Effects Of Different Picking Periods On Yield And Nutritional Quality Of Alfalfa Sprouts

Alfalfa(Medicago sativa L.)is a widely cultivated perennial leguminous forage crop.Its green sprouts have high nutritional value and potential value to be developed as a health-care vegetable.However,the size and quality of buds differed significantly in different stages of the spring rejuvenation period due to the length of growth time.Therefore,it is of great significance for the development of sprouts to explore the variation patterns of yield and quality of alfalfa sprouts under different harvest periods and different harvest ratios.This study adopted a full factorial randomized block design method,and set up three picking periods in the early stage of rejuvenation(April 12,2021),the middle stage of rejuvenation(April 21,2021),and the late stage of rejuvenation(April 30,2021).The changes of yield and nutritional quality of alfalfa sprouts were studied.The main results are as follows:(1)The biological yield of alfalfa sprouts was only 130.2g/m~2in the early stage of rejuvenation,which was too low to be picked;the biological yield and economic yield of alfalfa sprouts in the later stage of rejuvenation were the highest,which were 695.51g/m~2and 513.51 g/m~2respectively.(2)Crude protein(40.51%),calcium(1.37%),phosphorus(0.96%),potassium(1.21%),amino acids(10110.99mg/100g),essential amino acids(5505.28mg/100g),non-essential amino acids in mid-greening alfalfa sprouts(4605.72mg/100g),reducing sugar(6.67mg/g),soluble sugar(94.34mg/g)content were significantly higher than the other two periods.However,there were no significant differences in crude fat,iron,zinc,and V_Ccontents among the three periods.(3)The yield and nutritional quality of alfalfa sprouts were analyzed by principal component analysis,and the contribution rate of the first principal component was 72.02%,and the contribution rate of the second principal component was 27.98%.After standardizing each index and bringing it into the comprehensive score model,the comprehensive score ranking of the three periods is obtained:the middle stage of rejuvenation(3.977)>the early stage of rejuvenation(0.330)>the later stage of rejuvenation(-4.195).In conclusion,the content of crude protein,calcium,phosphorus,potassium,amino acid,reducing sugar,and soluble sugar of alfalfa sprouts in the mid-greening stage was the highest,and the nutrients were the most abundant,and the comprehensive score in the principal component analysis was the highest in this period,so the mid-greening stage was the highest in alfalfa sprouts Best time to harvest.