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Influence of wheat variety and dough preparation on FODMAP content in breads – a scientific study

Blog-Post_10-2020_EN

In a previous blog article we have already explained the meaning of the acronym FODMAPs (Fermentable, Oligo, Di, Monosaccharides and Polyols), whose excessive consumption has relevant negative health effects, such as irritable bowel syndrome. If you have not read it, we will be happy to link to the page here. This month we return with more interesting information on this topic.  

It is a scientific study on the "Influence of wheat variety and dough preparation on FODMAP content in yeast-leavened wheat breads", published in the Journal of Cereal Science in June 2020 and written by C.F.H. Longin, H. Beck, A. Gütler, W. Heilig, J. Zimmermann, S.C. Bischoff and T. Würschum.

The aim of this study was to investigate the content of FODMAPs in the flour of 21 wheat varieties and in 42 (2x21) breads produced with the mentioned flours in two very different processes. One process was with short fermentative breads (short fermentation of 110 minutes) with pressed yeast and the other process was with long fermentative breads (long fermentation up to 24 hours), also produced with pressed yeast with cultured sourdough.

Each of the varieties 1-10 and 21 represented a mixture of field beans grown at three different locations in an organic production system.

Varieties 11-20 were a combination of two replicas of a single conventional field where each variety was grown with two types of nitrogen as fertilizer, 130 and 230 kilograms per hectare, respectively.

With these flours, the loaves in the study were baked in a single day using two different dough fermentation times. The recipes were the same for the short and long fermented dough breads, except for the amount of yeast and water. In detail, the recipes were as follows:

Breads with short fermentation process: 

2 kg wholemeal flour
40 g salt
50 g fresh baking yeast
1.3 l hot water (25 °C)

All ingredients were mixed for four minutes at low speed and kneaded for one minute at high speed in a Häussler Alpha Kneader (Häussler GmbH, Heiligkreuztal). The dough was left to rest at room temperature for 30 minutes, folded once, left to rest for another 60 minutes, then divided and two loaves of dough weighing 850 g were formed by hand. After a final fermentation time of 20 minutes the loaves were transferred to a thermal oil oven (HEUFT Thermo-Oel GmbH, Bell) and baked at 250°C for 50 minutes. The total fermentation time of the dough was therefore 110 minutes for the short-fermented loaves.

 Breads with long fermentation process:

2 kg wholemeal flour
40 g salt
20 g fresh baking yeast
1.5 l cold water (16 ° C)

All ingredients were mixed at low speed for four minutes and kneaded at high speed in a Häussler Alpha Kneader for one minute.The dough rested for 60 minutes at room temperature, was folded once and kept in the refrigerator at 7°C for 17 hours. From then on, the dough was stored at room temperature for another 6 hours. The dough was then divided and two loaves of dough, each weighing 850 g, were formed by hand. After the last fermentation period of 20 minutes, the loaves were transferred to an oil oven and baked at 250°C for 50 minutes. The total fermentation time of the dough was 24 hours and 20 minutes for the long-fermented breads.

The preparation of the dough was programmed so that the short and long fermenting breads were baked in parallel. After baking, the breads were cooled to room temperature before taking samples for FODMAP analysis. Representative samples were taken from the breads including crumbs and crusts and frozen for FODMAP analysis. The frozen samples were then ground for extraction of FODMAPs.

According to Ziegler, the main components of FODMAPs in bread are fructose and excess fructose. Therefore, the saccharide content was analyzed with the Megazym fructose kit and the fructose and glucose content with the Megazym D-fructose / D-glucose test kit according to the recommendations and extraction protocol of the kit supplier. Subsequently, the excess fructose and the fructose-glucose difference were calculated.

 Results of the study

In previous studies, oligosaccharides, glucose, fructose and excess fructose were measured using enzyme kits. On average, the bread from both dough fermentations showed a reduced FODMAP content of > 65%. The average FODMAP content of both dough fermentations was 0.22 g per 100 g freshly baked bread.

These studies concluded that the FODMAP content tends to be lower in long fermentations compared to short fermentations. It was also found that the 21 wheat varieties differed up to five times in their potential to form FODMAPs in bread. In conclusion, the choice of a wheat variety with low saccharide content in combination with prolonged fermentation is relevant to minimize the volume of FODMAPs in bread.

Vegetables such as Jerusalem artichoke and garlic (> 10 g / 100 g fructose) and fruits such as pear, apple and watermelon (2-9 g excess fructose / 100 g) are known to be rich in FODMAPs. In contrast, cereals and cereal products have been found to contain much lower levels of FODMAP, but their high consumption makes them a potentially important source of daily FODMAP intake.

Thus, a number of studies have concluded that the preparation of the dough, together with the raw material chosen for making bread, has a strong influence on the amount of FODMAPs in the bread. In particular, the longer the fermentation time of the dough, the lower the content of FODMAPs in the bread.

Similarly, the use of sourdough and even the selection of certain sourdough strains further reduced the FODMAP content in the bread, as was seen in the studies mentioned above.

 Conclusions

Bakers who use prolonged dough fermentation usually reduce the amount of fresh yeast in the recipe and keep the dough at a low temperature during most of the fermentation. In contrast to several reports of prolonged dough fermentation, this study adjusted the yeast volume from 2.5% to 1%.

In addition, cold water was used and the dough was stored in a refrigerated room at 7°C for 17 hours of fermentation. Therefore, the lower initial concentration and low dough temperature slowed down the proliferation and activity of the yeast, limiting the degradation of FODMAPs. However, after 24 hours of dough fermentation, the concentration of FODMAPs was already slightly lower than in short fermented breads. 

These results show that long fermentation has the potential to reduce the FODMAP content in bread, but that accurate processing must be considered.

- conclusion of the study

In addition, the choice of the wheat variety influences the FODMAP content of the bread. Compared to flour wheat, Ziegler (2016) showed that the former emmer wheat variety, such as spelt, appeared to have a lower saccharide content than bread wheat. However, it was based on very few varieties per species, which is why in this study the investigation of the saccharide content of different wheat species was extended to nine varieties per species. While emmer contains on average the same amount of saccharides as wheat, spelt and especially spelt contain higher amounts. The studies by Biesiekierski (2011) and Ispiryan (2020) confirm that the lower FODMAP content in spelt breads may be due to the use of more traditional spelt recipes made with culture sourdough and prolonged fermentation.

All breads in this study had a low FODMAP content with a range of 0.08 to 0.37 g of PODMAPs per 100 g.

 Strategies to minimize the FODMAP content in bread

Choosing a wheat variety with low saccharide content, avoiding very short dough fermentations or even direct baking are only some of the strategies to reduce the FODMAP content. The combination of pressed yeast with culture sourdough fermentation (Menezes et al., 2019) or even the selection of specific sourdough strains (Fraberger et al., 2018) as well as the avoidance of the addition of sugars (sucrose, honey, inulin and others, e.g. Ispiryan et al., 2020) are additional factors to minimize the FODMAP content in bread. These strategies may be of particular interest when using cereals with high potential to form FODMAPs such as einkorn/spelt and rye (e.g. Biesiekierski 2011). However, the results of this study clearly show that a dough with short fermentation times of less than two hours is sufficient to produce bread with low FODMAP content.

Differences between wheat flour and spelt flour – ...
 

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