Improving the phytochemical composition of broccoli sprouts by elicitation

In order to increase the concentrations of bioactive compounds in broccoli sprouts, exogenous elicitors: methionine, tryptophan, chitosan, salicylic acid (SA) and methyl jasmonate (MeJA) were sprayed at different concentrations during germination. The effects of the elicitors on vitamin C, phenolic compounds and glucosinolate levels were assessed in 3, 5 and 7-days old seedlings. The application of 200, 300 μM SA and 0.01% chitosan induced increases, by 26%, 18% and 54%, respectively in the content of vitamin C in 5 days old broccoli sprouts. Flavonoid concentration was also increased by 31% and 33% after 10 μM MeJA and 100 μM SA treatments, respectively in 7 days old broccoli sprouts. In contrast, methionine or tryptophan solutions did not positively affect the vitamin C or the phenolic compounds in the sprouts. The individual classes of glucosinolates respond differently to the elicitor treatment. Methionine, a sulphur-containing amino acid, applied at 5 mM, significantly increased, by 32%, the levels of aliphatic glucosinolates. However, indole glucosinolates presented a significant response to the induction with tryptophan, SA or MeJA treatments. Tryptophan at 10 mM concentration augmented by 1.8-fold the indole glucosinolate concentration in 7 days old broccoli sprouts, and the treatments of 100 μM SA and 25 μM MeJA also induced significantly higher amounts of indole glucosinolates (by 33% and 51%, respectively) in 7 days old treated broccoli sprouts. Therefore, the application of elicitors could be a useful tool for improving the bioactive metabolites in broccoli sprouts for fresh consumption or functional ingredients for nutraceuticals foods.     

Natural Antioxidants in Purple Sprouting Broccoli under Mediterranean Climate

Abstract: Broccoli, (Brassica oleracea var. Italica), is generally recognized as a nutritive food rich in natural antioxidants, including vitamins and phenolics compounds. Phytochemical composition of 3 different purple sprouting broccoli varieties according with their production cycle: EEP (Extra Early), EP (Early), and LP (Late) were determined. The 3 cultivars tested were grown under the same conditions in an experimental field (SE Spain) where they were not previously cultivated since these cultivars are typical of cold, Northern‐European areas. EP variety showed greater growth according to the photosynthetic rate and C assimilation. However, it was not possible to obtain inflorescences for variety LP. The health‐promoting compounds (vitamin C, phenolic compounds, and glucosinolates) were higher in purple broccolis than in traditionally grown green broccolis and showed differences according to the variety. With respect to the use of broccoli byproducts as source of antioxidants, any variety would be suitable although the leaves of EP variety seems the richest in total phenolic acids, whereas the amount of anthocyanins was higher in LP variety, followed by EP and EEP varieties. Under our experimental conditions, the levels of glucosinolates were higher in purple broccoli than in green cultivars and also higher than other purple broccolis grown under different climate conditions. Therefore, the results reported data for production of the EEP and EP varieties in the Mediterranean climate with potential to obtain vegetables with improved nutritional quality. Practical Application: The results of this study reported data of the health‐promoting nutrients and natural antioxidants of EEP, EP, and LP purple sprouting broccoli varieties grown under the Mediterranean climate. The vitamin C, phenolic compounds, and glucosinolates in these purple varieties were higher than in traditionally grown green broccolis and other purple broccolis grown under different climate conditions.     

Analysis of the tumoral cytotoxicity of green tea-infusions enriched with broccoli

Broccoli has risen as rich in bioactive phytochemicals (glucosinolates and phenolic compounds) closely linked with the reduction of cancer risk. Green tea infusion is a beverage that also contains anticarcinogenic compounds, mainly represented by flavanols. The compounds present in new broccoli-enriched green tea drinks and their potential antitumoral activity in vitro were evaluated. The distinct compounds present in the prepared beverages were identified by HPLC-PAD-ESI-MSn and quantified by HPLC-PAD. Caco-2 and CCD-18Co cell lines were exposed to growing percentages (0.2-5%) of infusions of distinct combinations of plant material. The time-dependent cytotoxicity on the malignant cells was also achieved. Cell death was evaluated by trypan blue dye exclusion and a more efficient specific cytotoxic effect on Caco-2 cells was observed on the cells incubated with the mixture of broccoli and green tea than on cells exposed to control infusions. Broccoli added to green tea resulted in a combination of phytochemicals with antitumoral activity with potential for further developments in mechanistic models and the design of novel foods.     

