Effects of abscisic acid on glucosinolate content,isothiocyanate formation and myrosinase activity in cabbage sprouts

Effects of abscisic acid (ABA) on glucosinolate content, isothiocyanate formation and myrosinase activity in cabbage sprouts were investigated. Subsequently, their distributions in different organs were evaluated. ABA (50 μmol L^?1) significantly increased glucosinolate content, isothiocyanate formation and myrosinase activity by 72.65%, 268.15% and 67.69%, respectively, in 5‐day‐old sprouts. Application of ABA alleviated the decrease rate of glucosinolate content and increased the myrosinase activity during germination. Besides, isothiocyanate formation rapidly increased after germinating for 3 days. The glucosinolate content and isothiocyanate formation reduced by 46.51% and 38.01%, respectively, in fluridon (Flu)‐treated sprouts. Cotyledon of ABA‐treated sprouts had the highest glucosinolate content and isothiocyanate formation, indicating that ABA was necessary to enhance the isothiocyanate formation in cabbage sprouts by increasing glucosinolate content and myrosinase activity.     

Mycetozoal bloom in a hydroponic culture of garden cress (Lepidium sativum L.)

The role and importance of the true slime moulds (mycetozoans, Mycetozoa, formerly Myxomycetes) for agriculture and food industry are poorly documented, most probably because of a low popularity of these “macroscopic microorganisms” among researchers in the past. Here we report probably for the first time the massive occurrence of true slime moulds in their vegetative, plasmodial form in a product intended for direct consumption, i.e. in a household hydroponic culture of garden cress (Lepidium sativum L.). The plasmodia gradually produced numerous, stalked or sessile sporangia and plasmodiocarps, which made it possible to identify them as Didymium species complex (the stalked sporangia) and Didymium difforme (Pers.) Gray (the sessile sporangia and plasmodiocarps). The mycetozoans were transferred to in vitro culture where they were maintained for several weeks on oat flour. We briefly discuss the importance of this observation from the point of view of biochemical interactions between the plant and the true slime moulds in a general context of slime mould biology. Our observation indicates that the presence of mycetozoan material in food products may be frequent, while its influence on food safety and quality remains unknown.     

Changes in saccharide,amino acid and S‐methylmethionine content during malting of barley grown with different nitrogen and sulfur status

BACKGROUND: Changes in saccharide, amino acid and S‐methylmethionine (SMM) concentrations and enzyme activities during the malting of barley grown with different nitrogen (N) and sulfur (S) supplementation were investigated in order to clarify their relationship with N and S fertiliser levels. RESULTS: Concentrations of N and S in barley grain were significantly increased by the addition of N to the culture soil. Application of N decreased the starch concentration in grain. On the other hand, higher N fertilisation increased the β‐glucan concentration in grain and malt, thus decreasing the accessibility of β‐glucanase to its substrates. Proteolytic enzyme activity was significantly higher in the absence (?N treatment) than in the presence (+N treatment) of N fertiliser, making the concentration of the majority of amino acids in malt slightly higher in the ? N treatment. SMM was synthesised in grain after imbibition, and application of N increased the SMM content in malt. CONCLUSION: Although SMM can be controlled to a certain extent during kilning, a balanced supply of N and S during cultivation can also be helpful for the production of malt with lower SMM concentration. Adequate soil management is desirable to maintain the balance between good agronomic performance and high malt quality. Copyright © 2010 Society of Chemical Industry     

Influence of nitrogen and sulphur on the glucosinolate profile of rapeseed (brassica napus l)

