The colours of durum wheat: a review

Abstract

Abstract. Pigments are essential to the life of all living organisms. Animals and plants have been the subjects of basic and applied research with the aim of determining the basis of the accumulation and physiological roles of pigments. In crop species, the edible organs show large variations in colour. In durum wheat grain, which is a staple food for humans, the colour is mainly due to two natural classes of pigment: carotenoids and anthocyanins. The carotenoids provide the yellow pigmentation of the durum wheat endosperm, and consequently of the semolina, which has important implications for the marketing of end products based on durum wheat. Anthocyanins accumulate in the aleurone or pericarp of durum wheat and provide the blue, purple and red colours of the grain. Both the carotenoids and the anthocyanins are known to provide benefits for human health, in terms of decreased risks of certain diseases. Therefore, accumulation of these pigments in the grain represents an important trait in breeding programs aimed at improving the nutritional value of durum wheat grain and its end products. This review focuses on the biochemical and genetic bases of pigment accumulation in durum wheat grain, and on the breeding strategies aimed at modifying grain colour.

Quality characteristics of parental lines of wheat mapping populations

“…Polyphenol oxidase, in particular, abundant in the varieties richer of phenolics , is correlated with both dough darkening (Taranto et al 2012) and color alterations of noodles (Fuerst et al 2006) and bread (McCallum and Walker 1990). On the other hand, pigmented wheats -red, purple, or blue -are becoming the object of interest due to their high anthocyanin content (Ficco et al 2014). …”

Grain-specific reduction in lipoxygenase activity improves flour color quality and seed longevity in common wheat

“…For example, yellow color is preferred for pasta made by durum wheat consumed in Europe and for Japanese alkaline noodles made by common wheat that consumed in Japan and Southeast Asia. However, for Chinese style foods such as steamed bread and various Chinese noodles made from common wheat, a bright whiteness is required (He et al 2004;Fu 2008;Ficco et al 2014). To improve flour whiteness, some chemicals, including benzoyl peroxide, a free-radical initiator that produces carotenoid oxidation by a freeradical mechanism, are usually used by food industry.…”

“…Therefore, low LOX activity is desired for durum wheat varieties. However, for Chinese style foods such as steamed bread and various Chinese noodles made from common wheat, a bright whiteness is required (He et al 2004;Fu 2008;Ficco et al 2014). Thus, wheat varieties with higher LOX activity are generally desired.…”

“…This character is mainly determined by the concentration of the carotenoid pigment content which can be oxidative degradated by LOX (Borrelli et al 1999;Ficco et al 2014). LOX enzymes can catalyze the PUFAs, such as linoleic and a-linolenic, to produce the corresponding hydroperoxides, the radicals produced during the intermediate states of linoleate hydroperoxidation can cause oxidation of carotenoid pigments, and consequently, a significant proportion of the carotenoid pigments are lost during milling and pasta processing (McDonald 1979;Borrelli et al 1999;Leenhardt et al 2006a;Verlotta et al 2010).…”

Polyphenol oxidase activity and yellow pigment content in Aegilops tauschii, Triticum turgidum, Triticum aestivum, synthetic hexaploid wheat and its parents

“…The yellow pigment content (YPC) of wheat flour and its end-products, on the one hand, depends on the synthesis of carotenoids, and on the other hand, is also affected by the degradation of carotenoids during milling and processing. The lipoxygenases (LOXs) is responsible for the loss of yellow color during pasta making, while the effects of peroxidases (PERs) and PPOs on YPC are very little (Ficco et al, 2014). Generally, as for PPO activity, regardless of common wheat or durum wheat, the lower the PPO activity, the better the wheat quality.…”