Effect of Sodium Alginate in Combination with Zataria multiflora Boiss. on Phenolic Compounds, Antioxidant Activity, and Browning Enzymes of Fresh In-Hull Pistachio (Pistacia vera L.)

The color of fresh pistachio is used as a postharvest quality indicator. The present study was performed to investigate the chemical properties of fresh pistachios coated with different sodium alginate concentrations (1 and 1.5%), various amounts of Shirazi thyme essential oil (0.3 and 0.5%), and their combination during storage (2 ± 1°C and 85 ± 5% RH). Over the storage duration, chemical parameters were measured on days 13, 26, and 39. The results showed that although the application of sodium alginate in combination with thyme essential oil decreased polyphenol oxidase activity in comparison with other treatments, the highest total phenolics and phenylalanine ammonia lyase activity were found in pistachios coated with alginate (1%) + thyme essential oil (0.3% and 0.5%). In general, it was proven that treatments containing 1% alginate + 0.3% essential oil had the ability to maintain the quality of fresh pistachio fruit approximately over 39 days of storage.

Comprehensive Study of Light-Emitting Diodes (LEDs) and Ultraviolet-LED Lights Application in Food Quality and Safety

Light-Emitting Diodes (LEDs) and Ultraviolet Light-Emitting Diodes (UV LEDs) consist in a semiconductor of light, that are emerging in the market, due to their singular characteristics, as being a solid-state cold source of light, which has potential application in food preservation. For this reason, this study lens to provide a review of the effects of LED and UV LED application in fresh fruits and vegetables, under refrigeration storage. Analyzing the LED role, in extending the shelf-life of postharvest food, these present the capability of improving the quality physicochemical and microbiological of fruits and vegetables, such as: color (chlorophyll), weight loss, total phenolic and flavonoid content, phenylalanine ammonia-lyase activity and total soluble solids. In addition, it’s able to stop chemical reactions and increasing the activity of fruits and vegetable defenses. UV LED light, on the other hand, operates in an effective and straightway in the inactivation the food pathogens, such as Escherichia coli, Pseudomonas fluorescens and Salmonella spp, for example. Therefore, UV LED light can be applied to delay the senescence of foods, however, the wavelength must match the target organism, depending on the food.

Lepidium sativum Sprouts Grown under Elevated CO2 Hyperaccumulate Glucosinolates and Antioxidants and Exhibit Enhanced Biological and Reduced Antinutritional Properties

The nutritional and health-promoting properties of plants are largely determined by their tissue chemistry. Tuning growth conditions could affect the accumulation of phytochemicals and, therefore, enhance the biological activities. Herein, the impact of elevated CO2 (eCO2; 620 µmol CO2 mol−1 air) on growth and chemical composition of sprouts of three Lepidium sativum cultivars (Haraz, Khider and Rajab) was investigated. Changes in the sprout actions against some human chronic diseases were evaluated. eCO2 induced biomass accumulation (1.46-, 1.47- and 2-fold in Haraz, Khider and Rajab, respectively) and pigment accumulation and reduced the level of antinutrients in L. sativum cultivars. Compared to the control, eCO2 induced total glucosinolate accumulation (0.40-, 0.90- and 1.29-fold in Khider, Haraz and Rajab, respectively), possibly through increased amino acid production, and their hydrolysis by myrosinase. In line with increased polyphenol production, improved phenylalanine ammonia lyase activity was observed. The antioxidant, anti-inflammatory, hypocholesterolemic, antibacterial and anticancer activities of the produced sprouts were significantly improved by sprouting and eCO2 exposure. PCA indicated that the cultivars showed interspecific responses. Thus, the present study confirms the synergistic effect of sprouting with eCO2 exposure as a promising approach to produce more bioactive L. sativum sprouts.