Novel varieties of broccoli for optimal bioactive components under saline stress

BACKGROUND: Consumption of broccoli is increasing steadily worldwide because of the interest in its bioactive composition and nutritive value for health promotion. Novel broccoli cultivars to be established under current adverse conditions in production areas (aggressive environmental conditions and saline irrigation waters) need to maintain physical and nutritional quality for consumption and year‐round supply to the markets. The newly introduced cultivars ‘Naxos’ and ‘Parthenon’ have been selected as potential candidates to replace the currently underperforming ‘Nubia’ variety. We aimed to compare the physical and phytochemical quality (glucosinolates, hydroxycinnamic acids, flavonoids, vitamin C and minerals), as well as the in vitro antioxidant capacity of these three cultivars under conditions of environmental stress. RESULTS: ‘Parthenon’ showed equal productivity and nutritional composition to ‘Nubia’, whereas ‘Naxos’ presented in general the best results when compared to ‘Nubia’ and ‘Parthenon’. For phenolic compounds ‘Nubia’ presented the highest contents, although ‘Naxos’ seemed better adapted to saline stress conditions, as suggested by the lowest degree of variation in the contents of healthy phytochemicals, including phenolic compounds, when grown under such conditions. CONCLUSION: ‘Naxos’ broccoli performed best and is a suitable candidate to replace ‘Nubia’ for marketable, nutritive and phytochemical quality, especially in areas of production under adverse conditions as found in Mediterranean southeast Spain (semiarid climate with saline irrigation water). Copyright © 2011 Society of Chemical Industry     

Effect of nitrogen and sulfur fertilization on glucosinolates in the leaves and roots of broccoli sprouts (Brassica oleracea var. italica)

Broccoli (Brassica oleracea L. var. italica cv. Marathon) sprouts are a rich source of glucosinolates, particularly 4‐methylsulfinylbutyl glucosinolate (glucoraphanin), the precursor of the chemoprotective isothiocyanate, sulforaphane. Sulfur and nitrogen fertilization have been shown to influence the pattern and levels of glucosinolates in mature broccoli, but little information is available on the fertilization of sprouts, a transient stage of broccoli growth, which have been recommended for salads. Therefore, an experiment was set up to evaluate the effect of N and S fertilization on the glucosinolate content of the aerial part and roots of broccoli sprouts. Nitrogen was tested at 0, 45.5, 91.0 mg L^?1 and sulfur at 0, 14.6 and 29.2 mg L^?1. The results showed that total glucosinolates in the aerial part were significantly higher (P < 0.001) than in the roots. The major glucosinolates in the aerial part were 4‐methylsulfinylbutyl and 3‐methylsulfinylpropyl whereas in the roots they were 2‐phenylethyl and 4‐methylthiobutyl. Fertilization of broccoli sprouts had a significant (P < 0.001) detrimental effect on the levels of aliphatic glucosinolates whereas the opposite was noted for indole and aromatic glucosinolates, for some of the fertilization combinations tested. Overall, the results indicate that broccoli sprouts do not benefit from fertilization. Copyright © 2006 Society of Chemical Industry     

Genotypic effects on the phytochemical quality of seeds and sprouts from commercial broccoli cultivars

