The mallow, Malva aegyptiaca L. (Malvaceae): Phytochemistry analysis and effects on wheat dough performance and bread quality

Highlights

• Mallow leaves showed richness in flavonoids, phytosterols and dietary fiber.

• Addition of mallow resulted in an increase of wheat bread hardness and chewiness.

• Mallow enrichment decreased springiness and crust colour parameters of bread.

• No change in bread specific volume at 3% substitution level.

• 3% mallow improved nutraceutical quality without altering sensory properties.

Abstract

The effects of M. aegyptiaca leaves supplementation (1, 2, 3 and 5%) in wheat bread formulation were examined in order to obtain an antioxidant-enriched product. Mallow powder contained relatively high levels of dietary fiber and flavonoids. LC-HRESIMS analysis of the mallow ethanolic extract allowed the identification of 7 flavonoids, 6 terpenoids and 3 fatty acids. The (P/L) ratio of the dough increased with the increment of mallow powder level, whereas the deformation energy (W) decreased. At the highest substitution level, a reduction in bread specific volume and springiness, and an increase in hardness and chewiness were observed. Rising levels of mallow powder into bread increased flavonoids content and antioxidant capacity, and decreased crust colour parameters (L*, a* and b*). Sensory evaluation showed that mallow supplementation at 3% level remained acceptable. All these data suggest that M. aegyptiaca may be useful as a candidate for improving nutraceutical quality of bread.

Introduction

Nowadays, there is an increasing consumer demand for foods fortified with natural antioxidants in order to improve their general state of health and to reduce the risk of chronic diseases of oxidative stress origin. In fact, foods rich in antioxidants play an essential role in the prevention of cardiovascular diseases, cancers, inflammation and problems caused by cutaneous aging (Fan, Zhang, Yu, & Ma, 2006). Plants are an inexhaustible source of functional and bioactive compounds and they have been used for thousands of years for their preservative properties and also to enhance the flavour and colour of food. Currently, their incorporation into the formulation of conventional foods is becoming an interesting approach, which may significantly improve their nutraceutical potential and therefore they could become a “preventive model” for disease prevention (Zouari, 2015).

Bread made from white flour is considered as refined product with a low antioxidant capacity. Due to its widespread consumption throughout the world, it could be considered as an interesting vehicle for functional supplements. Dziki, Rózyło, Gawlik-dziki, and Świeca (2014) reviewed the current trends in the enhancement of antioxidant activity of wheat bread by the addition of raw materials rich in phenolic antioxidants, such as other cereals, spices, herbs, fruits and waste products from the food industry. However, few studies focused on the bread enrichment with green parts of vegetables. Moreover, many studies did not take into consideration the consumer acceptance of enriched breads (Dziki et al., 2014).

Malva aegyptiaca L. is a wild plant of the Malvaceae family, widespread in North Africa and edible by the local population. The macerate of M. aegyptiaca leaves was used in the treatment of dysentery, constipation and fevers. Besides, the cataplasm of leaves is also used in treating wounds, painful and skin-eruptions (Boual, Kemassi, Ould El Hadj Khelil, Michaud, & Ould El Hadj, 2011). It was reported that this vegetable contains several important nutrients such as essential minerals, n-3 and n-6 fatty acids, and various terpene compounds with valuable biological properties. Furthermore, this vegetable possesses an important antioxidant activity and thus has the potential to be used as a cheap natural source for reducing cellular oxidative damage (Zouari et al., 2011).

In the present work, M. aegyptiaca (common name: khoubbiza) leaves were used as a new functional ingredient for enhancing nutraceutical properties of wheat bread. Mallow leaves were characterized in terms of chemical and techno-functional characteristics. In fact, they were analyzed by Liquid Chromatography-High Resolution Electrospray Ionization Mass Spectrometry (LC-HRESIMS) technique in order to identify the phenolic compounds frequently associated with antioxidant activity. Then, the effects of mallow leaves powder substitution to wheat flour on alveographic properties of dough, and texture, antioxidant and sensory characteristics of bread were assessed.