Puratos Japan held Sourdough Seminar in Tokyo
Puratos Japan held Sourdough Seminar in Akasaka Prince Hotel in Tokyo.
The Sourdough Seminar was held on October 21, 2005 at the Akasaka Prince Hotel in Tokyo (organized by Puratos Japan). Sourdough symposia have previously been held in Europe in 1996 and 2003, attracting much attention from sourdough and other researchers internationally. This latest seminar was arranged in response to calls for a similar symposium to be held in Japan. Four authorities on sourdough, food microbiology and zymology from Italy, Belgium and Japan spoke passionately to an audience of Japanese bakery professionals. Below are excerpts from the speeches.
Fundamentals of sourdough physiology and biochemistry
Prof. Marco Gobbetti
The Sourdough ecosystem - Sourdough is a mixture of wheat, rye and water that has been fermented with lactobacilli (or lactobacilli and yeast). In order to take greater advantage of sourdough's potential, it is necessary to understand microbial reactions, and lactobacillic activity in particular.
Sourdough's characteristics include lactic acid fermentation and protein decomposition, the latent potential and plasticity in the activity of its lactobacilli and reacting in a way that adapts to the surrounding environment. An optimal balance can be achieved by combining internal factors (the reactions of carbohydrates anｄ enzymes contained in flour etc..) and external factors (fermentation temperature/time, ratio of water to flour), and this in turn affects the shelf-life, texture and flavour of the bread.
Carbohydrate metabolism - Besides lactate, ethanol, carbon dioxide and acetate, which plays an important role in creating bread's characteristic flavour, are produced in sourdough heterolactic fermentation. In order to produce more of this, the use of fructose as an external electron acceptor is important. Although fructose is a natural component of wheat flour, increasing its concentration by adding a small amount to the dough mixture produces acetic acid, which can greatly influence the flavour of a bread. Appropriate use of microbial activity can facilitate balanced production of lactobacilli and acetic acid.
Nitrogen compounds metabolism - In contrast to dough that is chemically acidified without using microbes, in the sourdough fermentation process enzymes found naturally in wheat flour promote protein decomposition by lactobacilli. The resultant free amino acids have a substantial impact on bread flavour. Arginine catabolism aids the production of lactobacilli and acetic acid. Arginine is naturally found in wheat flour. Adding a small amount extra arginine, however, will optimize lactobacillic activity.
Antimicrobial activity of lactobacilli - The lactobacilli in sourdough produces organic acids that suppress the development of mould in bread. In addition, they also produce amino acid synthesis, arginine catabolism, and inhibit microbial pollution of bread flavour caused by acetic acid production.
Eso-polysaccharides production - Dextran and other internal polysaccharides formed by lactobacilli increase dough's viscosity and boost its volume. These effects can be achieved by adding internal polysaccharides to dough.
Nutritional properties - Celiac disease is a self-propagating mucosal inflammation triggered by consumption of gluten. Due to an inability to digest and absorb gluten sufferers cannot normally eat foods that contain gluten. However, the results of an experiment showed that there were no adverse effects when celiac disease sufferers consumed bread in which gluten was at an advanced stage of decomposition after long-term fermentation for periods of 24 -48 hours.
Summary - Sourdough can have various effects on bread, however the microbes in sourdough are susceptible to environmental stress. By using stress-resistant microbes in appropriate conditions , it is possible to make high-quality bread with the characteristics of sourdough.
Development and Application of Novel Sour Dough on Breads and The Related Foods
Mr. Haruhiko Mori
Many varieties of lactobacilli are used in sourdough, but these have to be edible. I wondered whether it might be possible to produce a uniquely Japanese sourdough by applying the process used to brew sake. Ultimately this lead to the development of a new sourdough named "Hiroshima Sourdough".
Lactobacilli improve quality - Although dough fermentation volume drops when lactobacilli are added, the amounts of acetic and lactic acids produced increase, as does the amount of free amino acids, which have an impact on bread's flavour and taste. This happens because of lactobacillic activity or because the activity of enzymes contained in the raw ingredients is being suppressed by lactobacilli. It is difficult to achieve leavening volume during dough fermentation just by adding lactobacilli alone. However, by mixing in the acid-resistant yeast, Lactobacillus sakei (a lactobacillus originating from the type used in sake brewing), we succeeded in creating a new sourdough, and using this, we have developed and marketed a new bread called "Hiroshima Sourbread".
Lactobacilli fungus increases functionality- The lactobacilli contained in sourdough still maintain functionality even if died during baking. It has been shown that when eaten, the amount of bile excreted from the body increases as it bonds with the heat-killed lactobacillus fungus., suppressing the rise of cholesterol in the bloodstream and lowering levels of neutral fat and the arterial stiffness index as a result.
Increased functionality from production of GABA - Lactobacilli decarbonize glutamine and turn it into gamma-aminobutyric acid (GABA). GABA is said to be effective in lowering blood pressure, as a tranquilizer and in promoting the activity of the visceral organs and brain. We have succeeded in making a sourdough in which GABA is produced by the lactobacilli used in yoghurt or cheese-making. From now on,, I think we should see the benefits of sourdough in products other than bread. For example, it is possible to make a jelly product containing GABA by modifying the flavour of over-fermented sourdough. Through further research into bread-making with sourdough that contains GABA, and its characteristics, we hope to go on to find further applications.