Determining ontogenic diversity in vegetables, in general or Brassicas in particular, regarding the bioactive content, is an interesting task since the most promising Brassicaceae foods could have the highest nutritional and health-promoting properties. Therefore, vitamin C, phenolic compounds, glucosinolate content, and total antioxidant capacity were evaluated in commercial cultivars of broccoli (Brassica oleracea var. italica; cv. Nubia, cv. Marathon and cv. Viola) seeds and during the sprouting period. Vitamin C was not detected in dormant seeds and its content increased with the germination, reaching values ranging from 53 (cv. Nubia) to 64 (cv. Marathon) mg/100 g FW, at the end of the monitored period (14days). The total glucosinolate content in seeds and 3-day-old sprouts was higher in cv. Marathon (1005 and 556 mg/100 g FW, respectively), however cv. Viola sprouts registered the highest glucosinolate content 7 and 14 days after sowing (235 and 208 mg/100 g FW, respectively). Aliphatic glucosinolates were more affected by genetic factors than the indolic glucosinolates, being glucoraphanin the predominant glucosinolate in cv. Nubia and cv. Marathon, whereas glucoiberin was the major glucosinolate in cv. Viola. The flavonoid and total phenolic content was significantly higher in cv. Viola. Also, seeds of this cultivar showed the highest antioxidant capacity (2.7 mg Trolox/g FW).     

Broccoli-Derived By-Products—A Promising Source of Bioactive Ingredients

ABSTRACT: The regular dietary intake of broccoli on a weekly basis has been related to better health, but industrial use of broccoli by-products (crop remains) is negligible. Adding value to broccoli by-products in a country such as Spain, one of the main broccoli producers for the EU, is of scientific and economic interest. The present article is focused on the bioactive compounds (glucosinolates, phenolic acids, and flavonoids) and nutrients (vitamin C, minerals, and trace elements), as well as the in vitro radical-scavenging capacity (DPPH· test), of the broccoli products (harvest remains) resulting from greenhouse cultivation using 80 mM NaCl treatment, representative of the currently available irrigation water in the production areas of Murcia (SE Spain). The bioactive compounds and nutrient contents varied according to the cultivar, organ (leaves or stalks), and the saline stress (80 mM NaCl), in the cultivars Marathon, Nubia, and Viola. Cultivar Nubia was not affected dramatically by 80 mM NaCl and the contents of phytochemicals and nutrients in the by-products of Nubia fell within the range of health-promoting levels of edible commercial parts (inflorescences or flower heads). Therefore, adding value to broccoli agrowaste by obtaining bioactive ingredients and nutrients could benefit the food and drug industry. Practical Application: Many by-products of the agrifood industry may be useful as sources of nutrients and potentially functional ingredients, giving the opportunity to obtain added-value products. Previous studies have been focused on edible florets, but in this case we are interested in adding value to broccoli by-products that represent a real problem in the production sites because no intended use for this material has been envisaged. Therefore, the aim of this study was to add value to the broccoli-derived by-products, since recycling all this agrowaste to obtain bioactive ingredients for industry can boost profits and reduce costs and environmental problems.     

Seed Viability and Functional Properties of Broccoli Sprouts during Germination and Postharvest Storage as Affected by Irradiation of Seeds

ABSTRACT:  The viability of broccoli seeds and functional properties, such as ascorbic acid, carotenoid, chlorophyll, and total phenol contents, of broccoli sprouts grown from irradiated seeds were evaluated. The seeds were irradiated using electron beam and gamma ray at doses up to 8 kGy. High germination percentages (>90%) were observed in seeds irradiated at ≤4 kGy, but the yield ratio and sprout length decreased with increased irradiation dose. Irradiation at ≥6 kGy resulted in curling of the sprout roots. Germinated seeds contained higher amounts of nutrients than raw seeds but the nutritional quality of sprouts decreased during postharvest storage. Radiation treatment hampered the growth of irradiated seeds resulting in underdeveloped sprouts with decreased ascorbic acid, carotenoid, and chlorophyll contents. In addition, the decrease in functional content of sprouts was more substantial in samples grown from high-dose (5 kGy) irradiated seeds than that of the low-dose (1 kGy) treated ones. Seed irradiation did not negatively affect the total phenol content of sprouts. In general, electron beam and gamma irradiation of broccoli seeds showed similar effects on the viability and functional properties of sprouts.     

