Sor i z ( Sorghum oryzoidum ) is a relatively new cereal of hybrid origin ob tained at the Research Institute for Maize and Sorghum of Moldova. This paper presents and analy z es the results of the study of essential minerals content (K, Na, Ca, P, Mg, Fe) in native and hulled sorghum grains and their changes under the effect of hydrothermal treatment. The results show that the sorghum grains are a good source of essential minerals, especially of K, P and Mg and are less rich in Ca, Na and Fe. The experimental data have demonstrated that the technological process applied to obtain hulled sorghum leads to a considerable decrease in minerals content. Culinary treatment had a greater impact on the K content and lower on P and Mg content. The results will be used to optimize the parameters of raw material processing and culinary treatment with the aim of minimizing the mineral loss as well as for the nutritional value balance of sor i z sorghum dishes.
Cereals and food derivatives from cereals are the staple food of the population all over the world, only the crops being different from one country to another [
Cereal grains are the major source of dietary nutrients in the world. However, a large part of them is lost after processing (peeling, crushing, grinding, moisturizing, boiling, frying, expanding, etc.). The loss of mineral elements in the process of decortication depends on the types of cereals, their sizes, the degrees of peeling, etc [
The content of mineral elements is also influenced by culinary technological processes, which refer to the ability of cereals to boil in the shortest possible time, accompanied by the improvement of organoleptic qualities.
Prior to the culinary treatment, the cereals are subjected to technological processes of primary processing such as: sorting (sometimes sifting) and washing. The content of dry substances in the water after washing is: starch-about 41%, nitrogen—about 33% and sugar—about 13%. Some research on the influence of hydration (for 24 hours) of whole grains (corn, sorghum, rice, etc.) on the content of iron, zinc and phytates has shown that during hydration in the water passes a considerable amount of iron and less zinc [
Knowing the impact of processing on cereals could contribute to the selection of technological processes with a tolerant effect on nutrients, which will increase their accessibility and, respectively, will contribute to increasing public health.
Soriz (Sorghum oryzoidum) is a hybrid of sorghum that is characterized by glassy endosperm, similar to rice. It was obtained at the Institute for Scientific Research for Maize and Sorghum in the Republic of Moldova, by crossing Sudan grass (S. sudanense) and sorghum bicolor (S. bicolor) [
The advantages of this crop have many; sorghum is a local crop with high productivity, resistant to drought and high ambient temperatures, a source of macro- and micronutrients with high nutritional value. An important feature of soriz is the absence of gluten, which makes it an optimal alternative in the diver. Diversification of gluten-free products is a relevant and popular field of research, especially for the Republic of Moldova [
The paper presents and analyzes the results of the research of the content of essential mineral elements (K, Na, Ca, P, Mg, Fe) in whole grains of soriz and hulled soriz and the modification of their content in the culinary treatment.
The results obtained are useful for optimizing the manufacturing process and technological processing of sorghum grains and groats in order to minimize losses of mineral elements, evaluation and nutritional balance of sorghum-based preparations.
Whole grains of soriz and hulled soriz “Alimentar 1”, purchased at the Institute of Plant Protection and Organic Agriculture of the Academy of Sciences of Moldova, were used as research material. The following materials were used for research (
The ash content was determined after the removal of organic matter by dry
| No. | Raw materials used for determinations | Dry matter, % |
|---|---|---|
| 1. | Whole grains of soriz | 87.6 |
| 2. | Boiled whole grains (without prior hydration) Boiling time—115 ± 5 minutes | 29.4 |
| 3. | Whole grains cooked after pre-hydration Hydration time 8 hours. Boiling time—85 ± 5 minutes | 33.6 |
| 4. | Raw dehulling grains | 87.2 |
| 5. | Boiled dehulling grains Boiling time—40 ± 5 minutes | 21.0 |
ashing according to AOAC (2006) official method [
Minerals content analysis was determined according to AOAC, (2000) [
Minerals are considered to be essential in human nutrition [
The results obtained showed that whole grains of soriz have an important source of К (393.84 mg/%), Р (307.65 mg/%) and Мg (160.26 mg/%), comparable to cereals commonly used in food such as wheat, rye, buckwheat, rice, in which, according to the chemical composition of food, the content of these elements is within the following limits: K (328 - 425 mg/%), P (200 - 453 mg/%), Mg (96 - 153 mg/%). It is also noticeable the low content of Ca (13.89 mg/%), Fe (4.2 mg/%) and Na (1.2 mg/%) in soriz grains, which is characteristic, and for the cereals mentioned above, in which these elements are contained within the following limits: Ca (12 - 92 mg/%), Fe (2.6 - 12.1 mg/%), and Na (0.9 - 89.0 mg/%).
Boiling whole soriz grains (without prior hydration) reduces the content of potassium (23.36%), phosphorus (13.0%) and magnesium (8.78%) [
Prior hydration of soriz grains in water for 8 hours before boiling slightly reduced the final losses of P and Mg by 3.13 mg/% and 7.0 mg/%, respectively, possibly due to the shorter heat treatment period until the product is fully penetrated, but increased by about 3 mg/% the loss of potassium, which has a higher solubility than the first and can possibly diffuse into the water, including in the process of softening the grains.
