In a recent article published in foodsresearchers developed new types of gluten-free sourdough bread with a pseudo-grain formula containing Moringa oleifera, non-traditional culture that promotes health.
Study: Development of functional gluten-free sourdough bread with pseudocereals and enriched with Moringa oleifera. Image Credit: Created using DALL·E 3
The rise of gluten-free options
Bread is a staple food that is widely consumed throughout the world. While most people can consume wheat bread, people with celiac disease cannot. Others avoid gluten due to lifestyle and gluten sensitivity, which has increased the market for gluten-free products in recent years. As a result, pseudo-cereals, including buckwheat, quinoa and amaranth, which are naturally gluten-free, have also attracted a lot of attention.
Why Moringa and Sourdough?
Researchers postulate that adding Moringa plant leaf extract to bread may be safe for consumption by both healthy and celiac patients. In addition, sourdough fermentation can improve protein digestibility, total phenolic compound (TPC) content, antioxidant properties, micronutrient availability and functional characteristics of bread.
How bread is made and tested
In the present study, the researchers evaluated whether the fortification of gluten-free sourdough bread made from pseudocereals with Moringa oleifer leaf powder improves its nutritional properties, especially the content of protein, amino acids, soluble fiber and essential minerals.
They prepared six gluten-free bread recipes, three of which were control breads containing sourdoughs from quinoa, amaranth, or brown rice, abbreviated as Q, A, and BR. The other three breads were also leavened with quinoa, amaranth and brown rice, but included Moringa oleifera extract at a concentration of 6% in the flour, abbreviated QM, AM and BRM.
All six types of gluten-free sourdough bread were compared with gluten-free commercial bread (COM) on several parameters.
To make bread, the researchers performed a spontaneous fermentation every 24 hours for five days at 25–26°C, adding a 50:50 ratio of water and flour, following Tomić et al. method.
Nutritional breakdown: proteins, fats, etc
During the analysis, they determined the moisture, protein, total fat, ash, total nutrient composition, soluble and insoluble fiber of these breads (in grams per 100 g of bread) using the standard methods described by the Association of Official Analytical Chemists (AOAC) and their pH, total titratable acidity (TTA), lactic and acetic acid content.
In addition, they evaluated the colorimetric parameters of the bread, including coordinates of lightness, yellowness and redness (L*, b* and a*), saturation (C*) and tone (h*). The antioxidant activity of the breads was determined using four different assays.
The Folin-Ciocalteu method described by Singleton and Ross was used to determine TPC in bread and their sucrose, maltose, D-glucose and D-fructose (total sugar content) were also analyzed. Similarly, they used the Minekus et al. method to estimate the mineral bioavailability of all bread samples. In addition, the team determined the bread’s fatty acid and amino acid profiles and folate content.
Taste test and consumer acceptance
A total of 35 panelists performed a sensory analysis of all types of bread using hedonic tasting, evaluating their color, appearance, aroma, juiciness, texture, taste, general acceptance and purchase intention. They rated each bread sample on a scale of 1 to 5, where a score of one and five indicated that they did not like the bread at all and liked it very much, respectively.
During the statistical analysis, two-way ANOVA test helped to examine the differences in amino acids, fatty acids, proximate composition, mineral bioavailability, antioxidant capacity, folate and TPC content in all bread samples studied. The HSD Tukey post hoc test was used to compare least mean squares, where p < 0.05 was considered statistically significant.
In the control bread, Q bread has the highest amount of protein and BR the lowest. Since quinoa and Moringa oleifera were both high protein content and sourdough fermentation increased protein digestibility, QM bread achieved the highest protein content equivalent to 6.76 g/100 g.
Even the fat content of quinoa is higher than that of brown rice and amaranth, and the inclusion of moringa leaves further increases it. Thus, both Q and QM bread had a high total fat content (6.07 g/100 g); however, they were lower than COM bread, with a total fat equivalent of 3.25 g/100 g.
