Sourdough - is your loaf the real thing and does it really matter?

Image credit: balanchel

Sourdough has become quite trendy over the past few years which means many more commercial varieties of sourdough have popped up. Although in theory this is great as it increases the availability and reduces the cost of this time consuming bread, are you buying “true” sourdough?

Is it truly sourdough?

Sourdough is popular for three main reasons, it’s taste (a tangy sour flavour), texture, and the view it is healthier than the conventional loaf. Although the nutritional composition of sourdough bread depends on the type of flour (wholegrain or refined) used to make it, its basic nutritional profile resembles that of most other breads but it possess a few properties that make it a more nutritious and beneficial choice for consumers. The main benefits being:

• Increased absorption of nutrients. Research suggests sourdough bread is likely 24-50% lower in Phytates (referred to as antinutrients as they reduce absorbption of many nutrients) than conventional breads (1-3). Additionally, opting for wholegrain varieties of sourdough can help by further increasing mineral availability (2,4).

• Could be a source of antioxidants (5-6). 

• Higher folate (natural folic acid, B9) content (3,7). 

• Higher in prebiotics (non-digestible fibers) and has probiotic-like properties making it good for gut health and potentially easier to digest (4,8-9).

• May be a better choice for blood sugar control and could help to improve insulin sensitivity. This is due to sourdough having lower glycemic index (GI) meaning it causes your blood sugar levels to rise more slowly and is less likely to cause a spike in blood sugar. (4, 10-17). Therefore sourdough could be a good option for those worried about their blood sugar levels and insulin sensitivity (16-18).

• Lower Gluten content (4, 19-20). Gluten can of course cause digestive problems in people who are sensitive or allergic (21-22). Therefore, it’s gluten content makes sourdough more tolerated by many individuals who are sensitive to gluten. However, sourdough is not gluten free and should be avoided by those with gluten intolerance or celiac disease. Furthermore, even if you are not sensitive, gluten has been shown to result in inflammation which is a contributing factor in many conditions including non-celiac autoimmune conditions (23-24). As such reduced gluten diets are often recommended to those suffering with autoimmune conditions and other inflammatory disease. As such sourdough could be a great option for these individuals.

But why does it matter if it’s “true” sourdough? Sourdough takes many processes to make utlising an old form of bread leavening, relying on a mix of both wild yeast and lactic acid bacteria naturally present in flour, rather than baker’s yeast, the process as a result is much more lengthy but is what contributes to its benefits as well as it’s unique taste and texture (4, 8, 10, 19). Store-bought sourdough breads are often not made using this traditional method rendering them no better than your average loaf.

Buying your sourdough from artisan bakers or farmer’s markets increases the likelihood of it being “true” sourdough. Or if you fancy trying your hand at making your own you could checkout the courses and workshops available at Sourdough Sophia.

Stay happy and healthy,

Chel

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References:

1. Leenhardt, F., Levrat-Verny, M.A., Chanliaud, E. and Rémésy, C., 2005. Moderate decrease of pH by sourdough fermentation is sufficient to reduce phytate content of whole wheat flour through endogenous phytase activity. Journal of agricultural and food chemistry, 53(1), pp.98-102.

2. Lopez, H.W., Krespine, V., Guy, C., Messager, A., Demigne, C. and Remesy, C., 2001. Prolonged fermentation of whole wheat sourdough reduces phytate level and increases soluble magnesium. Journal of Agricultural and Food Chemistry, 49(5), pp.2657-2662.

3. Gobbetti, M., Rizzello, C.G., Di Cagno, R. and De Angelis, M., 2014. How the sourdough may affect the functional features of leavened baked goods. Food microbiology, 37, pp.30-40.

4. Poutanen, K., Flander, L. and Katina, K., 2009. Sourdough and cereal fermentation in a nutritional perspective. Food microbiology, 26(7), pp.693-699.

5. Coda, R., Rizzello, C.G., Pinto, D. and Gobbetti, M., 2012. Selected lactic acid bacteria synthesize antioxidant peptides during sourdough fermentation of cereal flours. Applied and Environmental Microbiology, 78(4), pp.1087-1096.

6. Michalska, A., Ceglinska, A., Amarowicz, R., Piskula, M.K., Szawara-Nowak, D. and Zielinski, H., 2007. Antioxidant contents and antioxidative properties of traditional rye breads. Journal of agricultural and food chemistry, 55(3), pp.734-740.

7. Kariluoto, S., Vahteristo, L., Salovaara, H., Katina, K., Liukkonen, K.H. and Piironen, V., 2004. Effect of baking method and fermentation on folate content of rye and wheat breads. Cereal Chemistry, 81(1), pp.134-139.

8. Chavan, R.S. and Chavan, S.R., 2011. Sourdough technology—a traditional way for wholesome foods: a review. Comprehensive Reviews in Food Science and Food Safety, 10(3), pp.169-182.