Clear influence of N and S applications on the profile of individual glucosinolates in the seeds of winter oilseed rape (Brassica napus L) was found in field experiments. The major effect of N was on the relative abundance of the four alkenyl glucosinolates. Increasing the N rate increased the relative proportion of 2-hydroxybut-3-enyl at the expense of pent-4-enyl, and to a lesser extent, 2-hydroxypent-4-enyl, in the double-low (low erucic acid and low glucosinolates) variety Cobra, but at the expense of but-3-enyl in the single-low (low erucic acid) variety Bienvenu. The results strongly suggest that a high N supply favours the hydroxylation step from but-3-enyl to 2-hydroxybut-3-enyl. In contrast, the major effect of S appeared to be on the relative abundance of the alkenyl and indole groups as a whole. Sulphur deficiency decreased the concentrations of the alkenyl glucosinolates more than those of the indole glucosinolates, whereas S application to a S-deficient crop resulted in a larger response in the alkenyl group than in the indole group. The more sensitive response of alkenyl glucosinolates to the plant S status is probably due to the requirement of methionine in their biosynthesis, as compared with the indole glucosinolates which are derived from tryptophan. Implications for changes in the glucosinolate profile in rapeseed are discussed.     

Interaction between nitrogen and sulfur by foliar application and its effects on flour bread‐making quality

BACKGROUND: Optimization of nitrogen (N) and sulfur (S) nutrition of wheat influences the bread‐making quality of grain. This study was conducted to determine whether the application of N and S in winter wheat at anthesis stage during two field trials could influence the absorption and distribution of N and S in grain and flour bread‐making quality RESULTS: The incorporation of ¹⁵N and ³⁴S tracers in various plant parts (leaves, stems, spikes) was determined by isotopic ratio mass spectrometry coupled with an elemental analyser (EA‐IRMS). The effects of foliar fertilization on percentage of ¹⁵N and ³⁴S recovery in various plant parts, grain yield, flour protein content, and dough properties were investigated after a combination of treatments: N (urea), S (micronized elemental S) and NS (both urea and micronized elemental S). Nitrogen (70–80%) and S (35–55%) were quickly assimilated during the days following application. Sixty days after application, 42–68% N and 6–12% S were recovered in the grain. When N and S fertilizers were applied simultaneously, N and S recoveries (68% and 12%), N/S ratios (11–14), flour protein content (115 g kg^?1) and dough strength (310 × 10^?4 J), swelling (21.8 mmH₂O) and extensibility (96.4 mm) were increased. CONCLUSION: A synergistic effect between the foliar applied N and S fertilizers appears to increase N and S assimilation in grain and may improve bread‐making qualities. Copyright © 2007 Society of Chemical Industry     

Comparative effects of sulfur and nitrogen fertilization and post‐harvest processing parameters on the glucotropaeolin content of Tropaeolum majus L.

Under natural conditions, the content of the bioactive compound glucotropaeolin in the vegetative tissue of Tropaeolum majus is too low to be used directly for the preparation of a mono‐drug. In the present study the influence of sulfur and nitrogen fertilization and the post‐harvest drying procedure on the glucotropaeolin content was evaluated in order to minimize losses of the active glucosinolate. In 2001, field experiments with three levels of nitrogen and sulfur fertilization were conducted on two different sites. Nitrogen fertilization had no consistent influence on the glucotropaeolin content while sulfur fertilization with 100 kg S ha^?1 enhanced the glucotropaeolin content in leaves and seeds significantly by factors of 1.4–2.1 and 1.6–1.8, respectively. The results of the post‐harvest treatment showed that a gentle drying procedure at 40°C in a ventilated oven induced an increase in the glucotropaeolin content in leaves of 1.4–3.2‐fold (from 10.7–25.5 to 30.9–44.6 µmol g^?1 dry weight) compared to sampling in liquid nitrogen followed by freeze‐drying of the samples. This paper delivers new insights into glucosinolate metabolism that will contribute significantly not only to warrant a high content of bioactive compounds in medicinal plants, but also to promote glucosinolate concentrations in various crops by appropriate post‐harvest treatments. Copyright © 2007 Society of Chemical Industry     

Effect of foliar nitrogen and sulfur on petit manseng (Vitis vinifera L.) grape composition

