In recent years, the attention towards microgreens is increasing due to the rise in public awareness of healthy eating worldwide. “Microgreens” are a young, immature, and tender edible seedling of edible plants harvested at 2-5 inches tall, 6 to 15 days post sowing when the cotyledonary leaves start to emerge or just before the fully developed first true leaves. Microgreens are harvested at ground level including stem and cotyledons. This category of food fall between the sprout and baby green (Murphy et al., 2010; Verlinden, 2020). These are very attractive due to their colors, texture, and flavors. So, microgreens can be used as a new ingredient in various dishes i.e., in salads, soups, dhal, chapatti, burger, sandwiches, etc. which help the dishes to enhance their texture, color, flavor and also it gives diversity to our food system (Lee et al., 2009).

The wide variety of vegetables, herbs, pulses, and other plants seeds can be used for the production of microgreens in a very small and large area (Fig 1). Microgreens production provides better access to adequate nutrition along with a diversified food system.

Microgreens are an emerging class of fresh and nutraceutical food gaining popularity worldwide as potential functional foods, due to the enrichment of vitamins, minerals, growth-promoting components, bioactive compounds, and several phytochemicals (Xiao et al., 2012; Ghoora et al., 2020). Microgreens have been found to contain human bioactive compounds i.e. ascorbic acid, tocopherol, phylloquinone, phenolics, minerals, and antioxidants more than a mature one. A nutritional comparison study between the lettuce microgreen and its mature leaf resulted in a higher concentration of the various minerals in the microgreens (Iron, Calcium, Magnesium, Zinc, Selenium, and manganese) with low content of nitrate than a mature one. Pigments play a very important role against several clinical conditions like thalassemia and hemolytic anemia and reduce the risk of some chronic diseases, such as cancer, cardiovascular diseases, skin diseases, and age-related eye diseases (Pinto et al., 2015).

History and its utilization

The history of microgreens, started in the 1980s when the use of immature and tender leafy vegetables as garnishing in the US was a Chef’s Garden (Lubow, 2006; Verlinden, 2020). Nowadays, these immature leafy vegetables have become a long-lived part of our diet. Since the 2000s, microgreens have been recognized as a functional food that supports better human health and longer life (Verlinden, 2020). The majority of crop species and varieties are used for microgreen production belong to Brassicaceae and Amaranthaceae’s families. Following, the most popular species, subspecies, and varieties are mustard, lentil, mungbean, cabbage, radish, pearl-millet, beet, chard, broccoli, kale, and arugula (Table1). Directly or indirectly wheat microgreen was a part of our diet since ancient times. Wheat, buckwheat, and rye are also grown in the form of microgreens as grain crops. The stage of consumption or harvesting of microgreens is also important for production strategies. The period from sowing to harvesting varies greatly from crop to crop (Pinto et al., 2015). Microgreens can also be grown or cultivated of mixed crops, thus the grower should select the crops that are having similar growth rates so that the whole crop can be harvested at once.

How to grow?

Microgreens can be produced in the garden, pot, tray as well as container, depending upon requirements. Microgreens are harvested just above the soil line. Harvested microgreens are highly perishable and immediately washed, cooled as soon as possible using good handling practices for food safety. Microgreens are generally packed in polyethylene packages and cooled to recommended temperatures before supplying to the market or consumers (Xiao et al., 2014). Moreover, their short production cycle has attracted greenhouse growers and small-scale farmers, thus, generating income for the farmers. The farmers can produce multiple cycles of microgreens compared to mature vegetables.

Table:1 List of various crops grown for microgreens.

Importance of microgreen

Nowadays, as the nutritional gap is increasing, the importance of functional foods and substantial interest for consumption of fruit and vegetable are continuously rising, the interest for the production of functional foods are also increasing to support human health and longevity. As the world’s population increases sharply, force us to revised our food system supply adequate nutrition to provide better health. An estimated, two billion lives are affected in developed and developing countries by a chronic deficiency of essential minerals and vitamins (micronutrients), collectively known as hidden hunger. Malnourishment statistics indicate the importance of functional food for us and our future generation too. Brassicaceae microgreens are known for their excellent source of minerals and bioactive components in a balanced human diet, and the consumption of microgreens could be a healthy-promoting strategy to meet the requirement of element dietary reference intakes, particularly for children. Thus, microgreens a very potential functional food can be an option to control the nutritional gap and malnutrition, which is also gaining popularity in the whole world. Due to the enrichment of various vitamins, minerals, phytochemicals, and health-promoting components, microgreens have the potential to prevent several lifestyle diseases, however when consumed in small quantities.

References:

Ghoora M.D., Babu D.R., Srividya N. Nutrient composition, oxalate content and nutritional ranking of ten culinary microgreens. J. Food Compos. Anal. 2020;91.

Lee, J.S., Kim, J.G., Park, S., Effects of chlorine wash on the quality and microbial population of ‘TahTasai’ Chinese cabbage (Brassica campestris var. narinosa) microgreen. Korean J. Hortic. Sci.27: 625−630 (2009).

Murphy, C. J., Llort, K. F., & Pill, W. G. (2010). Factors affecting the growth of microgreen table beet. International journal of vegetable science, 16(3), 253-266

Paradiso V.M., Castellino M., Renna M., Gattullo C.E., Calasso M., Terzano R., Allegretta I., Leoni B., Caponio F., Santamaria P. Nutritional characterization and shelf-life of packaged microgreens. Food Funct. 2018;9:5629–5640.

Pinto,E.,Almeida, A. A.,Aguiar, A. A., and Ferreira, I. M. P. L. V. O., Comparison between the mineral profile and nitrate content of microgreens and mature lettuces. J Food Compos Anal.37: 38-43(2015).

Sun J., Xiao Z., Lin L., Lester G.E., Wang Q., Harnly J.M., Chen P. Profiling polyphenols in five Brassica species microgreens by UHPLC-PDA-ESI/HRMSn. J. Agric. Food Chem. 2013;61:10960–10970

Verlinden, S. (2020). Microgreens: Definitions, Product Types, and Production Practices. Horticultural Reviews, 47, 85-124

Xiao Z., Codling E.E., Luo Y., Nou X., Lester G.E., Wang Q. Microgreens of Brassicaceae: Mineral composition and content of 30 varieties. J. Food Compos. Anal. 2016;49:87–93.

Xiao Z., Lester G.E., Luo Y., Wang Q. Assessment of vitamin and carotenoid concentrations of emerging food products: Edible microgreens. J. Agric. Food Chem. 2012;60:7644–7651

Xiao, Z., Lester, G.E., Luo, Y., Xie, Z., Yu, L. and Wang, Q., Effect of light exposure on sensorial quality, concentration of bioactive compounds and antioxidant capacity of radish microgreens during low temperature storage. Food Chem.151:472–79(2014).