Compressed Baker's Yeast: Mapping Patents on Post‐Fermentation Processes

Abstract

In the baking industry, fresh yeast is generally available as a compressed paste containing about 70% moisture. While much literature has been published on its growth conditions in fermentation tanks, little information may be obtained on the final steps of baker's yeast production. In this review, 226 patents were found on the separation of yeast cells from spent growth media as well as its dewatering, forming, and packaging in the compressed form. The latter corresponded to 21% of 1096 unique families of patented inventions filed worldwide between 1787 and 2014 on the production of fresh baker's yeast. Patent specifications disclosed key technical information not available in scientific journals. Particularly between 1890 and 1960, highly specific equipment such as centrifugal separators, rotary vacuum filters, and extruding and cutting units were proposed. Compressed yeast may contain small amounts of processing aids, including water-absorbing agents such as starch and salt, as well as plasticizing and whitening agents. Any variation in yeast solids and moisture contents will affect its gassing power and keeping properties. Disposal and proper treatment of very large volumes of spent growth media will remain a major challenge to the baker's yeast industry.

Active Dry Yeast: Lessons from Patents and Science

“…It was previously reported that most of the early inventors on active dry yeast worked in a rather empirical manner and had little knowledge of other patents or information disclosed in scientific articles (Gélinas, ). It is also known that thorough search of the patent literature would allow a unique perspective on the long‐term development of baker's yeast technology (Gélinas, ). We now report that several critical lessons in the production of active dry yeast could only be learned from the patent literature.…”

“…With 62 patents or 22% of total, inventors from the U.S.A. had the greatest interest in long‐term preservation of active yeast starters for foods. This contrasts with the production of fresh baker's yeast for which inventors from Germany were the most active to get patent protection (Gélinas, ). German and French citizens each had 14% of the patents, and other inventors were from Great Britain (12%), Japan (6%) and, with less than 5% of total, China, The Netherlands, Austria, Belgium, Sweden, Denmark, and 15 other countries.…”

“…This suggests that many inventions on active dry yeast were developed within yeast plants, without the input of ingredients or equipment manufacturers and contrary to the production of fresh baker's yeast (Gélinas, ). About half of the inventions, 57% of total or 158 original files were assigned to 90 companies, a proportion similar to fresh baker's yeast manufacturing (Gélinas, ). The most active companies in patenting were The Fleischmann Co. (later Standard Brands Inc., and Nabisco Brands, Inc.) from the U.S.A., Lesaffre & Cie from France, and The Distillers Co. Ltd. from Great Britain.…”

“…Letters patent for inventions describe much relevant technical information that is not available in the scientific literature (Tucker, ). Surveys of inventions disclosed in patent specifications have provided a thorough understanding of critical issues in the production of fresh baker's yeast (Gélinas, ). Such information was very helpful to understand long‐term market trends and the evolution of the technology in this field.…”

“…Baker's yeast concentrates were the first starters to be commercialized due to the historical importance of bread as human food. In the baking industry, yeast is generally available as a fresh and paste‐like product containing about 70% moisture, so it may be kept for only a few weeks in the refrigerator (Gélinas, ). Yeast would be one of the very few microorganisms that can be dehydrated without substantial loss of viability (Reed, ).…”