Sorry for the cheesy post title – I tried my hardest. At least our panna cotta came out beautiful, and, well, not that cheesy. The first step in making our panna cotta, after greasing and preparing the ramekins, was to bloom the gelatin in the…
Assumptions I chose tiramisu for my final integrative assignment, not just because it contains aromatic ingredients (espresso and cocoa), but because it also combines elements from all of the previous units in the chemistry half of this course: gluten formation in the ladyfingers, denaturation and…
Is there thickening/setting/solidifying due to protein denaturation and coagulation?
The thickening agent is the eggs, which are beaten (or lightly agitated) and then heated. The heating of the eggs denatures the proteins in them. Since denaturation is always followed by coagulation, the mixture becomes firm as the proteins in the egg have their hydrophobic insides exposed and stick together to hide them.
What is the source of the protein?
The source of the protein is the whole egg, whole milk, and the parmesan cheese. The eggs are the main protein in the recipe.
What is the means of protein denaturation?
Protein denaturation permanently alters the structure of a protein by breaking the non-covalent interactions holding the structure together, and the individual proteins unravel. Methods of protein denaturation include heating, agitation, and addition of acid. The unfolded proteins now have their internal hydrophobic regions exposed, and multiple unfolded proteins aggregate together in a process called coagulation. The proteins in this recipe begin to get denatured when the eggs are lightly beaten, or agitated. Following that the eggs are heated, this is when the majority of the denaturation occurs.
Is the protein diluted?
When a protein is diluted it impacts the level of heat needed to denature it. The more a protein is diluted the higher the temperature needed to denature it will be. The protein in this recipe is diluted prior to being heated. Cream, milk, soffritto, parmesan, and vegetables and herbs are all added to the eggs.
How is the dilution impacting coagulation and therefore the final texture of the cooked product?
The dilution of the egg proteins interferes with the processes of denaturation and coagulation. The sformati is cooked with steam in order to keep the baking temperature constant and prevent the egg proteins from coagulating too quickly and forcing out the diluting ingredients from the mixture (curdling).
Is there thickening/setting/solidifying due to gelation of starch?
No, there is no starch in this recipe. The thickening is done by protein denaturation and coagulation.
Is there a mixing of fat and water phases?
Yes, the cream, cheese, and olive oil contain fat phases, while the vegetables contain water phases. The milk and the eggs contain both fat and water phases.
What are the sources of the fat and the water?
The sources of fat include the egg yolks, cream, milk, cheese, and olive oil. The sources of water are the egg whites and the vegetables.
Is there emulsification of the two phases?
Yes, the custard is emulsified by the addition of the amphiphilic eggs. The milk in the custard is also an emulsion in and of itself.
How can you tell?
We can tell because all of these ingredients that contain water and fat phases combine to form a smooth custard. If the dish was not emulsified, you would see a layer of fat phase ingredients sitting on top of a layer of water phase ingredients – this would result in the custard weeping.
What is the emulsifier?
In the Sformati recipe the primary emulsifier are the eggs. Eggs are amphiphilic, meaning they have polar and non-polar regions and are able to interact with both water-based and fat-based ingredients. They contain lecithin, an emulsifying phospholipid. Additionally, milk is an emulsion. The process of homogenization makes it a much more stable emulsion by making all the milk fat globules around the same size and by coating them all partially in casein.
Today’s recipe deals primarily with the different chemical properties of eggs. We made meringa con zabaglione, or meringue tarts with custard and berries in English. The first step for us, and the first step in making pretty much any meringue, was to separate the egg…
Assumption For most of my life, I thought olive oil was as simple as anything else you can find in the baking aisle of the grocery store. It’s on the shelves directly alongside other oil products, such as canola, sunflower, and peanut oils, so I…
Biscotti, to me, has always been something that you get in cafés and coffee shops alongside your hot drink, because it’s usually the cheapest thing to eat on the menu. It’s one of my favorite baked goods, but I’ll admit that, for a long time, I’ve known very little about its origins or its chemical makeup. I’ve known that the name comes from the Latin for “twice baked,” as that’s how the cookie is prepared, and that it typically contains nuts and fillings such as almonds and chocolate pieces. After that, I did not know much at all about its origins in Italian history, or what ingredients aside from flour are necessary in the making of biscotti. I also did not know that the cookie is traditionally dipped in wine rather than hot coffee.
Biscotti is the plural form of the word biscotto, meaning “twice-cooked,” and it shares its origins with the word biscuit. The central ingredients of biscotti are flour, sugar, baking powder (in modern biscotti recipes – historically, ammonia was commonly used as a chemical leavening agent), eggs and salt. It also often includes fillings and flavorings such as nuts and chocolate, and is sometimes dipped in melted chocolate as well.
- Chemical analysis
For the chemical analysis of this dish, I will be referring to the instructions set out in the Kitchen Chemistry Unit 1 Recipe Booklet recipe for biscotti ai due sapori (cranberry and pistachio biscotti). This recipe makes use of all-purpose flour as a central ingredient, alongside sugar, baking powder, sea salt and eggs. Although biscotti is a dense, solid baked good, leavening is still required to keep the cookies from becoming flat and inedible.
