The effect of the germination temperature on the phytochemical content of broccoli and rocket sprouts

Formation, immunomodulatory activities, and enhancement of glucosinolates and sulforaphane in broccoli sprouts: a review for maximizing the health benefits to human

Broccoli sprouts have been considered as functional foods which have received increasing attention because they have been highly prized for glucosinolates, phenolics, and vitamins in particular glucosinolates. One of hydrolysates-sulforaphane from glucoraphanin is positively associated with the attenuation of inflammatory, which could reduce diabetes, cardiovascular and cancer risk. In recent decades, the great interest in natural bioactive components especially for sulforaphane promotes numerous researchers to investigate the methods to enhance glucoraphanin levels in broccoli sprouts and evaluate the immunomodulatory activities of sulforaphane. Therefore, glucosinolates profiles are different in broccoli sprouts varied with genotypes and inducers. Physicochemical, biological elicitors, and storage conditions were widely studied to promote the accumulation of glucosinolates and sulforaphane in broccoli sprouts. These inducers would stimulate the biosynthesis pathway gene expression and enzyme activities of glucosinolates and sulforaphane to increase the concentration in broccoli sprouts. The immunomodulatory activity of sulforaphane was summarized to be a new therapy for diseases with immune dysregulation. The perspective of this review served as a potential reference for customers and industries by application of broccoli sprouts as a functional food and clinical medicine.

High Growing Temperature Changes Nutritional Value of Broccoli (Brassica oleracea L. convar. botrytis (L.) Alef. var. cymosa Duch.) Seedlings

High temperature (HT) causes physiological and biochemical changes in plants, which may influence their nutritional potential. This study aimed to evaluate the nutritional value of broccoli seedlings grown at HT on the level of phytochemicals, macro- and microelements, antioxidant capacity, and their extracts' in vitro cytotoxicity. Total phenols, soluble sugars, carotenoids, quercetin, sinapic, ferulic, p-coumaric, and gallic acid were induced by HT. Contrarily, total flavonoids, flavonols, phenolic acids, hydroxycinnamic acids, proteins, glucosinolates, chlorophyll a and b, and porphyrins were reduced. Minerals As, Co, Cr, Hg, K, Na, Ni, Pb, Se, and Sn increased at HT, while Ca, Cd, Cu, Mg, Mn, and P decreased. ABTS, FRAP, and β-carotene bleaching assay showed higher antioxidant potential of seedlings grown at HT, while DPPH showed the opposite. Hepatocellular carcinoma cells were the most sensitive toward broccoli seedling extracts. The significant difference between control and HT-grown broccoli seedling extracts was recorded in mouse embryonal fibroblasts and colorectal carcinoma cells. These results show that the temperature of seedling growth is a critical factor for their nutritional value and the biological effects of their extracts and should definitely be taken into account when growing seedlings for food purposes.

Bioactive Compounds and Antioxidant Properties of Wild Rocket (Diplotaxis Tenuifolia L.) Grown under Different Plastic Films and with Different UV-B Radiation Postharvest Treatments

Rocket species are rich in nutrients with well-known bioactive activity, but their content depends on several factors, such as plant-UV radiation interaction. In this work, we measured the production of nutritional elements in wild rocket (Diplotaxis tenuifolia L.) leaves as a function of exposure to UV-B radiation by adopting a combined approach. The wild rocket plants were grown under three greenhouse cover films (A, B, and C) having different transmittivity to UV-B and the fresh-cut leaves were exposed to UV-B in postharvest for 45, 150, 330, and 660 s. The content of chlorophyll, carotenoids, phenolic compounds, ascorbic acid, and the antioxidant activity were determined. Chlorophyll, carotenoids, and total phenolic content were significantly increased by the combination of Film C and treatment with UV-B for 45 s. The predominant phenolic compounds were kaempferol, isorhamnetin, and quercetin. Film C also elicited an increase in ascorbic acid (the most abundant antioxidant compound in the range 374-1199 per 100 g of dry matter) and antioxidant activity. These findings highlighted an increase in bioactive compound content in the wild rocket when it was cultivated under Film C (diffused light film with a tailored UV-B transmission dose) and treated with UV-B radiation for 45 s postharvest, corresponding to an energy dose of 0.2 KJ m^-2.

