New Vegetable Brassica Foods: A Promising Source of Bioactive Compounds

Brassica rapa is grown in northwestern Spain to obtain turnip greens. The tops of the same plants (flower stems with buds) are cut and sell as turnip tops, increasing the value of the crop. This practice could be extended to other brassicas. The objectives of this work are to study the phytochemical potential of tops of coles (Brassica oleracea) and leaf rape (Brassica napus) compared to turnip tops and to compare tops of different coles (cabbage, kale, tronchuda cabbage), which differ in their morphology and use. We evaluated the content of glucosinolates and phenolic compounds and the antioxidant capacity in leaves and tops of the three species. We found that tops had higher amount of glucosinolates than leaves. Phenolic content and antioxidant capacity followed the opposite trend. Therefore, consumption of leaves and tops are complementary, since both type of organs are enriched with different types of compound. Local varieties of kale, curly kale, cabbage and curly leave cabbage are interesting because of their GSLs and phenolic content and antioxidant capacity in both leaves and tops. From the human health perspective, tops of coles and leaf rape are interesting as new crops to include in the diet.

Evaluation of Italian and Spanish Accessions of Brassica rapa L.: Effect of Flowering Earliness on Fresh Yield and Biological Value

A comparative study for evaluating Italian and Spanish accessions of Brassica rapa var. rapa L., including turnip greens and turnip tops, was carried out at different locations with a view to determine the effect of earliness on crop production, antioxidant activity, glucosinolates amount, and profile (GLSs) and total phenolics content. The accessions evaluated were represented by two turnip top local varieties (one Italian variety and a Galician one), four new synthetic varieties established by Misión Biológica de Galicia (MBG-CSIC), and three commercial varieties widely used by growers in Galicia and in Italy. The results showed a great variability regarding flowering time, fresh and dry weight of the leaves and flower buds, and the branch number per plant. The highest turnip greens production was found in two synthetic varieties (“SIN07” and “SIN01”) for both countries. Local varieties “BRS550” and “CM39” were also suitable for turnip greens production in Spain and Italy, respectively. For turnip tops, the highest production was found for “SIN07” in Spain, for “CM39” in Italy and for “BRS550” in both countries. We found a high diversity in the total and individual glucosinolate, phenolic content, and antioxidant activity among genotypes, geographical origins, and the different parts of the plant (leaf and flower). Varieties “SIN01” and “SIN07” showed the highest values in total GLSs, total aliphatic and gluconapin contents in turnip greens followed by the two commercial varieties. For turnip tops, the highest values in gluconapin, aliphatic, and total GLSs contents were found in “SIN01” and “BRS550”. Even though different varieties stand out over the rest depending on the location, “SIN01”, “SIN07”, “CM39”, and “BRS550” could be recommended for turnip greens production because of its high antioxidant activity. The study showed that the latest varieties are more productive and show higher bioactive compounds than the earlier ones and that it is possible to improve genotypes for different growing cycles. Therefore, these varieties could be proposed for further breeding programs for B. rapa production.

Analysis of the Acid Detergent Fibre Content in Turnip Greens and Turnip Tops (Brassica rapa L. Subsp. rapa) by Means of Near-Infrared Reflectance

Standard wet chemistry analytical techniques currently used to determine plant fibre constituents are costly, time-consuming and destructive. In this paper the potential of near-infrared reflectance spectroscopy (NIRS) to analyse the contents of acid detergent fibre (ADF) in turnip greens and turnip tops has been assessed. Three calibration equations were developed: in the equation without mathematical treatment the coefficient of determination (R2) was 0.91, in the first-derivative treatment equation R2 = 0.95 and in the second-derivative treatment R2 = 0.96. The estimation accuracy was based on RPD (the ratio between the standard deviation and the standard error of validation) and RER (the ratio between the range of ADF of the validation as a whole and the standard error of prediction) of the external validation. RPD and RER values were of 2.75 and 9.00 for the treatment without derivative, 3.41 and 11.79 with first-derivative, and 3.10 and 11.03 with second-derivative. With the acid detergent residue spectrum the wavelengths were identified and associated with the ADF contained in the sample. The results showed a great potential of NIRS for predicting ADF content in turnip greens and turnip tops.

CHAPTER XXXII

——'TWAS by a poor ass who had just turned in with a couple of large panniers upon his back, to collect eleemosunary turnip tops and cabbage leaves; and stood dubious, with his two forefeet on the inside of the threshold, and with his two hinder...

The heterogeneity of turnip-tops (Brassica rapa) seeds inside the silique affects germination, the activity of the final step of the ethylene pathway, and abscisic acid and polyamine content

The mature silique of turnip-tops (Brassica rapa L. cv. Rapa) contains seeds that are heterogeneous in colour. From these seeds, we have selected three homogeneous lots: black (B), dark brown (DB) and light brown (LB). The dry seeds of these lots contained different levels of free and conjugated 1-aminocyclopropane-1-carboxylic acid (ACC), polyamines (PA) and ABA, the levels of the latter being inversely related to the germinative capacity. The water uptake (WU) rate was much faster in LB seeds than in B. This fact was probably related to the breaking of the seed coat, the speed of which was B >> DB > LB. The ABA, spermidine (Spd) and spermine (Spm) contents decreased in the seeds during germination, whereas the putrescine (Put) levels rose sharply (B > DB > LB). For the first time in seeds, heterogeneity is reported with respect to ethylene sensitivity and synthesis. Whereas exogenous ethylene did not alter the percentage of germination in lot B, germination was higher in DB and LB (LB�>> DB) in the presence of ethylene. The final step of the ethylene pathway was altered concomitantly with this change in germinating capacity, affecting the levels of 1-(malonylamino)cyclopropane-1-carboxylic acid (MACC), ACC, ACC–oxidase (ACO) and ethylene production. The gene BrACO1, recently characterised by us, is expressed differently in the three seed lots, particularly in the LB, where little transcription occurs. Finally, ethylene inhibits Put, Spd and Spm levels at different intensities in the three lots. The results point towards variation in the channelling of ACC towards synthesis of ethylene and / or PA, caused by the heterogeneity.