不同胁迫处理方法对西兰花茎中硫苷和异硫氰酸盐含量的影响

摘要

以西兰花(Brasica oleraceaL.var.italica Plench)茎试材,研究不同的机械切分、4℃低温贮藏、热激和浸泡胁迫处理对其中的硫苷和异硫氰酸盐(ITCS)含量的影响,结果表明:机械切分、低温贮藏、热激和浸泡胁迫处理对其中的硫苷和异硫氰酸盐的含量均有显著的影响(P＜0.05).切分尺寸为(1.0 ×0.2×0.5) cm时,茎中硫苷的含量最低为22.85 μmol/100 gDW,异硫氰酸盐的含量最高为653.74 mg/gDW.4℃下贮藏时,随着贮藏时间的延长与对照组相比硫苷降解和异硫氰酸盐生成的速度越来越慢,贮藏时间为8h时,硫苷降解和异硫氰酸盐生成的速率达到最低.在25℃下,将西兰花茎浸泡在不同pH的磷酸-柠檬酸缓冲液、Zn2+浓度和抗坏血酸溶液中2h,发现pH7.5缓冲液浸泡西兰花茎中硫苷的含量最低,为19.65 μmol/100gDW,异硫氰酸盐的含量最高,为654.36mg/gDW.Zn2+浓度为100μmol/L时,硫苷的含量达到最低,为19.09 μmol/100gDW达到最低,异硫氰酸盐的含量最高为为608.32 mg/gDW.抗坏血酸浓度为50 μmol/L时,西兰花茎中硫苷的含量最低,为9.96μmol/100 gDW,异硫氰酸盐的含量达到最高,为291.06 mg/gDW.不同温度热激处理结果表明,温度为35℃时硫苷的含量最低为26.44 μmol/100 gDW,异硫氰酸盐的含量最高,为597.13 mg/gDW.机械切分、适宜浓度的Zn2+、抗坏血酸和适宜的温度、pH有利于硫苷的降解和异硫氰酸盐的生成,而低温抑制硫苷的降解和异硫氰酸盐的生成.%The effects of different mechanicals cutting with different sizes of broccoli,storage temperature (4 ℃),heat shock and soaking stress treatments on the contents of glucosinolates and isothiocyanates (ITCS) in broccoli stems (Brasica oleracea L.) were investigated.The results showed that mechanical segmentation,low temperature storage,heat shock and soaking stress treatments had a significant impact on the contents of glucosinolates and isothiocyanates.When the segmentation size was 0.1 cm × 0.2 cm × 0.5 cm,the content of glucosinolate was at the lowest of 22.85 μmol/100g DW,while the content of isothiocyanates was at the highest of 653.74 mg/g DW.When stored at 4℃,with the extension of storage time,the degradation rate of glucosinolates and the generation rate of isothiocyanates was much slower compared with the control group.The degradation rate of glucosinolates and the generation rate of isothiocyanates reached the lowest at 8 hours storage.When the broccoli stems were immersed into different pH phosphate-citrate buffer and Zn2 + and ascorbic acid solutions at 25 ℃ for 2 hours,it was found that at pH d 7.5,the lowest content of glucosinolates was at 19.65 μmol/100gDW,and the highest content of isothiocyanates was 608.32 mg/gDW.When Zn2+ concentration was 100 μmol/L,glucosinolate was at the lowest of 19.09 μmol/100gDW,and isothiocyanates was at the highest of 608.32 mg/g DW.When the concentration of ascorbic acid reached to 50 μmol/L,glucosinolate was at the lowest of 9.96 μmol/100gDW,and the isothiocyanates was at the highest of 291.06 mg/gDW.Heat shock treatment with different temperatures showed the lowest contents of glucosinolate was 26.44 μmol/100gFW,and the highest contents of isothiocyanate was 597.13 mg/gDW at 35℃.In summary,the mechanical segmentation,proper concentration of Zn2+ and ascorbic acid,suitable temperature and pH were critical to the degradation of glucosinolate and the generation of isothiocyanates,while low temperature had the opposite effect.