Search Results (27)

Cold storage is widely used for the postharvest preservation of fruits and vegetables; however, okra, as a tropical vegetable, is susceptible to chilling injury under low-temperature storage conditions, leading to quality deterioration, reduced nutritional value, and significant economic losses. Nitric oxide (NO), as an important signaling molecule, plays a crucial role in the postharvest preservation of fruits and vegetables. To investigate the effects of different concentrations of nitric oxide on the postharvest quality of okra under cold storage, fresh okra pods were treated with sodium nitroprusside (SNP), a commonly used NO donor, at concentrations of 0 (control), 0.5 (T1), 1.0 (T2), 1.5 (T3), and 2.0 mmol·L⁻¹ (T4). The results showed that low-concentration NO treatment (T1) significantly reduced weight loss, improved texture attributes including hardness, springiness, chewiness, resilience, and cohesiveness, and suppressed the increase in adhesiveness. T1 treatment also effectively inhibited excessive accumulation of cellulose and lignin, thereby maintaining tissue palatability and structural integrity. Additionally, T1 significantly delayed chlorophyll degradation, preserved higher levels of soluble sugars and proteins, and enhanced the activities of key antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), contributing to improved oxidative stress resistance and membrane stability. In contrast, high-concentration NO treatments (T3 and T4) led to pronounced quality deterioration, characterized by accelerated membrane lipid peroxidation as evidenced by increased malondialdehyde (MDA) content and relative conductivity, and impaired antioxidant defense, resulting in rapid texture degradation, chlorophyll loss, nutrient depletion, and oxidative damage. These findings provide theoretical insights and practical guidance for the precise application of NO in extending shelf life and maintaining the postharvest quality of okra fruits. Full article

Chilling stress inhibits the growth of okra (Abelmoschus esculentus L.), reduces its overall agricultural yield, and deteriorates fruit quality. Therefore, it is crucial to elucidate the mechanism through which okra plants respond to chilling stress. This study investigates the molecular mechanisms of chilling tolerance by comparing the transcriptome and metabolome of chilling-tolerant (Ae182) and chilling-sensitive (Ae171) okra varieties. We found that Ae182 exhibits higher antioxidant enzyme activities, including SOD, POD, CAT, and APX, suggesting it mitigates oxidative stress more effectively than Ae171. Metabolomics analysis revealed that Ae182 produces higher levels of jasmonic acid (JA) and JA-isoleucine (JA-Ile) under chilling stress, potentially activating genes that alleviate oxidative damage. Additionally, integrated analyses identified key transcription factors, such as AP2, BHLH, and MYB, associated with JA and chilling stress. These findings provide candidate genes for further research on chilling resistance in okra. Full article

Okra (Abelmoschus esculentus) is an important agricultural crop of the Malvaceae family, cultivated across tropical, subtropical, and warm temperate regions. However, okra production faces numerous challenges from diverse pest species, including insects, nematodes, arachnids, and mites, that significantly reduce its yield. Major economic pests include the cotton aphid, cotton spotted bollworm, Egyptian bollworm, cotton mealybug, whitefly, cotton leafhopper, cotton bollworm, two-spotted spider mite, root-knot nematode, reniform nematode, cotton leaf roller, and flea beetle. Additionally, less prevalent pests such as the blister beetle, okra stem fly, red cotton bug, cotton seed bug, cotton looper, onion thrips, green plant bug, and lesion nematode are also described. This review also addresses fungal and oomycete diseases that present high risks to okra production, including damping-off, powdery mildew, Cercospora leaf spot, gray mold, Alternaria leaf spot and pod rot, Phyllosticta leaf spot, Fusarium wilt, Verticillium wilt, collar rot, stem canker, anthracnose, and fruit rot. In addition to these fungal diseases, okra is also severely affected by several viral diseases, with the most important being okra yellow vein mosaic disease, okra enation leaf curl disease, and okra mosaic disease, which can cause significant yield losses. Moreover, okra may also suffer from bacterial diseases, with bacterial leaf spot and blight, caused primarily by Pseudomonas syringae, being the most significant. This manuscript synthesizes the current knowledge on these pests. It outlines various management techniques and strategies to expand the knowledge base of farmers and researchers, highlighting the key role of integrated pest management (IPM). Full article

The aim of this study was to develop an innovative sourdough using dehydrated okra (Abelmoschus esculentus L.) pod flour and to use it in the production of bread. Three different flours (sun-dried S, freeze-dried F, oven-dried O) were individually mixed at 9% with wheat flour (Dough Yield 300) and fermented (N₀: 8.0 log₁₀ CFU/g) for 14 h, using Lactiplantibacillus plantarum ITM21B, Weissella cibaria C43-11 or Leuconostoc mesenteroides C43-2M. The results showed that after fermentation, the content of organic acids (lactic, acetic and propionic), exopolysaccharides (EPS), l-glutamic acid and total free amino acids (TFAA) increased and the high molecular weight proteins were converted into smaller proteins. Sourdough based on Leuc. mesenteroides and O flour (O_LeuMes) was selected to evaluate its applicability in bread making. It was included in the yeast-leavened bread formulation at 20 or 40% (0.6% and 1.21% w/w O flour replacement). The results showed that fermentation limited the negative effects of unfermented O flour on bread quality attributes, mainly the specific volume and firmness. Bread with O_LeuMes at 40% was improved in TFAA, EPS and l-glutamic acid content and showed a higher specific volume and lower moisture and firmness compared to bread with the unfermented O flour. Full article

The quality of okra is crucial in satisfying consumer expectations, and the tenderness of okra is an essential parameter in estimating its condition. However, the current methods for assessing okra tenderness are slow and prone to errors, necessitating the development of a better, non-destructive method. The objective of the present study is to develop and test a non-destructive robotic sensor for assessing okra freshness and tenderness. A total of 120 pods were divided into two sets and stored under different conditions: 60 pods were kept in a cold chamber for 24 h (considered tender), while the other 60 pods were stored at room temperature for two days. First, the samples were assessed non-destructively using the force sensor of a collaborative robot, where a jamming pad (with internal granular fill) was capable of adapting and copying the okra shapes while controlling its force deformation. Second, the okra pods were evaluated with the referenced destructive tests, as well as weight loss, compression, and puncture tests. In order to validate the differences in the tenderness of the two sets, a discriminant analysis was carried out to segregate the okra pods into the two categories according to the destructive variables, confirming the procedure which was followed to produce tender and non-tender okra pods. After the differences in the tenderness of the two sets were confirmed, the variables extracted from the robotic sensor (maximum force (F_max), first slope (S₁), second slope (S₂), the first overshoot (O_s), and the steady state (S_s)) were significant predictors for the separation in the two quality categories. Discriminant analysis and logistic regression methods were applied to classify the pods into the two tenderness categories. Promising results were obtained using neural network classification with 80% accuracy in predicting tenderness from the sensor data, and a 95.5% accuracy rate was achieved in distinguishing between tender and non-tender okra pods in the validation data set. The use of the robotic sensor could be an efficient tool in evaluating the quality of okra. This process may lead to substantial savings and waste reduction, particularly considering the elevated cost and challenges associated with transporting perishable vegetables. Full article

Okra (Abelmoschus esculentus (L.) Moench) pod storage is challenging due to its high water content and tendency to lignify. Sodium hydrosulfide (NaHS) served as an H₂S donor in this investigation. Compared with the control group, the group treated with 0.5 mmol/L NaHS solution effectively maintained the appearance quality, and its weight loss was only 6.21% at 20 days. The H₂S treatment not only preserved tissue nutrients but also significantly enhanced catalase (CAT), ascorbic acid peroxidase (APX), and superoxide dismutase (SOD) activities while decreasing oxidant damage. In addition, H₂S slowed down lignin synthesis by inhibiting the activities of key enzymes such as phenylalanine ammonialyase (PAL), cinnamate 4-hydroxylase (C4H), and cinnamyl alcohol dehydrogenase (CAD) in the lignin biosynthesis pathway. Transcriptome analysis revealed that H₂S affects 34 genes in the phenylpropanoid biosynthesis pathway, such as AePAL, Ae4CL1, AeCCOAOMT1, AePOD, etc., which inhibit lignin synthesis of okra pods. All in all, moderate H₂S can improve postharvest quality and extend the shelf-life of okra pods by enhancing antioxidant capacity and delaying lignification; the results will provide an overview of its application in the preservation of okra pods. Full article

