Impact of low-doses gamma radiation on phytochemicals and bioactive compounds in barley microgreens.

Purpose: Microgreens have gained wide acceptance among consumers due to their low calorie content and rich composition of micronutrients and antioxidants, making them one of the best microgreen options. Therefore, this research is intended to investigate the effect of γ-rays on its growth and functional components and to confirm the possibility of using barley microgreens as a complementary and efficient food source.

Material and methods: Barley grains were exposed to various doses (10, 20, 30, and 40 Gy) of gamma rays, as well as the un-irradiated sample is considered as the control. The stimulating effects on growth and biochemical components of barley microgreens were evaluated.

Results: The results revealed that plant height increased significantly in response to gamma radiation exposure, and the maximum increase (23.87 cm) was obtained at a dose of 30 Gy. Otherwise, Ch a, Ch b, and carotenoid significantly increased (1.33, 0.941, and 0.181 mg/g FW), respectively at 30 Gy compared to the control (0.937, 0.448, and 0.132 mg/g FW), respectively. Also, the soluble sugars, proteins, and total free amino acids content were enhanced by increasing the dose level, and the maximum increase was noticed at 40 Gy of gamma rays. A remarkable increase was observed in the phenolic and flavonoid contents at 40 Gy (5.65 and 2.65 mg/g FW), respectively compared to control (4.57 and 2.16 mg/g FW). In the amino acids profile, glutamic acid was predominant, and the amino acids group was improved markedly by gamma rays compared with the control, and the dose of 40 Gy gave the greatest contents (141.60 µg/g DW), followed by 30 Gy (139.58 µg/g DW) in the control (121.34 µg/g DW). Current findings indicated that γ-rays have negative effects on γ-tocopherol, cholesterol, and stigmasterol, and the maximum decrease was observed with 40 Gy (21.774, 199.335, and 722.778 mg/kg DW), respectively. In contrast, it had positive effects on the values of ergosterol, α-tocopherol, and β-sitosterol (3580.674, 5255.511, and 5281.320 mg/kg DW), respectively.

Conclusions: The results showed that treatment of barley grain with low doses of gamma rays stimulated; growth, biochemical compound, and antioxidants production, increasing the nutritional value of barley microgreens, improving microgreens defense and supporting the use of these grains as a complementary and efficient food.