Sourdough for delicious sweet pastries

Viennese pastries and the extensive brioche family are now starting to become rather ordinary. Fermentation time is shortened and very often presentation and volume take precedence over taste. Keen to share their know-how, the baking technicians in the Baking Center™ invite you to rediscover sweet pastries made with sourdough that combine taste, preservation and productivity.


Most traditional brioches (mouna, panettone, colomba, pandoro, pan dulce, pogne de Roman, Vendée brioche…) used to be seeded with natural sourdough. Some still are, and this gives them a clear advantage. For example, Panettone, the famous Italian brioche, owes its long preservation (30 days generally) to the use of sourdough. Moreover, its soft, mellow texture and its long crumb with extended air holes are much appreciated. Many bakers are now loath to prepare their natural sourdough, as it is so tricky to maintain and cultivate the flore (yeasts and lactic bacteria) through the refreshing periods. Indeed, the flore's sensitivity to changes in the flour, atmospheric conditions and water quality means that a new culture must be started as soon as they observe a disturbance in activity and a change in the bread's taste.

Starting to use sourdough again in the 21st century.

As stated by Professor Calvel, "brioche dough prepared with direct seeding are very often enriched with emulsifying additives, generally esterified fatty acid mono- and di-glycerides (E471) which, combined with ascorbic acid (E300) and intense kneading, produce a more voluminous, lighter brioche, whose crumb is like cottonwool, inconsistent and not tempting to chew". So how can we make a difference with a very fresh brioche, with a stringy texture, but melting and which keeps for a long time?
There are two solutions for bakery professionals. First of all, the starter will produce a final ready-to-use sourdough in less than 24 hours, without the need for refreshing. The perfect starter for sweet pastries is quite simply a combination of pure yeast strains and lactic bacteria selected from natural sourdough flore and stabilised. After being suspended in water at 30-35°C, these living microorganisms are used to seed the "flour and water" mix in order to obtain a final ready-to-use sourdough. The sourdough matures in 16 to 24 heures at a temperature of 28-30°C. The French Institut National de la Boulangerie-Pâtisserie en France in fact stresses that "the starter eliminates the delicate phases of starting up and maintaining the sourdough developed according to traditional methods and ensures that performance is consistent and results can be reproduced". With this in mind, Lesaffre has developed the Saf Levain LV1 starter, particularly suited to preparing panettone, the recipe for which you can find on the Louis Lesaffre Cup site. For all sweet pastries, it is better for the sourdough to be guided towards the production of lactic acid rather than acetic acid. Care should therefore be taken over the choice of flours (not too high a flour type) and the activity parameters (see summary table).

Liquid sourdough brioches

The other solution, just as effective, is to use live liquid sourdough with guaranteed biomass. This ready-to-use sourdough is incorporated straight into the kneading dough. For bakery professionals, Lesaffre has worked on a liquid ready-to-use sourdough, which guarantees metabolic fermentation activity for 6 weeks at 0/+6 °C (patented process). This living sourdough called "Sourdough cream", is quite simply obtained by the natural fermentation of flours derived from organic farming methods, so it provides all the qualities of spontaneous sourdough, such as aromatic richness, lactic and acetic acidity and the development of a typical texture. For example, you can prepare a sourdough brioche by incorporating 10% Sourdough Cream and 3.5% sweet dough yeast (per flour weight). The sensorial analysis division of the Baking Center™ has carried out a survey to measure the characteristics of liquid sourdough brioches objectively. Its expert "taste" panel revealed the enhancing effect of the sourdough taste (see brioche taste comparison). "The general aroma is more intense and the aromatic notes, like butter, linger longer in the mouth. On the other hand, the acidity is scarcely identifiable, due to the richness of the recipe", notes Camille Dupuy, Lesaffre sensorial analysis manager. As regards the texture (see brioche texture comparison), the 10% liquid sourdough brioche proves firmer with a less elastic crumb. In the mouth, there is more freshness, which means it is less "sticky" to chew. As for the appearance of the slices, no significant difference has been observed.
Naturally, it is also possible to make sourdough croissants. However, if you make raw or frozen pre-proved croissants, it is advisable not to keep them in the freezer for too long. Like all sourdough-based products (bread, brioches…), rancid notes tend to develop if they are kept at temperatures below freezing.

