| Broccoli,one of the main vegetables in our daily life,is rich in vitamins,carbohydrates,proteins,minerals and many other nutrients,which is known as the "crown of vegetables".Broccoli also contains glucosinolates,polyphenols and other bioactive phytochemicals,thereby showing the prevention and treatment of lung cancer,stomach cancer,breast carcinoma and other cancers as well as diabetes and cardiovascular diseases.Therefore,it possesses high value to researchers and consumers.With the increasing consumption of broccoli,a large number of by-products also come up.As the world's largest exporter of broccoli,broccoli waste has caused a huge burden on vegetable producing areas in China.These wastes have not been properly and efficiently utilized,resulting in waste of resources,food safety and environmental problems.Therefore,it is necessary to study the broccoli wastes,to clarify the composition of nutrients and bioactive ingredients,and to provide sufficient theoretical basis for further development and utilization.Discarded broccoli leaves were selected as the research odject to explore some of the bioactive ingredients,and its functional applications in formaldehyde scavenging and skin's ultraviolet protection were preliminary studied.The specific experimental contents and conclusions are as follows:The contents of sulforaphane(conversion of glucoraphanin to sulforaphane),total ascorbic acid,total phenolics,total flavonoids,total proteins in broccoli leaves were 92.5±4.9 ?g/g(dry weight),436.4± 11.2?g/g(fresh weight),3.15±1.2 mg/g(dry weight),2.48±0.24 mg/g(dry.weight)and 89.375±4.59 mg/g(dry weight)respectively,the contents of total ascorbic acid,total phenolics and total proteins were higher than that of edible portions,and ribulose-1,5-diphosphate carboxylase/oxygenase(Rubisco)occupied most of the proteins in broccoli leaves.The formaldehyde scavenging ability of broccoli leaf lyophilized powder and influence of different factors on formaldehyde scavenging rate were evaluated,results showed that lyophilized powder had the ability of formaldehyde scavenging.Orthogonal experiment of temperature,time,pH and solid-liquid ratio was carried out on the basis of single factor experiment,and the optimal parameter combination was obtained:65 ?,24 h,pH 9,0.04 g/mL,and 98.27%of scavenging rate was obtained at this experimental condition,showing that broccoli wastes exhibited formaldehyde scavenging activity to a certain extent and could be further studied in this field.The protective effects of 5 crude extracts(ME,PE,DE,EE and SCE)on skin damage induced by UVB irradiation in C57BL/6 mice were investigated.The results showed that ME and SCE could significantly increase the levels of quinone oxidoreductase 1(NQO1)and glutathione transferase(GSH-T)in skin tissues,and had an obvious inhibitory effect on the rise of myeloperoxidase(MPO);pathological analysis showed that the skin tissues treated by ME and SCE were in good condition,while the skin tissues in other sample groups were accompanied by the tendency of pathological symptoms,indicating that ME and SCE have better protective effect on UVB radiation.The composition of each solvent extract was analyzed by LC-MS,results showed that polyphenols in each sample were quite different.Chlorogenic acid and caffeic acid were detected in both ME and SCE,in addition,ME also contained syringaldehyde and syringic acid;sinapic acid was detected in PE,DE and EE.Considering that most of the above ingredients belong to phenolic compounds,and some of them are generally recognized for their UV protective effects,thereby,contents of total phenolic in each extract were determined,the result indicated that ME and SCE contained higher total phenolic content(2.70 and 3.77 mg/mL for ME and SCE,while 0.49,0.88 and 0.96 mg/mL for PE,DE and EE).This further proved that the combination of phenolic compounds and sulforaphane was the main influencing factor for skin UVB protection. |
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