Recently, many studies have reported the properties and functionality of okra pectin. However, these studies are about green okra pods, and pectin in red okra pods, stems, and roots has not been reported. Therefore, this study aimed to optimize the red okra extraction method using response surface methodology (RSM) analysis and evaluate the effects of extraction time, temperature, solvent ratio, and pH on the extract yield and crude pectin content. Based on RSM analysis, 4.35 h, 98.04 °C, 23.34 solvent ratio, and pH 3.36 are the optimal parameters for extracting crude pectin from red okra, and the crude pectin content was predicted to be 40.83%. When red okra was extracted under these extraction conditions (4 h, 100 °C, 23 solvent ratio, and pH 3), the extraction yield was 45.26%, and the crude pectin content was 38.42%, which was similar to the yield obtained under the conditions derived from the RSM analysis. In addition, the pH control using hydrochloric acid was replaced with citric acid, and the changes in extract yield and crude pectin content were compared. When citric acid was used, the extract yield was 49.15% (8.6% increase), and the crude pectin content was 42.76 ± 2.56% (11.3% increase); compared to when hydrochloric acid was used, the yield increased. Finally, the standardization of red okra raw materials was determined by analyzing the extraction yield and crude pectin content by part, harvest time, and size of red okra using the established extraction method using citric acid. As a result, it was confirmed that the extraction yield obtained from the established extraction method was reached from the extraction of red okra fruits up to 12 cm in size that were harvested between July and November. Additionally, compared to the non-pectin fraction, the crude pectin fraction isolated from red okra pod extract showed significantly higher total phenolic content (TPC) and total flavonoid content (TFC). These findings, reported for the first time, may contribute to the development of processes to purify red okra pectin, functional evaluation studies of pectin, and potential applications of red okra extract in various industries and research. Full article

Okra (Abelmoschus esculentus) is an important vegetable that has been indigenized in African countries where it is consumed as a relish. There is still, however, a lack of documented cultivation techniques for better yields. An organic medium-enclosed trough (OMET) system is a growing technique that has been developed to reduce water and nutrient seepage during plant production. The study objectives evaluated the effect of OMET on the growth, yield, and nutritional attributes of okra. A complete randomized block design was established to accommodate the two treatments: OMET and non-OMET, in a micro-plot under field conditions. The stem diameter and plant height were recorded weekly during plant growth, and a clear increasing trend in OMET over non-OMET was observed from week 4 of transplantation. The OMET growing technique significantly increased the stem diameter and plant height by 37 and 48%, respectively. When evaluating the yield attributes, a similar trend was observed, where the OMET system significantly increased the yield attributes of okra as follows: biomass by 50%, the number of branches by 50%, the number of pods per plant by 49%, fresh pod weight by 53%, and pod length by 51%, while there was no significant difference in pod diameter width. Non-essential amino acids compounds, including arginine, serine, glycine, aspartate acid, glutamic acid, alanine, and proline and essential amino acids, including histidine, threonine, methionine, lysine, tyrosine, leucine, phenylalanine, asparagine and glutamine, were highly maintained in OMET compared to non-OMET. OMET enhanced the upregulation of proteins, Ca, Mg, K, Mn, Na, P and Zn elemental nutrients in the disposal of less irrigation water than non-OMET. This growing technique could be recommended for small-scale and commercial farming to improve the okra production of nutrition. Full article

Drought stress restricts the growth of okra (Abelmoschus esculentus L.) by disrupting its biochemical and physiological functions. The current study was conducted to evaluate the role of selenium (0, 1, 2, and 3 mg Se L⁻¹ as a foliar application) in improving okra tolerance to drought (control (100% field capacity-FC), mild stress (70% FC), and severe stress (35% FC)) imposed 30 days after sowing (DAS). Drought (severe) markedly decreased chlorophyll (32.21%) and carotenoid (39.6%) contents but increased anthocyanin (40%), proline (46.8%), peroxidase (POD by 12.5%), ascorbate peroxidase (APX by 11.9%), and catalase (CAT by 14%) activities. Overall, Se application significantly alleviated drought stress-related biochemical disturbances in okra. Mainly, 3 mg Se L⁻¹ significantly increased chlorophyll (21%) as well as anthocyanin (15.14%), proline (18.16%), and antioxidant activities both under drought and control conditions. Selenium played a beneficial role in reducing damage caused by oxidative stress, enhancing chlorophyll and antioxidants contents, and improved plant tolerance to drought stress. Therefore, crops including okra especially, must be supplemented with 3 mg L⁻¹ foliar Se for obtaining optimum yield in arid and semiarid drought-affected areas. Full article

In modern agriculture, the substrate industry prefers porous materials for plants to provide water and nutrients in soilless cultivation. Composted sawdust is such a substrate. The sawdust industry is interested in avoiding composting sawdust because it is time and labor-consuming. The study objective was to evaluate whether non-composted (fresh) Bombax ceiba (red cotton tree) sawdust with added nutrients could be an alternative to composted sawdust for okra production. The sawdust was mixed with nutrients in the form of banana peels (a potassium source), eggshells (a calcium source), and urea (a nitrogen source). We conducted two independent pot experiments. Treatments were viz.: T₁: non-fertilized 100% sandy clay loam soil (control) (vol/vol); T₂: non-composted 100% B. ceiba sawdust (vol/vol); T₃: non-composted 80% B. ceiba sawdust + 20% banana peels (vol/vol); T₄: non-composted 60% B. ceiba sawdust + 20% banana peels + 20% eggshells (vol/vol); T₅: non-composted 60% B. ceiba sawdust + 20% banana peels + 20% eggshells (vol/vol) + urea (@ 91 kg N ha⁻¹). In both experiments, the germination of okra seeds was unaffected by the sawdust mixtures. The phenological development of okra was significantly greater in non-fertilized clay loam soil than in any non-composted sawdust mixtures. Plant height, leaf relative water content, stability index of the membrane, root length, chlorophyll content index, root and shoot dry and fresh weight, stem diameter, and single leaf area of okra were lower in all non-composted B. ceiba sawdust mixtures compared to the control. In contrast to T₂, T₅ resulted in fewer days before the first flower developed, an increase in the number of pods plant⁻¹, length of pod plant⁻¹, the diameter of the pod, fresh and dry weight of pod plant⁻¹, and the seed numbers pod⁻¹. It is concluded that amending non-composted B. ceiba sawdust with banana peels, eggshells, and urea (T₅) enhanced its perspective as a growth medium for okra. Nonetheless, the amendments were unlikely to establish an adequate yield of okra, as was the case with non-fertilized sandy clay loam soil. Full article

In this work, stable and spherical silver nanoparticles (AgNPs) were synthesized in situ from silver salt (silver nitrate) using the aqueous extract of the okra plant (Abelmoschus esculentus) at room temperature and ambient pH conditions. The influences of different parts of the plant (such as the leaves, stems, and pods) on the chemical-reducing effectiveness of silver nitrate to silver nanoparticles were investigated. The aqueous extract of the leaves was found to be more effective in the chemical reduction of silver nanoparticles and in stabilizing them at the same time. The silver nanoparticles produced were stable and did not precipitate even after storage for 1 month. The extract of the stem was less effective in the reduction capacity followed by the extract of the pods. The results indicate that the different amounts of phytochemicals present in the leaves, stems, and pods of the okra plant are responsible for the chemical reduction and stabilizing effect. The silver nanoparticles were characterized by UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The surface plasmon resonance (SPR) peak at 460 nm confirmed the formation of silver nanoparticles. The nanoparticles were spherical with an average size of 16 nm and polycrystalline with face-centered cubic (fcc) structures. The z-scan technique was used to study the nonlinear refraction and absorption coefficients of AgNPs at wavelengths of 488 and 514 nm under C.W. mode excitation. The nonlinear refraction index and nonlinear absorption coefficients were calculated in the theoretical equations in the experimental data. The antibacterial properties of the nanoparticles were evaluated against Gram-positive and Gram-negative bacteria. Full article

Okra (Abelmoschus esculentus L.), a tropical annual crop, is a highly perishable vegetable. Okra pods deteriorate rapidly after harvesting. The pods undergo physical and physiological changes that diminish storability and quality. The purpose of this study was to investigate the effect of bio-stimulants on the storability and quality of okra pods stored at 4 °C and 25 °C for 12 days. Dipping okra pods for 5 min in a solution of 0.5% ascorbic acid, citric acid, or salicylic acid pre-storage significantly extended the shelf life and preserved the quality of the pods compared to the control condition at 4 °C and 25 °C. Citric acid and ascorbic acid were the most effective in preserving most traits. Citric acid reduced the loss in weight, firmness, appearance, and prevented decay at 4 °C and 25 °C. Ascorbic acid decreased the loss of moisture and the degradation of carbohydrates, vitamin C and lycopene at 4 °C and 25 °C. Salicylic acid decreased the degradation of protein at 25 °C. The low temperature was highly effective in decreasing the loss or degradation of most of the studied traits. Taken together, bio-stimulants and storing at 4 °C played a prominent role in extending the shelf life and preserving the quality of okra pods. Full article

