Effect Of NaCl And CaCl₂ Treatment On The Nutritional And Functional Properties Of Broccoli Sprouts

Antioxidants riched in broccoli could prevent a variety of chronic diseases,such as cancer,cardiovascular disease and diabetes.Besides,the content of antioxidant substances in sprouts was significantly higher than that of trophosomes.Besides,the bioactive substances in the body were also unceasingly being synthesized and decomposed during germination.Therefore,changing germination conditions could increase sprouts biomass,improve the nutrition and function quality of sprouts.The present study aimed at investigating the nutritional and functional properties of germinated broccoli sprouts(cultivar YouXiu)treated with NaCl.Firstly,the changes of physiological and biochemical,membrane lipid peroxidation,reactive oxygen species(ROS)metabolism,antioxidant component content,and antioxidant enzyme activity were investigated during the germination in broccoli sprouts treated with NaCl at various concentrations.Then nutrient substances content,energy metabolism,photosynthesis as well as the chloroplast ultrastructure after these treatments were measured.After optimizing the optimal concentration of NaCl and CaCl2 on the enrichment of glucosinolates(GLS)and isothiocyanates(ITCs)in broccoli sprouts,the expression of gene related with GLS metabolism was investigated.The main results were listed as follows:1.NaCl treatment significantly increased malondialdehyde and ROS content,electrolyte leakage and cell membrane permeability in broccoli sprouts.The damage of membrane became more severe with increasing NaCl concentration.The content of antioxidant components,such as ascorbic acid and anthocyanin,and antioxidant enzymes also increased simultaneously and significantly treated with NaCl especially in 40 and 80 mM concentrations.Besides,NaCl treatment significantly promoted broccoli sprouts growth,which was mainly dur to the improvement on hormone content and enhancement on antioxidant activity.2.There was no significant difference on energy metabolism,but the photosynthesis in broccoli sprouts significantly increased by NaCl treatment.Simultaneously,the chloroplast ultrastructure changed,for example,the chloroplast became larger and the number of grana increased.With the increasing NaCl concentration,the photosynthesis and chloroplast rapid fluorescence value increased at first and then decreased.Treatment with 40 and 80 mM NaCl significantly increased total protein,total sugar and chlorophyll content and leaf area of sprouts,resulting in the promoed photosynthesis,thus improved the growth and biomass of sprouts.3.The growth of broccoli sprouts showed a concentration-dependent effect with NaCl treatment:low NaCl concentration(40 and 80 mM)promoted sprouts growth by raising antioxidant capacity and photosynthesis ability.Contrarily,high concentration of NaCl(160 and 200 mM)could result in severe membrane damage and photosynthesis inhibition,which further inhibited the growth of sprout.4.The treatment of NaCl and CaCl2 significantly increased the content of GLS and ITCs,but no significant difference was observed on the MYR activity.One-factor experimental showed that GLS and ITCs contents increased continuously and then decreased with the increase of NaCl concentration,while no significant differences were detected under different CaCl2 concentrations.By optimizing the concentration of NaCl and CaCl2,both GLS and ITCs contents reached the maximum value under the optimum concentration of 174.09 mM NaCl combined with 10.48 mM CaCl2,which was 5.57 and 3.54?mol/10 sprouts,respectively.5.Individual treatment with 174.09 mM NaCl significantly increased the content of GLS and ITCs in broccoli sprouts but had no significant effect on MYR activity.Meanwhile,treatment with 10,48 mM CaCl2 significantly improved ITCs content,but showed no significant effects on GLS content and MYR activity.In addition,the combination of NaCl and CaCl2 had synergistic reaction on GLS accumulation and ITCs formation.Under the treatment of NaCl combined with CaCl2,the content of GRA,GNA and GER increased,which was due to the enhanced transcription factor and genes expression related to the metabolism of aliphatic GLS.