Glucosinolates in broccoli sprouts (Brassica oleracea var. italica) as conditioned by sulphate supply during germination

Sulphur (S) fertilization is essential for primary and secondary metabolism in cruciferous foods. Deficient, suboptimal, or excessive S affects the growth and biosynthesis of secondary metabolites in adult plants. Nevertheless, there is little information regarding the influence of S fertilization on sprouts and seedlings. An experiment was set up to evaluate the effect of S fertilization, supplied as K(2)SO(4) at 0, 15, 30, and 60 mg/L, on the glucosinolate content of broccoli sprouts during the germination course of 3, 6, 9, and 12 d after sowing. Glucosinolate concentration was strongly influenced by germination, causing a rapid increase during the first 3 d after sowing, and decreasing afterwards. The S supply increased aliphatic and total glucosinolate content at the end of the monitored sprouting period. S-treated sprouts, with S(15), S(30), and S(60) at 9 and 12 d after sowing presented enhanced glucosinolate content. Overall, both germination time and S fertilization were key factors in maximizing the bioactive health-promoting phytochemicals of broccoli. Practical Application: Germination with sulphate is a simple and inexpensive way to obtain sprouts that contain much higher levels of glucosinolates (health promoting compounds), than the corresponding florets from the same seeds.     

Antioxidant content of edible sprouts: effects of environmental shocks

BACKGROUND: Edible sprouts are thought to be rich in health‐promoting phytochemicals that are known to prevent a number of chronic and degenerative diseases. In mature plants, environmental shocks have been used to enhance health‐promoting phytochemicals. The primary objective of this study was to use environmental shocks involving high light and chilling in sprouts of alfalfa, broccoli and radish to improve their phenolic composition. RESULTS: Young sprouts had high total phenolic content and correspondingly high antioxidant capacity, both of which declined sharply with plant age. Exposure of sprouts to high light or chilling resulted in higher total phenolic content and antioxidant capacity compared with untreated controls. During recovery following shock treatments, high light produced a stronger response in increasing the levels of individual phenolic compounds. Alfalfa sprouts subjected to high light and chilling accumulated about 2.0 and 1.5 times significantly higher concentration of ferulic acid respectively, while high light induced 83% more sinapic acid in broccoli sprouts compared with untreated controls. Myricetin, while not detected in 5‐day‐old control or chilling‐treated radish sprouts, accumulated in response to high light. Environmental shocks did not adversely affect the dry biomass accumulation. CONCLUSION: Environmental shocks involving high light and chilling enhanced the antioxidant phenolic content in sprouts of alfalfa, broccoli and radish, suggesting that this approach can be successfully used to enhance the health‐promoting qualities of these sprouts. Copyright © 2009 Society of Chemical Industry     

Natural antioxidants and antioxidant capacity of Brassica vegetables: A review

Dietary antioxidants, such as water-soluble vitamin C and phenolic compounds, as well as lipid-soluble vitamin E and carotenoids, present in vegetables contribute both to the first and second defense lines against oxidative stress. As a result, they protect cells against oxidative damage, and may therefore prevent chronic diseases, such as cancer, cardiovascular disease, and diabetes. Brassica vegetables, which include different genus of cabbage, broccoli, cauliflower, Brussels sprouts, and kale, are consumed all over the world. This review focuses on the content, composition, and antioxidant capacity both lipid- and water-soluble antioxidants in raw Brassica vegetables. The effects of post-harvest storage, industrial processing, and different cooking methods on stability of bioactive components and antioxidant activity also are discussed.     

Basis for the new challenges of growing broccoli for health in hydroponics

BACKGROUND: Variations in the contents of phytochemicals with biological activity in broccoli could originate as a result of genetic and environmental factors. An understanding of the effects of growth conditions on the bioactive compounds in broccoli is essential for improving its quality and nutritive value. Using salinity (40 mmol L^?1 NaCl), and foliar sprayed compounds (methionine, tryptophan and chitosan) as different stress conditions, broccoli developed in soilless culture in the greenhouse was analysed for biologically active phytochemicals (glucosinolates, caffeoyl‐quinic, ferulic and sinapic derivatives and vitamin C). RESULTS: The application of elicitors during head formation could be beneficial for the enrichment in phytochemicals in broccoli. Management practices for increasing a given phytochemical (e.g., glucoraphanin or glucobrassicin) may be related to a decreased level of natural antioxidants (hydroxycinnamic acids). Growing broccoli hydroponically in the greenhouse in winter (Mediterranean climate) needs the supporting treatment of abiotic stress during development (i.e., NaCl, elicitors). CONCLUSION: The use of hydroponic growth conditions for broccoli and the application of stress factors (elicitors) at head induction and during development may serve the purpose of enhancing its nutritional quality to deliver a health‐promoting food. Copyright © 2008 Society of Chemical Industry     

