Louise Slade, Scientist Who Studied the Molecules in Food, Dies at 74

Louise Slade, a groundbreaking food scientist whose work you can thank for soft-from-the-freezer ice cream, extra-chewy cookies and potato chips that retain their satisfying crunch despite being baked and not fried, died on Oct. 7 in Morristown, N.J. She was 74.

Harry Levine, her partner in both life and research and her only immediate survivor, confirmed the death, in a hospital, but did not provide a cause.

It has been said that cooking is an art but baking is a science, and perhaps no one understood that adage better than Dr. Slade, whose research focused on how to keep dough, bread, cookies and crackers tasting delicious even after weeks on a grocery store shelf.

Traditional food science was sometimes derided, even by its own practitioners, as “cook and look,” with researchers testing different ingredients while adjusting countless variables to get different results — a time-consuming and expensive process that revealed little about the underlying chemistry.

Dr. Slade’s great insight, which she developed over some 25 years as a scientist at General Foods and Kraft, was to consider food not as a combination of discreet ingredients but as a system of interacting molecules. By understanding those interactions, one could build predictive models for how, for example, to tweak a bread recipe to make it stay fresh longer without chemical preservatives.

“She was the only person I knew who could swim among the molecules and understand them at their most fundamental level,” Hamed Faridi, the executive director of the McCormick Science Institute, said in an interview. “Her strength was her impressive knowledge of how those molecules interact to create flavor and texture.”

Specifically, she recognized that natural polymers, like proteins and starches, are everywhere in food, and that they act in similar ways to synthetic polymers, like plastics and many fabrics. As a result, she found, many of the same principles that are applied in synthetic polymer science could be used in food science as well. Among other advances, Dr. Slade was able to show how ice cream could be formulated to stay soft in the freezer — much the way some plastic stays flexible even in the cold.

Her insight likewise proved valuable when it came to packaged baked goods like cookies, potato chips and crackers, which need to retain their respective chewiness and crunch through temperature swings and exposure to moisture, light and air.

And those qualities need to be consistent. Despite being made from organic materials like flour, which can vary widely from crop to crop, every single Oreo cookie needs to take and retain an exactingly specific shape and texture through production, shipping, storage and, finally, dunking in milk.

“A lot of what Louise established was how to make products consistent and stable without putting in a lot of additives consumers don’t want,” Todd Abraham, who worked with Dr. Slade at Kraft, said in an interview.

Dr. Slade provided not just a framework for answering those challenges but also a voluminous amount of research: She and Dr. Levine, who worked together for much of their professional careers, published some 260 papers and received 47 patents. She once estimated that the patents she received for her corporate employers were worth more than $1 billion.

Louise Slade was born on Oct. 26, 1946, in Florence, S.C. Her father, Charles, ran a lumber-treatment factory, and her mother, Loraine (Browning) Slade, was a homemaker.

Louise showed early promise as a ballet dancer, so much so that her parents arranged for her to study at the Juilliard School in Manhattan. Although she easily held her own among her elite classmates, she became convinced that she was too tall and ill proportioned to make it as a prima ballerina.

She left ballet to attend Barnard College, where she received a bachelor’s degree in biology in 1968. She had wanted to study botany as a graduate student, but there was little funding for the field available at the time, so she took up biochemistry. She received her master’s and Ph.D. from Columbia in 1974, after which she moved to the University of Illinois as a postdoctoral fellow.

Dr. Slade went to work in 1979 as a scientist for General Foods (which later merged with Kraft), where she met Dr. Levine. It was a perfect pairing: She was working on frozen dough, he was working on frozen desserts — two types of food that, because of their high water content, stood to benefit from a systematic molecular understanding.

Over the next two decades, they developed what they called food polymer science. Considered novel at the time, it now provides the basic research paradigm for an estimated 75 percent of processed foods.

Credit…via Harry Levine

After Dr. Slade retired in 2006, she founded the Food Polymer Sciences Consultancy, with Dr. Levine as an associate. In 2018 the American Chemical Society held a three-day symposium in recognition of the transformative role she and Dr. Levine had played in their field.

She also began to work with the Monell Chemical Senses Center, an independent research institution in Philadelphia that studies taste and smell; she eventually joined its board.

Personally frugal and well compensated for her corporate work, Dr. Slade became one of Monell’s chief donors, giving more than $2 million in her lifetime, Dr. Gary Beauchamp, the center’s emeritus director, said.

Much of her later work focused on making everyday foods healthier by finding novel ways to reduce salt and carbohydrate content without sacrificing taste, texture or structure.

Over the last decade she investigated anti-inflammatory compounds in extra-virgin olive oil, which she contended were a critical part of the oil; her final paper, published this year, demonstrated how those compounds are bound to proteins within olives.

In 2005 the Department of Agriculture and a group of universities in the Northwest honored Dr. Slade by naming a new wheat strain Louise in her honor. Developed according to her research, it is described, in the scientific literature, as “biscuit friendly.”

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