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•OW and EW reduced the boron and sodium content in leaves of capsicum seedlings.•OW (0.4 ppm) showed a higher ratio of root mass versus root length.•Catalase activity increased under ...OW and EW treatments but kept the TBARS levels.•Sanitizer treatments cause microbial load reduction; OW higher than EW.
Ozonated water has been extensively used in the food industry as an effective sanitizer to prolong the shelf life of fruit and vegetables during the postharvest. Recently, the disinfection of water used in primary production has been a critical point in preventing plant losses during the growing of the crop, especially in the nursery crop. In this study two different irrigation treatments have been used: ozonated water (OW, 750 mV), and electrolyzed water (EW, 495 mV), compared to a control treatment using water without any sanitizer treatment, in capsicum seedling plants grown under greenhouse conditions. The results showed the control to have the highest Ca, Mg, and Zn values with respect to the OW and EW treatments. However, no significant differences were observed in these minerals in the vegetal plant tissue. Capsicum leaves, irrigated with EW and OW, showed a minor content in B and Na. Moreover, the sanitizing treatments provided plants with a higher number of leaves. Sanitizer treatments did not affect the net photosynthesis or antioxidant compounds, total phenolic compounds, nor the vitamin C. At day 49 lower DHAA and lipid peroxidation were observed in treated samples. A higher catalase activity was measured in OW and EW irrigation treatments compared to the control, preventing the lipid peroxidation. Additionally, OW and EW reduced the microbial load in the water (E. coli and total Enterobacteriae) and OW reduced the mould and yeast of water and the mesophilic load of capsicum seedlings.
l-Citrulline is a nonessential amino acid precursor of arginine and indirectly a precursor of nitric oxide (NO), which is a vasodilator and increases mitochondrial respiration. On the other hand, the ...antioxidant pomegranate ellagitannins are precursors of urolithin A, which has been associated with mitophagy and increased muscle function. To elucidate if a single dose of watermelon enrichment with these compounds could have a positive effect after high-intensity exercise (eight sets of eight repetitions of half-squat exercise), a double-blind randomized crossover in vivo study was performed in healthy male subjects (n = 19). Enrichment juices maintained basal levels of blood markers of muscle damage, such as lactate dehydrogenase and myoglobin, and showed a significant maintenance of force during the exercise and a significant decrease in the rating of perceived exertion and muscle soreness after exercise. A positive effect was observed between l-citrulline and ellagitannins, improving the ergogenic effect of watermelon juice.
L-Arginine (Arg) has been widely used due to its functional properties as a substrate for nitric oxide (NO) generation. However, L-citrulline (CIT), whose main natural source is watermelon, is a ...non-essential amino acid but which has important health potential. This review provides a comprehensive approach to different studies of the endogenous synthesis of CIT, metabolism, pharmacokinetics, and pharmacodynamics as well as its ergogenic effect in exercise performance. The novel aspect of this paper focuses on the different effects of CIT, citrulline malate and CIT from natural sources such as watermelon on several topics, including cardiovascular diseases, diabetes, erectile dysfunction, cancer, and exercise performance. CIT from watermelon could be a natural food-sourced substitute for pharmacological products and therefore the consumption of this fruit is promoted.
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•The photosynthesis rate was not affected by OW (0.4 ppm) or EW (3 ppm free chloride).•The aerial development and crop yield were not affected by any treatments.•Antioxidant activity ...and catalase increased under OW treatment.•OW reduced boron assimilation by the watermelon seedling.•OW can be used as a positive irrigation treatment in nursery crops.
Ozonated water is an important postharvest sanitizer and an interesting alternative to keep nursery crops sanitized. Ozonated water (OW, 750 mV) and electrolyzed water (EW, 495 mV) were compared to a control (CTRL, water without sanitizer treatment), applied as overhead micro sprinkler irrigation, in grafted watermelon seedling plants grown under greenhouse conditions. As results we found a reduction in micronutrients (Fe, Mn, Cu, Zn and B) and macronutrients (Ca and Mg) in grafted watermelon leaves treated with OW, although the OW did not affect the photosynthesis rate or plant development. Additionally, EW reduced the vitamin C content at days 45 and 57 compared to the OW and CTRL samples. OW and EW showed higher total phenolic content (TPC) than the CTRL at days 45 and 49. However, no significant differences were observed in TPC and antioxidant capacity among treatments at day 57. On the other hand, catalase activity increased in OW samples after days 49 and was maintained at day 57, but no significant changes in lipid peroxidation was observed among treatments. As main conclusion, OW caused a moderate stress in grafted watermelon seedlings increasing the oxidative status to balance the redox system that could provide plants with higher bioactive compounds.