Zinc oxide nanoparticles mediated substantial physiological and molecular changes in tomato

There has long been debate about how nanoproducts meet agricultural requirements. This study aimed to investigate tomato responses to the long-time foliar application of zinc oxide nanoparticles (ZnO-NP; 0 and 3 mgl-1) or bulk type (BZnO). Both ZnO-NP and BZnO treatments, especially the nanoform, were significantly capable of improving growth, biomass, and yield. The ZnO-NP treatment upregulated the expression of the R2R3MYB transcription factor by 2.6 folds. The BZnO and ZnO-NP treatments transcriptionally up-regulated WRKY1 gene by 2.5 and 6.4 folds, respectively. The bHLH gene was also upregulated in response to BZnO (2.3-fold) or ZnO-NP (4.7-fold). Moreover, the ZnO-NP application made a contribution to upregulation in the EREB gene whereas the bulk compound did not make a significant change. Upregulation in the HsfA1a gene also resulted from the ZnO-NP (2.8-fold) or BZnO (1.6-fold) supplementation. The MKK2 and CAT genes displayed a similar upregulation trend in response to the supplements by an average of 3-folds. While the application of ZnO-NP slightly down-regulated the histone deacetylases (HDA3) gene by 1.9-fold, indicating epigenetic modification. The supplements, especially the nano-product, enhanced concentrations of K, Fe, and Zn in both leaves and fruits. The concentrations of Chla, Chlb, and carotenoids were increased in response to the BZnO or ZnO-NP treatments. Likewise, BZnO or ZnO-NP mediated an increase in activity of nitrate reductase and proline content in leaves. These treatments increased soluble phenols and phenylalanine ammonia-lyase activity. With a similar trend, the BZnO or ZnO-NP application improved the activities of catalase and peroxidase enzymes. The reinforcement in metaxylem and secondary tissues resulted from the applied supplements. This study provides comprehensive comparative evidence on how ZnO-NPs may remodel the chromatin ultrastructure and transcription program, and confer stress tolerance in crops. This study also underlines the necessity of providing integrated transcriptome and proteome data in future studies.

Effect of Three Nanoparticles (Se, Si and Cu) on the Bioactive Compounds of Bell Pepper Fruits under Saline Stress

The bell pepper is a vegetable with high antioxidant content, and its consumption is important because it can reduce the risk of certain diseases in humans. Plants can be affected by different types of stress, whether biotic or abiotic. Among the abiotic factors, there is saline stress that affects the metabolism and physiology of plants, which causes damage, decreasing productivity and quality of fruits. The objective of this work was to evaluate the application of selenium, silicon and copper nanoparticles and saline stress on the bioactive compounds of bell pepper fruits. The bell pepper plants were exposed to saline stress (25 mM NaCl and 50 mM) in the nutrient solution throughout the crop cycle. The nanoparticles were applied drenching solution of these to substrate (Se NPs 10 and 50 mg L−1, Si NPs 200 and 1000 mg L−1, Cu NPs 100 and 500 mg L−1). The results show that saline stress reduces chlorophylls, lycopene, and β-carotene in leaves; but increased the activity of some enzymes (e.g., glutathione peroxidase and phenylalanine ammonia lyase, and glutathione). In fruits, saline stress decreased flavonoids and glutathione. The nanoparticles increased chlorophylls, lycopene and glutathione peroxidase activity in the leaves; and ascorbate peroxidase, glutathione peroxidase, catalase and phenylalanine ammonia lyase activity, and also phenols, flavonoids, glutathione, β-carotene, yellow carotenoids in fruits. The application of nanoparticles to bell pepper plants under saline stress is efficient to increase the content of bioactive compounds in fruits.

Enzymatic activity in azuki bean seedlings subjected to salinity and water deficiency

Salinity and water deficiency are factors that limit the initial development of crops, directly interfering with the efficiency of food production. Studies on the behavior of cultivable species under stress are important to determine management actions; therefore, the mechanisms involved in post-stress recovery should be investigated. The objective of this study was to evaluate the effect of water and salt stress on enzymatic activity in azuki bean seedlings. The experimental design was a completely randomized, 4 × 6 factorial arrangement (four reagents: CaCl2, KCl, NaCl, and polyethylene glycol 6000 (PEG 6000) × six osmotic potentials: 0.0, -0.2, -0.4, -0.8, -1.2, and -1.6 MPa). The quantification of protein content and analysis of enzyme (catalase, peroxidase, and phenylalanine ammonia-lyase) activity in seedlings were performed on the 10th day after sowing. NaCl is toxic and recovery of azuki bean seedlings was less likely under salt stress owing to reduced enzymatic activity. In contrast, seedlings subjected to KCl treatment showed increased production of antioxidant enzymes.

