Quinoa enriched in calcium and gamma-aminobutyric acid and a method for its preparation

Abstract

This invention discloses quinoa with enhanced calcium and γ-aminobutyric acid (GABA) enrichment and its preparation method. The method uses quinoa as raw material, treats it with food-grade calcium chloride, and controls temperature and humidity conditions to increase the enrichment of calcium and GABA in the quinoa. After drying, quinoa rich in calcium and GABA is obtained. This method is simple to operate, low in cost, and can biofortify the calcium and GABA content in quinoa, resulting in a calcium content of 240–280 mg / 100g dry matter, meeting the calcium-rich requirements of GB28050, and a GABA content of 180–290 mg / 100g dry matter. It also reduces the phytic acid content in quinoa to 39–160 mg / 100g dry matter. The calcium content is increased by 6–7 times compared to the raw quinoa, and the GABA content is increased by 11–18 times, while the phytic acid / calcium ratio is reduced to 3–20% of that in the raw quinoa. This invention provides biofortified quinoa with a lower phytate / calcium ratio, which facilitates calcium absorption. The resulting quinoa can be used in flour products, baked goods, etc., increasing their calcium and γ-aminobutyric acid (GABA) content while reducing the phytate / calcium ratio.

Description

Technical Field

[0001] This invention belongs to the field of high-value-added processing of quinoa to enhance its nutritional content and reduce the phytate / calcium ratio in quinoa. Specifically, it relates to a quinoa enriched with calcium and γ-aminobutyric acid (GABA) and its preparation method. This invention promotes the increase of calcium and GABA content in quinoa through biofortification, thereby reducing the phytate / calcium ratio. The aim is to promote high-value-added processing of quinoa raw materials, enhance its nutritional value, and it is applicable to agricultural product processing and the production of calcium- and GABA-enriched foods. Background Technology

[0002] Calcium deficiency has become a significant mineral nutrition problem affecting human health. Compared to simply relying on calcium tablets or supplements, improving nutrition through a regular diet aligns better with a "food-based" approach. Calcium biofortification of grains is a safer, more comprehensive, and more sustainable long-term strategy for alleviating calcium deficiency. Most calcium added during food processing is calcium carbonate, which has poor solubility and is not easily absorbed by the body. Calcium biofortification not only increases calcium content in grains but also promotes the synthesis of functional components by activating key enzymes within the seeds.

[0003] Grains are high in phytic acid, an anti-nutritional factor. For example, the phytic acid content in wheat, brown rice, corn, barley, and oats is approximately 1.13, 0.89, 0.89, 0.99, and 0.77 g / 100g, respectively; quinoa contains approximately 1.03–1.22 g / 100g. Phytic acid can bind with calcium to form calcium phytate, reducing calcium solubility and thus inhibiting absorption and utilization. Simply increasing the calcium content in grains will cause calcium to combine with phytic acid to form calcium phytate, thereby affecting calcium absorption. Therefore, it is necessary to reduce the phytic acid content while increasing the calcium content, thus lowering the phytic acid content in grains.

[0004] Biofortification has become an important direction in food and crop nutrition improvement research in recent years. Among them, calcium biofortification of staple crops and reduction of phytate / calcium ratio is a safer, more comprehensive, and more sustainable long-term strategy for alleviating calcium deficiency. At present, research on the effects of exogenous calcium on cereals has focused on alleviating abiotic stresses such as salt, alkali and drought through exogenous calcium treatment. However, calcium fortification of germinated quinoa with exogenous calcium to increase its γ-aminobutyric acid and reduce the phytate / calcium ratio remains to be explored.