Vineyard applications of foliar nitrogen (N) and sulfur were evaluated in the Yadkin Valley of North Carolina in 2011 and 2012 as a means to modify grape composition of Vitis vinifera cv. petit manseng. Four treatments were applied each year in a randomized complete block design with six replicates of six vines each: untreated control, soil N at 30?kg/ha, foliar N at 15?kg/ha and foliar N at 15?kg/ha plus sulfur at 5?kg/ha. Fruit ammonia and yeast assimilable nitrogen (YAN) concentrations increased in foliar-treated vines both seasons compared to control vines. Total glycosides (TGGs) increased ～80% in foliar N/sulfur-treated vines compared to control vines in 2011, and TGGs increased ～157% in foliar N/sulfur-treated vines relative to glycoside level in foliar N alone in 2012. Foliar N and foliar N/sulfur applications increased the majority of amino acid concentrations analyzed in 2011. Measured concentrations of various amino acids, partly responsible for aroma and flavor of petit manseng wines, were differentially dependent on the method of N application. Foliar applied nitrogen may be an effective technique to contribute to berry composition optimization of petit manseng grown in a warm, humid climate.     

Nitrogen fertilisation in coriander (Coriandrum sativum L.): a review and meta‐analysis

Nitrogen (N) fertilisation is one of the most important external inputs in assessing coriander seed yield and plant growth. Recent concerns related to the misuse of N fertilisers in agricultural environments, however, stress the opportunity for a fine‐tuning of N management in order to optimise the use of this element, avoiding losses and reducing environmental hazards. In this study, some results from the literature concerning N fertilisation in coriander are reviewed and, by means of statistical analysis, an attempt is made to derive from them some general suggestions about practices of N fertilisation. In most cases examined, N fertilisation allowed a 10–70% increase in seed yields in comparison with each respective untreated control. The efficiency of use of this element, however, has proven to be greatly dependent on the overall fertility conditions of the growing site. The greatest yield advantages were actually found in more favourable environments, whereas in low‐yielding environments plants reached their maximum yield with a comparatively reduced N supply. In low‐yielding environments a careful risk/benefit assessment of this practice is therefore advisable. No definite conclusion could be drawn at this stage about essential oil yield and composition in relation to N fertilisation. Copyright © 2009 Society of Chemical Industry     

The effect of pH,salts and sugars on the rheological properties of cress seed (Lepidium sativum) gum

Effect of shear rate (15–600 s^?1), gum concentration (1–2%), pH (3–9), sucrose (10–40%), lactose (5–15%), NaCl (100–300 mm ) and CaCl₂ (5–50 mm ) was evaluated on apparent viscosity (η_a), flow behaviour index (n), consistency coefficient (K) and yield stress (τ₀) indices of cress seed gum (CSG) solutions. Different rheological models were used to fit the experimental data, although the Herschel–Bulkley model was found the best model. An increase in gum concentration led to an increase in τ₀, η_a, and k and a decrease in n values. The addition of salts lowered the k value; however, the n value showed slight significant change. The presence of sugar resulted in the enhancement of n, k, τ₀ and η_ap values. The existence of yield stress and pseudoplastic behaviour of CSG, its stability against salts, wide range of pH and synergic effect of sugar make it a good thickener and stabiliser in food formulations.     

Effects of timing and rate of N supply on leaf nitrogen status, grape yield and juice composition from Shiraz grapevines grafted to one of three different rootstocks

