Health

The rise and rise of YEAST

Tilak Nagodawithana Ph.D

In a country like Sri Lanka where rice has been the staple food for centuries, it is not surprising to find that the per capita consumption of bread and for other bakery goods has remained low over the years, relative to those of developed nations. Yeast, as we well know, is the key ingredient needed to provide the flavor nuances and the much needed leavening power to provide the familiar bread matrix. Currently, with further dwindling bread consumption, the disappointing market potential it has created for yeast in Sri Lanka, is thus understandable.

Yeast

Yeast cells

Following the thirty year war, a handful of entrepreneurs showed interest to take advantage to fill this void by looking at the possibility of building production facilities. But all such surveys carried out stopped in the tracks primarily due to the limited captive markets in Sri Lanka.

In recent years this situation has further worsened with the increase of wheat pricing in the world market. An additional issue which can be less important but nevertheless critical is a possible shortage of locally produced molasses. This is the substrate for making yeast, and currently, it is being used extensively for making alcoholic drinks which ironically, in Sri Lanka has immediate payback.

Currently, the entire supply of yeast and yeast related products are imported. As a result, there is a substantial foreign exchange drain which can easily be avoided by investing on yeast production facilities in areas where sugar cane plantations are expanding. This report, therefore, is to bring the reader's attention to other far reaching goals yeast manufacturers in the developed world already have in place, for increasing their product lines and thereby improving their profitability.

Yeast is, without doubt, the most important group of microorganisms commercially exploited and safely consumed by mankind today. Many authorities believe that Egyptians have discovered the extraordinary properties of yeast 6000 years ago when some freshly crushed grapes left exposed to air turned into a pleasant and intoxicating beverage which they subsequently named as wine.

Early findings

The early "Oenologists" quite accidently found out that when they carefully scraped the white sediment that precipitated to the bottom of every batch of wine and added to the next batch of fresh juice, the wine made second time was as good as the previous batch. After these humble beginnings, production of wine and subsequently beer developed as an art and craft in complete absence of scientific know-how.

Legend has it that it did not take too long before some enterprising baker of flatbread, added a portion of a primitive wine sediment to his dough, looking to improve its quality. To his surprise, the dough leavened (puffed) and improved the flavor and texture of flatbread. The twin arts of baking and wine making and subsequently brewing then became profitable ventures within communities at the time without any understanding of the basic principles associated with such processes.

The very existence of the microbial world was unknown to mankind until the microscope was invented by a Dutch lens grinder, A van Leeuwenhoek in 1680. He first observed the microbial world when he examined a drop of fermenting beer through a handmade single lens microscope. However, the work he brilliantly begun was not extended for over a century. Finally, in 1850s, Louis Pasture discovered that these changes in composition of "wine" are as a result of metabolic changes in sugary media, caused by the action of live yeast. These painstaking studies by Pasteur followed by his brilliant interpretations of his results gave to the world the basic knowledge upon which most of our modern industrial biotechnology has been built.

Yeasts are represented by numerous strains that were chosen and adapted for specific industrial fermentations. They include Baker's yeast, wine yeast, top and bottom fermenting brewer's yeast and distiller's strains used for alcohol production from molasses and other sugary materials. Strain improvement by conventional methods, genetic manipulation and protoplast fusion has contributed to superior strains for the aforementioned processes.

Earliest commercial production of Baker's yeast probably occurred in Holland around the early 1780s. In their process, sugar solution was slowly fed to an aerated suspension of yeast and the process was named as Zulaufer/fahren.

This process was widely accepted by not only the yeast manufacturers but the entire fermentation industry as an incremental feeding or fed-batch process. Thus the baker's yeast industry has contributed greatly to the entire fermentation industry by the introduction of the fed-batch process which now has wide application in the production of organic acids, amino acids, enzymes, vitamins, and in the antibiotic industry.

