Wheat. Peter R. Shewry

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Wheat - Peter R. Shewry


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b). These contributions are higher in Poland, with bread providing 21.9% of energy, 16.5% of protein, 35.4% of fibre, 24.9% of iron, and 20.7% of folate (vitamin B9) (Laskowski et al. 2019). The wide consumption and low price of bread therefore make it an excellent vehicle for delivering improved nutrition to large populations at low cost.

      The nutritional and health impacts of wheat are discussed in detail in Chapter 9, with the following sections focusing on more practical aspects of the processing of wheat for food, particularly bread.

      1.4.1 The Development of Milling and Baking

      Raw wheat seeds are tough, unpalatable, and relatively indigestible unless milled or crushed. At Ohalo II, there is evidence that seeds were crushed between grindstones, long before the advent of agriculture. Crushing would have exposed the starchy endosperm and dramatically increased the bioavailability of nutrients, particularly that of carbohydrate. It would also have speeded the rate with which blood sugar was increased, i.e. the glycaemic index (Rubel 2011).

      Of particular importance for the adoption of wheat as a food crop were the properties of the dough formed by mixing the flour released from crushed or milled grain with water. Wheat doughs have unique visco‐elastic properties that confer significant functional and organoleptic qualities on wheat products, particularly bread and other baked goods. Baking dates back at least 14 000 years (Henry et al. 2011, 2014; Arranz‐Otaegui et al. 2018), and possibly much earlier (Rubel 2011). In particular, doughs made from wheat, far more than from other cereals, are able to trap carbon dioxide released during fermentation by yeast, and hence can produce baked foods with low density. This is the basis of the diverse forms of leavened bread. Yeast spores may occur naturally on the surface of cereal grains and some fermentation occurs readily in wheat dough left to rest. However, it is probable that early bakers used sourdough systems (mixtures of lactobacilli and yeasts), with starters being carried over from batch to batch as in artisan bakeries today. Bread production was clearly important in the Uruk culture (6000–5100 BP) of lower Mesopotamia, and cuneiform writings from around 4000 BP include Sumerian poems and myths about the invention of bread, along with recipes. The Egyptians appear to have perfected leavened bread production by 4000 BP.

Schematic illustration of stone querns on display at the Archaeological Museum, University of Stavanger, Norway.

      Source: Photographs kindly provided by Per Storemyr (Per Storemyr Archaeology and Conservation).

Photos depict the milling room and detail of a mill in a bakery complex at the port of Rome.

      Source: described by Bakker 1999).

Photo depicts a modern roller mill and miller.

      Source: Photograph kindly provided by Dr. Mervin Poole, Heygates Ltd., UK.

      1.4.2 The Cultural Significance of Bread


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