Influence of high-intensity pulsed electric field processing parameters on antioxidant compounds of broccoli juice

The effect of high-intensity pulsed electric field (HIPEF) processing parameters (electric field strength, treatment time, and polarity) on broccoli juice carotenoids, vitamin C, total phenolic (TP) content and antioxidant capacity (AC) was evaluated. Results obtained from HIPEF-processed broccoli juice were compared with those of thermally treated (90 °C/60 s) and untreated juices. HIPEF processing parameters influenced the relative content (RC) of bioactive compounds, and the relative AC (RAC). Maximum RC of lutein (121.2%), β-carotene (130.5%), TP (96.1%), vitamin C (90.1%) and RAC (5.9%) was reached between 25 and 35 kV/cm and from 2000 μs to 500 μs. The highest RAC and RC of bioactive compounds were observed in HIPEF treatments applied in bipolar mode, except for vitamin C. HIPEF-treated broccoli juice exhibited greater RC of bioactive compounds and RAC than juice treated by heat. HIPEF technology could be considered a promising option for preserving the antioxidant quality of broccoli juice.Industrial relevanceVegetable juices are becoming more and more popular because of their wide range of health-related compounds. Particularly, broccoli juice is attracting the food industry attention because it contains high amounts of vitamins, carotenoids and phenolic compounds, among other bioactive compounds. Broccoli juice requires treatment conditions that protect its microbial, nutritional and sensorial quality. HIPEF is a non-thermal technology for liquid food preservation that inactivates microorganisms and enzymes without compromising the nutritional and sensorial features of foods. Consequently, this technology could be used in the food industry as an alternative for thermal treatment to preserve the bioactive compounds present in vegetable juices, offering to consumers a healthy product.     

Effect of climatic and sulphur fertilisation conditions,on phenolic compounds and vitamin C,in the inflorescences of eight broccoli cultivars

Flavonoids, hydroxycinnamoyl derivatives (sinapic and ferulic acid derivatives+caffeoyl-quinic acid derivatives) and vitamin C were quantified by HPLC-MS in five commercial and three experimental cultivars from freshly harvested broccoli inflorescences ( Brassica oleracea L. var. italica). In order to identify differences due to genetic and agronomic factors, the broccoli cultivars were grown under different climatic and agronomic conditions, i.e. early (winter) and late (spring) seasons with poor (15 kg/ha) and rich (150 kg/ha) sulphur fertilisation. The predominant sinapic and ferulic acid derivatives in all broccoli cultivars were 1,2-diferuloylgentiobiose, 1,2,2'-trisinapoylgentiobiose and 1,2'-disinapoyl-2-feruloylgentiobiose. In addition, the compounds 1,2-diferuloylgentiobiose, 1-sinapoyl-2,2'-diferuloylgentiobiose and 1,2,2'-triferuloylgentiobiose were identified in broccoli inflorescences for the first time. Extreme agronomic and environmental conditions (late season and rich sulphur fertilisation which could induce different stress situations on the plant) enhanced the phenolic content. Thus, total flavonoids showed the highest content, followed by total sinapic and feruloyl acid derivatives and total caffeoyl-quinic acid derivatives. In general, cultivars grown under rich fertilisation and late season conditions showed higher vitamin C content than those grown under the poor and early ones. Finally, results showed that commercial cultivars rendered higher amounts of phenolic compounds and vitamin C than the experimental ones.     

