Impact Of Non-Thermal Technologies On The Nutritional Properties And Quality Of Wheat Seeds And Plantlet Juice

Low-acid juices are favored by a wide range of consumers due to their excellent functional nutrition,such as aiding digestion,purifying the blood,and strengthening the immune system,which in turn has led to an increase in demand for plant-based beverages such as wheat plantlet juice.Wheat plantlet（WG）,a plant of the wheat family,has high nutritional and medicinal value and has been traditionally used to treat various diseases such as myelodysplastic syndrome and thalassemia.Wheat plantlet juice（WGJ）is rich in many nutrients,including chlorophylls,carotenoids,vitamin C,minerals,bioflavonoids and phenolics,and has important preventive effects on many diseases.Studies have shown that WGJ is effective in improving sleep and fatigue,lowering blood pressure and blood sugar,improving digestion and weight loss,maintaining healthy skin,teeth,eyes,muscles and joints,and improving heart and lung function as well as mental function,and can be used to help treat ulcers,skin burns,diabetes,anemia,eczema,cancer,kidney swelling,the common cold,and constipation.Currently,most commercial fruit and vegetable juices are enriched with multivitamins（e.g.,A,C and E）that are usually artificial,and the use of some preservatives such as butylhydroxyanisole（BHA）,butylhydroxytoluene（BHT）and tetrabutylhydroquinone（TBHQ）as food additives,resulting in a degree of carcinogenicity and genotoxicity of the product.The traditional process of producing natural fruit and vegetable juices relies on high processing temperatures for the extraction and dissolution of their functional nutrients and other materials,and high heat input can lead to lower quality or even adverse changes in fruit and vegetable juices.To improve the disadvantages of traditional thermal processing,new technologies such as pulsed electric field（PEF）and ultrasound（US）technologies have been widely used in food processing,such as assisting functional nutrient extraction and promoting food component modification,and these means are also effective methods to control seed dormancy,enhance seed growth characteristics and improve the quality of freshly squeezed fruit and vegetable juices.Therefore,in this study,PEF and US non-thermal processing techniques were introduced from seed growth to juice preparation of wheat plantlets to examine their effects on the growth characteristics of wheat plantlets and the overall quality of wheat plantlet juice and to investigate the related mechanisms.The specific results of the study are as follows:The effect of PEF on the growth of wheat plantlets was studied.All growth parameters of wheat plantlet seeds were elevated with increasing electric field intensity（2-6 k V/cm）and number of pulses（25-50）.Under the condition of electric field intensity of 6 k V/cm and the number of pulses of 50,the water uptake rate of wheat plantlet seeds during growth increased significantly compared with the untreated group,reaching a maximum of 56.56%,and the germination rate and juice yield increased by more than 10%and 20%,respectively;among the growth parameters,the plant fresh weight,dry weight and seedling length increased by 52.87%,47.15%and 10.00%,respectively;the plant The number of green leaves in the leaves increased from 6 to 12 per plant,and the number of senescent leaves decreased from 8 to 2 per plant,while the leaf area increased significantly.The above results showed that the pulsed electric field could stimulate the growth of wheat plantlets and improve their growth parameters,and the effect of high electric field intensity and high pulse number was more significant.The changes in the nutrient fraction of wheat plantlet juice extracted from plants treated with the above PEF conditions were further investigated.Wheat plantlets were treated with PEF at 6k V/cm and 50 pulses and then germinated overnight,and after 14 days,wheat plantlets were harvested from 2 cm above the soil and the juice was extracted.The total phenolic content increased by 18.56%and the corresponding DPPH radical scavenging capacity increased by 75.9TroloxμM;the contents of soluble protein,various mineral elements and free amino acids were significantly increased（p<0.05）.The above results reflect that PEF treatment can improve the nutritional properties of wheat plantlet juice.The effect of thermal co-ultrasonic（TUS）treatment on the quality of wheat plantlet juice was investigated.Wheat plantlet juice was treated in a controlled-variable ultrasonic hot water bath under the conditions of ultrasonic frequency（40 k Hz）,ultrasonic power（70%,420 W）,bath temperature（30,45 and 60°C）and treatment time（20 and 40 min）,and the bioactive compounds,free amino acids,mineral content and microbial parameters of the treated wheat plantlet juice were determined.The results showed that browning and juice viscosity was significantly increased in the TUS treatment group,while total titratable acid,p H and Brix did not change significantly.The total number of colonies of wheat plantlet juice was significantly reduced by sonication at 60°C for 40 min（p<0.05）.Therefore,the thermal synergistic sonication treatment could enhance the nutritional quality of wheat plantlet juice while achieving sterilization effects.PEF and US were used in combination to investigate the combined effects of both on wheat plantlet juice.Compared with the physical field treatment group alone,US+PEF treatment resulted in wheat plantlet juice with higher total phenolic content,total flavonoid content and chlorophyll content,and its ORAC assay and DPPH assay showed stronger antioxidant capacity;meanwhile,US+PEF treatment significantly reduced peroxidase and polyphenol oxidase activities,from 0.87Abs min^-1 and 0.031 Abs min^-1,respectively Abs min^-1 to 0.27 Abs min^-1 and 0.016 Abs min^-1,respectively,as well as reducing the total number of microorganisms,yeast and mold（3.92 to 2.11log CFU/m L）,and E.coli（1.95 to 0.96 log CFU/m L）in the product;the quality of the juice was analyzed using Fourier Transform Infrared（FT-IR）and Surface Enhanced Raman Spectroscopy（SERS）were used to analyze the juice quality and the wheat plantlet juice of the synergistic treatment group provided stronger Raman peaks,indicating an increase in its nutrient molecules.Therefore,the superimposed treatment of the two physical fields mentioned above significantly improved the quality of wheat plantlets and reduced their storage difficulty.