[0005] For human health, γ-aminobutyric acid (GABA) is a novel functional factor with physiological functions such as lowering blood pressure, promoting sleep, and enhancing memory. It is also an important and indispensable inhibitory neurotransmitter, playing a crucial physiological role in the central nervous system. GABA is a non-protein four-carbon amino acid widely found in plants, synthesized through glutamate decarboxylation or polyamine degradation. GABA acts as an endogenous signaling molecule during plant growth and development, playing a positive role in combating various biotic and abiotic stresses. However, its content in plants is limited. For example, wheat contains only 4.5 mg / 100g of GABA; different varieties of brown rice contain approximately 1.75–16.97 mg / 100g; barley grains average approximately 8.00 ± 3.92 mg / 100g; and millet contains 11.4 mg / 100g. Therefore, increasing the γ-aminobutyric acid (GABA) content in quinoa through calcium absorption is beneficial for improving its nutritional value and developing high-value-added products.

[0006] For seeds like quinoa, which possess a unique seed coat structure and are rich in saponins, calcium signaling may play a unique regulatory role in seed coat rupture, radicle breakthrough, and seedling morphogenesis. Exogenous application of appropriate concentrations of calcium can significantly improve the germination rate and vigor index of seeds in various crops. Furthermore, calcium nutrition is closely related to the stress resistance of quinoa during germination. In this process, on the one hand, sufficient calcium supply can strengthen the cell membrane system, reduce electrolyte extravasation under stress conditions, and maintain intracellular homeostasis; on the other hand, the calcium signaling pathway is a core hub for plants to sense and respond to environmental stress. Calcium ions can bind with calmodulin to form a complex, activating the rate-limiting enzyme in the γ-aminobutyric acid (GABA) pathway, promoting an increase in GABA content. Therefore, utilizing calcium to promote efficient and excessive GABA synthesis is a powerful measure beneficial to quinoa processing.

[0007] Quinoa is rich in nutrients, including vitamins, protein, carbohydrates, and dietary fiber. The calcium content of raw quinoa is 30-40 mg / 100g dry matter, and the γ-aminobutyric acid (GABA) content is approximately 17.75 ± 0.83 mg / 100g dry matter. After harvesting, quinoa is primarily processed using non-biological methods such as hulling, grinding, crushing, extrusion, and steaming. These are primary processing methods for agricultural products, which are not conducive to obtaining high-value-added quinoa products, and such high-value-added quinoa products are also lacking.

[0008] Germination, as a green and efficient biofortification method, can improve the nutritional quality of grains. It increases the total phenolic content in grains such as brown rice, wheat, buckwheat, and oats, while also improving the bioavailability and accessibility of nutrients and bioactive substances in the human gut. Current research on germinated grains focuses on components such as starch, protein, γ-aminobutyric acid (GABA), and total phenols, and their functional effects. Current research on quinoa germinated to a sprout length >25mm focuses on its starch decomposition, protein content, phytic acid degradation, and antioxidant functions. However, research on controlling the GABA content and phytic acid / calcium ratio after quinoa germination is lacking. This invention, by controlling the sprout length of quinoa germination and exploring the multiple effects of calcium, determines the beneficial effects of calcium and GABA on the biofortification of quinoa, thereby improving the nutritional value of quinoa and facilitating the development of high-value-added products.

[0009] Using exogenous calcium solution to germinate quinoa not only increases the calcium content of quinoa, resulting in calcium-rich foods, but also utilizes calcium to promote the synthesis of gamma-aminobutyric acid (GABA) and improve the phytic acid / calcium ratio, thereby enhancing the nutritional value of quinoa products. This method is worth further development. It can promote the increase of calcium and GABA content in quinoa, thereby increasing the added value of quinoa products, which can be used in noodle products, baked goods, etc., to increase their calcium and GABA content. Summary of the Invention

[0010] The purpose of this invention is to enrich quinoa with calcium and γ-aminobutyric acid and its preparation method.

[0011] The objective of this invention can be achieved through the following processes and measures:

[0012] 1. After washing the quinoa seeds with water, soak them in a food-grade CaCl2 solution. The food-grade CaCl2 solution used should be 20-50 mM, and the soaking time should be 0.5-1 hour at a temperature of 18-28℃.

[0013] 2. Place the quinoa in a germination tray to germinate, cover the surface with two layers of gauze and keep the gauze moist with food-grade CaCl2 solution;

[0014] 3. Place the germination trays in a temperature and humidity control system. The operating temperature range of the system should be 15–25°C, and the humidity range should be 80–95%.

