Optimization On Culture Conditions Of Tartary Buckwheat Sprouts And Its Quality Analysis

Tartary buckwheat is a well-known dual-purpose medicinal and food grain crop,mainly cultivated in the mountainous alpine areas of southwestern China.Tartary buckwheat sprouts germinated from healthy seeds are a new type of sprout vegetable harboring crisp texture,unique flavor,various kinds of nutrition,and abundant bioflavonoids and other active functional ingredients,which altogether endow the sprouts consumers’preference,good utilization value and broad market prospects.Tartary buckwheat sprouts in the current market are mainly cultivated in the fields and its yield and quality is prone to be impaired by weather,temperature,insect pests and other factors,which seriously affects the rapid development of tartary buckwheat sprouts industry.Greenhouse planting,a new trend of modern sprout vegetable industry,can effectively break through the constraints of soil conditions and arable land resources,greatly improving production efficiency,and improve the quality of sprout vegetables at the same time.In this study,we investigated the effect of various factors of sand soil method on tartary buckwheat sprout growth,further screened and optimized the hydroponic growth conditions of tartary buckwheat sprouts,and evaluated the quality of tartary buckwheat sprouts cultivated by different methods using Xiqiao 1 as experimental materials.The results may provide a basis for large-scale production of high-quality tartary buckwheat sprouts.The main research results are as follows:1.Screening and optimization of the cultivation conditions of tartary buckwheat sprouts in flask-sand soil method.Firstly,a single factor test was applied to preliminarily study the effects of sandy soil substrate ratio(4:0～4:3),soil depth(5～7 cm),and planting density(2100～3500 seeds/m~2)on the growth of tartary buckwheat sprouts;the sandy soil substrate ratio,followed by the planting density,and finally the depth of soil covering,was further identified as the key factor affecting the growth of tartary buckwheat sprouts through orthogonal test and the optimal cultivation conditions were determined as:planting density of 2100 seeds/m~2,the sand-soil matrix mass ratio(m/m)of 4:0,and the covering soil depth of 7cm.After cultivated for 18 days under these conditions,germination rate,leaf number,fresh weight and leaf area of the tartary buckwheat sprouts can be up to 84.6%,530 pieces/100plants,35.7 g/100 plants and 449.8 cm~2/100 pieces,respectively.2.Optimization of the cultivation conditions of tartary buckwheat sprouts in flask-hydroponics method.The concentration ratio of nitrogen,phosphate and potassium fertilizer suitable for the growth of tartary buckwheat sprouts was preliminarily screened through a single factor test and orthogonal test was used to further determine the optimal concentration of nitrogen,phosphate and potassium fertilizer,which was 0.3g/L,0.3g/L and0.3g/L,respectively.After cultivated for 18 days under these conditions,germination rate,leaf number,fresh weight and leaf area of the tartary buckwheat sprouts can be up to 86.5%,560 pieces/100 plants,39.6 g/100 plants and 480.2 cm~2/100 pieces,respectively.3.Screening and optimization of the cultivation conditions of tartary buckwheat sprouts in sprouting plate-hydroponics method.Firstly,a preliminary study investigated the effects of four commercial compound fertilizers on the growth of tartary buckwheat sprouts.The results showed that compound fertilizer F4 was more beneficial to the growth of tartary buckwheat sprouts than the other three.When the tested concentration was 0.75 g/L,germination rate,stem length,dry weight and fresh weight of the tartary buckwheat sprouts can be up to 90.1%,7.56 cm,7.89 g/100 plants and 35.33 g/100 plants,respectively.On this basis,the optimal concentration of nitrogen,phosphate and potash fertilizer were determined as follows:nitrogen fertilizer,phosphate fertilizer and potash fertilizer was 0.30 g/L,0.2 g/L,and 0.30g/L,respectively,using a series of single factor and orthogonal experiments.Under these conditions,seedling rate,leaf number,leaf area,stem length,dry weight and fresh weight of the tartary buckwheat sprouts can be up to 94.8%,620 pieces/100 plants,495.2 cm~2/100pieces,6.78 cm,11.45 g/100 plants and 41.1 g/100 plants,respectively.The systemic scoring method was further used to comprehensively evaluate the sensory indicators of the tartary buckwheat sprouts obtained along the cultivation period,and finally found the suitable harvest period was 15～18 d.During this period,the tartary buckwheat sprouts possessed bright green and shiny leaves,slightly sweet taste,plenty of juice,crisp texture,and better quality.4.Analysis of the nutritional quality of tartary buckwheat sprouts.The quality of the tartary buckwheat sprouts cultivated in 6 different methods were comprehensively evaluated through the determination of chlorophyll,carotenoids,soluble sugars,soluble proteins,fats,amino acids,phenolic acids and other main nutritional functional components.The results showed that tartary buckwheat sprouts cultivated by the sprouting plate-hydroponics method contained higher content of carotene and chlorophyll,which was up to 13.08 mg/100g and was 41.41%higher than that of tartary buckwheat sprouts cultivated in the fields on the whole.Sprouting plate-hydroponics method also promoted the biosynthesis of soluble sugars and soluble proteins,which were 57.34%and 90.33 higher than that of sprouts cultivated in the fields,respectively.The amino acids content of sprouts in sprouting plate-hydroponics method was higher than that of sprouts cultivated in soil culture and can be up to 31.9 g/100g;the total flavonoid content was 87.49 mg/g.For rutin,vitexin,isovitexin,quercetin and other phenolic acids,the sprouts cultivated by the sprouting-plate method contained the most abundance,which was 1.33 mg/g and 2.16 mg/g,6.84 mg/g,11.01 mg/g,45.85 mg/g and11.56 mg/g,respectively,increased by 74.35%,115.7%,110.62%,72.62%,35.05 and 42.78%,respectively,compared with that of sprouts cultivated in the fields.The results can lay an important foundation for the large-scale production of high-quality tartary buckwheat sprouts in greenhouse,which will help promote the production and processing technology of tartary buckwheat sprouts in our country,and is also beneficial to the rapid and healthy development of tartary buckwheat industry.