Effects of fresh-cut and storage on glucosinolates profile using broccoli as a case study

Glucosinolates(GLS) contribute to the unique flavour, nutrition, and plant defence of the Cruciferous vegetables. Understanding the GLS changes through postharvest processing is essential for defined preservation. In this study, four different fresh-cut types, whole flower(W),floret(F), quarterly cut floret(QF) and shredded floret(FS) of broccoli, were stored for 0, 1, 2 and 3 day(s) to explore GLS responses to postharvest treatments. As a result, seven GLS were identified, mainly including glucoraphanin(RAA), neoglucobrassicin(NEO), and glucobrassicin(GBC)and accounting for 52.69%, 20.12% and 14.99% of the total GLS(21.92 ± 0.48) μmol · g ^(-1 )DW, respectively. FS had the sharpest decrease in GLS after three days of storage(6.55 ± 0.37) μmol · g-1DW, while QF had the least(10.16 ± 0.33) μmol · g ^(-1 )DW. All GLS components decreased over storage, except for 4-methoxyglucobrassicin(4 ME) in FS and QF, suggesting its key role in serious wound defence. The results suggested certain postharvest approaches influenced the flavour and nutrition of broccoli.

Effects of a Composite Soil Amendment on the Quality of Pak Choi(Brassica rapa L. Chinensis Group) Growing in Pb-contaminated Soils

In the present study, a pot experiment was carded out to investigate the effects of a composite soil amendment at different levels （0, 600, 900 and 1 200 mg/kg） on the soil organic matter content, pH, Pb uptake and nutritional quality of pak choi （Brassica rapa L. Chinensis Group） grown in the soils contaminated by four levels （800, 1 200, 1 600 and 2 000 mg/kg） of Pb. The results showed that 900 mg/kg soil amendment increased the soil organic matter content by 24.19%- 60.00%, but had no significant influence on soil pH. Comparing with control （without amendment application）, the security and nutritional quality of pak choi were obviously improved by applying the soil amendment. In detail, 900 mg/kg soil amendment improved the content of Vc of pak choi growing in 800, 1 200, 1 600 and 2 000 mg/kg Pb-contaminated soils by 13.27%-69.30%, the content of soluble sugar by 54.17%- 87.50%, the dry matter weight by 28.36%-33.39%, and decreased the content of Pb by 19.11%-35.72% and the content of crude fiber by 20.83%-31.03%, respectively. These data indicated that the composite amendment can be used for the in situ repair of Pb-contaminated soils, and the recommended dosage is 900 mg/kg.

Studies on the Simultaneous Determination of Cr(Ⅲ)and Cr(Ⅵ)by Ion Chromatography(IC)

The research aimed to develop and validate an ion chromatography method for the simultaneous analysis of Cr(Ⅲ) and Cr(Ⅵ)from pumpkin. A new analytical method based on ion chromatography techniques was developed by the Cr(Ⅲ) pre-column derivatization and Cr(Ⅵ) post-column derivatization. The ion chromatography condition was optimized and the detection sensitivity was improved. Cr(Ⅲ) and Cr(Ⅵ) were determined by 365 and 530 nm,respectively. The temperature of water bath,the heating time for pre-column derivatization,and the flow rate of post-column derivative liquid were screened on the basis of single factor experiment,the effects of various factors were determined by the method of L16( 43) orthogonal experiment design. Considering the results of orthogonal experiments and the variation tendency of peak area under different factors,the optimum derivatization conditions were chose as follows: the flow rate of post-column derivative liquid is0. 5 m L/min,the temperature of water bath for pre-column derivatization is 100 ℃ and the heating time is 5 min. The conditions were optimized by means of orthogonal experiments under the p H of leacheate ranged from 6. 5 to 6. 8 and the I-concentration of 5 mmol/L. Under optimized derivatization conditions,the detection limits for Cr(Ⅲ) and Cr(Ⅵ) were 0. 17 and 0. 019 mg,respectively. And the average recoveries of Cr(Ⅲ) in pumpkin were in the range of 82%-85%. Results indicated that pumpkin does not contain Cr(Ⅵ) according to this ion chromatography method of simultaneously determination for Cr(Ⅲ) and Cr(Ⅵ).

Analysis on Composition and Content of Glucosinolates in Broccoli Flowers and Leaves

Glucosinolate composition and content were evaluated in flowers and leaves of 12 different broccoli varieties. The results indicated that there were 9 glucosinolates in broccoli,namely Glucoiberin(IBE); Progoitrin(PRO);Sinigrin(SIN);Glucoraphanin(RAA);Gluconapin(NAP);4-Hydroxyglucobrassicin(4OH);Glucobrassicin(GBC);4-Methoxyglucobrassicin(4ME);Neoglucobrassicin(NEO).Total glucosinolate content in flowers was 1-5 times higher than in leaves. The predominant glucosinolate in broccoli was glucoraphanin.