The development of gluten-free sourdough bread technology with rowan powder

N. Dubrovskaya¹, O. Savkina²*, L. Kuznetsova² and O. Parakhina³

¹Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya street 29, RU195251 St. Petersburg, Russia
²St. Petersburg Branch, State Research Institute of the Baking Industry, Podbelskogo Highway 7, RU196608 St. Petersburg, Pushkin, Russia
³Institute of Refrigeration and Biotechnologies, ITMO University, Lomonosova street 9, RU191002 St. Petersburg, Russia
*Correspondence: 1103savkina@mail.ru

Abstract:

A new form of technology was developed which focused on gluten-free bread with gluten-free sourdough and rowan powder (from the botanical species Sorbus aucuparia). This new form of technology allows organoleptic characteristics to be improved, along with structure, texture, microbial spoilage resistance, and the shelf life of gluten-free bread. The gluten-free dry microbial composition with lactic acid bacteria was developed as a starter for sourdough. The lactic acid bacteria, L. brevis E38, was experimentally selected for dry microbial composition on the basis of its antagonistic activity against ropy bread disease pathogens (B. subtilis and B. licheniformis). The dependence was revealed of the accumulation of acetic acid and lactic acid in the sourdough on the microbial composition during fermentation. A gluten-free sourdough technology was developed which involved a new starter, rice, and soy flour at a ratio of 0.2:2:1. It was shown that the use of soy protein slows down the fermentation process in the sourdough. An increase – in acidity levels of between 7.5–9.5 times higher in the dough with sourdough and rowan powder when compared to dough without sourdough. Sourdough usage allowed compressibility of the crumb to be increased by between 1.8–2 times, with a specific volume of 19.0% and a porosity of 9.8% and 11.5%, and for the sensory characteristics to be improved as perceived by consumers. It was proved that microbial composition with a lactic acid bacteria, L. brevis E38, inhibits ropy disease and mould development in bread. The results of the present study showed that the addition of sourdough and rowan powder can be used to improve the quality of gluten-free bread.

Key words:

dry microbial composition, Gluten-free bread, lactic acid bacteria, mould, quality, ropy disease, rowan powder

A study of factors which influence mould spoilage in flat (sourdough) bread

L. Kuznetsova & O. Savkina*

Institute of Refrigeration and Biotechnologies, ITMO University, Lomonosova Street 9, 191002 St Petersburg, Russia;
*Correspondence: 1103savkina@mail.ru

Abstract:

Bakery products are an excellent substrate for the development of microbial spoilage, especially mould spoilage and lime disease (otherwise known as chalk disease), because they have high levels of water activity aw = 0.94-0.97 and pH 5.5-6.0. Sliced bread in its packaging is highly susceptible to moulds and lime disease during storage. The aim of this study was to investigate the effects shown by the microbial contamination of flour quality, and the type of sourdough and organic acid, especially acetic acid, on mould spoilage in wheat and rye wheat bread. Microbial contaminations were studied in two batches of wheat flour and three batches of rye flour which had been manufactured in Belarus and Russia and in sourdough bread which had been produced using this flour. Investigated here was the impact of the quality and type of sourdough with various starter cultures of micro-organisms and the impact of the content of organic acid, especially acetic acid, on mould spoilage in wheat and rye wheat bread. The content of organic acids, including acetic acid, in different types of sourdough which has been prepared using different starter cultures and in different kinds of sourdough bread which have been studied using liquid chromatography. It was found that, in spite of the presence in flour of spore-forming bacteria, yeasts, and fungi, microbial contamination of the finished product immediately after baking was absent. It was proven that the use of starter cultures and sourdough can slow down or prevent entirely the microbial spoilage of bread. It was found that the content of acetic acid which had been accumulated during the fermentation of various types of sourdough served to effect the presence of mould spoilage on sourdough bread.

Key words: