Fruit Ascorbic Acid Research Articles

One-pot synthesis smartphone-assisted test strip based on food-grade Fe-β-Cyclodextrin nanozymes for rapid colorimetric analysis of ascorbic acid in foods and supplements

Accurate on-site analysis of food quality is of great significance for ensuring public health. Among them, ascorbic acid (AA) is an essential micronutrient widely used as an additive in juices and drugs to improve food quality and human health. In this work, we developed food-grade Fe-β-Cyclodextrin(Fe-β-CD) nanozymes based on inexpensive and readily available β-cyclodextrin and iron ions for the detection of AA. Fe-β-CD confirmed excellent peroxidase-like activity and oxidized colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to oxide TMB. AA could inhibit the oxidation reaction and cause blue to fade. Based on the above principles, Fe-β-CD nanozymes exhibited a low detection limit (3.4 μM) for detecting AA, with a wide linear range (10–300 μM). This method had been successfully used for the detection of AA in fruits and vitamin C tablets, and the results were consistent with the specified values. More importantly, an integrated smartphone-assisted Fe-β-CD@test strip colorimetric application platform constructed by one-pot method, the test strip also had better stability, and could be combined with smartphones to achieve convenient AA detection without using any instruments, which showed enormous potential for rapid and low-cost colorimetric detection of AA.

A Smartphone-Enabled Colorimetric Microneedle Sensing Platform for Rapid Detection of Ascorbic Acid in Fruits.

Achieving rapid extraction and detection of analytical solutions from plant tissues to circumvent cumbersome procedures and reduce the dependence on detection instruments remains a challenge. Herein, a colorimetric microneedle integrated platform was developed for the rapid extraction and detection of plant fluids for testing purposes. Colorimetric microneedle patches (CMPs) offer a swift and effective method to swiftly extract and detect ascorbic acid (AA) within 10 min from various fruit crops like mango, nectarine, apple, pear, and kiwifruit, facilitated by a smartphone application. CMPs are constructed for the rapid and sensitive analysis of AA with good linearity amid the range 0.05-25 μM and a low limit of detection of 30 nM. The novel CMPs demonstrate significant potential as a rapid detection platform for AA in plants. CMPs offer significant advantages over traditional ultraviolet spectrophotometry, such as simplified operational procedures and accelerated extraction and detection processes. This establishes robust groundwork for conducting in situ extraction and molecular detection of diverse crops across a spectrum of application scenarios.

Low-cost digital colorimetric sensor for rapid on-site determination of ascorbic acid in vegetable- and fruit-based purees and juices

Ascorbic acid is essential for human health due to its potent antioxidant properties; however, excessive intake can lead to adverse effects. This has created a high demand for simple and cost-effective analytical techniques to determine this analyte outside of laboratory settings for food quality control. In this study, a portable colorimetric sensor was developed for the quantitative on-site determination of ascorbic acid. The technique is based on the reduction of phosphorus heteropoly acid by ascorbic acid, resulting in the formation of a blue-colored product. The heteropoly acid was immobilized on a polymer template in the sensor's indicator zone with menthol used as an environmentally friendly extractant to enhance the device’s stability and extend its shelf life. The colorimetric sensor demonstrated reliable detection with a low limit of detection of 5 mg kg−1, calculated based on a blank test using 3σ. Under optimized conditions, the linear detection range was 15–150 mg kg−1. The disposable sensors were applied to determine ascorbic acid in fruit and vegetable juices and purees for baby food, with recovery rates between 88 % and 110 %. This easy-to-produce and ready-to-use technique presents significant potential for mass on-site screening of ascorbic acid in food samples.

Comparative transcriptome analysis of cucumber fruit tissues reveals novel regulatory genes in ascorbic acid biosynthesis.

Ascorbic acid (AsA) is one of the most abundant natural antioxidants, and it is an important indicator of the nutritional value of cucumber fruit. The aim of this study was to elucidate the regulatory mechanism affecting AsA metabolism in cucumber fruit. In this study, the AsA content in the fruit of two cucumber cultivars (H28 and H105) was significantly higher in the exocarp and endocarp than in the mesocarp. To clarify the regulation of AsA in cucumber fruit, the transcriptomes of three fruit tissues (i.e., the exocarp, mesocarp, and endocarp) of two cucumber cultivars (H28 and H105) were sequenced. Transcriptomic profiling combined with transcription factors (TFs) and correlation analysis were performed to reveal that three genes, including CsaV3_5G014110 (phosphomannomutase, PMM), CsaV3_2G004170 (GDP-mannose-3', 5'-epimerase, GME) and CsaV3_5G006680 (dehydroascorbate reductase, DHAR), were expressed at higher level in the exocarp and endocarp than in the mesocarp. In both two cultivars, CsaV3_4G028360 (ethylene-responsive transcription factor, ERF) was negatively correlated with PMM and GME, and positively correlated with DHAR. CsaV3_6G042110 (ethylene-responsive transcription factor, ERF) was positively correlated with PMM and GME, and negatively correlated with DHAR. CsaV3_6G032360 (mitogen-activated protein kinase, MAPK) as positively correlated with PMM, GME and DHAR. These six genes are considered the key candidate genes for further research. This study provides insight for further study on the regulation of AsA biosynthesis in cucumber fruit and provide potential candidate genes for future genetic improvement of cucumber germplasm with enhanced AsA accumulation.

Impact of thermal processing on polyphenols, carotenoids, glucosinolates, and ascorbic acid in fruit and vegetables and their cardiovascular benefits.

Bioactive compounds in fruit and vegetables have a positive impact on human health by reducing oxidative stress, inflammation, and the risk of chronic diseases such as cancer, cardiovascular (CV) diseases, and metabolic disorders. However, some fruit and vegetables must be heated before consumption and thermal processes can modify the amount of nutraceuticals, that is, polyphenols, carotenoids, glucosinolates, and ascorbic acid, that can increase or decrease in relation to different factors such as type of processing, temperature, and time but also the plant part (e.g., flower, leaf, tuber, and root) utilized as food. Another important aspect is related to the bioaccessibility and bioavailability of nutraceuticals. Indeed, the key stage of nutraceutical bioefficiency is oral bioavailability, which involves the release of nutraceuticals from fruit and vegetables in gastrointestinal fluids, the solubilization of nutraceuticals and their interaction with other components of gastrointestinal fluids, the absorption of nutraceuticals by the epithelial layer, and the chemical and biochemical transformations into epithelial cells. Several studies have shown that thermal processing can enhance the absorption of nutraceuticals from fruit and vegetable. Once absorbed, they reach the blood vessels and promote multiple biological effects (e.g., antioxidant, anti-inflammatory, antihypertensive, vasoprotective, and cardioprotective). In this review, we described the impact of different thermal processes (such as boiling, steaming and superheated steaming, blanching, and microwaving) on the retention/degradation of bioactive compounds and their health-promoting effects after the intake. We then summarized the impact of heating on the absorption of nutraceuticals and the biological effects promoted by natural compounds in the CV system to provide a comprehensive overview of the potential impact of thermal processing on the CV benefits of fruit and vegetables.

Foliar application of sodium selenite affects the growth, antioxidant system, and fruit quality of strawberry.

Selenium (Se) plays a vital role in various physiological processes in plants and is regarded as an essential micronutrient for human health as well. In this study, sodium selenite solution at 10, 40, 70, and 100 mg·L-1 concentrations was foliar sprayed, and the strawberry plant growth, antioxidant system, and fruit quality with an emphasis on sugar and acid content were assessed. The results showed that 10 mg·L-1 of sodium selenite treatment promoted plant growth, while all the treated concentrations could enhance photosynthesis, the antioxidant system in leaves, the content of Se, and ascorbic acid in fruits. More importantly, 40 mg·L-1 sodium selenite treatment significantly increased fruit weight, total soluble solid, total phenolic content, and anthocyanins, as well as improved the shape index. Furthermore, it decreased the total flavonoid and proanthocyanidin content. Particularly, sodium selenite treatment at 40 and 70 mg·L-1 largely increased the ratio of soluble sugars to titratable acid. The changes of predominant sugars and organic acids during fruit development were further investigated. The sucrose, fructose, and glucose content was upregulated by sodium selenite treatment through upregulating the activities of sucrose phosphate synthase (SPS) and acid invertase, as well as the FaSPS expression. In addition, sodium selenite treatment inhibited the activity of citrate synthase and phosphoenolpyruvate carboxylase, rather than modulating their transcript levels to reduce the citric acid content. This work presented a potentially efficient approach to enhance plant growth and fruit quality and supplement Se in strawberry, providing insights into the mechanism of regulating sugar and acid metabolism by Se.

Visual fluorescence detection kit for Cr (VI) based on biological matrix-derived carbon dots and assisted for AA

In this study, a novel green donkey-hide gelatin carbon dots (D-CDs) were synthesized by hydrothermal method and a portable detector based on Cr (VI) fluorescent test strips was prepared. The synthesized D-CDs exhibited bright blue fluorescence which was used for the detection of Cr (VI) and ascorbic acid (AA). It still exhibited high sensitivity and acceptable selectivity under high concentration of other interfering ions. The morphology and elemental characteristics of D-CDs were characterized. Meanwhile, the “on-off” quenching mechanism of Cr (VI) on D-CDs was studied by ultraviolet-visible absorption spectra, fourier transform infrared spectroscopy and fluorescence spectra. Then a D-CDs/Cr (VI) fluorescence sensing platform was constructed, and reopened by AA, thus eliciting an “on-off-on” fluorescence reaction. Under the optimal conditions, the fluorescence intensity was quenched significantly with the increase of Cr (VI) concentration and restored by the good reducibility of ascorbic acid (AA), with the linear ranges of 0.5–400 μM and 1–400 μM, respectively. The detection limits of Cr (VI) and AA can be as low as 0.08 μM and 0.14 μM. Consequently, it has low toxicity and can be successfully used as a fluorescent probe to determine Cr (VI) in river water and AA in fruits with satisfactory results. It not only lays a foundation for the development of fluorescence sensor in the field of environment and food, but also provides a good application prospect for its detection of heavy metal ions and AA.

Effect of Foliar Sprays of Phenylalanine, Nano-potash and Potassium Sulphate on Fruit Quality Attributes of Apple (Malus x domestica Borkh) cv. Ambri

The present investigation was carried out at Experimental field of Ambri Apple Research Centre (AARC), Shopian, SKUAST-Kashmir, during the year 2022-2023. Eight treatments, viz; control (water spray), potassium sulphate (5 g per litre of water), phenylalanine (@ 0.1, 0.2 and 0.3%), nano-potash (@ 1, 2 and 3ml/l of water) were selected for colour improvement. The treatments were applied 30 days prior to harvest. The experiment was laid in complete randomised block design with 3 replications having 3 trees per replication. The results showed that all the treatments outperformed control in terms of chemical characteristics. The treatment T4 (Phenylalanine @ 0.3%) significantly excelled in all the treatments applied. Significantly higher anthocyanin content (14.41 mg/100g), antioxidants (75.71 %), total sugars (12.98 %), TSS (16.23 %), fruit chlorophyll (0.59 mg/g fw) and fruit ascorbic acid (23.93 %) was recorded in T4 (Phenylalanine @ 0.3%) as compared to other treatments. According to the current study, apple cultivar Ambri responded favourably to the application of foliar phenylalanine in improving chemical traits, which otherwise lacks in this cultivar. The application of Phe @ 0.3% , 30 days prior to harvest proved superior in enhancing the quality attributes, notably the anthocyanin content of apple cv. Ambri.

Performance of Different Hybrids of Chilli (Capsicum annuum L) under Prayagraj Agro-Climatic Condition

The experiment was conducted on Performance of hybrids of chilli with eight hybrids during 2023-2024 at the Vegetable Research Field of Department of Horticulture, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj. The observations were taken and recorded on various growth, yield and quality contributing parameters. The results from the present investigation revealed that based on the mean performance of eight hybrids of Chilli, hybrids 21CHIHYB-3 and 21CHIHYB-7 were found superior in terms of Fruit yield (q/ha). 21CHIHYB-1 was found to be best in terms of growth parameters (plant height, number of branches). However, on the basis of earliness parameters (flowering), hybrid 21CHIHYB-2 performed best. On the basis of Ascorbic Acid in Fruits, 21CHIHYB-1 is the best and the Total soluble solids was found best in 21CHIHYB-7. The highest gross return was found in the 21CHIHYB-3 and the B:C ratio was found in the same with 3.3. The experiment was laid out in Randomized Block Design with 3 replications and 8 varieties of Chilli.

Comparative evaluation of the biochemical composition of fruits Malus spp.

To determine and compare the content of biochemical compounds in fruits of nine cultivars of M. domestica Borkh. and ten of Malus spp. (given in the research materials), to select the most promising for use in further breeding and recommend for use in various directions, considering the biochemical complex of characters, taste, and marketable qualities of fruits. The dry matter content, a sum of sugars, titratable acids, tannins, and ascorbic acid was evaluated for two years according to generally accepted operating methods. The large-fruited apple cultivars were found to have values of dry matter (11.2-22.8%) and small-fruited (15.5-30.9%); the total amount of sugars in large-fruited cultivars varies from 6.7 to 10.9%, in small-fruited from 7.5 to 12.7%; the amount of ascorbic acid in fruits of M. domestica fruits averaged from 6.0 to 12.2 mg.100 g-1, in crabapple from 6.6 to 22.8 mg.100 g-1; titratable organic acids in fruits of large cultivars ranged from 0.74 to 1.67%, in small ones from 1.50 to 2.34%; tannins content was found in the range from 0.06 to 0.52% in high-fruited cultivars and from 0.29 to 2.61% in lower-fruited ones. Comparative evaluation of the biochemical composition of fruits between large-fruited and small-fruited species and cultivars of apple trees showed that representatives of Malus spp. are more promising for use in breeding and industrial purposes. The dynamics of the decrease of dry soluble substance's weight and the increase of ascorbic acid content in apple tree fruits were also noted.

Influence of Irrigation Water Acidity, Chemical Fertilizer and Propagation Method on the Contents of Nutrient Elements of Strawberry (Fragaria x ananassa Duch.) cv. Festival

The experiment was conducted to study the effect of the reproduction method and acidity of irrigation water and chemical fertilization plus their interactions on the strawberry fruit of the cv. Festival indicators. The percentage of total soluble solids, total acidity, total sugars, ascorbic acid content, and nitrate content were estimated. Results showed the superiority of the method of propagation using the plant tissue culture technique. The ascorbic acid content was 32.73 mg.100 g-1 fresh mass for the method of propagation by runners. Also, the water treatment with pH 5.5 was superior for the total sugars content in fruits 6.72% and the content of ascorbic acid 32.71 to 73 mg.100 g-1 fresh mass compared to the control treatment. As for the triple interaction, the method of propagation with runners and pH water 5.5 and the fertilizer recommendation of macro-elements outperformed in the percentage of T.S.S and carbohydrate content in the strawberry fruits reached 11.70% and 10.41%, respectively, but the total acidity decreased to 2.37 mg.g-1 for the same combination. In contrast, the highest content of ascorbic acid in fruits 44.81 mg.100 g -1 of fresh mass was recorded by using the propagation method of tissue culture technique. Moreover, the lowest nitrate content was 11.19 mg. 100 g -1 dry mass when using the propagation method of runners and pH of irrigation water at 6.5 plus the fertilizer recommendation of macro-elements.

Kiwifruit Monodehydroascorbate Reductase 3 Gene Negatively Regulates the Accumulation of Ascorbic Acid in Fruit of Transgenic Tomato Plants.

Ascorbic acid is a potent antioxidant and a crucial nutrient for plants and animals. The accumulation of ascorbic acid in plants is controlled by its biosynthesis, recycling, and degradation. Monodehydroascorbate reductase is deeply involved in the ascorbic acid cycle; however, the mechanism of monodehydroascorbate reductase genes in regulating kiwifruit ascorbic acid accumulation remains unclear. Here, we identified seven monodehydroascorbate reductase genes in the genome of kiwifruit (Actinidia eriantha) and they were designated as AeMDHAR1 to AeMDHAR7, following their genome identifiers. We found that the relative expression level of AeMDHAR3 in fruit continued to decline during development. The over-expression of kiwifruit AeMDHAR3 in tomato plants improved monodehydroascorbate reductase activity, and, unexpectedly, ascorbic acid content decreased significantly in the fruit of the transgenic tomato lines. Ascorbate peroxidase activity also increased significantly in the transgenic lines. In addition, a total of 1781 differentially expressed genes were identified via transcriptomic analysis. Three kinds of ontologies were identified, and 106 KEGG pathways were significantly enriched for these differently expressed genes. Expression verification via quantitative real-time PCR analysis confirmed the reliability of the RNA-seq data. Furthermore, APX3, belonging to the ascorbate and aldarate metabolism pathway, was identified as a key candidate gene that may be primarily responsible for the decrease in ascorbic acid concentration in transgenic tomato fruits. The present study provides novel evidence to support the feedback regulation of ascorbic acid accumulation in the fruit of kiwifruit.

Ultrasound-Assisted Hydrothermal Synthesis of Highly Fluorescent Sulfur Quantum Dots for Fe3+ Ion and Ascorbic Acid Detection in Real Samples.

In this work, the ultrasound-assisted hydrothermal synthesis method offers a facile method to synthesize highly efficient photoluminescence sulfur quantum dots (SQDs). Impressively, a switchable fluorescent "on-off-on" sensor was developed using the acquired SQDs, which are capable of sequentially detecting iron ions (Fe3+) and ascorbic acid (AA) with exceptional sensitivity and selectivity. Meanwhile, SQDs and Fe3+ formed complexes through coordination, causing the fluorescence quenching of SQDs because of the static quenching effect. Upon the addition of AA into the SQDs/Fe3+ system, a redox-reaction-mediated mechanism leads to the recovery of fluorescence. The fluorescence intensity of SQDs exhibits a linear relationship with the concentrations of Fe3+ and AA in the ranges 5-30 and 20-100 μM, respectively. Notably, the detection limits achieved are 14.31 nM for Fe3+ and 0.64 μM for AA. Moreover, the chemosensor was successfully employed for monitoring Fe3+ in real water samples and AA in fruits. These results demonstrate the excellent analysis and detection capabilities of SQDs in the complex environment.

Comparative Metabolomic and Transcriptomic Analyses Reveal Distinct Ascorbic Acid (AsA) Accumulation Patterns between PCA and PCNA Persimmon Developing Fruit.

Persimmon fruit has a high nutritional value and significantly varies between pollination-constant astringent (PCA) and pollination-constant non-astringent (PCNA) persimmons. The astringency type affects sugar, flavonoids, and tannin accumulation and is well known in persimmon fruit. However, the impact of the fruit astringency type on ascorbic acid (AsA) accumulation is limited. In this study, typical PCA varieties ('Huojing' and 'Zhongshi5') and PCNA varieties ('Yohou' and 'Jiro') of persimmon fruit were sampled at four developing stages (S1-S4) to provide valuable information on AsA content variation in PCA and PCNA persimmon. Persimmon fruit is rich in ascorbic acid; the AsA content of the four varieties 'Zhongshi5', 'Huojing', 'Jiro', and 'Youhou' mature fruit reached 104.49, 48.69, 69.69, and 47.48 mg/100 g. Fruit of the same astringency type persimmon showed a similar AsA accumulation pattern. AsA content was significantly higher in PCA than PCNA fruit at S1-S3. The initial KEGG analysis of metabolites showed that galactose metabolism is the major biosynthetic pathway of AsA in persimmon fruit. There were significant differences in galactose pathway-related metabolite content in developing PCA and PCNA fruit, such as Lactose, D-Tagatose, and D-Sorbitol content in PCA being higher than that of PCNA. Combined gene expression and WGCNA analyses showed that the expression of the GME (evm.TU.contig4144.37) gene was higher in PCA-type than in PCNA-type fruit in S1-S3 and exhibited the highest correlation with AsA content (r = 690 **, p < 0.01). Four hub genes, including the DNA methylation gene, methyltransferase gene, F-box, and Actin-like Protein, were identified as potential regulators of the GME gene. These results provide basic information on how astringency types affect AsA accumulation and will provide valuable information for further investigation on AsA content variation in persimmon fruit.

Smartphone readable colorimetry and surface-enhanced raman scattering (SERS) dual-mode sensing platform for ascorbic acid detection based on GeO2 composite nanozymes

Ascorbic acid (AA) is an essential micronutrient, which is widely used as an additive in beverages and medicines to improve food quality and human health. Herein, we developed a smartphone readable colorimetry and Surface-enhanced Raman scattering (SERS) dual-mode platform based on GeO2 @Fe3O4/Au NPs nanocomposite to detect AA. GeO2 @Fe3O4/Au NPs have excellent peroxidase-like activity and can oxidize colorless 3,3′,5,5′-tetramethylbenzidine into blue 3,3′,5,5′-tetramethylbenzidine oxide. AA can inhibit the oxidation of 3,3′,5,5′-tetramethylbenzidine, which lead to fading. Based on the above principles, we developed an innovation for micro-detection of AA using oxidized 3,3′,5,5′-tetramethylbenzidine as probe molecule, combined with smartphone readable colorimetry and SERS dual-mode detection. Under optimum conditions, the detection range of AA is 0.5 μmol/L − 340 μmol/L and 10−9 μmol/L − 100 mol/L, the detection limit is 0.6689 μmol/L and 6.162 × 10−13 mol/L, respectively. The method was successfully used for AA in fruits, vitamin C beverages and vitamin C tablets, and the results are consistent with the prescribed values.

Potassium-phosphorus fertilization to reduce salt stress in West Indian cherry

West Indian cherry stands out in the Brazilian fruit scenario due to the nutritional quality of its fruits, making it a promising crop in the generation of employment and income. However, the occurrence of water sources with high concentrations of salts is a limiting factor for the expansion of crop area. In this context, the objective was to evaluate the production and post-harvest quality of West Indian cherry cv. BRS 366 Jaburu under prolonged saline stress and potassium-phosphorus fertilization combinations in the second year of cultivation. The experiment was carried out in 250 L lysimeters in a greenhouse in the municipality of Campina Grande-PB, Brazil. Treatments were distributed in randomized blocks in a 5 × 4 factorial scheme, with five levels of electrical conductivity of irrigation water - ECw (0.6, 1.4, 2.2, 3.0, and 3.8 dS m−1) and four combinations of potassium-phosphorus fertilization (100/100, 85/85, 60/60, and 45/45% of K2O/P2O5 recommendation for the second year of cultivation) with three replicates. Irrigation water salinity of up to 3.8 dS m−1 does not compromise the post-harvest quality of West Indian cherry. The increase in water salinity reduces mean fruit weight and water consumption of plants, while waters with electrical conductivities of 3.0 and 2.0 dS m−1 promote the maximum values of total soluble solids and ascorbic acid in the fruits, respectively. The supply of 45/45% K2O/P2O5 of the fertilization recommendation provides the higher content of ascorbic acid in West Indian cherry fruits and, when associated with ECw of 1.4 dS m−1, promotes the higher production of the crop.

Application of Lavender and Rosemary Essential Oils (EOs), Their Mixture and Eucalyptol (EOs Main Compound) on Cucumber Fruit Quality Attributes and Microbial Load

Cucumber (Cucumis sativus L.), one of the most widely consumed vegetables, presents high perishability during storage and marketing if it is not handled and stored properly. Currently, there is an increased interest of the food industry to reduce waste (due to quality losses) and to utilize natural products for the preservation of fresh commodities. This study’s goal was to evaluate the effects of lavender (Lav) and rosemary (Ros) essential oils (EOs), their mixture (Lav + Ros, 1:1 v/v) and their main compound (eucalyptol) via vapor phase on cucumber’s postharvest quality. The outcomes of this study demonstrated that 200 μL/L of Lav and Ros EOs increased the respiration rate of cucumbers after 10 days of storage at 11 °C, while 100 μL/L of the EOs mixture and Eucalyptol (100 and 200 μL/L) had no effect on respiration, on the same day. The application of Eucalyptol (100 and 200 μL/L) resulted in less acceptable fruits (less pleasant aroma and unpleasant taste). A decrease in fruit firmness was found in cucumbers exposed to Lav 200 μL/L and Ros 100 μL/L. Interestingly, Eucalyptol was found to accelerate the fruit ripening index after five days of storage, and to decrease organoleptic properties of the fruit (i.e., aroma, taste) on the fifth day of storage. The fruit revealed increased oxidative stress (i.e., increased lipid peroxidation), especially at a high concentration (200 μL/L) of Eucalyptol after 10 days. This has resulted in the activation of other non-enzymatic antioxidant mechanisms such as the increase in fruit ascorbic acid content. Notably, no effects on fruit weight loss, total soluble solids and color were observed with the examined treatments. Overall, this study suggests that the investigated products (EOs and their main compound) have a putative role in postharvest storage for the preservation of cucumbers. However, further investigation is needed for the determination of the optimum application conditions (i.e., concentration, time and method of application) on cucumbers and other fresh produce.