9. Sakandar, H.A., Hussain, R., Kubow, S., Sadiq, F.A., Huang, W. and Imran, M., 2019. Sourdough bread: A contemporary cereal fermented product. Journal of Food Processing and Preservation, 43(3), p.e13883.

10. Katina, K., Arendt, E., Liukkonen, K.H., Autio, K., Flander, L. and Poutanen, K., 2005. Potential of sourdough for healthier cereal products. Trends in Food Science & Technology, 16(1-3), pp.104-112.

11. De Angelis, M., Damiano, N., Rizzello, C.G., Cassone, A., Di Cagno, R. and Gobbetti, M., 2009. Sourdough fermentation as a tool for the manufacture of low-glycemic index white wheat bread enriched in dietary fibre. European Food Research and Technology, 229(4), pp.593-601.

12. Scazzina, F., Del Rio, D., Pellegrini, N. and Brighenti, F., 2009. Sourdough bread: Starch digestibility and postprandial glycemic response. Journal of Cereal Science, 49(3), pp.419-421.

13. De Angelis, M., Rizzello, C.G., Alfonsi, G., Arnault, P., Cappelle, S., Di Cagno, R. and Gobbetti, M., 2007. Use of sourdough lactobacilli and oat fibre to decrease the glycaemic index of white wheat bread. British Journal of Nutrition, 98(6), pp.1196-1205.

14. Östman, E.M., Nilsson, M., Elmståhl, H.L., Molin, G. and Björck, I.M.E., 2002. On the effect of lactic acid on blood glucose and insulin responses to cereal products: mechanistic studies in healthy subjects and in vitro. Journal of cereal science, 36(3), pp.339-346.

15. Sahin, A.W., Zannini, E., Coffey, A. and Arendt, E.K., 2019. Sugar reduction in bakery products: Current strategies and sourdough technology as a potential novel approach. Food Research International, 126, p.108583.

16. Bo, S., Seletto, M., Choc, A., Ponzo, V., Lezo, A., Demagistris, A., Evangelista, A., Ciccone, G., Bertolino, M., Cassader, M. and Gambino, R., 2017. The acute impact of the intake of four types of bread on satiety and blood concentrations of glucose, insulin, free fatty acids, triglyceride and acylated ghrelin. A randomized controlled cross-over trial. Food research international, 92, pp.40-47.

17. Lappi, J., Selinheimo, E., Schwab, U., Katina, K., Lehtinen, P., Mykkänen, H., Kolehmainen, M. and Poutanen, K., 2010. Sourdough fermentation of wholemeal wheat bread increases solubility of arabinoxylan and protein and decreases postprandial glucose and insulin responses. Journal of cereal science, 51(1), pp.152-158.

18. Maioli, M., Pes, G.M., Sanna, M., Cherchi, S., Dettori, M., Manca, E. and Farris, G.A., 2008. Sourdough-leavened bread improves postprandial glucose and insulin plasma levels in subjects with impaired glucose tolerance. Acta diabetologica, 45(2), pp.91-96.

19. Gobbetti, M., De Angelis, M., Di Cagno, R., Calasso, M., Archetti, G. and Rizzello, C.G., 2019. Novel insights on the functional/nutritional features of the sourdough fermentation. International journal of food microbiology, 302, pp.103-113.

20. Rizzello, C.G., De Angelis, M., Coda, R. and Gobbetti, M., 2006. Use of selected sourdough lactic acid bacteria to hydrolyze wheat and rye proteins responsible for cereal allergy. European Food Research and Technology, 223(3), pp.405-411.

21. NHS, 2019 “Coeliac Disease” Available at: https://www.nhs.uk/conditions/coeliac-disease/ (Accessed: 15 Sep 2021).

22. Catassi, C., Bai, J.C., Bonaz, B., Bouma, G., Calabrò, A., Carroccio, A., Castillejo, G., Ciacci, C., Cristofori, F., Dolinsek, J. and Francavilla, R., 2013. Non-celiac gluten sensitivity: the new frontier of gluten related disorders. Nutrients, 5(10), pp.3839-3853.

23. Lerner, A., Shoenfeld, Y. and Matthias, T., 2017. Adverse effects of gluten ingestion and advantages of gluten withdrawal in nonceliac autoimmune disease. Nutrition reviews, 75(12), pp.1046-1058.

24. Cosnes, J., Cellier, C., Viola, S., Colombel, J.F., Michaud, L., Sarles, J., Hugot, J.P., Ginies, J.L., Dabadie, A., Mouterde, O. and Allez, M., 2008. Incidence of autoimmune diseases in celiac disease: protective effect of the gluten-free diet. Clinical Gastroenterology and Hepatology, 6(7), pp.753-758.