Standardization of technology for microgreen production

Abstract

Microgreens are new class of vegetables that are gaining popularity in the recent years due to their attractive appearance coupled with vivid flavors. They are young immature greens produced from seeds of vegetables or herbs which are harvested at its true leaf stage. Most of the research works in this area are carried out with temperate species of crops whose seeds are very expensive. Hence there is a need to popularize the microgreens of tropical species at an affordable price with minimum inputs, so that it is easily accessible to common people. The study entitled “Standardization of technology for microgreen production” was conducted at the Department of Vegetable Science, College of Agriculture, Vellanikkara during January to October 2021. The study was experimented with wheat, ragi, green gram, horse gram, amaranthus and mustard whose seeds were collected from the local market. It was conducted as four experiments (standardization of seed treatment, standardization of media, standardization of seed density and to assess the nutritional value and yield under different growing conditions). The first experiment was to standardize seed treatment done using two chemicals hydrogen peroxide and vinegar treated at different concentrations. The observations on germination percentage, seedling vigour and yield were recorded. The seed treatment did not show any effect on growth of microgreens when compared to the control on the parameters recorded. The microscopic observation of freshly harvested microgreens for fungal contamination indicated absence of any contamination in the fresh microgreens. The experiment on standardizing growing media was carried out using five media viz, sterile sand, cocopeat, coir mat, tissue paper and newspaper. The observation on yield, seedling height, nutritional value of microgreens and microscopic observation on fungal growth were recorded. Yield was observed to be highest in microgreens grown on cocopeat media and lowest was recorded in microgreen grown on newspaper media and among the crops it was highest for green gram microgreens (1.03 to 1.49 kg/m2). The seedling height showed a slight decrease in ragi and mustard microgreens grown on newspaper and comparing the crops, it was observed to be maximum in green gram microgreens (10.23- 10.54 cm). The nutritional parameters recorded were not showing any difference when sown in different media. The wheat microgreens were observed to rich source of vitamin C, beta carotene and protein, ragi microgreens were showing more calcium and vitamin C and beta carotene content, green gram microgreen were rich in protein, vitamin C and calcium, horse gram microgreens were rich in vitamin C, chlorophyll, beta carotene and crude protein, amaranthus microgreens possess high iron, calcium, beta carotene and vitamin C content and mustard microgreens were rich in protein and beta carotene, iron and vitamin C. Microscopic observation on freshly harvested produce revealed that there is absence of fungal contamination in microgreens. The seed density for microgreen production was standardized in the third experiment. The seeds were sown at three densities viz, low, medium and high density for each crop. The observations recorded included yield, seedling height and microscopic observation on fungal growth. The yield was recorded to be highest when sown at high density for wheat (705 g seeds/m2), ragi (520g seeds/m2) and amaranthus(120g seeds/m2) microgreens and medium density planting yielded highest for green gram (850g seeds/m2), horse gram (617 g seeds/m2) and mustard (440 g seeds/m2) microgreens. The seedling height recorded was observed to be on par except for green gram and horse gram microgreens, where highest seedling height was found in medium density planting. No fungal contamination was observed in microscopic observation of fresh produce. Nutritional value and yield of microgreens grown under two conditions (room condition and rain shelter) were studied in fourth experiment. The parameters recorded were yield, seedling height, nutrient content under two conditions, organoleptic evaluation and shelf life of microgreens. The yield was observed to be significantly high when raised under rain shelter condition than room condition. Among the crops it was highest for green gram microgreens (2.261 kg/m2). The seedling height was observed to reduce under rain shelter condition. Nutritional content was also observed to be high when planted under rain shelter for all parameters viz, iron, calcium, beta carotene, vitamin C, crude protein, crude fibre, chlorophyll, oxalates and nitrates. Organoleptic evaluation revealed highest total mean rank for mustard microgreens (54.56) raised under room condition. The shelf life study revealed that the storage period of microgreens can be extended when it is stored in ziplock PPE bag under low temperature condition. In this study, several aspects of microgreens production viz, seed treatment, growing media, seed density, growth conditions and shelf life were standardized. The results indicate that microgreen cultivation can be recommended both as a commercial and household venture.