Anthocyanin Content of Crackers and Bread Made with Purple and Blue Wheat Varieties

Abstract

Purple and blue wheats contain anthocyanins in the outer layers of the wheat kernel, and therefore purple and blue wholemeals can be a source of anthocyanins when developing processed cereal products. However, cereal processing is anticipated to cause significant anthocyanin losses. In this study, the anthocyanin content of crackers and bread made from one purple and three blue wholemeals was measured during processing and after baking. LC-MS/MS was used to confirm the presence of anthocyanins, and to tentatively identify them. Mixing and baking steps significantly decreased the anthocyanin content, whereas resting and fermentation steps did not. Purple and blue wholemeal samples reacted differently, indicating that the starting anthocyanin content, localization and composition may have some impact on anthocyanin retention. Additionally, dough systems with decreased pH were more protective of anthocyanins during intermediate processing steps, as were high-temperature, short-time baking procedures. This research provides insights into the processing steps that cause significant anthocyanin losses, and proposes some modifications to formulation and processing conditions which can further reduce losses.

Genetic Mapping of Flavonoid Grain Pigments in Durum Wheat

“…Pigmented wheats with red, purple, blue, and black grains have attracted the attention of the food industry for their large content of flavonoid compounds and associated antioxidant activity [51]. In particular, colored whole grains are regarded as promising new functional foods due to their anthocyanin content located in outer layers (pericarp, aleurone, testa) of grains [52]. Numerous in vivo and in vitro studies have demonstrated the high antioxidative activity of anthocyanins [23,53] and their health effects, including cardio-protection, anti-diabetes, anti-obesity, anti-cancer, and anti-aging-affiliated pathology [51,52,54].…”

Purple Wheat: Food Development, Anthocyanin Stability, and Potential Health Benefits

“…The overall loss of TAC is greater in bread crust than that of bread crumb. Similarly, the anthocyanin concentration dramatically dropped after mixing and baking of purple and blue wheat bread doughs, but not after the fermentation or proofing steps [ 39 ]. Although the anthocyanin loss during baking cannot be completely prevented, it can be slowed down or controlled by altering the variables of the bread-making process.…”

“…Although the anthocyanin loss during baking cannot be completely prevented, it can be slowed down or controlled by altering the variables of the bread-making process. This may include using high-temperature, short-time baking processes, as well as a dough making process at a low pH [ 39 , 40 ]. For example, the fermentation of purple wheat with Lactiplantibacillus plantarum No.…”

“…Crackers made from wholegrain purple and blue wheat flours have been found to contain 37–45 µg/g anthocyanins [ 39 ]. This level is about 70% lower than that of the initial flour.…”

“…The majority of the anthocyanin content of purple wheat flour (50%) is lost during dough mixing, whereas blue wheat flour loses more anthocyanin during baking than during mixing. This might be explained by the location of anthocyanin pigments in both types of wheat (e.g., in the pericarp of purple wheat and in the aleurone layer of blue wheat) and their interactions with other components during mixing, where oxidative stress damage takes place, while heat damage occurs during oven baking [ 39 ]. A bran-enriched high fiber cracker with a high amount of anthocyanins (56 µg/g) was developed as a functional food [ 36 ].…”