[0015] 4. Germinate the quinoa until the sprouts are 6-10 mm long, then dry them at 40-60℃ until the moisture content of the quinoa is less than 13% to obtain quinoa fortified with calcium and γ-aminobutyric acid.

[0016] The obtained quinoa has a calcium content of 240–280 mg / 100g dry matter, which is 6–7 times higher than that of raw quinoa, and meets the calcium-rich requirements of GB 28050. The obtained bio-fortified quinoa has a γ-aminobutyric acid (GABA) content of 180–290 mg / 100g dry matter, which is 11–18 times higher than that of raw quinoa. The phytic acid content in the quinoa is reduced to 39–160 mg / 100g dry matter, and the phytic acid / calcium ratio is reduced by 3–20% compared to that of raw quinoa. The obtained quinoa can be used in flour products, baked goods, etc., to increase their calcium and GABA content.

[0017] Further details on the advantages and beneficial effects achieved:

[0018] The calcium content in quinoa prepared according to the above scheme, when the percentage of calcium content in the food is greater than 30% of the Nutrient Reference Value (NRV), can be indicated as calcium-rich, referring to the claims and conditions of nutrient content in GB28050-2025 "Nutrition Labelling of Prepackaged Foods".

[0019] The obtained quinoa can be used whole or ground into powder for use in flour products, baked goods, etc., increasing its calcium and γ-aminobutyric acid content, and also facilitating the development of foods with certain antioxidant properties.

[0020] The obtained quinoa contains an added phytochemical—γ-aminobutyric acid (GABA), which can be used to develop foods that are beneficial to human health. Detailed Implementation

[0021] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0022] Example 1

[0023] After washing the quinoa seeds with water, soak them in a 40mM food-grade CaCl2 solution at 28℃ for 1 hour. Then, germinate the quinoa seeds in a germination tray with the same 40mM food-grade CaCl2 solution. Cover the surface with two layers of gauze and keep the gauze moist with the same concentration of food-grade CaCl2 solution. Place the germination tray in a 25℃, 95% humidity environment until the quinoa sprouts reach a length of 10mm. Collect the germinated quinoa and dry it at 50℃ until the moisture content is less than 13%, thus obtaining quinoa fortified with calcium and γ-aminobutyric acid. The calcium content was tested to be 270 mg / 100g dry matter, which is 6.8 times higher than that of raw quinoa, and meets the calcium-rich requirements of GB 28050. The obtained bio-fortified quinoa has a γ-aminobutyric acid (GABA) content of 290 mg / 100g dry matter, which is 18 times higher than that of raw quinoa. The phytic acid content in the bio-fortified quinoa is reduced to 39 mg / 100g dry matter, which is 3% lower than that of raw quinoa. The reduced phytic acid / calcium ratio in the obtained bio-fortified quinoa is beneficial to calcium absorption and can be used in flour products, baked goods, etc., to increase their calcium and GABA content.

[0024] Example 2

[0025] After washing the quinoa seeds with deionized water, soak them in a 20mM food-grade CaCl2 solution at 20℃ for 0.5h. Then, place the quinoa seeds in a germination tray with a 20mM food-grade CaCl2 solution for germination. Cover the surface with two layers of gauze and keep the gauze moist with the same concentration of food-grade CaCl2 solution. Place the germination tray in a 15℃, 90% humidity device until the quinoa sprouts reach 8mm in length. Collect the germinated quinoa and dry it at 40℃ until the moisture content of the quinoa is less than 13%, thus obtaining quinoa fortified with calcium and γ-aminobutyric acid. The tested quinoa contains 240 mg / 100g dry matter, which is 6 times higher than that of raw quinoa, and meets the calcium-rich requirements of GB 28050. The bio-fortified quinoa contains 230 mg / 100g dry matter, which is 14.2 times higher than that of raw quinoa. The phytic acid content in the bio-fortified quinoa is reduced to 100 mg / 100g dry matter, and the phytic acid / calcium ratio is reduced by 12% compared to that of raw quinoa. The reduced phytic acid / calcium ratio in the resulting bio-fortified quinoa facilitates calcium absorption and can be used in flour products, baked goods, etc., to increase their calcium and γ-aminobutyric acid content.

