History of Yeast Discovery

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Questions and Answers

Who were the three individuals that independently concluded yeast was a living organism?

F. Woehler, J. J. Berzelius, T. Swann

Justus von Liebig, J.J. Berzelius, Louis Pasteur

C. Cagniard de la Tour, T. Swann, F. Kuetzing (correct)

C. Cagniard de la Tour, Louis Pasteur, F. Woehler

What origin does the word 'yeast' trace back to?

Latin meaning 'bubbles'

Sanskrit meaning 'boiling' (correct)

Greek meaning 'life'

Old English meaning 'fermentation'

What was the primary criticism of the view that fermentation was initiated by living organisms?

It was seen as promoting vitalism. (correct)

It was based on outdated methods.

It lacked experimental evidence.

It contradicted established chemical theories.

Which chemist proved that fermentation was initiated by living organisms?

Louis Pasteur Signup and view all the answers

What type of fermentation did Pasteur show to be caused by living organisms in 1857?

Lactic acid fermentation Signup and view all the answers

What incorrect definition of fermentation did Pasteur provide?

Life without air Signup and view all the answers

What significant process did Pasteur's discoveries contribute to?

The process of pasteurization Signup and view all the answers

What did many chemists believe was the cause of fermentation before Pasteur's conclusions?

Molecular vibrations Signup and view all the answers

Who were the significant figures that initiated the era of modern medical bacteriology?

Pasteur and Koch Signup and view all the answers

Which theory did Pasteur propose after discovering that specific microorganisms cause diseases?

Germ Theory of Infectious Disease Signup and view all the answers

What important method did Koch discover related to microorganisms?

Isolation of Microorganisms in Pure Culture Signup and view all the answers

What term was first used in English in 1885 related to the study of microorganisms?

Microbiology Signup and view all the answers

What resistance did J. von Liebig have regarding Pasteur's work?

He thought living organisms were not causative agents in fermentation. Signup and view all the answers

How did the discoveries in the 1870s and 1880s impact societal views on infectious diseases?

They revolutionized understanding and reduced fear of invisible diseases. Signup and view all the answers

In what manner was food microbiology established as a scientific discipline?

Based on the action of specific microorganisms. Signup and view all the answers

What did the concept of biogenesis replace?

The theory of spontaneous generation. Signup and view all the answers

What significant breakthrough was achieved regarding fermentation?

Fermentation was linked to living microorganisms. Signup and view all the answers

Which substance was first recognized as an enzyme in 1833?

Diastase Signup and view all the answers

How did French chemists A. Payen and J. F. Persoz identify that diastase could convert starch into sugar?

Through a detailed investigation using malt extract. Signup and view all the answers

What term was used to describe organic catalysts involved in fermentation and digestion?

Ferments Signup and view all the answers

What discovery did William Irvine make in 1785?

He found that aqueous extracts of sprouted barley can dissolve starch. Signup and view all the answers

What concept did the vitalists introduce regarding the classification of ferments?

Ferments were divided into organized and unorganized types. Signup and view all the answers

What was the first true recognition of enzymes tied to?

The digestion of food. Signup and view all the answers

Which statement about pepsin is accurate?

Pepsin dissolves meat without being destroyed in the process. Signup and view all the answers

What positive association does the word 'mold' have in East Asia compared to the West?

Equivalent to yeast Signup and view all the answers

Which substance was referred to as 'yellow robe' in ancient Chinese records?

Aspergillus Signup and view all the answers

What was a significant limitation of the fermentation practices in East Asia prior to the 1870s?

Unawareness of microorganisms Signup and view all the answers

Around which century did the Chinese first document distinct names for types of molds used in fermented soy foods?

Sixth century AD Signup and view all the answers

Which of the following statements best describes the early evolution of the fermented foods industry in East Asia?

Advanced through empirical trial-and-error methods Signup and view all the answers

What is a common feature of molds compared to yeasts and bacteria?

Their growth can be seen with the naked eye Signup and view all the answers

What process was commonly used around the 10th century in East Asia regarding koji?

Deliberate use of a koji starter Signup and view all the answers

What transformation occurs to koji during the fermentation process?

It develops a fragrant white mycelium Signup and view all the answers

What term was anglicized from 'enzym' in the 1880s?

