are pretty simple.
1. Material – At this point in time, I really don't see any good reason to buy a spatula that is not heat-resistant. A good silicone spatula is flexible, durable, stable, stain resistant, and should be heat resistant to 600ยบF or more. Although a good new rubber spatula might have a few advantages, rubber spatulas are not heat resistant, prone to stains, and can get a bit “gummy” over time. If I had an active enough kitchen that I could take advantage of a wide variety of spatulas, I might be willing to stock a few silicone spatulas and a few rubber spatulas, each for their own unique purpose, but personally, I would greatly prefer to have consistent spatulas that are all good (or at least good enough) for any application
2. Construction – Spatulas (and many other kitchen tools) have the potential to be fertile grounds for contamination and bacteria or mold growth. The best way to prevent this is to clean utensils well, and this is infinitely easier if there are fewer gaps and seams and joints. That means any spatula that is a single piece will be much easier to clean and keep clean. One-piece construction also means that the head of the spatula will never fall off or slip from the handle. There are very few rubber spatulas that offer 1-piece construction, so once again, silicone offers a distinct advantage. Having 1-piece, all-silicone construction also means that when using the spatula for “hot” applications, you never have to worry about melting or scorching the handle of a silicone-headed 2-piece spatula.
3. Price – This is, honestly, a minor consideration. A good quality $10 spatula will usually be much more durable than a $2 spatula, but the difference in price between a “good” spatula and a “cheap” spatula isn't really that significant. With some kitchen tool, the price range is pretty broad. For example, frying pans can range from $10 to $200+, but even a very high quality spatula with a prestigious brand name probably won't cost more than $25-30, and a good quality tool can be found quite easily for $10-15.
My favorite spatula is a Chef'n brand 1-piece silicone model similar to this one { }, although my specific spatula is not colored.
This has been a wonderful tool in my kitchen for quite a few years, but has picked up a couple small nicks and dings, so I'm probably in need of a new one. I'll probably wander through local stores for a new spatula, but I'd be pretty happy if I could either find the exact same model or perhaps something like this one { }

I would be perfectly content to use a brand other than Chef'n, but my current Chef'n spatula has been a wonderful tool so I'd be happy to display some brand loyalty.
Do I really put this much thought into something as pedestrian and work-a-day as a spatula? Well, yes, but it's almost by accident. As with many kitchen tools and other things, you don't really think about preferences or quality until you accidentally buy something that has some very obvious advantages. That was the case with this spatula.

Tuesday, October 9, 2012

Food as Science

One of the greatest things about food is that there is a LOT of fascinating science going on that can be explored by anyone. The conditions are (usually) safe, the ingredients can be pretty inexpensive (although some can be very expensive), and the result can (usually) be eaten. Take advantage of these things when it's time for a meal. Thinking about the science behind simple processes like whipping and baking and frying can dramatically improve the quality of the food you prepare.