Yeast cells have a minimum N requirement to ferment a must through to dryness, so that grape N content (hence must N) becomes critical in meeting that prerequisite. Viticultural practices aimed at meeting that N requirement are of special relevance because interactions between rootstock and vineyard nitrogen supply strongly influence scion mineral nutrient status as well as shoot vigour, and via those processes, fruit composition. Such outcomes were investigated in a field trial involving Shiraz on three rootstocks viz. Teleki 5C, Schwarzmann and Ramsey. Five N supply regimes, varying from 0 to 80 kg/(haseason), were imposed through a drip-irrigation system during two periods (either flowering to veraison, or post-harvest to leaf-fall, or both) over three successive growing seasons. Post-harvest N supply increased scion leaf N and nitrate N concentrations at flowering for vines on Teleki 5C and Schwarzmann. By veraison, N recently applied in the flowering to veraison period elevated these indicators of N status in all vines on all rootstocks. Grape yields from vines on Teleki 5C and Schwarzmann were elevated by N supply after harvest, whereas juice soluble solids levels were lowered. Free amino acids in Shiraz juice were dominated by non-assimilable N, amounting to about 50% or more of the total free amino-N in the juice. Increasing N supply increased free amino acid concentrations in the juice of berries from vines on all rootstocks, but only vines on Schwarzmann derived any benefit from N supplied after harvest. The highest concentrations of free amino acids were measured in the berries from vines on Schwarzmann receiving 80 kg N/(ha.season). Of immediate practical relevance for N management of Shiraz grapevines on either Teleki 5C or Ramsey rootstocks, the minimum value for assimilable free amino-N concentration required to ferment a must through to dryness was not achieved if vineyard N application was limited to the post-harvest period.     

Effect of N-acetyl-cysteine on liposomal and muscle model oxidation induced by reactive oxygen, nitrogen, and sulfur

N-acetyl-cysteine (NAC), a naturally occurring thiol, is found in some fruits and vegetables, sometimes in concentrations higher than glutathione. The objective of this research was to determine the antioxidative effect of NAC in liposomal and muscle models challenged by different oxidizing systems, three that produce reactive oxygen species, two that produce reactive nitrogen species, and two that produce reactive sulfur. The antioxidative effect of cysteine and NAC was compared in the liposomes and NAC and BHT were compared in the muscle homogenates. Lipid hydroperoxides (LOOH), TBARS, and sulfydryls (protein and non-protein) were analyzed. Results indicated that NAC is a more effective inhibitor of lipid oxidation in systems induced by free radicals and reactive nitrogen than those that are induced by peroxides. NAC appears to be at least mildly antioxidative in both liposomal and muscle models, although it did not completely inhibit oxidation in liposomes and generally was not as effective as BHT in the muscle models.     

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     

Influence of colour type and previous cultivation on secondary metabolites in hypocotyls and leaves of maca (Lepidium meyenii Walpers)

BACKGROUND: Maca is an Andean crop of the Brassicaceae family which is mainly known for its fertility‐enhancing properties following consumption. The hypocotyls display various colours ranging from white to black. Each colour has different biological effects. The aim of this study was to analyse the concentrations of major secondary metabolites in hypocotyls and leaves of maca in a controlled planting experiment in the Peruvian Andes at 4130 m above sea level. The effects of colour type and of previous cultivation of the field were examined. RESULTS: In the hypocotyls, the colour type effect was significant for most secondary metabolites; exceptions were β‐sitosterol and campesterol. The lead‐coloured, yellow and violet maca hypocotyls were rich in glucosinolates, macaene and macamides, respectively. Previous cultivation affected macaene, campesterol and indole glucosinolate concentrations. Effects on metabolite concentrations in the leaves were minor. Hypocotyls were richer in macaene, macamides and glucosinolates than were leaves, and were poorer in β‐sitosterol and total phenols. CONCLUSION: Colour type has to be considered in maca production, as colour associates with variations in concentrations of distinct bioactive metabolites. Leaves may be interesting for animal nutrition purposes as they contain essentially the same secondary metabolites as the hypocotyls but in clearly lower concentrations. Copyright © 2010 Society of Chemical Industry     

Effects of parity and supply of rumen-degraded and undegraded protein on production and nitrogen balance in Holsteins

