Hong Sik "Peter" Park came to America in 1959 with $20, an alarm clock and his judo kit. He spent his first few months at Iowa State University subsisting on peanut butter sandwiches and raw eggs.

Always, his heart was full of gratitude.

"One of the most important things to him and many Koreans of his generation was gratitude to the U.S.," said Rose Park, one of his three daughters. "He was really a quiet, humble man, and very hardworking."

Park would go on to have an influential career in food science and notched a number of dairy industry innovations, including authoring a patent for calcium-fortified yogurt that helped usher in the now widespread use of functional ingredients.

Park, 86, died of cancer May 6 at his home in Rochester.

"He had such deep knowledge of everything about dairy technology, from ingredients to finished products to processing," said Rachel Kyllo, a vice president at Kemps who worked with Park.

He led research and development at Marigold Foods (now Kemps) for nearly three decades.

"Peter was ahead of his time," Kyllo said. "He led true innovation at Kemps."

Hong Sik Park was born Jan. 15, 1937, in Seoul, the eldest of eight children born to Jong Rok Park, a tailor, and Jin Bae Kim.

As a child he helped his family make ends meet — including selling pencils and cigarettes on the street — and he endured the Korean War.

Park later recalled, in a 2015 interview, the liberation of South Korea and the lasting effect it had on him: "That's why I did everything in my life. To give back, to pay back everything the U.S. did for Korea."

Park completed a year of military service and studied for two years at the prestigious Seoul National University, where a professor encouraged him to study food science in the U.S. — in part to help boost South Korea's practically nonexistent dairy industry.

After arriving in 1959, Park received his bachelor's and master's degrees from Iowa State University in 1962 and 1964. While in Ames, he taught free and well-attended judo classes six days a week on top of his ambitious studies.

"English was his second language, and there was no Google Translate," Rose Park said. "It would take him hours to get through some of those textbooks."

He earned a Ph.D. in food science from the University of Wisconsin-Madison in 1972.

Park spent 27 years at Marigold, retiring as the vice president of research and development. His 1986 patent for producing calcium-fortified yogurt has been cited more than 30 times by companies including General Mills, Kraft and Hershey.

Park also led the development of Kemp's Yo-J, a blend of juice and yogurt.

"That had a very long life and was the first of its kind — it was a precursor of what people know today as smoothies," Kyllo said. "He was just incredibly bright and always on the forefront of trends."

After retirement, Park volunteered as a technical advisor for the Seoul Dairy Cooperative, South Korea's largest dairy company. He donated consulting fees toward scholarships for dairy science students and to research.

Rose Park said her father wanted to write memoirs to encourage immigrants, saying that "with hard work you can make it here."

"He was always grateful to the U.S. for opening up and welcoming an immigrant with nothing," she said.

In addition to his daughter Rose, Park is survived by his wife of 56 years, Young Ja "Catherine" Park; daughters Eunice Park and Erica Park; and two grandchildren.

A celebration of life will be held at Resurrection Catholic Church in July.