Genetic diversity analysis of crop genetic resources is a prerequisite for parental selection with suitable and complementary profiles for breeding. The objectives of this study were to determine genetic diversity present among okra accessions using simple sequence repeat (SSR) and complementary phenotypic markers and to select genetically divergent and superior parental accessions for pre-breeding. Twenty-six preliminarily selected okra accessions were assessed using nine highly polymorphic SSR markers and phenotyped under drought-stressed (DS) and non-stressed (NS) environmental conditions using a 13 × 2 alpha lattice design with two replications. Data were collected on the following eleven phenotypic traits: plant height (PH), days to 50% maturity (DTM), fresh pod length (FPL), dry pod weight (DPW), dry pod length (DPL), number of pods per plant (NPPP), pod yield per plant (PYPP), total above-ground biomass (AGB), harvest index (HI), root weight (RW), and root to shoot ratio (RSR). The SSR markers revealed an expected mean heterozygosity value of 0.54, indicating moderate genetic diversity among the tested okra accessions. Cluster analysis based on phenotypic and SSR markers differentiated the accessions into three distinct genetic groups. Wide phenotypic variation was observed for PH, FPL, NPPP, and PYPP under NS and DS conditions. PYPP was positively and significantly correlated with FPL (r = 0.81), ABG (r = 0.69), and HI (r = 0.67) under DS conditions, and FPL (r = 0.83) and AGB (r = 0.60) under NS conditions. Genetically complementary accessions such as LS04, LS05, LS06, LS07, LS08, LS10, LS11, LS15, LS18, LS23, LS24, and LS26 were identified for their high yield potential and related yield-improving traits under DS conditions. The identified accessions are recommended as parents for hybridization and selection programs to improve the yield potential of okra under drought-stressed environments. Full article

There is limited evidence that Enterobacter hormaechei can improve plant physiology and yield through soil phosphate (P) and potassium (K) amelioration. This study unraveled the effect of different soil inoculation methods i.e., free-cell and encapsulated (alginate bead containing sugar-protein hydrolysate and molasses) E. hormaechei 40a with different rates of PK-fertilization on okra P and K uptake, and soil rhizosphere bacterial community. The results revealed that 3HB (half-dose PK-fertilizer + encapsulated strain 40a) had the highest soil available P (SAP) and K (SAK), as well as P and K uptake for all plant organs, followed by 3F (full-dose PK-fertilizer), 3HI (half-dose PK-fertilizer + free-cell strain 40a), and 3H (half-dose PK-fertilizer), and improved yield by up to 75.6%. Both inoculated and full-dose fertilizer treatments produced larger pods (>15 cm) compared to 3H. We discovered increased bacterial richness and diversity in both 3HB and 3HI samples compared to uninoculated treatments. Both 3HB and 3F treatments were positively correlated with the increasing abundance of Acidobacteriales, Burkholderia caballeronia paraburkholderia, Gemmataceae, and Sphingomonas along with the SAP and SAK. The plant-beneficial effect of one-time 3HB treatment on okra growth and yield was comparable to biweekly inoculation in 3HI, suggesting a new cost-effective farming approach in precision agriculture. Full article

Okra is a kind of flavonoid-rich food which was reported to have a variety of health functions. Flavonoids are the major polyphenolic compounds in okra and are thought to play a role in reducing the risk of disease. The aim of this study was to isolate and identify the flavonoids composition in okra pods and explore the activity of the main flavonoids components identified on inhibiting tumor cell proliferation in vitro. Six individual flavonoids were identified by HPLC-MS/MS: quercetin-3-gentiobioside (Q3G), quercetin-3-sambubioside (Q3S), rutin, quercetin-7-glucoside (Q7G), isoquercitrin (ISO) and quercetin-3-malonylglucoside (Q3M), which were all separated well within 30 min. The analytical method was validated by the recovery of spiked samples and so on. Moreover, four main flavonoids components, namely Q3G, Q3S, ISO and Q3M, exhibited significant (p < 0.05) inhibition of NCI-N87, A375, A549 cells proliferation (25−100 μmol/L) and of HFLS-RA (200−300 μmol/L) in different levels, according to MTT method, respectively. It is demonstrated that the flavonoids components of okra exhibited a noteworthy development prospect as a possible nutraceutical dietary supplement. Full article