(599e) Frozen Desserts Elective: Integrating Food Science and Engineering Principles

The new elective course, Ch 255 Food Science: Frozen Desserts, was piloted at the Albert Nerken School of Engineering during the Fall 2024 semester. The curriculum design, implementation, outcomes, and logistical aspects—such as budgeting, classroom space and equipment—will be discussed.

Course Overview:

This course delves into the science and engineering behind the creation of frozen desserts. The structure and physicochemical properties of each ingredient in the formulation are discussed. Fat, sweeteners, proteins, aromas, emulsifiers, and stabilizers each play a role in determining the characteristics of the product. With this knowledge, students develop recipes with various formulations and ingredients and collaborate in teams to produce small batches of frozen dessert. Students evaluate the impact of each variable on the physical and organoleptic properties of their creations through systematic experimentation.

The freezing process is as important as the ingredients. Principles of thermodynamics are used to describe phenomena such as freezing point depression, heat transfer, and phase changes. Millions of water crystals and air bubbles are created under agitation in the scrape-surface freezers, followed by blast or flash freezing to grow the ice crystals and harden the mixture. Students evaluate how the number and size of water crystals and air bubbles influence the texture, density, and taste of the product.

Growing concerns regarding safety, health, and sustainability aspects of various ingredients are discussed. For example, natural and artificial flavors and sweeteners, saturated and unsaturated fats, animal and plant-based ingredients, allergens, and dietary requirements.

Regulatory and safety aspects standard to the frozen dessert and food industry are highlighted. Students learn to keep high safety standards around handling, pasteurization, and storage of ingredients and products, as well as follow hygienic practices around tools and equipment.

Implementation:

The course Ch 255 was designed to be interdisciplinary; therefore, enrollment is open to all students from the school of engineering, not just chemical engineers. This is a 3-credit, 200-level course that meets once a week for 3 hours. Enrollment is capped at 16, with students split into four workstations. The class meets in a classroom equipped with a sink. It is important to work outside the chemistry lab since students need to test and taste their classwork.

Sessions include short lectures, experimentation, group presentations, and production of small-scale batches. To support inclusion in the classroom, ingredients are selected to adhere to cultural and religious dietary needs. Once formulations are optimized, the frozen dessert production can be scaled up. Small scale batches are prepared using stand mixers with 1-liter freezing bowls, while large scale batches are prepared with a scrape-surface freezer with 14-liter capacity. Hardening is done in upright freezers overnight.

Lessons incorporate concepts from diverse courses like physical chemistry, organic chemistry, heat and mass balance, phase transitions, instrumental analysis, or biochemistry. Therefore, content is based on ice cream textbooks as well as books and scientific articles from multiple fields.

Assignments and classwork challenge students to apply their engineering, math and coding skills. For example, analyzing FT-IR spectroscopy data using partial least squares (PLS) to determine sugar composition of syrups, predicting freezing curves of mono- and disaccharide solutions, balancing mass of sugar, fat and water in formulations. Analytical instruments—such as FT-IR spectrometer, Brix refractometer, rotational viscometer, dynamic light scattering (DLS), and optical microscope—are also incorporated into the lessons.

Outcomes and Future:

Student motivation is a crucial part of the learning process, and ice cream proved to be an exceedingly motivating subject. High motivation helped achieve the learning goals by boosting engagement, creativity and initiative. Each team worked on optimizing a frozen dessert formula and incorporated highly creative flavors. They also took the initiative to scale up production and share their creations at two campus events producing a combined total of about 50 kg and distributing close to 500 portions of frozen desserts. The interdisciplinary composition of the class pushed students to recognize and integrate their diverse skill set.

New modules will be added next semester; some planned additions include:

- Comparing the physical properties of hydrocolloids used in the food industry

- Assessing stability of emulsions as a function of particle size

- Calculating the latent heat of the freezing bowls

- Measuring melting and congealing points of mixtures of saturated and unsaturated fats

- Observing air bubbles and fat globules at freezing temperature under the microscope