Why does the Dorot Jewish Division have in its cookbook collection a booklet of pectin recipes? After all, pectin—a gelling agent used in making jams, pie fillings, and jellybeans, among other things—may be very useful in confectionery, but it's hardly a staple ingredient in Jewish cookery. Yet one particular manufacturer of pectin played a fateful role in the life of a certain Jewish family during World War II.

"Opekta," a name derived from the German "Obstpektin aus dem Apfel [Fruit pectin from apples]" was trademarked in 1928, with the company's headquarters in Cologne. The firm produced many editions of a recipe booklet in German ("Ready with Opekta in 10 minutes") as well as in Dutch ("Jams and jellies in 10 minutes"). In 1933 the company decided to expand and sent one of its directors, a German Jew named Otto Frank, to set up a branch in Amsterdam. By 1934, Otto had brought his entire family to live in Amsterdam: his wife Edith and two daughters, Margot and Anne. The firm's Amsterdam address was 400 Singel, and the staff included Miep Gies (who appeared in a 1938 promotional film for the product).

After Germany invaded the Netherlands in May 1940, Opekta was renamed Gies & Co. (after Jan Gies, a bookkeeper at the firm and Miep's husband) to avoid being confiscated as a Jewish business. In December 1940, the company moved to 263 Prinsengracht. It was in a "secret annex" within the Prinsengracht building that Otto Frank and his family hid during the war, and where Anne Frank composed her famous diary. After the war, Otto Frank, the sole survivor of his family, returned to Amsterdam to manage Opekta until 1953, when he retired. He died in 1980.