[0026] Example 3

[0027] After washing the quinoa seeds with deionized water, soak them in a 50mM food-grade CaCl2 solution at 18℃ for 0.75h. Then, place the quinoa seeds in a germination tray with a 50mM food-grade CaCl2 solution for germination. Cover the surface with two layers of gauze and keep the gauze moist with the same concentration of food-grade CaCl2 solution. Place the germination tray in a 20℃, 85% humidity device. Germinate until the quinoa sprouts are 6mm long. Collect the germinated quinoa and dry it at 60℃ until the moisture content of the quinoa is less than 13%, thus obtaining quinoa fortified with calcium and γ-aminobutyric acid. The calcium content was tested to be 280 mg / 100g dry matter, which is 7 times higher than that of raw quinoa, and meets the calcium-rich requirements of GB 28050. The bio-fortified quinoa has a γ-aminobutyric acid (GAA) content of 180 mg / 100g dry matter, which is 11 times higher than that of raw quinoa. The phytic acid content in the bio-fortified quinoa is reduced to 160 mg / 100g dry matter, and the phytic acid / calcium ratio is reduced by 20% compared to that of raw quinoa. The reduced phytic acid / calcium ratio in the resulting bio-fortified quinoa facilitates calcium absorption and can be used in flour products, baked goods, etc., to increase their calcium and γ-aminobutyric acid content.

[0028] Although the invention has been described in detail with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art should be able to make various modifications and alterations without departing from the spirit and scope of the invention. Therefore, the scope of protection of the invention should be considered as defined by the appended claims.

Claims

1. A quinoa enriched with calcium and γ-aminobutyric acid and its preparation method, characterized in that... The processing steps are as follows: After washing the quinoa seeds with water, soak them in a food-grade CaCl2 solution, then place the quinoa in a germination tray, cover the surface with two layers of gauze and keep the gauze moist with the food-grade CaCl2 solution, place the germination tray in a temperature and humidity device, and germinate until the quinoa sprouts are 6-10 mm long. After drying, the bio-enhanced quinoa enriched with calcium and γ-aminobutyric acid is obtained.

2. The quinoa enriched with calcium and γ-aminobutyric acid and its preparation method according to claim 1, characterized in that, The food-grade CaCl2 solution is 20-50 mM, and the solution is soaked at a temperature of 18-28℃ for 0.5-1 h.

3. The quinoa enriched with calcium and γ-aminobutyric acid and its preparation method according to claim 1, characterized in that, The temperature and humidity equipment operates within a temperature range of 15–25°C and a humidity range of 80–95%.

4. The quinoa enriched with calcium and γ-aminobutyric acid and its preparation method according to claims 1-3, characterized in that, The obtained quinoa sprouts are 6-10 mm long and dried at 40-60℃ until the quinoa moisture content is less than 13%, thus obtaining quinoa. Its calcium content is 240-280 mg / 100g dry matter, which is 6-7 times higher than that of the raw quinoa, and meets the calcium-rich requirements of GB 28050. The bio-fortified quinoa has a γ-aminobutyric acid (GABA) content of 180-290 mg / 100g dry matter, which is 11-18 times higher than that of the raw quinoa.

5. Quinoa enriched with calcium and γ-aminobutyric acid, and its preparation method according to claims 1-4, characterized in that... The phytic acid content in quinoa is reduced to 39–160 mg / 100g dry matter, and the phytic acid / calcium ratio is reduced by 3–20% compared to that of the raw quinoa. The bio-fortified quinoa of this invention has a lower phytic acid / calcium ratio, which facilitates calcium absorption. The resulting quinoa can be used in flour products, baked goods, etc., increasing their calcium and γ-aminobutyric acid (GABA) content.