Phenylalanine Response in Rice Kernel Under Chitosan Nanoparticles Spraying

Background: Since phenylketonuria patients have a metabolic defect, should use specific foods that have low phenylalanine levels. These foods are usually produced by hydrolysis processes. The most important problems of the foods are unpleasant to taste and expensive. The main objective of this study was to investigate the possibility of reducing the amount of phenylalanine in rice kernel under spraying of chitosan nanoparticles. Treatments were different concentrations of chitosan nanoparticles spraying (0,500,1000,1500 µlL-1). The treatments effects were studied in a randomized complete block design with four replications. Experimental variables were phenylalanine, phenylalanine ammonia-lyase activity and total grain protein. Results: The results showed that the total protein and phenylalanine level in rice kernel decreased under all concentrations of chitosan nanoparticles compared to the control, while the activity of phenylalanine ammonia-lyase was higher than that of the control. In this experiment, 1000 µlL-1 of chitosan nanoparticles was found as the optimum concentration, since minimum phenylalanine level and maximum phenylalanine ammonia-lyase activity were affected by this concentration. Conclusion: Our results indicated that chitosan nanoparticles spraying during the grain growth was able to reduce phenylalanine level in rice kernel.

Sodium Lignosulfonate Improves Shoot Growth of Oryza Sativa via Enhancement of Photosynthetic Activity and Reduction of Stress Response

Lignosulfonate (LS) is a by-product obtained during sulfite pulping process and is commonly used as a growth enhancer in plant growth. However, the underlying growth promoting mechanism of LS on shoot growth remains largely unknown. Hence, this study was undertaken to determine the potential application of eco-friendly LS chelated ion complex (NaLS and CaLS) to enhance recalcitrant indica rice MR219 shoot growth and to elucidate its underlying growth promoting mechanisms. The NaLS was shown to be a better shoot growth enhancer as compared to CaLS, with optimum concentration of 300 mg/L. Subsequent comparative proteomic analysis revealed an increase of photosynthesis-related proteins and stress regulator proteins abundance in NaLS-treated rice as compared to MSO (control). Consistently, biochemical analyses showed a significant increase of rubisco activity, total chlorophyll, total sugar and total protein contents in NaLS-treated rice, implying NaLS role in empowering photosynthesis activities that led to plant growth enhancement. In addition, low level of peroxidase activity, malondialdehyde content and phenylalanine ammonia lyase activity were also observed in NaLS-treated rice. These results suggest that NaLS plays a role in modulating cellular homeostasis to provide a conducive cellular environment for plant growth. Taken together, NaLS improved shoot growth of recalcitrant MR219 rice by upregulation of photosynthetic activities and reduction of cellular stress leading to better plant growth.

Impact of the Static Magnetic Field on Growth, Pigments, Osmolytes, Nitric Oxide, Hydrogen Sulfide, Phenylalanine Ammonia-Lyase Activity, Antioxidant Defense System, and Yield in Lettuce

Magnetic fields are an unavoidable physical factor affecting living organisms. Lettuce seeds (Lactuca sativa var. cabitat L.) were subjected to various intensities of the static magnetic field (SMF) viz., MF0 (control), SMF1 (0.44 Tesla (T), SMF2 (0.77 T), and SMF3 (1 T) for three exposure times (1, 2, and 3 h). SMF-treated seedlings showed induction in growth parameters and metabolism comparing to control. All photosynthetic pigments were induced markedly under SMF, especially chlorophyll a. SMF at different intensities boosted osmolytes, non-enzymatic antioxidants, and the phenylalanine ammonia-lyase activity over non-magnetized seedlings. Oxidative damage criteria viz., hydrogen peroxide, superoxide radical, and lipid peroxidation, as well as polyphenol oxidase activity, were kept at low values under SMF-treated seeds relative to control, especially SMF2. Electron donors to antioxidant enzymes including nitrate reductase, nitric oxide, and hydrogen sulfide induced via SMF exposure and consequently the activities of superoxide dismutase, glutathione-S-transferases, catalase, and peroxidases family enzymes were also stimulated under SMF, whatever the intensity or the exposure period applied. All these regulations reflected on the enhancement of lettuce yield production which reached 50% over the control at SMF3. Our findings offered that SMF-seed priming is an innovative and low-cost strategy that can improve the growth, bioactive constituents, and yield of lettuce.