Paolo Sambo

Selenium Fertilization Alters the Chemical Composition and Antioxidant Constituents of Tomato (Solanum lycopersicon L.)

Although selenium (Se) is a known anticarcinogen, little is known regarding how Se affects other nutritional qualities in crops. Tomato ( Solanum lycopersicon ) was supplied with 0-50 μM selenate and analyzed for elemental composition and antioxidant compounds. When supplied at low doses (5 and 10 μM) via the roots, Se stimulated the synthesis of phenolic compounds in leaves and reduced the levels of Mo, Fe, Mn, and Cu in roots. At higher doses (25 and 50 μM Se) leaf glutathione levels were 3-5-fold enhanced. Supply of selenate via foliar spray (0, 2, or 20 mg Se plant(-1)) resulted in Se-biofortified tomato fruits, with Se levels low enough not to pose a health risk. The Se-biofortified fruits showed enhanced levels of the antioxidant flavonoids naringenin chalcone and kaempferol and a concomitant decrease of cinnamic acid derivatives. Thus, tomato fruits can be safely enriched with Se, and Se biofortification may enhance levels of other neutraceutical compounds.

Selenium Biofortification in Radish Enhances Nutritional Quality via Accumulation of Methyl-Selenocysteine and Promotion of Transcripts and Metabolites Related to Glucosinolates, Phenolics, and Amino Acids

Two selenium (Se) fertilization methods were tested for their effects on levels of anticarcinogenic selenocompounds in radish (Raphanus sativus), as well as other nutraceuticals. First, radish was grown on soil and foliar selenate applied 7 days before harvest at 0, 5, 10, and 20 mg Se per plant. Selenium levels were up to 1200 mg Se/kg DW in leaves and 120 mg Se/kg DW in roots. The thiols cysteine and glutathione were present at 2–3-fold higher levels in roots of Se treated plants, and total glucosinolate levels were 35% higher, due to increases in glucoraphanin. The only seleno-aminoacid detected in Se treated plants was Se-methyl-SeCys (100 mg/kg FW in leaves, 33 mg/kg FW in roots). The levels of phenolic aminoacids increased with selenate treatment, as did root total nitrogen and protein content, while the level of several polyphenols decreased. Second, radish was grown in hydroponics and supplied with 0, 5, 10, 20, or 40 μM selenate for 1 week. Selenate treatment led to a 20–30% increase in biomass. Selenium concentration was 242 mg Se/kg DW in leaves and 85 mg Se/kg DW in roots. Cysteine levels decreased with Se in leaves but increased in roots; glutatione levels decreased in both. Total glucosinolate levels in leaves decreased with Se treatment due to repression of genes involved in glucosinolates metabolism. Se-methyl-SeCys concentration ranged from 7–15 mg/kg FW. Aminoacid concentration increased with Se treatment in leaves but decreased in roots. Roots of Se treated plants contained elevated transcript levels of sulfate transporters (Sultr) and ATP sulfurylase, a key enzyme of S/Se assimilation. No effects on polyphenols were observed. In conclusion, Se biofortification of radish roots may be achieved via foliar spray or hydroponic supply. One to ten radishes could fulfill the daily human requirement (70 μg) after a single foliar spray of 5 mg selenate per plant or 1 week of 5–10 μM selenate supply in hydroponics. The radishes metabolized selenate to the anticarcinogenic compound Se-methyl-selenocysteine. Selenate treatment enhanced levels of other nutraceuticals in radish roots, including glucoraphanin. Therefore, Se biofortification can produce plants with superior health benefits.

Capsicum chinensis L. growth and nutraceutical properties are enhanced by biostimulants in a long-term period: chemical and metabolomic approaches

Two biostimulants, one derived from alfalfa plants (AH) and the other obtained from red grape (RG), were chemically characterized using enzyme linked immuno-sorbent assays, Fourier transform infrared (FT-IR) and Raman spectroscopies. Two doses (50 and 100 mL L−1 for RG, and 25 and 50 mL L−1 for AH) of biostimulants were applied to Capsicum chinensis L. plants cultivated in pots inside a tunnel. The experimental design consisted of the factorial combination of treatment (no biostimulant, plus AH, plus RG) at three doses (zero, low, and high) and two time-course applications (at the second and fourth week after transplantation) and the effects were recorded at flowering and maturity. Both biostimulants contained different amounts of indoleacetic acid and isopentenyladenosine; the AH spectra exhibited amino acid functional groups in the peptidic structure, while the RG spectra showed the presence of polyphenols, such as resveratrol. These results revealed that at flowering, RG and AH increased the weights of fresh leaves and fruits and the number of green fruits, whereas at maturity, the biostimulants most affected the fresh weight and number of red fruits. At flowering, the leaves of the treated plants contained high amounts of epicatechin, ascorbic acid, quercetin, and dihydrocapsaicin. At maturity, the leaves of the treated plants exhibited elevated amounts of fructose, glucose, chlorogenic, and ferulic acids. Moreover, green fruits exhibited a high content of chlorogenic acid, p-hydroxybenzoic acid, p-coumaric acid and antioxidant activity, while both AH- and RG-treated red fruits were highly endowed in capsaicin. The 1H high-resolution magic-angle spinning (HRMAS)-nuclear magnetic resonance (NMR) spectra of red fruits revealed that both products induced a high amount of NADP+, whereas RG also increased glucose, fumarate, ascorbate, thymidine and high molecular weight species. Our results suggested that AH and RG promoted plant growth and the production of secondary metabolites, such as phenols.