Advantages to use the sourdough in Japanese market
Mr. Daihachi Iga
We have compared and analyzed the flavour make-up of many breads which have been selling well, but have not found any one trend common to "good breads". This lead us to rethink the concept of "good bread" and we realized that the mouthfeel provided by the airholes that perforate a bread's internal structure is more important than its flavour. Many factors control and contribute to making "good bread". If we focus our attention on two elements, "taste and mouthfeel" and the ratio of the importance of each to making "good bread", the significance of mouthfeel is generally around 60 - 80%, while taste is around 20-40%. When breads are made with sourdough, the organic acids and amino acids released by lactobacillic activity add to the flavour and aroma of the bread and enhance its "goodness". Previously, it was often thought that acidity from organic acids was the main element in the flavour of bread made from sourdough. However, the role of amino acids in contributing to the Maillard reaction and generating aroma components is more important than that of organic acids.
Usage in frozen dough and hard bread is one application of sourdough. Bread made from frozen dough is typically lacking in flavour components, but use of sourdough can compensate for this.
In Japan, many people think of hard bread as being heavy and crusty, but as penetration of sourdough-based, crispy, light bread (especially light roll bread) which is easy to eat increases, the market for hard bread or table bread looks set to expand further.
The market for cereals is growing due to a growth in health-consciousness. Bread containing soybean milk and mixed grains are now available. The rogue aroma of these ingredients can easily come to the fore, but the use of sourdough provides a way of masking these rogue aromas. With the rapid ageing of society, sourdough is also likely to be valuable as a means of producing breads so soft that they can be eaten without extensive chewing, and of bringing out a deeper flavour and aroma that will be appreciated by elderly people whose sense of taste is often weak.
Maintenance and control are problems encountered when using sourdough. In retail bakeries, in particular, where long working hours have often become systematized, many invisible workhours are being wasted. I would like to suggest using commercial sourdough as a means of reducing these labor hours. In this way, the labor hours previously devoted to sourdough maintenance and control, can be redirected to the creativity that should define retail bakeries, and this will lead to a richer variety of original products.
Industrial solutions to optimize bread flavour
Mr. Stefan Cappelle
When developing bread products it is important to understand consumers. At present there are 3 consumer trends: time-saving convenience, the pleasure of choosing from a wide-ranging variety, and a health-consciousness and interest in nutritional fortification and functional foods. Of course, these trends are all premised on the fact that a product taste must also good.
At Puratos, we are conducting sensory analysis into the question "What's your flavour?", or in other words, people's taste preferences. We use the results of this research to promote efficiency in product development by analyzing what kind of flavours of products will be accepted in the market.
Currently, bread-makers have to address needs for simplified production processes, automation, reduced labour hours, safe and stable quality, as well as consumers' demands for product safety, variety and the traditional, delicious flavour of bread. Commercially produced sourdough can help in meeting these needs. Using our many years' experience in developing bread ingredients, Puratos has developed easy and ready-to-use natural sourdoughs, which are slowly fermented before being processed into powder or liquid form, and eliminate the need for complicated dough management by the baker. Not only do these products release bakers from the time-consuming process required to make sourdough, but they also facilitate the consistent manufacture of products with a traditional bread flavour.
A comparison of profiles by sensory analyses of breads made with sourdough products and those without shows that the various elements that comprise bread flavour such as malt flavour, acidity, and bitterness were more pronounced in the breads made with sourdough.
At Puratos, we have developed various sourdough products. "Carmen" is one example. Traditional Italian panettone is made by a process of fermentation over many days. Although it is extremely difficult to achieve consistent commercial production of panettone, we succeeded in developing Carmen by isolating bacteria that produce dextran through lactate fermentation from Panettone madre. The dextran contained in Carmen allows bakers to make products with the soft, moist and elastic mouthfeel and long shelf-life characteristic of a long period of maturation, even when the actual fermentation process is much shorter.
Brief History of Lecturers
Prof. Marco Gobbetti
Prof. Gobbetti's specialism is food microbiology. Senior scientist in the Food Technology Course. A world authority on food microbiology. In addition to collecting over 400 types of sourdough bacteria from all around Italy and conducting joint research with Puratos into sourdough and its fermentation, he is also involved in research into the effects of sourdough bacteria on lowering allergic reactions in humans.
Dr. Haruhiko Mori
Dr. Mori has a doctorate in engineering. His specialism is in industrial microbiology. He has previously held such positions as head of the microbiology research unit at a research foundation specializing chiefly in zymology. In 2002 he was awarded the Brewing Society of Japan's Technological prize. He is also known for having developed "Hiroshima Sourbread"
Mr. Daihachi Iga
Mr. Iga graduated from Department of microorganism, National Fisheries University. He assumed his current position after working in food research and development at companies such as Asahi Kasei Corporation and Japan Tobacco inc.. He has given reports and published theses on various topics concerning breadmaking, such as freeze-resistant yeast, bread texture design, measuring the physical properties of fermented dough and the effects of polysaccharide thickeners in breadmaking.
Mr. Stefan Cappelle
Majored in microbiology and lactobacteriology at Ghent University in Belgium. Since joining Puratos in 1997, he has been involved in the research and development of sourdough products and bread-making technology. He has extensive experience in introducing sourdoughs in industrial bakeries.