When making biscotti, you’re not aiming for a chewy texture, or a well-risen loaf of dough full of trapped air, like in breadmaking. Biscotti should be dense and dry, so it’s not necessary to form lots of gluten or to use a powerful leavening agent such as yeast. However, gluten formation and leavening are still important to prevent the biscotti from going completely flat, or simply crumbling into dust. Thus, all-purpose flour (which has a medium protein content) is kneaded together with eggs. It’s worked until the dough stops being crumbly and starts to come together in a solid mass, indicating the formation of gluten. Baking powder, a chemical leavening agent, gives the dough a slight rise so it becomes a loaf that can be sliced before the cookies are baked again. Heat then causes the liquid ingredients in the dough to evaporate, so double-baking the biscotti makes it extra dry, perfect for dipping in a beverage.
- Cultural analysis
We haven’t talked much about the history of biscotti in the Eatalians section, but we have spoken plenty about flour and its significance in Italian culture. At the turn of the 19th century, Italy was a country marked by widespread hunger, and shaped by the availability of flour. The ability to afford goods baked with flour (bread in particular, but including biscotti as well) was a matter of life and death, as discussed in readings such as Black Bread and Ruin.
Additionally, regionality and locality are central facets of Italian cuisine. The landscape of Italy is pocked with mountains and extremely varied regional climates that, historically, made travel and the spread of culinary ideas between regions difficult. Thus, the type of flour that was available in a singular region often influenced that region’s traditional fare. Regions such as Sicily were characterized by the production of durum, while rye was grown in Southern Tyrol, because it can tolerate the colder, alpine weather. Biscotti is a Tuscan dish – Tuscany, which resides in Central Italy, is characterized by a mild climate and fertile plains, making it conducive to the cultivation of wheat.
I also did some of my own research into biscotti as an individual dish. In ancient Rome, biscotti was a staple food eaten by soldiers and travelers, because it was perfect for transport – it would not stale, as it already had been staled in the oven when baked a second time. The dish re-emerged in Tuscany during the Renaissance, when it was deemed the perfect baked good to soak up the local Vin Santo due to its crunchy texture and mild flavor.
While Jewish and Italian cuisine intersect in many ways, and Jewish-Italian communities (including, but not limited to, the Italkim) have been prevalent in Italy since the Roman times, the Jewish cookie mandelbrot is not closely related to the Italian biscotti. Instead, mandelbrot has origins in Eastern European Ashkenazi communities. It is similar in texture but softer than biscotti due to its higher oil content and the inclusion of butter. However, it’s interesting that similar dishes are often developed concurrently by different groups of people in different places, using different sets of ingredients available to them.
- Integration and Reflection
It is often said that necessity is the mother of invention, and I find that this holds true for nothing so much as it does for food. Not only are regional cuisines defined by the resources available within a specific region, individual dishes are also often invented to serve a certain function or fulfill a particular need. This is especially the case for biscotti, which was purposely staled in the oven in order to make it last longer for soldiers and travelers, and which was shaped in its invention by the availability of wheat flour in Tuscany. In this way, chemistry is used as a tool to achieve what is necessary, and to further the goals of culinary invention. For biscotti, this occurs through the use of chemical leavening to keep the biscuit edible in spite of its texture, the formation of gluten via wheat flour to bind the biscuit, and the application of heat to dry out and preserve the biscotti. Biscotti is thus an exemplary demonstration of the intersection between cultural history and chemistry in food.
The recipe we made today is something of a mouthful, both to pronounce and to eat: pitta ‘mpigliata, a traditional pastry from the Calabrian region of southern Italy. We started making the pastry by putting together the filling, a mixture of chopped walnuts, raisins, honey,…
I’m Jessica, and welcome to my Kitchen Chemistry blog! This is a particularly exciting course for me, not only because I love all things food-related – cooking, baking, food writing, culinary documentaries, and so on – but also because I avidly keep up with The Great British Bake-Off, and I would love to be able to say I know the science behind why Kim-Joy’s naan bread flopped last season.
The last time I took a chemistry class was in high school, but I actually kind of liked it, especially when compared to physics, and maybe even biology (who needs to know that many parts of the cell? I’m alive, so I imagine they’re all doing their jobs just fine). This is definitely a course I’m looking forward to for the rest of the semester, and I hope to be a more knowledgeable cook as well as scientist when it’s complete.
I’m also very excited about the intersection of this course with the other half of its cluster, Eatalians. Culinary history, the sociology of food, and how that relates to the science of its preparation is a whole big topic that interests me greatly. In addition to the GBBO, I’ve hungrily consumed all of Anthony Bourdain’s Parts Unknown (multiple times!), his book A Cook’s Tour, David Chang’s Ugly Delicious, Samin Nosrat’s Salt Fat Acid Heat, and many more. The last book I read was Robin Sloan’s
Sourdough, which was very passionate on the subject of fermentation, so the ciabatta lesson is one I’m probably most looking forward to – if not because I’ve never been able to make a loaf of bread that looked quite right.
Thanks for stopping by, and look forward to my first creation – breadsticks!