Preliminary hydration of the grains had a more tolerant impact on most of the minerals studied. Thus, the Fe content of hydrated and boiled soriz grains is 3.48 mg/%, and in cooked grains without hydration −3.22 mg/%, which is a reduction of 17.1% and −23.3% respectively, compared to native samples. The boiling of the grains contributed to the increase of the share of Ca (by 15.80%) and Na (by 41.66%), compared to the native grains, and the share of Ca and Na in the boiled grains after prior hydration increased by 67.97% and 70.83% respectively in hydrated and boiled grains.
During the boiling process, the redistribution of the substances in the product takes place through mass transfer and diffusion processes. Thus, the increase in the mass fraction of calcium in the dry mass of boiled sorghum grains could be explained by the low solubility of Ca and sodium, possibly by locating this element in the inner layers of the grain, which slows down the diffusion of Na into the environment.
The nutritional value of cereals depends a lot on their processing methods (peeling, crushing, grinding, hydrothermal treatment, etc.) [
It has been established that the content of mineral elements investigated in native soriz hulled grains is lower than in grains, with the exception of Na. Thus, the dehulling of the grain led to a decrease in the content of К 2.5 times, Р—2.9 times, Mg—de 3.7 times, Са—de 2.4 times and Fe—3.2 times. This can be explained by the concentration of the mentioned mineral substances mainly in the upper layers of the grain which are removed in the process of peeling the grains. The potassium content in dehulled grains is slightly higher than in whole grains (1.2 times), which is possibly explained by the location of this element in the inner layers of the soriz grain.
In sorghum hulled grains, as in whole grains, the major part of the mineral elements is represented by K (157.4 mg%), Р (104.78 mg/%) and Mg (43.53 mg/%), and Са, Fe, Na in insignificant amounts, respectively 5.90; 1.33 and 1.27 mg/%.
Boiling the husked grains led to an even more significant reduction in the share of potassium (78.82%) and phosphorus (9.74%) in the finished product. The mass fraction of the other mineral elements (Ca, Mg, Fe) in the dry mass of the cooked husked grains has increased, which could be explained by their lower solubility in relation, for example, to that of potassium.
Analyzing the mineral content of whole grains and peeled boiled soriz grains (
| Mineral elements | Whole grains of soriz | Boiled whole grains (without prior hydration) | Whole grains cooked after pre-hydration | Raw dehulling grains | Boiled dehulling grains | |
|---|---|---|---|---|---|---|
| mg/% | ||||||
| 1 | K | 393.84 ± 0.02 | 301.87 ± 0.01 | 290.17 ± 0.02 | 157.40 ± 0.01 | 33.33 ± 0.01 |
| 2 | Na | 1.20 ± 0.01 | 1.70 ± 0.01 | 2.05 ± 0.02 | 1.27 ± 0.03 | 1.31 ± 0.04 |
| 3 | P | 307.65 ± 0.02 | 267.69 ± 0.08 | 277.30 ± 0.03 | 104.78 ± 0.02 | 94.57 ± 0.01 |
| 4 | Ca | 13.89 ± 0.05 | 16.09 ± 0.01 | 23.33 ± 0.01 | 5.90 ± 0.06 | 24.52 ± 0.01 |
| 5 | Mg | 160.26 ± 0.01 | 146.19 ± 0.01 | 157.41 ± 0.05 | 43.53 ± 0.01 | 55.28 ± 0.01 |
| 6 | Fe | 4.20 ± 0.03 | 3.22 ± 0.02 | 3.48 ± 0.02 | 1.33 ± 0.01 | 2.13 ± 0.01 |
sodium, calcium and iron is nutritionally insignificant and does not differ significantly in boiled sorghum grains and crepes.
Based on the results of the research, the following conclusions can be drawn:
Whole grains of soriz, like other traditional cereals in the regional diet (wheat, rye, buckwheat, rice), are an important source of potassium, phosphorus and magnesium, but are poor in some essential mineral elements in human nutrition such as calcium and iron.
The shelling of sorghum beans has a negative impact on the content of mineral elements.
Boiling whole grains with pre-hydration has a more tolerant impact on the mineral content and could be recommended as a preliminary step in the cooking process of cereals.
This research was funded by state project “Personalized Nutrition and Intelligent Technologies for My Well-Being”, No. 20.80009.5107.10, running at Technical University of Moldova and Contributions regarding nutritional eradication of gluten consumption diseases, No. 21.00208.5107.06/PD.
The authors declare no conflicts of interest regarding the publication of this paper.
Siminiuc, R. and Coșciug, L. (2022) Influence of Culinary Treatment on Soriz Mineral Elements (Sorghum Oryzoidum). Food and Nutrition Sciences, 13, 78-84. https://doi.org/10.4236/fns.2022.131008