Optimization of Antimicrobial and Physical Properties of Alginate Coatings Containing Carvacrol and Methyl Cinnamate for Strawberry Application

Increasing strawberry consumption has led to a growing safety concern because they are not washed after harvest. An antimicrobial edible coating could be an effective postharvest technique to ensure microbial safety and, at the same time, retain overall quality of the fruits. Response surface methodology was used to optimize the antimicrobial activity against Escherichia coli O157:H7 and Botrytis cinerea and several physical properties (turbidity, viscosity, and whitish index) of an alginate coating. A full factorial design was used to select the concentrations of carvacrol and methyl cinnamate on the basis of their effect against E. coli and B. cinerea. A central composite design was then performed to evaluate the effects/interactions of the two antimicrobials on the coating characteristics. The results from analysis of variance showed the significant fitting of all responses to the quadratic model. To attain the desirable responses, the optimal concentrations were 0.98% (w/w) carvacrol and 1.45% (w/w) methyl cinnamate.

Effect of grafting and ripening conditions on some qualitative traits of ‘Cuore di bue’ tomato fruits

BACKGROUNDnGrafting technique is increasingly being employed in order to obtain high production in difficult soils and to reduce chemical application. The present experimental work addressed the effect of grafting of tomato, cv. Profitto (P), on to the rootstocks Beaufort (B) and Big Power (BP) on fruit quality. Both fruit left to ripen on the plant and fruit stored at low temperature (4 °C) were included in the quality assessment.nnnRESULTSnVitamin C and fructose content decreased in B and BP in fruits stored at 4 °C, whereas fruits ripened on the plant showed higher sugar concentrations. The free phenolic acids extracted were identified as caffeic acid, p-coumaric acid, chlorogenic acid and ferulic acid. Higher antioxidant compound content was consistently shown by P. Cold storage conditions caused a higher phenolic acid production due to the increase of ferulic acid. Compared with ripening on the plant, percentage differences ranged between 14.3% (caffeic acid) and 12.5% (p-coumaric and chlorogenic acids). Total phenol content was also affected by maturation, showing higher values in fruits ripened on the plant than under cold storage conditions.nnnCONCLUSIONSnIt was possible to observe a significant relationship between tomato fruit quality and grafting and relevant differences in fruit ripening conditions.

Boron application improves on yield and chemical composition of strawberry

Abstract Boron (B) is an essential micronutrient required for normal plant growth and development. Boron management is challenging because the optimum B application range is narrow and the application rates vary from one soil to another. Boron deficiency is widespread in the Anatolia region of Turkey. This may impact on yield and mineral contents of leaves and fruits of strawberry (Fragaria×ananassa cv. Fern) especially in B-deficient calcareous Aridisols in Eastern Anatolia, Turkey. A 2-year field experiment was conducted to study yield and quality response of strawberry to B application. Boron fertilizer application affected plant yield and chemical composition. B application decreased tissue nitrogen (N) and calcium (Ca) but increased tissue phosphorus (P), potassium (K), manganese (Mn), zinc (Zn) and copper (Cu) content. We conclude that a B addition of 5.5 kg ha−1 is sufficient to elevate soil B levels to non-deficient levels.

Magnetic Purification of Curcumin from Curcuma longa Rhizome by Novel Naked Maghemite Nanoparticles

Naked maghemite nanoparticles, namely, surface active maghemite nanoparticles (SAMNs), characterized by a diameter of about 10 nm, possessing peculiar colloidal stability, surface chemistry, and superparamagnetism, present fundamental requisites for the development of effective magnetic purification processes for biomolecules in complex matrices. Polyphenolic molecules presenting functionalities with different proclivities toward iron chelation were studied as probes for testing SAMN suitability for magnetic purification. Thus, the binding efficiency and reversibility on SAMNs of phenolic compounds of interest in the pharmaceutical and food industries, namely, catechin, tyrosine, hydroxytyrosine, ferulic acid, coumaric acid, rosmarinic acid, naringenin, curcumin, and cyanidin-3-glucoside, were evaluated. Curcumin emerged as an elective compound, suitable for magnetic purification by SAMNs from complex matrices. A combination of curcumin, demethoxycurcumin, and bis-demethoxycurcumin was recovered by a single magnetic purification step from extracts of Curcuma longa rhizomes, with a purity >98% and a purification yield of 45%, curcumin being >80% of the total purified curcuminoids.