Modified atmosphere packaging (MAP) has the potential to extend the shelf-life of fresh-cut lettuce mainly by limiting the oxidation processes. However, exposure to light conditions has been ...described as causing browning and quality loss. The influence of O
2 partial pressures (
pO
2) and light exposure during storage on the shelf-life of fresh-cut Romaine lettuce was studied. Fresh-cut lettuce was exposed daily during storage to different light conditions: light (24
h), darkness (24
h) and photoperiod (12
h light
+
12
h darkness). Changes in respiration rate, headspace gas composition, sensory quality, colour, electrolyte leakage, stomatal opening, water loss, texture and compositional constituents related to browning such as vitamin C and individual and total phenolic compounds were evaluated. Different weight samples (75–275
g), packaged with an initial
pO
2 of 0.5–2.0
kPa balanced with N
2, reached
pO
2 from 0.1 to 1.5 at the steady-state. Atmospheres with low
pO
2 (0.2–0.5) at the steady-state preserved lettuce quality by the control of browning and the prevention of off-odours and off-flavours. Light exposure during storage positively influenced the number of open stomata (74% in light vs 24% in darkness) which contributed slightly to weight loss. Consumption of O
2 in samples exposed to light differed significantly from those stored in photoperiod or darkness (10.6
±
7.0, 18.3
±
3.5 and 25.8
±
8.6
nmol
O
2
kg
−1
s
−1, respectively). Packages exposed to light showed higher
pO
2 compared with packages stored in darkness while those exposed to photoperiod had intermediate values. Moreover, location of the packages in the shelves affected package headspace gas composition and thus, packages near the front of the shelves showed higher
pO
2 than those at the back. The different light conditions did not influence the content of vitamin C or the individual and total phenolic compounds. This study shows that under light conditions respiration activity was compensated by photosynthesis resulting in a higher
pO
2. Thus, browning of fresh-cut Romaine lettuce can be promoted by light exposure during storage as it increases headspace
pO
2.
A comparative study of antioxidant compounds, flavonoids and vitamin C, and also antioxidant activity was carried out in four species of Brassicaceae vegetables used for salads: watercress ( ...Nasturtium officinale R. Br.), mizuna Brassica rapa L. subsp. nipposinica (L.H. Bailey) Haneltand, wild rocket Diplotaxis tenuifolia (L.) DC., and salad rocket Eruca vesicaria (L.) Cav.. The characterization of individual phenolic compounds by HPLC-DAD-MS/MS-ESI in watercress and mizuna completes the polyphenol study previously reported for wild rocket and salad rocket. The qualitative study of flavonoids in watercress leaves showed a characteristic glycosylation pattern with rhamnose at the 7 position. Isorhamnetin 3,7-di- O-glucoside was identified in mizuna leaves and may be considered a chemotaxonomical marker in some B. rapa subspecies. Brassicaceae species showed differences in the quantitative study of flavonoids, and the highest content was detected in watercress leaves. Watercress and wild rocket leaves had the highest content of vitamin C. The antioxidant activity evaluated by different methods (ABTS, DPPH, and FRAP assays) showed a high correlation level with the content of polyphenols and vitamin C. In conclusion, the Brassicaceae leaves studied, watercress, mizuna, wild rocket, and salad rocket, presented a large variability in the composition and content of antioxidant compounds. These baby leaf species are good dietary sources of antioxidants with an important variability of bioactive compounds.
Ascorbic Acid (AA) is a natural and powerful water-soluble antioxidant associated with long-lasting food products. As time passes, the AA content in products sharply decreases, and they become ...increasingly degraded. There are several techniques to precisely quantify AA concentrations. However, most of them employ costly laboratory instruments, such as High-Performance Liquid Chromatography (HPLC) or complex electrochemical methods, which make unfeasible recurrent AA measurements along the entire supply chain. To address this issue, we contribute with an in-field and real-time voltammetric method, carried out with a low-cost, easy-to-use, and portable device. An unmodified Screen-Printed Electrode (SPE) is used together with the device to achieve short reading times. Our method has been extensively tested in two multifruit juices using three different SPEs. Calibration curves and Limit of Detection were derived for each SPE. Furthermore, periodic experiments were conducted to study the shelf life of juices under consideration. During the analysis, a set of assays for each SPE were implemented to determine the remaining AA amount per juice and compare it with that obtained using HPLC under the same conditions. Results revealed that our cost-effective device is fully comparable to the HPLC equipment, as long as the juice does not include certain interferents; a scenario also contemplated in this article.
