The industrial applicability of the sourdough rich in dextran was then investigated by producing a variety of bakery products, with the results showing that the dextran improved freshness, mouthfeel, crumb structure and softness.
"Improvement of flavour, softness and freshness answers one of the main concerns of the bakery industry which is to create baked products with outstanding organoleptic quality for all consumers," wrote the authors in the journal Food Microbiology (Vol. 24, pp. 155-160).
With a distinct aroma and flavour, sourdoughs are traditionally produced through a lengthy fermentation process, which has become incompatible with the fast pace of commercial bread production.
Dextrans refer to a group of carbohydrates that are produced mainly by lactic acid bacteria, with a basic polysaccharide structure of (1-6) linked alpha-D-glucopyranosyl residues. The structure of the dextran produced is dependent on the bacterial strain used and the conditions of its culture.
The Puratos researchers evaluated different bacterial strains and found that the Lactobacillus mesenteroides LMGP-16878, produced a dextran that was considered highly attractive for bakery applications, being of a high molecular weight and a linear chain structure.
This strain was then used to prepare different bakery products using the sourdoughs, including milk bread, butter brioche, and rye breads. A consumer panel of 205 people in Nantes (France) was used to evaluate the products, compared to standard, non-sourdough, products. It was reported that the volume of the bread as well as crumb softness was improved for each of the bakery products produced.
"The advantages of this specific type of dextran and the dextran containing sourdoughs in bakery applications are multiple," wrote the authors. "More water can be bound in the dough: as dextran is a hydrocolloid, it can bind high amounts of water. Higher dough yield often leads to an improved freshness of the end product. Dextran improves dough stability and gas retention through a structure build up of the dextrans and interaction with gluten network Mouthfeel is improved: a moister mouthfeel is obtained by addition of dextran."
This research, said the researchers, "open new perspectives for the use of sourdough fermentation in baked products, extending its applications to domains such as health and pleasure."
"The application fields of dextran containing sourdoughs are multiple: from rich wheat doughs (fat, sugar) up to very heavy rye dough systems (rye breads)," they said.
The company recently announced it is to construct a new sourdough plant in the US, designed to address increasing demand for its ready to use fermented sourdough line, which has until now been produced exclusively in Europe.
The New Jersey facility, which is expected to be completed by March 2007, will produce three of the company's four liquid products in its Sapore sourdough line.
Puratos, which has currently seen more success from its liquid products than its powdered products, said it hopes the construction of the new facility will allow it to more than double its US sales of the line by 2009.