QM bread had the highest total, insoluble and soluble dietary fiber, while COM bread had the lowest. The high fiber content of moringa leaf powder increases it further (24.97 g/100 g).
Moringa oleifer also significantly increased the ash content of the reformulated bread, especially the QM bread (2.33 g/100 g), while the COM bread obtained a much lower ash content (0.01 g/100 g).
The carbohydrate content of bread depends on the amount of moisture, ash, fat, fiber and protein. As Moringa leaf-enriched breads have higher lipid, ash, fiber and protein content, they are low in carbohydrates, with AM bread having the lowest level (36.27 g/100 g) . Overall, bread A had the highest carbohydrate content, equivalent to 48.98 g/100 g.
BR bread has the highest pH; however, in general, bread enriched with Moringa leaves, due to its high mineral content, has significantly lower pH values (p < 0.05) than the control bread.
The addition of moringa leaves significantly reduces the lightness (L*) and tone (h*) coordinate parameters; however, on the contrary, it significantly increases the reddening coordinate (a*). It also slightly reduces the values of saturation (C*) and coordinates of yellowness (b*).
The darkening of color observed after the addition of Moringa leaf can be considered a positive point, since gluten-free breads usually have a poor color. It also improves flavor and texture but does not increase acceptability among consumers who prefer the sensory qualities contributed by pseudocereals alone.
Furthermore, the addition of Moringa leaf significantly increased TPC and antioxidant activity of bread to 64.54%, 96.37% and 71.15% in QM, AM and BRM, respectively. The increase in TPC of all six formulated gluten-free breads was statistically significant compared to the COM bread (p<0.05).
It should be noted that AM bread has the highest total folate content, antioxidant capacity and TPC due to the high content of moringa compounds equivalent to 32.90 mg GAE/g DW and bioactive compounds in amaranth such as p-hydroxybenzoene acid, vanillic, rutin and gallic acids.
In terms of mineral bioavailability, BR bread has a higher content of iron (Fe) and calcium (Ca) minerals, which are particularly important for celiac patients who are deficient in these trace elements. BR bread obtained greater mineral bioavailability mainly due to low phytic acid content. The control sourdough bread also had higher bioavailability of most minerals, including Fe, Ca, Mn (manganese), Zn (zinc), Sr (strontium), S (sulfur), and B (boron).
All pseudocereals, quinoa, buckwheat and amaranth are rich sources of amino acids. Thus, Q, A, and BR bread had high amounts of methionine, phenylalanine, cysteine, and hydroxyproline, equivalent to 66.79, 213.73, 69.04, and 0.26 g/100 g, respectively. Given its high content of all folate-mono glutamates, BRM bread can be great for celiac patients who are usually deficient in folate.
In the sensory evaluation, the QM bread scored the highest in terms of aroma and texture characteristics, while the A bread emerged as the winner in terms of appearance, taste, color and acceptability. BRM bread scored lowest for aroma, taste and overall acceptability.
Compelling health benefits and future prospects
According to the authors, this is the first time that gluten-free sourdough bread containing pseudocereals has been enriched with Moringa oleifera, a drought tolerant and highly productive crop with several health benefits.
The inclusion of Moringa significantly increased the nutritional richness, especially in terms of protein, amino acids and essential minerals. In addition, it increases the levels of soluble dietary fiber in bread, which has health benefits. Accordingly, bread enriched with moringa leaves has high antioxidant capacity, TPCs, folic acid content, amino acid content of phenylalanine and cysteine, total sugars and fatty acids such as docosahexaenoic acid (DHA).
Additionally, a panel of tasters found this new formulation acceptable and agreed that it meets the requirements for labeling as a functional food.
Overall, reformulated gluten-free pseudocereal sourdough bread enriched with Moringa can promote the health of all people. They may be most beneficial for people with celiac disease who have nutritional deficiencies due to their reliance on gluten-free bread.