Eight Holstein cows (4 primiparous and 4 multiparous) were used in a replicated 4 × 4 Latin square design to determine milk production response and N balance when diets had no NRC-predicted excess of rumen-undegradable protein (RUP) or rumen-degradable protein (RDP), 10% RUP excess, 10% RDP excess, or 10% excess of both RUP and RDP. Diets were fed as a total mixed ration with (dry matter basis) 25% alfalfa silage, 25% corn silage, 19 to 21% corn grain, and varying proportions of solvent soybean meal and expeller soybean meal as primary sources of supplemental RDP and RUP, respectively. Milk yield and dry matter intake (DMI) were recorded daily, and total collection of feces and urine was completed in the last 3 d of each 21-d period. Dietary crude protein averaged 17.5 and 18.5% for the recommended and excess RDP diets, respectively, and 17.3 and 18.4% for the recommended and excess RUP diets, respectively. When cows were fed excess RUP diets in the form of expeller soybean meal, DMI and milk production increased, but the opposite was true when the diets contained excess RDP in the form of solvent soybean meal. Milk composition was not affected by RDP, RUP, or by parity, and there were no parity × RDP interactions for any of the measurements. However, apparent digestibility of neutral detergent fiber, dry matter, and N increased in multiparous cows but not in primiparous cows because of excess RUP. The increase in the yield of milk N with excess RUP was not influenced by parity, but multiparous cows retained more of the additional N apparently absorbed, whereas primiparous cows excreted the additional apparently absorbed N in the urine. Overall, the difference in urinary N due to parity (70 g/d) was about 4 times greater than the impact of dietary treatments (17 g/d). Our results suggest that multiparous cows have either a much larger urea pool or a greater demand to restore body protein mobilized earlier in lactation compared with primiparous cows. Reduction in urinary N excretion in commercial dairy herds could be obtained by separately balancing rations for first and later lactations.     

Influence of nitrogen fertilizer application rate on winter wheat (Triticum aestivum L.) flour quality and Chinese noodle quality

BACKGROUND: Understanding wheat flour noodle quality responses to N management will improve the quality of recommendations made to growers for specific end‐uses. Two winter wheat cultivars, with six N rates, planted during the course of a 2‐year experiment were used to determine the effect of N application rate on Chinese white noodle quality. RESULTS: Wheat flour protein content, development time (DT) and stability time (ST) increased with N application rate, maximal at 360 kg N ha^?1 and decreasing thereafter. When the N fertilizer application rate changed from 0 to 270 or 360 kg N ha^?1, redness (a*) and yellowness (b*) of both flour and noodle increased, while brightness (L*) decreased. The hardness and chewiness of cooked noodles improved at lower N application rate and degenerated at higher N rate. CONCLUSION: A low rate of N fertilizer application (from 0 to 270 kg N ha^?1) improved flour quality. Flour protein content and protein quality parameters displayed a significant negative correlation with brightness (L*) values. Generally, high flour protein content and protein quality, as well as good noodle texture, could be achieved by topdressing N fertilizer (in the range 270–360 kg N ha^?1). Copyright © 2009 Society of Chemical Industry     

The nitrogen content of potato (Solanum tuberosum L.) tubers in relation to nitrogen application—the effect on amino acid composition and yields

The effect of nitrogen application on the nitrogen content and yield of amino acids from potato tubers was studied in one experiment in 1983 and two in 1984. Increasing fertiliser N over the range 0–250 kg ha^?1 raised tuber nitrogen concentrations from 0.68–0.81 to 1.27–1.49% DM. Applying half the fertiliser on the seedbed and half at tuber initiation did not increase tuber nitrogen concentrations compared with a single broadcast application at planting. Increasing tuber nitrogen concentrations had little effect upon the proportion recovered in amides or the different amino acids. Yields of some nutritionally essential amino acids were, therefore, substantially increased up to a maximum of 256 kg ha^?1 in 1982 and 308 and 384 kg ha^?1 in 1984 at the highest fertiliser level. These yields were significantly higher (P<0.01) than those found with the nitrogen application rate optimal for tuber dry matter production (213, 195 and 331 kg N ha^?1, respectively) in the same experiments. Methionine and cystine were the limiting essential amino acids. As the amount of each amino acid contained in a unit weight of fresh tuber increased with nitrogen supply, application of more nitrogen than is needed for maximal tuber dry matter production increased protein yields without decreasing the nutritional quality.