Moringa leaves are rich in nutrients and functional ingredients. About 25g of dried moringa leaf powder contains 270% of VA, 42% of protein, 125% of calcium, 70% of iron and 22% of VC for young children, and for pregnant and breastfeeding women, moringa leaf can also maintain the health of breastfeeding women, the fetus or the baby, and provide a large amount of iron, protein, copper, sulfur, and VB. Moringa leaves are known to lower blood sugar, protect the heart and liver, treat ulcers, fight cancer, and have antibacterial and anti-inflammatory properties. Due to its rich nutrient content and functionality, moringa leaves have become a health food and dietary supplement that is added to foods such as bread, cookies, yogurt and cheese.

Zhu Hong, Qiu Ju, and Wang Jing from the Institute of Food and Nutritional Development, Ministry of Agriculture, used moringa leaf powder as a dietary supplement and added it to wheat flour. Important dough quality parameters, such as powder properties, dough stretching properties, and pasting properties, were selected as indexes to evaluate the effect of adding moringa leaf powder with different particle sizes on wheat flour dough, and to study the degree of improvement of the rheological properties of ultra-micro crushed moringa leaf powder on wheat flour dough, in order to clarify the effect of moringa leaf powder on the quality of wheat flour dough, and provide theoretical reference for the application of moringa leaf powder in the pasta industry.

Particle size distribution of moringa powder

The median particle size D0.5 of the ultra-micro pulverized powder and the 60-mesh sample were 148.1 μm and 22.1 μm, respectively, which indicated that the average particle size was greatly reduced after ultra-micro pulverization, and the median size was lower than 25 μm, so the ultra-micro powder was successfully produced. The average degree characterizes the width of the particle size distribution, and a small average degree indicates that the particle size of the powder is concentrated in a relatively narrow range.

The effects of different particle sizes and the addition of moringa powder on the color of wheat flour.

Effect on the color of wheat flour

L* values and increased with decreasing particle size of moringa leaf powder particles, and ultramicro-milling significantly increased the brightness of the powder. The reason that ultra-micro-milling can increase the brightness of moringa powder is that the decrease in particle size increases the surface area of the particles, which exposes the internal structure of cellulose, hemicellulose, proteins, etc., increases the reflection of light and improves the brightness.

Effect on wheat flour flour properties

The addition of Moringa leaf powder significantly decreased the stabilization time of the dough from 5.3 min to about 2 min, indicating a decrease in gluten strength. This was due to the dilution of gluten concentration by moringa leaf powder.

The degree of weakness is expressed as the difference in height between the median of the bandwidth of the curve when the dough reaches the formation time point and the median of the bandwidth of the curve 12 min after this point, which also characterizes the mixing resistance of wheat flour.

The greater the degree of weakening, the weaker the gluten, the easier the dough is to rheumatize, and the workability deteriorates. With the addition of Moringa leaf powder, the weakening degree values of wheat flour were significantly increased, which also said that the gluten strength of the flour was reduced and toughness was weakened.

Effect on the tensile properties of wheat flour dough

The maximum tensile resistance and elongation of the dough tended to decrease significantly with the addition of Moringa leaf powder. The maximum tensile resistance decreased from 234.9 BU to about 130 BU, especially after the addition of Moringa leaf powder with larger particle size, the maximum tensile resistance decreased to 114.7 BU.

The elongation decreased from 143.1 mm to 120-130 mm, which may be attributed to the addition of Moringa leaf powder, which not only diluted the gluten content, but also hindered the intertwining of gluten protein molecules, which resulted in weakening of the gluten and decreasing of the elasticity of the risen gluten.

Effects on the pasting characteristics of wheat flour

The effect of adding Moringa leaf powder on the pasting temperature of wheat flour was not significant. The peak viscosity of wheat flour decreased significantly from 531 BU to the level of 303-355 BU with the addition of moringa leaf powder, and the smaller the particle size of the added moringa leaf powder, the greater the decrease in peak viscosity.

Moringa leaf powder also contained a certain amount of dietary fiber, similar to wheat bran, and these components led to a decrease in peak viscosity. Starch composition, particle size, degree of starch breakage and protein in wheat flour are important factors affecting the pasting characteristics of wheat flour.

Conclusion.

This experiment clarified the trend of different particle size of Moringa leaf powder on important quality indexes of wheat dough. After adding 5% moringa leaf powder, the water absorption and pasting temperature of wheat dough did not change significantly, but the formation time, stabilization time, maximum tensile resistance, elongation, peak viscosity, and regrowth value decreased significantly, and the attenuation value increased significantly.

Among these indexes, there was no significant difference in the degree of influence of particle size of Moringa leaf powder on the formation time and stabilization time of wheat dough, but there was a greater difference in the influence of maximum tensile resistance and elongation. The smaller the particle size of Moringa leaf powder, the smaller the effect on maximum tensile resistance and the greater the effect on elongation, peak viscosity, and regrowth value.

In addition, it was also found that the brightness of moringa leaf powder after ultra-micro-milling was enhanced and its negative effect on wheat flour quality was relatively small. It is clear from the above study that if moringa leaf powder is to be added as a nutrient-fortified ingredient in pasta products, different types of wheat flour should be selected according to the type of pasta products in order to achieve the quality of the flour mixture after the addition of moringa leaf powder in accordance with the requirements of the products.