Stages

In general, there are five to seven stages of propagations, progressively getting larger in volume with every change of stage, in the production of Bakers' yeast: the laboratory stage in which the pure culture from slants is transferred to growth flasks; then to two to three stages of set batch (substrate and nutrients all in) where the contents of the preceding stages are transferred via sterile piping to the succeeding stages of increasing volume; then to two stages of fed-batch (incremental sugar feeding) fermentations and finally the commercial stage which often carries 50,000 gallons of fermenting liquid. The final content is eventually centrifuged, and the separated cream is pressed and sold as pressed cake or turned to noodles and dried in air-lift dryers to produce Active Dry Yeast (ADY)

Yeast production is important not only for baking, brewing and distillery fermentation but also for the production of a variety of value added products. In this category, the most important segment is the flavor and flavor enhancing yeast extracts which are gaining immense popularity in the vastly expanding food industry. Additionally, there is a high demand for yeast extracts in the fermentation industry as a cost effective microbial growth nutrient.

Adding yeast extracts to complex media to improve their nutritional properties is way to reduce the cost of production of a variety of products such as in the manufacture of drugs, antibiotics, enzymes, hormones, citric acids, and other important organic chemicals, where microbial fermentation is the standard production procedure. Additional to such fermentations, there is a lucrative market for yeast extracts for the production of starter cultures for the sausage and dairy processing industries. The volumes of yeast extracts consumed by this heavily funded fermentation industries are so enormous that it now has become the most lucrative sector in the yeast and yeast-related businesses.

In growth media, in order to ensure microbial growth and effective product synthesis, the composition of the medium must be chosen carefully. Some industrial organisms require simple nutrients that will enable to synthesize all or most of the intrinsic organic intermediates required to sustain life and to allow growth and in the process, produce useful metabolites. At the opposite end, most industrial organisms developed more recently from genetic engineering have certain unique nutrient requirements which yeast extract are known to supplement readily and cost effectively. Yeast extract manufacturers also in turn have responded effectively to meet these demands.

Good demand

Yeast extract is a concentrate of soluble material derived from yeast following hydrolysis of the cell material, particularly the proteins, soluble carbohydrates, and nucleic acid. This is generally carried out by use of its own hydrolytic enzymes (autolysis) or added enzymes in order to release the cell contents in a highly degraded form. It is commercially available most commonly as powders but also as concentrated pastes of different color, composition and flavor.

The writer is the President of Esteekay Associates Inc.,Milwaukee, USA

To be continued

Your SMILE matters!

Ishara Jayawardane

Your smile is one of the most vital means of communicating with the rest of the world. You show your pleasure and many other behavioral characteristics through a smile and connect with society through a smile. Therefore having shiny clean teeth is an attribute that builds and restores confidence. If you take a love relationship the initial attraction can be sparked with a smile.

President of SLDA, Dr. Suresh Shanmuganathan. Pictures by Sarath Peiris

Project Manager and National Coordinator of LIVE, LEARN. LAUGH ) Dr. Prasad Amaratunga

General Secretary, Sri Lanka Dental Association (SLDA) Dr. Vipula Wickremasinghe

Oral Care is a primary concern of Unilever with the Dental Community coming to accept the importance of Fluoride as a preventive measure to combat Dental Cavity which is a serious medical health disorder.

Signal has been instilling good oral hygiene habits to the people of Sri Lanka giving them the confidence to smile for more than three decades. Signal is endorsed by FDI World Dental Federation (the largest global dental association) as well as the Sri Lanka Dental Association (SLDA) Signal has partnered with the SLDA to drive many nation wide campaigns in promoting the importance of dental hygiene in schools and communities.

"Only 10 - 40 percent of children visit a dentist for a check up annually. Brushing must be promoted and regular check ups are very important. Dental caries, also known as tooth decay or a cavity, is a substantial problem in Sri Lanka and brushing with fluoride containing toothpaste is very important. If you brush with a fluoride related toothpaste it fills the mouth with fluoride.

Fluoride never occurs in the free state. Its compounds are present in rocks and minerals, as water passes through, the fluoride dissolves in it. Water bodies are sources of fluoride. Other common sources of fluoride are in tea and coffee and vegetables. We have natural resources in Sri Lanka to meet the Caries problem. There are 27 million caries in Sri Lanka people and," said General Secretary of Sri Lanka Dental Association (SLDA), Dr. Vipula Wickremasinghe.

The Burden of Oral Disease cause Pain and Suffering, Impairment of Function, Reduced Quality of Life and Social Disability. Dental caries, Gum disease, tooth loss are some Oral Diseases.