Pointing out the benefits

The aromatic richness provided by sourdough is the result of a number of volatile compounds produced during fermentation, as well as the formation of amino acid taste precursors and the formation of organic acids, such as lactic acid which enhances the taste in sweet and buttery pastries. This is a significant benefit when producing high quality brioche doughs…
In addition to the taste, sourdough will have an impact on the crumb texture (generally firmer), as well as the preservation and nutritional density of the finished products. Sourdough is now considered to be a true functional ingredient, and a worthy alternative to the use of additives. Indeed, it extends the life of bread products while slowing the regression of the starch. Thus, a panettone (pH between 4.7 and 5.1) containing 30% to 60% sourdough (sourdough flour/total flour) can keep for up to 6 months at ambient temperature. A Vendée brioche (pH of 5) with 10% sourdough (sourdough flour/total flour) will keep for 1 month.Apart from the impact of the organic acids produced, some strains of lactic bacteria with proteolytic and amylolytic qualities prove highly effective in slowing the onset of staleness. In addition, sourdough is a natural preservative with the ability to curb the growth of mould and contaminating bacteria. Manufacturers are therefore increasingly using sourdough, especially for the production of "pains au lait" (sweet buns), to avoid having to use a preserving additive, calcium propionate (E282).

Nothing but good!

The production of organic acids and the reduction in pH can lead to a number of hydrolytic activities that are nutritionally useful. First of all, there is the breakdown of phytic acid, present in abundance in strong flour or whole flour (see insert). Furthermore, sourdough fermentation could be a possible option for reducing the glycaemic index of sweet pastries, insofar as they produce a less open crumb. In addition, organic acids may slow gastric drainage. To recap, the glycaemic index (GI) is a tool for classifying carbohydrates according to the speed at which they are absorbed in the intestines after a meal. A low GI food reduces insulin secretion during the post-prandial phase in healthy subjects and also helps to improve control of glycaemia both in healthy subjects and diabetics. A recent study (1) also showed that sourdough could be used to make sweet pastries for gluten-intolerant coeliac sufferers. In fact, the activity of yeast proteases and lactic bacteria helps reduce by at least 10 ppm the gluten in sourdough-fermented wheat flour. A large number of studies are currently under way to understand and control the effects of sourdough, and also to find new applications to develop healthy, attractive, good bread-making products.

((1) Study published in the Journal Pediatr.Gastroenterol. Nutr. 2010 Dec. under the title "Gluten-free sourdough wheat baked goods appear safe for young coeliac patients: a pilot study"

Insert

Fibre-rich croissants and brioches

Fibre-rich croissants and brioches are gradually appearing on store shelves, mainly thanks to the recommendations of health organisations. For example, the French industrial baker Harry’s has developed a 5-cereal brioche. The Japanese Vie de France (Yamazaki group) recently brought out a croissant made from whole cereals. In order to optimise the nutritional benefits of mineral-rich whole cereals, the use of sourdough is advantageous. Phytic acid, naturally present in whole cereals, generally in the form of calcium or magnesium salts, reduces and even inhibits the absorption of several cations (Zn, Cu, Co, Mn, Ca, Fe) by forming insoluble phytates. During sourdough fermentation, the reduction in pH due to the activity of lactic bacteria helps to trigger phytate hydrolysis, thus releasing the precious minerals which become bio-available.

Comparison of "tastes" profiles: sourdough brioche and reference brioche

Comparison of "texture" profiles: sourdough brioche and reference brioche

Guide your sourdough towards producing lactic acid

 

+ lactic acid

PARAMETERS

+ acetic acid

Liquid sourdough

PHYDRATATION

Firm sourdough

High

TEMPERATURES

Low

Weak

OXYGENATION

High

 

Little difference in the appearance of the two brioches: the reference and the 10% liquid sourdough brioche