不同采后处理对青花菜功能成分和品质的影响

青花菜富含维生素C和芥子油苷等抗癌功能成分,是一种世界范围的重要蔬菜。青花菜的食用部分为花球,呼吸非常旺盛,易衰老黄化,是一种非常难贮藏的蔬菜,采后过程中容易造成营养和品质的下降,研究不同采后处理对青花菜功能成分和品质的影响,不仅在采后生理研究领域有较大的意义,而且对青花菜产业有重要指导作用。本文结合国内外研究报道,分析了冷藏、气调、薄膜包装、乙烯抑制剂1-甲基环丙烯处理和光处理等采后处理方式对采后青花菜产品功能成分和品质的影响,从芥子油苷等功能成分生物合成和代谢的角度解析了可能的机制,在此基础上全面总结和评价青花菜各种采后处理方法,并对该领域未来研究方向及其应用前景进行了展望。     

Potential bioactive compounds in health promotion from broccoli cultivars grown in Spain

Glucosinolates, phenolic compounds and vitamin C were evaluated in two commercial and 12 experimental cultivars of broccoli (Brassica oleracea L var italica) grown under uniform cultural conditions. The predominant glucosinolates in all broccoli cultivars were 4‐methylsulphinylbutyl glucosinolate (glucoraphanin) and 3‐indolylmethyl glucosinolate (glucobrassicin). Other glucosinolates such as 4‐OH‐glucobrassicin and N‐methoxyglucobrassicin were detected in lower amounts. The total glucosinolate concentration ranged from 3.0 µmol g^?1 dw (dry weight) in Pentathlon (experimental cultivar) to 28.3 µmol g^?1 dw in I‐9905 (experimental cultivar). Flavonoids, caffeic acid derivatives and sinapic acid derivatives were quantified in methanol extracts. The largest content of flavonoids was found in the commercial cultivars Marathon and Lord, around 60 mg kg^?1 fw (fresh weight). The vitamin C content of broccoli ranged from 43.1 mg per 100 g fw in Lord (commercial cultivar) to 146.3 mg per 100 g fw in SG‐4515 (experimental cultivar). © 2002 Society of Chemical Industry     

等离子体处理对西兰花芽苗生产及活性物质含量的影响

为实现西兰花芽苗中萝卜硫素、多酚、黄酮等生物活性物质的富集,以此来降低生产成本,本研究采用等离子体处理诱导方法,研究等离子体处理条件对不同品种西兰花芽苗生长和活性物质的影响。结果显示:等离子体处理电压、时间对西兰花芽苗发芽状态及活性物质含量都有显著影响（P<0.05）,在电压30 kV,处理时间2 min条件下,西兰花芽苗发芽5 d后发芽率、芽长、芽重较对照都有显著增加,萝卜硫素含量达到3.24 mg/g DW,较未处理提高了6.75倍。不同品种西兰花芽苗中萝卜硫素、总酚、总黄酮含量及抗氧化活性存在显著差异（P<0.05）,其中马尼拉的萝卜硫素和总硫苷含量最高,而曼陀绿和绿玉的总酚和总黄酮含量最高。等离子体处理后文兴、马尼拉、绿玉和绿剑的总酚和总黄酮含量及抗氧化能力较对照处理均有所提高。综上,西兰花芽苗经等离子体处理是富集萝卜硫素的有效方式,可显著提升芽苗功效并降低萝卜硫素获取成本。     

Development of a Novel Functional Soup Rich in Bioactive Sulforaphane Using Broccoli (Brassica oleracea L. ssp. italica) Florets and Byproducts

Broccoli florets are rich in health-promoting compounds such as glucoraphanin, the precursor of the bioactive compound sulforaphane. In addition, broccoli byproducts such as stalk also contain health-promoting compounds and represent attractive ingredients in the development of functional foods. The bioconversion of glucosinolates into bioactive isothiocyanates is affected by many factors including heat and therefore cooking of Brassica such as broccoli may result in significant loss of sulforaphane production. The aim of this study was to develop a suitable food system as a vehicle for the delivery of sulforaphane in the human diet in adequate quantities. To this end, the feasibility of dry-mix ready soup as a food matrix for the delivery of broccoli floret and byproducts was evaluated. In particular, this study investigated the bioconversion of glucosinolates into bioactive isothiocyanates during the cooking process of this novel food product by microwave heating. In addition to total isothiocyanate and sulforaphane content, other key physical and biochemical quality attributes of the broccoli floret- and byproduct-enriched soups were investigated. Total isothiocyanate and sulforaphane content in floret- and stalk-enriched soups was high in both cases and increased in the order stalk<floret. The overall acceptability of stalk containing soups was not significantly different compared with the control soups, whereas floret containing soups received significantly lower acceptability scores. These results suggest that ready soups prepared by microwave heating represent a feasible food product for the delivery of broccoli florets and byproducts which is compatible with the bioconversion of glucosinolates into bioactive isothiocyanates.     