The use of organic biostimulants in hot pepper plants to help low input sustainable agriculture

BackgroundWorld demand for agricultural products is increasing. New insights are required in order to achieve sufficient and sustainable yields to meet global food request. Chemical fertilizers have been studied for almost 200xa0years, and it is unlikely that they could be improved. However, to produce food for a growing world population, various methods to increase the efficiency of chemical fertilizers are investigated. One approach to increasing crop productivity is the development of environment-friendly organic products named biostimulants which stimulate plant growth by enhancing the efficiency of chemical fertilizers. Most studies have tested these products in short-term experiments, but little information is available on their effect on plants at the maturity stage of growth. On this account, this paper focuses on the effects of two biostimulants, red grape skin extract (RG) and alfalfa hydrolyzate (AH), throughout the entire plant development.ResultsThe findings obtained in the present investigation demonstrate the effectiveness of RG and AH in improving growth and the nutritional value of peppers. Specifically, the two biostimulants increased the phenol concentration, antioxidant activity, and ascorbic acid concentration in fruits, as well as the capsaicin concentration in plants. Differences in effectiveness between RG and AH were likely related to the characteristics of the starting matrixes as well as to the industrial processes used for their production. The efficiency of RG and AH in promoting plant growth and yield could also be due to their content in indole-3-acetic acid (IAA), isopentenyladenosine (IPA), phenols, and amino acids.ConclusionsIn the light of these results, the application of biostimulants could be considered as a good strategy for obtaining high yields of nutritionally valuable vegetables with lower environmental impact.

Electrostatic and Conventional Spraying of Alginate-Based Edible Coating with Natural Antimicrobials for Preserving Fresh Strawberry Quality

Microbial contamination and mold growth are common causes of strawberry deterioration during storage. The growing need for extending shelf-life while enhancing the overall quality of perishable fruits has generated increasing interest in the development of novel preservation technologies. This study used electrostatic spraying (ES) technology as an innovative and efficient technique for the application of edible alginate coating enriched with carvacrol and methyl cinnamate (natural antimicrobials) on fresh strawberries. The efficiency of the electrostatic technology was compared to non-electrostatic (conventional) spray (NES) technology in terms of transfer efficiency and coating evenness. Furthermore, physicochemical and textural parameters (such as weight loss, visible decay, firmness, surface color, total soluble phenolic content, and antioxidant capacity) of ES and NES coated fruits were studied and compared to uncoated controls. ES technology demonstrated higher transfer efficiency and evenness than NES, which led to a significant reduction of visible decay over uncoated controls. The delay in microbial spoilage by ES (11xa0days) was greater than by NES (10xa0days) and uncoated strawberries (7xa0days). ES coating significantly inhibited strawberry decay with only 5.6xa0% of infected fruits, compared to 16.6 and 8.3xa0% for control and NES fruits after 13xa0days of storage, respectively. At the end of 13xa0days of storage, ES coating demonstrated superior performance on strawberry firmness, color retention, and weight loss reduction. Additionally, no differences were observed between uncoated and coated fruits with regard to their antioxidant and total soluble phenolics.

Effect of grafting on biochemical and nutritional traits of ‘Cuore di Bue’ tomatoes harvested at different ripening stages

Abstract In the last years, ‘Cuore di Bue’ tomato has been one of the most important types requested from the market because of its special flesh texture and flavour, which is very pleasing to the consumer. The present study aims to verify if rootstock affects some specific qualitative traits of this tomato fruits during ripening process. The main quality traits during ripening of tomato fruits of cultivar ‘Profitto’ ungrafted and grafted on ‘Beaufort’ and ‘Big Power’ rootstocks were determined. Results showed that different ripening stages and grafting combinations affected, sometimes strongly, tomato fruits quality. Among phenolics, gallic, cinnamic and p-coumaric acids declined during ripening, whereas chlorogenic, caffeic and ferulic acids increased in the last ripening stages. The quality of tomato fruits was also influenced by grafting. As far as quality parameters (colour, °Brix, electrical conductivity, pH, titratable acidity) and sugar content are concerned, there were significant differences. Strong differences are attributable also to the contents of phenolic acids. In particular, ungrafted Profitto plants showed more p-coumaric and caffeic acid content than the other two grafted treatments. Profitto and Profitto×Beaufort showed more chlorogenic and cinnamic acid than Profitto×Big Power variety. The last one variety showed a completely different chlorogenic acid accumulation pattern and contained more gallic and ferulic acid than the other two. The nutritional value of grape tomatoes ‘Cuore di Bue’ considerably increased with ripening stage. Grafting has a significant effect on various biochemical and nutritional properties in tomato fruit. Many chemical compounds related to the antioxidants group have been involved in these changes showing a significant decrease in grafted fruits. Concerning other parameters such as pH, EC and Brix, the graft leads to very small changes.