Salad vegetables could be relevant as dietary sources of natural antioxidants. A better knowledge of their composition can be useful for understanding their potential bioavailability and biological ...activities. The antioxidant compounds, polyphenols and vitamin C, have been determined in five varieties of lettuce (iceberg, romaine, continental, red oak leaf, lollo rosso) and one variety of escarole (frissé). The polyphenol study by HPLC-DAD-MS/MS ESI allowed the identification of two compounds previously not reported in lettuce; quercetin and luteolin rhamnosyl-hexosides. Qualitative and quantitative differences were observed between the polyphenol profiles. Caffeic acid derivatives were the main phenolics in green varieties, while flavonols were detected in higher quantities in red varieties and escarole, and anthocyanins were only present in red-leafed varieties. The highest total phenolic content was observed in red-leafed varieties while the highest level of vitamin C was detected in the continental variety. The red varieties showed the highest antioxidant activity by all the methods assayed.
The novel hormetic effect of UV-C as an emerging treatment applied in crops was evaluated. In a first trial, different UV-C treatments (0.3, 0.6 and 0.9 kJ m−2) were applied twice per week with ...respect to untreated UV-C samples (control) during the development of spinach until baby stage. Additionally, in a second trial, UV-C pretreated and not pretreated baby spinach were inoculated with Alternaria alternata and the UV-C treatments were maintained until the mature stage. The control samples showed a lower total phenolic content than the UV-C treated samples. The low UV-C treatment showed the highest vitamin C content and FRAP antioxidant capacity whilst the medium-high UV-C treatments showed the highest DPPH antioxidant capacity and catalase activity, although no effect on lipid peroxidation was described. Spinach treated with 0.9 kJ m−2 reduced the yeast count by 0.82 log CFU g−1 f.w. with respect to the control, and the hormesis effect reduced the Alternaria spp. count in pretreated UV-C samples.
•Hormetic doses of UV-C increased the total polyphenol content.•The antioxidant status of spinach leaves can be improved by hormetic doses of UV-C.•The oxidative level of spinach increased after Alternaria alternata inoculation.•Fungal infections could be reduced by hormetic doses of UV-C.•UV-C treatments could decrease the chemical fungicides used in crops.
Aqueous chlorine dioxide (ClO
2) has been postulated as an alternative to sodium hypochlorite (NaClO) for fresh-cut produce sanitization with the advantage of avoiding the risks associated with ...chlorination by-products. However, little is known about its influence on preserving quality and the potential formation of trihalomethanes (THMs) under typical processing conditions. The suitability of aqueous chlorine dioxide (3
mg
L
−1) as an effective sanitizer of fresh-cut iceberg lettuce stored under active modified atmosphere packaging (MAP) at refrigerated conditions was determined and compared with sodium hypochlorite (100
mg
L
−1). Fresh-cut lettuce washed with tap water was used as a control. The epiphytic microbiota were characterized by the evaluation of the major relevant microbial groups such as mesophiles, psychrophiles,
Pseudomonas spp.,
Enterobacteriaceae, lactic acid bacteria, yeasts and moulds. Additionally, gas composition, sensory quality, vitamin C and individual and total phenolics were monitored after washing and during storage for 3
d at 4
°C followed by 7
d at 8
°C. In general, the natural microbiota of fresh-cut lettuce after washing and storage was equally affected by the different washing solutions, with the exception of yeasts which showed the highest growth after 10
d storage in samples washed with chlorine dioxide. None of the tested washings negatively affected sensory quality, which was acceptable after 10
d storage. Additionally, the content of bioactive compounds was not significantly affected either by washing solution or by storage time. The potential formation of THMs was evaluated by the analysis of lettuce washed in water with a chemical oxygen demand (COD) of 700
mg
L
−1 treated for 30
min with sodium hypochlorite (100
mg
L
−1) or chlorine dioxide (3.7
mg
L
−1). Trihalomethane formation was only detected in the process water in which sodium hypochlorite was applied (217
±
38
μg
L
−1). However, THMs formation in fresh-cut lettuce was negligible despite the sanitation procedure. The formation of THMs was only detected in fresh-cut lettuce when sodium hypochlorite was used under very extreme conditions where lettuce was washed in water with a high level of organic matter (COD
=
1800
mg
L
−1), high sodium hypochlorite concentration (700
mg
L
−1) and long contact time (60
min). Our data suggest that aqueous chlorine dioxide is as suitable as sodium hypochlorite for fresh-cut lettuce sanitation with the advantage of preventing the formation of THMs.
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