Discussion On The Method Of Improving Tuber Germination Of Tiger Nuts And Its Multifunctional Application

Tiger nuts are a new oil crop with rich nutritional value,high oil production,drought tolerance,low water consumption,and high yield characteristics,they used as grains,oil,and feed,adapts to the growth of desertification marginal areas in China,and initially has the substitution advantage of new energy.However,the cultivation and production technology of tiger nuts is immature,the sources of tiger nuts varieties are single,the high-yield variety are lacking,and tiger nuts are hard to storage,the sudden low temperature during summer in North China and the cold weather during late spring in South China are extremely unfavorable to the germination and growth of tiger nuts,which is directly related to the biomass.In this study,six varieties of tiger nuts were used as materials to study the yield potential of tiger nuts from different sources（202201,202202,202203,202204,202205 and 202206）by the field hole sowing method.Four representative strains of tiger nuts（202201,202202,202203 and 202204）were used as materials to study the effects of four storage factors such as genotype,temperature,water content and time on the germination of tiger nuts by orthogonal design.Round strain tiger nuts 202203 were used as materials to study the effects of different temperatures（15,20,25,30,35 and 40℃）on the germination,the effects of different concentrations of H₂O₂（0.01%,0.1%,1%,3%,5%）on germination under stress temperature and its mechanism,effects of different concentrations of H₂O₂（0.01%,0.1%,1%,3%,5%）on the repair of aged tiger nuts and its mechanism,two-factor multi-level experiment,single-factor experiment,orthogonal experiment and response surface experiment were used to optimize the product formula,and the production of multifunctional products of tiger nuts was studied by considering the influence of raw material addition ratio on sensory and product stability.The results of this study show that:（1）Among all the tested tiger nuts strains,the strain 202203 has the highest yield per plant,number of grains per hole,total yield,oil yield,fiber yield and sugar yield,which are 141.47±4.17 g,167±2.21 grains、9054.11±266.62 kg·hm^-2、1657.51±48.81 kg·hm^-2、553.51±16.30 kg·hm^-2、2127.11±62.64 kg·hm^-2,it has high yield and high economic potential and can be used as a follow-up test material.（2）The order of factors affecting the germination of tiger nuts after storage were tiger nuts genotype>temperature>water content>storage time.Tiger nuts strain 202203,tuber with 18%water content,stored at 4℃for 120 d,the germination rate can reach85.00±5.77%.（3）Germination of tiger nuts is sensitive to temperature.It could not germinate at temperatures lower than 15℃.Tiger nut germination was significantly inhibited at 20℃,and optimum temperature for germination of tiger nuts was 35℃.（4）1%H₂O₂ soaking can effectively improve the germination capacity of tiger nuts under temperature stress.H₂O₂ soaking treatment at 20℃significantly promoted the germination ratio of tiger nuts（P<0.05）.Compared with the control,the germination ratio treated with 1%H₂O₂ soaking increased from 51.67±9.28%to 98.33±1.67%,the germination potential increased from 18.33±4.41%to 95.00±0.00%,the germination index increased from 2.89±0.63 to 36.83±1.19,and the average germination days reduced from 7.86±0.22 days to 5.54±0.01 days.After 1%H₂O₂ soaking treatment,the SOD,POD,CAT and amylase activity in tiger nuts tubers increased first and then decreased,accompanied by lower malondialdehyde content and higher content of soluble sugar,soluble protein.1%H₂O₂ soaking seeds significantly increased the contents of IAA and GA₃（P<0.05）,but ABA content increased first and then decreased.H₂O₂ promoted the germination of tiger nuts under temperature stress mainly through the regulation the endogenous hormones level,antioxidant enzymes activity,amylase activity,soluble sugar and soluble protein content.（5）H₂O₂ treatment mainly repaired tiger nuts aged tubers by regulating antioxidant enzyme and amylase activity,MDA content,osmotic regulatory substance content and endogenous hormone level to repair the aged tuber of tiger nuts and promote tuber germination and seedling growth.When the concentration of H₂O₂ was 1%,the repair effect was the best,the germination rate,germination potential and germination index all increased significantly（P<0.05）,but the average germination days did not change significantly（P>0.05）,The agronomic traits of seedlings increased first and then decreased with the increase of H₂O₂ concentration.Physicochemical analysis showed that after H₂O₂ treatment,soluble sugar and soluble protein content increased first and then decreased,MDA content decreased significantly（P<0.05）,amylase content decreased first and then increased,CAT、SOD activities and GA₃ and ABA content increased first and then decreased.Grey correlation analysis found that GA₃ was the most important factor affecting the repair effect of aged tiger nuts.（6）Tiger nuts can be used to make cookies and beverage.With the increase of tiger nuts,the hardness,chewiness,cohesiveness and adhesiveness of cookies decreased,while the indexes of flexibility,ash content,fat content,crude fiber content,water content,flavonoids content and antioxidant activity increased.Physical and chemical analysis showed that WJF2:NTF16 were the best recipe for cookies.The fat content,ash content,crude fiber content and flavone content of cookies were 14.42±0.33%,1.60±0.03%,1.33±0.02%and 2.81±0.09 g·100 g^-1,respectively.The comprehensive score of cookies was 107.13,and the sensory score reached 38.81,which were significantly higher than CK（P<0.05）The optimum formula of the beverage was that the addition of tiger nuts/coffee powder was 27.8 g/2.2 g,sugar was 15.14 g,milk powder was 32.01 g,monoglyceride was 0.8%,sucrose fat was 1%,xanthan gum was 0.08%,CMC-Na was0.1%,under this formula,the highest sensory score predicted by response surface model was 91.449,the actual sensory score was 89.29,and the centrifugal sedimentation rate reached the lowest 0.71±0.03%.