EXPERIMENTAL STUDIES OF THE PROCESS OF OBTAINING MILK FROM MAIZE GRAIN

ABSTRACT

This article investigates the process of obtaining “maize milk” through the germination of maize grains followed by grinding and extraction. Scientific analyses indicate that maize grains possess several advantages in terms of nutritional composition compared to other cereal crops. In particular, their high fat content, energy value, gluten-free nature, and wide industrial applicability make maize a universal and economically significant cereal crop. Consequently, maize serves not only as a key resource for ensuring food security but also as a promising raw material in the fields of dietetics and biotechnology.

АННОТАЦИЯ

В данной статье исследуется процесс получения «кукурузного молока» путем проращивания зерен кукурузы с последующим измельчением и экстракцией. Научные анализы показывают, что зерна кукурузы обладают рядом преимуществ с точки зрения питательного состава по сравнению с другими зерновыми культурами. В частности, высокое содержание жира, энергетическая ценность, отсутствие глютена и широкое промышленное применение делают кукурузу универсальной и экономически значимой зерновой культурой. Следовательно, кукуруза служит не только ключевым ресурсом для обеспечения продовольственной безопасности, но и перспективным сырьем в области диетологии и биотехнологии.

Keywords: maize, extract, maize milk, protein, starch, grain, fiber, carbohydrates

Ключевые слова: кукуруза, экстракт, кукурузное молоко, белок, крахмал, зерно, клетчатка, углеводы

Introduction. Deep processing technology of maize encompasses a systematic sequence of operations designed to efficiently extract and valorize the primary valuable constituents of maize grains, including  starch, proteins, lipids (oils), dietary fiber, and associated micronutrients such as water-soluble vitamins and minerals. These processes typically incorporate techniques such as hydrolysis, enzymatic treatment, fermentation, extrusion, and wet or dry milling, yielding high-value intermediates and end-products for utilization in the food, animal feed, pharmaceutical, biochemical, and industrial sectors. Beyond elevating the economic value of derived products, deep processing optimizes resource efficiency, minimizes waste generation, and contributes significantly to the principles of circular economy and sustainable agricultural development [1, 2, 6].

The adoption of advanced maize deep processing technologies facilitates the creation of innovative, value-added commodities. The choice of specific processing methodologies is predominantly dictated by the target application and required physicochemical or functional attributes of the final product. For example, maize-derived starch finds extensive application not only within the food industry (e.g., as thickeners, sweeteners, or modified starches) but also in non-food sectors, including packaging materials, textiles, adhesives, and biodegradable plastics (bioplastics) production [ 3,7,].

Scientific evaluations consistently indicate that maize grains exhibit distinct nutritional and compositional advantages over many other cereal crops. Notable attributes include elevated lipid content, superior energy density, inherent gluten-free composition, and versatile industrial utility, positioning maize as a universally applicable and economically strategic cereal crop. Consequently, maize represents a highly promising feedstock not merely for bolstering global food security but also for advancing applications in clinical nutrition (dietetics) and biotechnology [4,5, 8, 9].

 Materials and methods.Within the framework of the present study, experimental investigations were conducted to evaluate the aqueous extraction of maize grains for the selective isolation of carbohydrates, proteins, lipids, water-soluble vitamins, and minerals. Furthermore, the suitability of the resultant extracts as functional enriching agents was assessed across diverse segments of the food industry. For the experimental phase, three locally adapted maize varieties were selected: “Uzbekiston 601YESV”, “Uzbekiston 300MV hybrid”, and “Kamalak 100”. The chemical composition of these varieties was determined using a portable infrared analyzer Infrared Portable Analyzer IAS-3120, with the detailed compositional profiles summarized in Table 1.

Table 1.

Detailed description

As evident from the data in the table, the chemical composition of maize grains exhibits variability depending on the variety, as well as on soil-climatic conditions and agronomic practices employed during cultivation.

Results and discussion. In the subsequent stage of the experiments, 1 kg samples were taken from each of the selected varieties. These samples were soaked in 1 liter of warm water at room temperature for 24 hours. Following soaking, the grains were spread on specially prepared trays to initiate germination. The germination process was conducted at a controlled temperature of 18–20 °C over a period of 6 days (Figure 1).

Figure 1. Germination process of maize grains:  a) day 1;  b) day 6.

Subsequently, 200 g samples were taken from each of the germinated grain batches. To each 200 g sample, 200 ml of distilled water preheated to 60 °C was added. The mixture was then homogenized using a laboratory blender for 2÷6 minutes until a homogeneous, porridge-like slurry was obtained. The resulting slurry was subjected to mechanical pressing using a laboratory press apparatus to separate the maize milk (aqueous extract). The extracted liquid fraction, referred to as maize milk, was collected for further analysis and application studies.

The analysis of the process of obtaining milk from maize by varieties, with a soaking duration of 6 days and a water-to-grain ratio of 1:3, is presented in Table 2.

Table 2.

Analysis of the milk extraction process from corn by varieties

As can be seen from the data presented in Table 2, when the milks extracted from the selected soybean varieties in Uzbekistan—namely Uzbekiston 601 YeSV, Uzbekiston 300 MV, and Kamalak 100—were analyzed for their pH value and density, it was clearly established that the indicators of the Kamalak 100 variety are closest to those of cow’s milk.

The dependence of milk yield on the duration of grinding, which varied within the interval of 1 to 6 minutes at a water-to-grain ratio of 1:3, is presented in Table 3.

Table 3.

The influence of grinding duration on milk yield.

The data presented in Table 3 indicate that an increase in the grinding duration of germinated maize grains directly affects the milk extraction process. As grinding duration increases, particle size decreases, leading to enhanced extraction efficiency. When grinding duration varied from 2 to 5 minutes, the milk yield increased significantly. Beyond 5 minutes, although particle size continued to decrease, no substantial further improvement in milk yield was observed. Therefore, it can be concluded that grinding germinated maize grains for 5 minutes is sufficient for optimal results.

Conclusion. In the traditional method, corn extract (corn milk) is obtained through grinding the grains, heat treatment, and extraction with a specific amount of water. In the proposed method, germinating the maize grains prior to extraction significantly improves the taste of the resulting corn milk and increases extraction efficiency. This improvement can be attributed to the enzymatic breakdown of starch in the grains into sugars during germination. In summary, substituting cow's milk with corn milk in food products enhances their organoleptic and physicochemical properties. This approach is particularly beneficial for extending the shelf life of the product and reducing its production cost.

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