"Tooth decay or Dental Caries is an infectious disease which continues to be a serious oral health problem globally and every toothpaste should have fluoride in it. The cause for caries is inadequate oral hygiene along with dietary habits comprising of sugar and sticky foods and high oral bacterial counts. However more is not necessarily better. Ingestion is a concern here. Large quantities of toothpaste should not be swallowed. It can have adverse effect on the teeth. In the case of children parental supervision is important," said President of the SLDA, Suresh Shanmuganathan.

"Live, Learn, Laugh (LLL)" campaign was launched in the North Western Province with the simple of objective of inculcating habit of brushing twice a day with fluoride toothpaste in Children. Currently being on phase two of the project, during the month of May, 50 schools will be reached and an the end of the year another 50 schools will be introduced to be a part of the project.

"In Sri Lanka, cancer in the mouth is higher than cancers in other parts of the body. Fluoride makes the tooth stronger and resistant to Dental Caries. Brushing twice a day is important. The importance of LIVE, LEARN, LAUGH campaign is to spread the message amongst students of this importance of fluoride, Oral Health and Dental Problems. We conduct seminars on Oral Health for School Children. We also encourage students to start health clubs in schools- there are so many clubs so why not a health club?" said Project Manager and National Coordinator of LIVE, LEARN, LAUGH, Dr. Prasad Amaratunga.

Twenty percent of the households do not use fluoridated toothpaste. Signal in its stride to introduce the concept of bushing twice a day using fluoridated toothpaste introduced the '21 day night time brushing challenge'. This initiative was introduced in 2009 and since then has increased the Night time brushing practice from 30 percent of the population in 2009 to 40 percent by 2011. The signal '21 day challenge' was planned and implemented with the goal of promoting children to brush their teeth at night using fluoridated toothpaste for 21 days consecutively.

The effectiveness of fluoride toothpaste has been assessed since the 1940's in over one hundred clinical trials and the anti tooth decay efficacy of fluoride toothpaste has been confirmed.

Ways to reduce alcohol

The Centre for Addiction and Mental Health (CAMH) has released a summary report outlining policy strategies to reduce the harms related to alcohol, with a focus on the province of Ontario, Canada.

In the report titled 'Reducing Alcohol-Related Harms and Costs in Ontario: A Provincial Summary Report,' CAMH Senior Scientist Norman Giesbrecht outlines Ontario's policy strengths and provides recommendations to help decrease the $2.9 billion attributed annually to the direct and indirect costs of alcohol use in Ontario.

"While there are policy measures in place, there is still work to be done in various areas, such as alcohol pricing and advertising in order to address drinking behaviours that can be harmful," said Dr. Giesbrecht. "For instance, we know that more than 75 per cent of Ontarians consume alcohol, and that approximately 22 per cent of Ontarians drink above the recommended drinking guidelines."

Positioning alcohol use as a public health matter, Dr. Giesbrecht is recommending 10 policy improvements:

Adjusting alcohol prices to keep pace with inflation, preventing alcohol prices from becoming cheaper relative to other goods over time.

Maintain government-run monopolies which regulate access to alcohol by maintaining effective alcohol control strategies such as enforcement of the legal drinking age, the regulation of pricing, and hours and days of sale.

Consider increasing the minimum legal drinking age to 21 years of age.

Limiting the availability of alcohol by reducing the hours of operation, starting with LCBO licensed agency stores in smaller rural communities.

Strengthening drinking and driving regulations by lengthening license suspension periods, particularly for repeat offenders, and impounding vehicles during suspension.

Prohibiting the advertisement of price or sales incentives by all alcohol retailers and tightening restrictions on sponsorship, specifically those targeting youth and young adults.

Ontario is encouraged to support a consistent physician screening, referral and brief intervention protocol by implementing a fee for service code that is specific to these activities.

The Smart Serve Responsible Beverage Service program is encouraged to incorporate scenario-based activities into its training program and to require periodic retraining.

Implement mandatory alcohol warning labels on alcohol packaging that include topics relevant to alcohol use such as drinking and driving, the risks of underage drinking, and chronic diseases.

Develop a provincial alcohol strategy that emphasizes alcohol specific policies and interventions that have been recommended by the World Health Organization.

"In order to refine and implement these recommendations it will require leadership, commitment to reducing alcohol-related harms and a spirit of collaboration among key stakeholders," said Dr. Giesbrecht.

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