Food Science Experiment: Hibiscus Lemon Matcha Cheesecake

I wanted to do a series of recipes that would spark joy during COVID-19 and hopefully reduce some of the anxiety people are experiencing, as well as combat the weight gain that many are struggling with from being within 6 ft of their fridge at all times. So, I decided to create tea-time inspired nerve-calming treats that are easier on your waistline, so you can feel good about indulging!

My first idea was inspired by my love of matcha. It has antioxidant properties, is both calming and mentally stimulating, and has a unique bitter taste that can counterbalance the sweetness of desserts to make a unique flavor.(1) If you want to learn more about matcha, I’d highly recommend The Book of Matcha, it has details about the history of its usage as well as some great recipe ideas. Now matcha is great on its own, but I’ve learned from personal experience that matcha/green tea in general tastes even more interesting with a floral or sour element. Inspired by what I had on hand in my pantry, I decided to add ground hibiscus berry tea and lemon zest to help diversify the flavor profile. The combination of bitter, acidic, floral, and sweet allows for a more nuanced flavor for the cheesecake.

The first iteration of this recipe was a no-bake cheesecake, but the texture was a turn off. I adapted a recipe for Matcha Cheesecake from The Book of Matcha.(1) The result was just okay and didn't really taste like a traditional cheesecake texture-wise, it was light and mousse-like rather than rich and dense. However, the matcha levels were quite good, so that part of the recipe was working. So, I borrowed some aspects from The Book of Matcha recipe as well as  inspiration from a baked cheesecake recipe from liveloveandsugar.com for the next iteration of the recipe.(2) The resulting cheesecake was silky, smooth, and delicious: but I wanted to know why it had changed so drastically. So I did some research on the subject to see what science had to say.

According to Bakerpedia, a cheesecake is a cake with a custard filling, while a no-bake cheesecake is not a true custard, it is more like a mousse.(3) A custard is a mixture of milk and eggs along with other ingredients that is thickened through cooking. A mousse is a mixture of milk and other ingredients with the addition of whipped cream/egg whites to create a thickened product.(4)

A baked cheesecake is defined more broadly as a type of shortened cake. A basic baked shortened cake contains flour, milk, and egg white proteins that provide structure, whereas the fat, sugar, and egg yolks are tenderizing and moistening. In a baked cake, the heat causes flour to gelatinize to form gluten to build structure that makes it stand up. Heat also causes egg and milk proteins to coagulate, which also helps set the structure. Thus, the gelatinization and the coagulation in the baked cheesecakes were the key elements that allowed the thickening and setting to occur. (5)

In a no-bake cheesecake, the thickening and stabilization of the cheesecake doesn’t occur from the starch gelatinization and protein coagulation; it is due to a combination of gelation and the folding of air from whipped cream. Gelation occurs when the gelatin, made from proteins extracted from collagen in animal bones/skin, is activated via heat and then thickens with cooling. In gelation, the long and thin protein strands of gelatin form cross linkages around water molecules, trapping the liquid in place creating an elastic solid. In the no-bake cheesecake, the heat came from the cream that was heated and mixed with the gelatin sheets and the cooling came when it was combined with the other ingredients and allowed to set in the fridge. Then, cream was whipped and folded into the mixture and allowed to cool further til it was fully set. (5)

Overall, the processes of gelatinization/protein coagulation in a baked cheesecake and gelation in a no-bake cheesecake appear to achieve similar ends. They both allow the cake to thicken and maintain its shape. However, the key factor that impacted the texture was the addition of air. In the no-bake cheesecake, whipped cream was folded in, which created a lighter texture than the baked cheesecake.

The texture of the no-bake cheesecake was very mousse-like: it was very light and had air bubbles present from whipping the cream at a high speed. The texture of the baked cheesecake was more dense: it was very smooth and thick with no air bubbles, this is because I mixed it at a very low speed. That thick, silky texture was preferable to the light, airy texture in this situation because it is more characteristic of a typical cheesecake. Before my research I had hypothesized that perhaps gelatin was the cause of the texture difference between the baked and the no bake cheesecake, but after researching I determined it was most likely the whipping process that made the most difference. Thus, when making a cheesecake, I learned that low speed is key. The slower the batter is mixed, the less air is incorporated, which means less air bubbles in the finished dessert, resulting in a silky thick texture.

Overall, I was more pleased with the baked cheesecake because of the texture. The flavors were great in both, and I will share the recipe of the baked cheesecake below if you would like to try it. The hibiscus lemon matcha flavor combo was very successful. This cheesecake recipe is also lower fat, lower sugar, and full of those healthy antioxidants from the green tea and hibiscus tea powders. Now that’s a dessert I can feel good about enjoying!

Reference List:

1. Cheadle, L. and Kilby, N. (2016). The Book of Matcha. Sterling Epicure.
2. Conchar, L. (2018). Mini Cheesecakes Life, Love, and Sugar. https://www.lifeloveandsugar.com/mini-cheesecakes/ Accessed 5/5/20.
3. Wallace, D. (2015). Cheesecake. Bakerpedia. https://bakerpedia.com/processes/cheesecake/ Accessed 5/4/20.
4. Hochman, K. (2010). Chocolate Mousse. The Nibble. https://www.thenibble.com/reviews/main/desserts/chocolate-mousse-recipe.asp Accessed 5/4/20.
5. Brown, A.C. (2019). Understanding Food: Principles and Preparation (6th) Cengage Learning, Inc.

Mini Hibiscus Lemon Matcha Cheesecakes 

Servings: 4

          Ingredients

Graham Cracker Crust:

3 tbsp unsalted butter, melted

3 tbsp agave

142 g crushed graham cracker

Cheesecake Filling

4 oz cream cheese

34 g truvia sugar

3 tsp matcha powder

3 tsp hibiscus berry tea, crushed into powder with mortar and pestle, plus more for decorating

Zest of 1 medium lemon, plus more for decorating

¼ cup + 3 tbsp hot water
10 g flour

38 g nonfat greek yogurt

1 large egg

Directions

1.     Preheat oven to 325°F. Spray 4 non-stick tartlet pans, placing on top of a baking sheet, or cupcake pan.

2.     Combine crust ingredients, press into pan with back of spoon.

3.     Bake 5-10 minutes until lightly browned, let cool.

4.     Reduce oven to 300°F.

5.     Mix cream cheese, truvia sugar, and flour on the lowest speed of mixer, scraping sides as needed, until combined.

6.     Add plain greek yogurt, brewed tea, and lemon zest to mix, beat on low until well combined.

7.     Add egg and mix until fully incorporated.

8.     Fill tartlet pans with cheesecake mixture until mostly full.

9.     Bake for 15 min at 300°F.

10.  Turn off oven and leave door closed for 10 min.

11.  Crack door of oven and let cool an additional 15 to 20 min

12.  Put in the fridge to finish cooling until ready to serve.

13.  Decorate with lemon zest and hibiscus powder and enjoy!