Enzyme Signup and view all the answers

Who successfully extracted the fermentation enzyme from yeast in 1897?

Eduard Buechner Signup and view all the answers

What scientific fields expressed a notable interest in the study of enzymes?

Microbiology, Biochemistry, Fermentation Technology Signup and view all the answers

What conclusion was drawn about ferments as a result of Buechner’s findings?

Enzymes behave like organized ferments. Signup and view all the answers

What challenging question did Conn raise regarding enzymes in 1901?

How can enzymes act without being a part of the reaction? Signup and view all the answers

Which enzyme was the first to be purified and crystallized by J.B. Sumner in 1926?

Urease Signup and view all the answers

What was the significance of Buechner's work in the field of enzyme research?

It opened a new era in enzyme and fermentation studies. Signup and view all the answers

What was the primary impact of the collapse of the vitalist position on scientific understanding?

It established a unified set of laws for all organisms. Signup and view all the answers

Study Notes

Discovery of Yeast as a Living Organism

Solid evidence for yeast's living nature emerged between 1837 and 1838 through independent studies by C. Cagniard de la Tour, T. Swann, and F. Kuetzing.
These investigations concluded that yeast reproduces by budding, marking a pivotal understanding in fermentation.

Origin of the Term "Yeast"

The word "yeast" derives from the Sanskrit term meaning "boiling," reflecting its historical connection to key fermented foods like wine, beer, and bread.

Debate on Fermentation and Vitalism

Early views connecting fermentation to living organisms faced scrutiny from prominent chemists like Justus von Liebig, J. J. Berzelius, and Friedrich Woehler.
Critics argued against the revival of vitalism, the belief that life processes are driven by a unique vital principle beyond physical and chemical laws.

Contributions of Louis Pasteur

Louis Pasteur provided conclusive evidence that fermentation is initiated by living organisms during the 1850s and 1860s.
In 1857, he identified that lactic acid fermentation results from living organisms, and in 1860, he established that bacteria cause milk souring.
Pasteur's work laid the foundation for pasteurization, revolutionizing food safety.

Pasteur's Major Works and Theories

In 1877, Pasteur published "Etudes sur la Biere," outlining fermentation's role, incorrectly defining it as "Life without air."
He correctly linked specific microorganisms to specific fermentations and end products, which marked a shift in understanding fermentation.

Impact of Koch's Discoveries

Robert Koch's discovery of the anthrax bacillus in 1877 led to the establishment of the germ theory of disease, correlating specific microorganisms with specific diseases.
Koch developed methods for isolating microorganisms, significantly advancing microbiological studies.

The Decline of Vitalism

The discovery of enzymes led to a collapse of the vitalist perspective, establishing that fermentation operates under the same physical and chemical laws governing non-living entities.
The term "enzyme" replaced "ferment" in scientific vocabulary, resulting from Eduard Buechner's 1897 revelation that enzyme-rich extracts from yeast could ferment sugar solutions.

Emergence of Microbiology and Biochemistry

The terms "biochemistry" (1869) and "microbiology" (1885) emerged, although understanding of their respective subjects took time to permeate public knowledge.
Fundamental discoveries in enzymes and their relation to fermentation opened new research avenues in multiple scientific fields.

Historical Context of Fermentation in East Asia

The koji-making process in East Asia dates back to at least 300 BC in China, with significant developments in Japan by the third century AD.
Early makers of fermented foods distinguished various molds without scientific understanding or terminology related to microbial fermentation processes.

Traditional Fermentation Practices

By the sixth century AD, Chinese agriculture records mention specific molds for soy fermentation, indicating an empirical understanding of fermentation.
The traditional fermentation industries in East Asia relied on trial-and-error practices until the late 19th century, long before scientific methodologies were adopted.

Influence of Enzymes on Fermentation

Research on enzymes advanced over the years, culminating in the understanding that they are essential catalysts in biological processes, including fermentation.
As scientific knowledge progressed, methods of producing and understanding fermented foods improved, leading to greater culinary and nutritional applications.

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Description

This quiz explores the significant findings in the history of yeast, particularly the discoveries made in the late 1830s by researchers like C. Cagniard de la Tour, T. Swann, and F. Kuetzing. Learn about how these findings changed our understanding of yeast as a living organism that reproduces through budding. Dive into the etymology of the word 'yeast' and its cultural importance in food production.