斯佩耳特小麦种

演化史

斯佩耳特小麦是六倍体，其中两套染色体源自节节麦，其余四套源自已驯化的四倍体二粒小麦的某个栽培种。

普通小麦的染色体组成和斯佩耳特小麦相同，且两者可杂交，因此有些人视两者为同一物种的不同亚种。然而目前尚不确定两者间的演化关系。

使用

人类在公元前5000年就开始种植。由于其含有中等分量的麸质，因此适合焗烤。

在德国，为了避免遇到天候不佳造成损失，有时会在斯佩耳特小麦半成熟时就先采收晒，称为绿谷。因为绿谷的味道不错，有些农人会固定将一部分的斯佩耳特小麦提前收成为绿谷。

营养

斯佩耳特小麦含有大约57.9%的碳水化合物（不包括9.2%纤维素），17.0%蛋白质和3.0%的脂肪，以及食用矿物质和维生素。

斯佩耳特小麦与常见的小麦是近亲，因此不适合乳糜泻的人群食用。 然而一些对小麦过敏的人却可以食用斯佩耳特小麦。

Spelt (Triticum spelta), also known as dinkel wheat, is a species of wheat. It is a relict crop, eaten in Central Europe and northern Spain. It is high in protein. In Australia it is marketed as a health food.

Spelt was cultivated from the Neolithic period onward. It was a staple food in parts of Europe from the Bronze Age to the Middle Ages. It is used in baking, and is made into bread, pasta, and beer.

It is sometimes considered a subspecies of the closely related common wheat (T. aestivum), with the botanical name Triticum aestivum subsp. spelta. It is a hexaploid, most likely a hybrid of wheat and emmer.

Description

Spelt is a species of Triticum, a large stout grass similar to bread wheat. Its flowering spike is slenderer than that of bread wheat; when ripe, it bends somewhat from the vertical. The spike is roughly four-edged. The axis of the spike is brittle and divided into segments; it shatters into separate segments when fully ripe. Spelt differs from bread wheat in that each seed (a caryopsis, botanically a fruit with its wall fused to the single seed inside) stays fully encapsulated by its husk.

Confusion with other wheats

Especially in the context of descriptions of ancient cultures, the English word spelt has sometimes been used for grains that were not T. spelta, but other species of hulled wheat such as T. dicoccum (emmer) or T. monococcum (einkorn, also known as "little spelt", in French petit épeautre). This confusion may arise either from mistranslation of words found in other languages that can denote hulled wheat in general (such as Italian farro, which can denote any of emmer, spelt or einkorn; spelt is sometimes distinguished as farro grande ('large farro'), emmer as farro medio ('medium farro'), and einkorn as farro piccolo ('little farro')), or changing opinions about which actual species of wheat are described in texts written in ancient languages. Thus, the meaning of the ancient Greek word ζειά (zeiá) or ζέα is either uncertain or vague, and has been argued to denote einkorn or emmer rather than spelt. The ancient Roman grain denoted by the Latin word far, although often translated as 'spelt', was in fact emmer.

Evolution

Hybridisation and polyploidy

Like common wheat, spelt is a hexaploid wheat species, which means it has six sets of chromosomes. It is derived from a hybridisation event between a domesticated tetraploid wheat such as durum wheat and another wheat species, increasing the number of sets of chromosomes. Genetic evidence indicates an initial hybridisation of a domesticated tetraploid wheat and the diploid wild goat-grass Aegilops tauschii. It further shows that spelt could have arisen as the result of a second hybridisation, this time of bread wheat and emmer, giving rise to European spelt. The spelt genome continues to influence the breeding of modern hexaploid bread wheat through recent hybridisation.

Spelt, being closely related to bread wheat, is a likely source of alleles to increase wheat's genetic diversity, and so improve crop yields. Analysis of the Oberkulmer cultivar of spelt found 40 alleles that could contribute to increased yield. Among the differences were spelt's larger grain size, greater fertility of tillers, and longer fruiting spikes. Pm5 is an effector-triggered resistance gene for powdery mildew.

Nutrition

A 100-gram (3+1⁄2-ounce) reference serving of uncooked spelt provides 1,400 kilojoules (340 kilocalories) of food energy and is a rich source (20% or more of the Daily Value) of protein, dietary fiber, several B vitamins, and numerous dietary minerals (table). Highest nutrient contents include manganese (143% DV), phosphorus (57% DV), and niacin (46% DV). Spelt contains about 70% total carbohydrates, including 11% as dietary fibre, and is low in fat (table).

Spelt contains gluten, and is therefore suitable for baking, but this component makes it unsuitable for people with gluten-related disorders, such as celiac disease.

In comparison to hard red winter wheat, spelt has a more soluble protein matrix characterized by a higher gliadin:glutenin ratio.

Products

In Germany and Austria, spelt loaves and rolls (Dinkelbrot) are widely available in bakeries. The unripe spelt grains are dried and eaten as Grünkern ("green grain"). In Australia it is grown organically for the health food market. Dutch jenever makers sometimes distil with spelt, while beer brewed from spelt exists in Bavaria and Belgium.