The assessment of summer apple cultivars for biochemical fruit composition and productivity

Relevance. In industrial horticulture, the cultivar plays an important role. Correctly selected rootstock will allow identifying the possibility of a cultivar. It is the rootstock that controls growth, has a great influence on the rate of fertility, fruiting and marketable qualities of the fruits of the grafted cultivar. The introduction of apple graft-rootstock combinations into wide production to obtain consistently high yields with fruits of high commodity and biochemical qualities requires a rational selection of cultivars and rootstocks.Methods. Apple cultivars Orlinka and Yablochny Spas were studied for yield indicators in accordance with the «Program and methodology of fruit, berry and nut variety study». The assessment of the biochemical composition of fruits was carried out at VNIISPK in the laboratory of biochemical and technological evaluation of cultivars and storage according to generally accepted methods «Methods of biochemical research of plants» and «Evaluation of cultivars by the chemical composition of fruits».Results. As a result of studying the biochemical composition of the fruits of apple cultivars grown on clonal rootstock 62-396 and dwarf intercalary rootstocks 62-396 and 3-17-38, it was found that the content of soluble solids in the fruits of Orlinka on the studied rootstocks was greater than that of Yablochny Spas. The highest sugar content in fruits was in Orlinka on dwarf intercalary rootstocks 62-396 and 3-17-38: 11.00% and 11.54%, respectively. In the fruits of Yablochny Spas, titrated acids were less in all variants of the experiment than in Orlinka. There were no significant differences in the accumulation of ascorbic acid in fruits between cultivars and graft-rootstock combinations. During the entire period of study, the resulting yield in Orlinka significantly exceeded the yield of Yablochny Spas.

Solid-phase extraction of gallic acid and ascorbic acid in fruits using polymerized deep eutectic solvent-modified substrate.

Aim: Novel substrates were synthesized by porous and nonporous polymerization of deep eutectic solvents on magnetic silica nanoparticles and introduced for dispersive solid-phase extraction of two analytes. Materials & methods: The prepared substrates were characterized, and an extraction procedure was implemented to select the best substrates and eluent. The central composite design acted to optimize the effects of parameters that influenced the extraction efficiencies. Results: For gallic and ascorbic acids, the limits of detection were obtained at 0.136 and 0.165μM, respectively, with linear ranges of 0.6-125.2 and 0.5-106.8μM, respectively. Conclusion: The substrate produced good extractions even after being used three-times and was successfully applied for the analysis of real samples.

Overexpression of RrGGP2 and RrDHAR Increases Ascorbic Acid Content in Tomato

Ascorbic acid (AsA) is the most abundant antioxidant in plants and is an important nutritional index for agricultural products. Some plants, such as Rosa roxburghii Tratt., contain exceptionally high levels of AsA, but are relatively unpalatable. In view of its role in human health, as well as plant growth and development, we examined the effects of two important AsA regulatory genes from R. roxburghii in tomato, with the aim of producing a crop of higher nutritional quality. RrGGP2 and RrDHAR were cloned from R. roxburghii fruit. The overexpression vectors were made using 35S promoters and mediated by Agrobacterium tumefaciens to obtain the overexpression lines. A PCR and qRT-PCR verified that the two genes had been inserted and overexpressed in the tomato leaves and fruits. The results showed that the overexpression of RrGGP2 increased tomato leaf and fruit AsA content by 108.5% and 294.3%, respectively, while the overexpression of RrDHAR increased tomato leaf and fruit AsA content by 183.9% and 179.9%. The overexpression of RrGGP2 and RrDHAR further changed the expression of genes related to AsA metabolism, and the upregulation of one such gene, SlGGP, may have contributed greatly to the increase in AsA. Results here indicate that RrGGP2 contributes more towards fruit AsA accumulation in tomato than RrDHAR.