Thermosonication of Broccoli Florets Prior to Fermentation Increases Bioactive Components in Fermented Broccoli Puree

The aim of this study was to compare the effects of thermosonication (18 kHz at 60 °C for 7 min) pre-treatment with thermal treatment alone (60 °C for 7 min) of broccoli florets prior to pureeing and fermentation on selected bioactive components of fermented broccoli puree. Both thermal and thermosoncation pre-treatments significantly increased the rate of acidification of broccoli puree compared to control untreated broccoli puree, with the time to reach pH 4 being 8.25, 9.9, and 24 h, respectively, for thermally treated, thermosonicated, and control samples. The highest sulforaphane yield of 7268 µmol/kg dry weight (DW) was observed in the thermosonicated samples, followed by 6227 µmol/kg DW and 3180 µmol/kg DW in the thermally treated and untreated samples, respectively. The measurable residual glucoraphanin content was 1642 µmol/kg DW, 1187 µmol/kg DW, and 1047 µmol/kg DW, respectively, in the thermonsonicated, thermally pre-treated, and control fermented samples, indicating that pre-treatment specially by thermosonication increases the extractability of glucoraphanin. The higher sulforaphane yield in the thermosonicated and thermally pre-treated samples could be due to increased extractability and accessibility of glucoraphanin and interaction with myrosinase in addition to the inactivation of epthiospecifier protein (ESP), which directs conversion away from sulforaphane into sulforaphane nitrile.

Packaging With Different Color Bags Under Light Exposure Improves Baby Mustard (Brassica juncea var. gemmifera) Postharvest Preservation

Effect of packaging baby mustard into bags of different color under light exposure on its visual quality and the content of chlorophyll, carotenoids, and glucosinolates at 20°C was investigated. Packaging with seven color bags under light exposure prolonged the shelf life, especially green (GB), blue (BB), and transparent (TB) bags with holes, and their shelf life was 1.7, 1.6, and 1.6 times that of the control, respectively. The GB and BB treatments delayed the deterioration of the sensory quality in baby mustard during storage. The BB and TB treatments not only increased chlorophyll and carotenoids content in baby mustard during storage but also enhanced the accumulation of glucosinolates by inhibiting their degradation, especially the BB treatment. Overall, the results demonstrate that the BB treatment is a promising technique for maintaining the postharvest quality of baby mustard.

Environmental Conditions and Agronomical Factors Influencing the Levels of Phytochemicals in Brassica Vegetables Responsible for Nutritional and Sensorial Properties

Recently, the consumption of healthy foods has been related to the prevention of cardiovascular, degenerative diseases and different forms of cancers, underlying the importance of the diet for the consumer’s health. Fruits and vegetables contain phytochemicals that act as protective factors for the human body, through different mechanisms of action. Among vegetables, Brassica received a lot of attention in the last years for the phytochemical compounds content and antioxidant capacity that confer nutraceutical value to the product. The amount of healthy bioactive compounds present in the Brassica defines the nutritional quality. These molecules could belong to the class of antioxidant compounds (e.g., phenols, vitamin C, etc.), or to non-antioxidant compounds (e.g., minerals, glucosinolates, etc.). The amount of these compounds in Brassica vegetables could be influenced by several factors, depending on the genotypes, the environmental conditions and the cultivation techniques adopted. The aim of this study is to highlight the main phytochemical compounds present in brassicas used as a food vegetable that confer nutritional and sensorial quality to the final product, and to investigate the main factors that affect the phytochemical concentration and the overall quality of Brassica vegetables.

Potential of Germination in Selected Conditions to Improve the Nutritional and Bioactive Properties of Moringa (Moringa oleifera L.)

Moringa oleifera L. is greatly appreciated for its high content of phytochemicals. Although most parts of moringa tree have been widely studied, seeds remained scarcely explored. The first goal of this study was to investigate the effectiveness of germination to improve the nutritional composition (proximate composition and levels of vitamins B1 and B2), content of bioactive compounds (glucosinolates, phenolics and γ-aminobutyric acid, GABA) and antioxidant activity of moringa seed. Germination improved protein, fat, fiber, riboflavin, phenolics, some individual glucosinolates (GLS) and GABA contents, as well as the antioxidant potential in moringa sprouts, but the extent of the improvement depended on germination conditions. The second objective of this work was to identify the optimal germination conditions to maximize nutritional and bioactive quality of moringa by applying multi-response optimization (response surface methodology, RSM). RSM models indicated that 28 °C and 24 h were the optimal conditions to enhance the accumulation of riboflavin, phenolics and antioxidant activity of sprouts, while the highest GABA and total GLS contents were observed at 36 °C for 96 h and thiamine achieved the maximum content at 36 °C for 24 h. These results show that moringa sprouts are promising functional foods that might be also used as ingredients for the elaboration of novel foodstuffs.