Time dependence of bioactive compounds and antioxidant capacity during germination of different cultivars of broccoli and radish seeds

Optimisation of the germination process of different cultivars of broccoli (Brassica oleracea var. italica cv. Lucky, cv. Tiburon and cv. Belstar) and radish (Raphanus sativus cv. Rebel and cv. Bolide) seeds in relation to the content of glucosinolates (GLS), vitamin C and total antioxidant capacity was carried out in order to maximise the health-promoting properties of Brassica sprouts. The content of total and individual GLS varied between species, among cultivars, and germination time. Glucoraphanin in broccoli and glucoraphenin in radish were the predominant GLS in raw seeds (61–77 and 63–129 μmol/g DM, respectively) and, although their content decreased during germination, they were maintained in rather large proportions in sprouts. Vitamin C was not detected in raw seeds and its content increased sharply in broccoli and radish sprouts (162–350 and 84–113 mg/100 g DM, respectively). Raw brassica seeds are an excellent source of antioxidant capacity (64–90 and 103–162 μmol Trolox/g DM in broccoli and radish, respectively) and germination led to a sharp increase. Germination of broccoli cv. Belstar and radish cv. Rebel for 4 days provided the largest glucoraphanin and glucoraphenin content, respectively, and also brought about large amounts of vitamin C and antioxidant capacity.     

Analysis of phenolic compounds and isoflavones in soybean seeds (Glycine max (L.) Merill) and sprouts grown under different conditions

Soybeans (Glycine max (L.) Merill) are popularly known as a healthy food in many Asian countries and are mostly consumed as soymilk, tofu, and fermented products such as miso, temph, and sufu. The objective of this study was to determine the variation and composition of phenolic compounds and isoflavone contents in soybean seeds [Glycine max (L.) Merill] and sprouts [Kongnamul] grown under dark conditions (producing yellow soybean sprouts) and in green and yellow boxes (producing green soybean sprouts). In seven soybean cultivars, the total phenolic content ranged from 6.67 μg⁻¹ in Pureunkong to 72.33 μg⁻¹ in Poongsannamulkong. The average total phenolic content in the green soybean sprouts (48.33 μg⁻¹) was higher than in the yellow soybean sprouts (29.75 μg⁻¹). The total phenolic content in the yellow soybean sprouts varied from 9.88 μg⁻¹ to 47.71 μg⁻¹, and the total phenolic content in the green soybean sprouts varied from 29.21 μg⁻¹ to 79.70 μg⁻¹. Only four phenolic compounds, p-hydroxybenzoic acid, salicylic acid, p-coumaric acid, and ferulic acid, were detected in all soybean cultivars. Syringic acid was not detected in yellow soybean sprouts, and myricetin was only detected in yellow soybean sprouts (4.65 μg⁻¹) from the Pureunkong cultivar grown under dark conditions. The total isoflavone content in soybean seeds ranged from 2.1 μg⁻¹ in Sowonkong to 33.0 μg⁻¹ in Pureunkong, and the mean total isoflavones was 10.61 μg⁻¹. Green soybean sprouts had higher average total isoflavones (1389.4 μg⁻¹) than yellow soybean sprouts (559.2 μg⁻¹), and the total isoflavone content was highest in the Pureunkong yellow soybean sprouts (756.3 μg⁻¹) and the Sowonkong green soybean sprouts (2791.6 μg⁻¹). In soybean sprouts, the higher the (malonyl)-daidzin or (malonyl)-genistein content, the higher the total isoflavone level. Our study suggests that producing soybean sprouts enriched in isoflavones under coloured-light sources is feasible.