Fruit Quality Research Articles

Effectiveness of KMnO4 and activated carbon on the quality and storage properties of mango fruit

Cat Hoa Loc mango (Mangifera indica L.) is a well-known variety in Vietnam because of its distinct taste and aroma. However, it has a short shelf life and can suffer post-harvest losses if not handled and packaged correctly. The demand for fresh Cat Hoa Loc mangoes has been increasing worldwide, and this has led to the development of effective handling methods to extend their shelf life. To address this issue, this study was conducted to evaluate the effectiveness of KMnO4 and activated carbon in preserving the quality and shelf life of Cat Hoa Loc mangoes in Vietnam. The Cat Hoa Loc mango variety in Cao Lanh, Dong Thap province, was chosen for the study. The study used five replications of a completely randomized block design. Six different treatments with KMnO4 and activated carbon (1:1 ratio) were tested, including 0; 4; 8; 12; 16; 20 g/box. Six mangoes were stored in perforated cartons (36x26x9 cm) at room temperature (28-30°C) during the study period. The study evaluated several parameters to assess the quality and shelf life of the mangoes, including weight loss, fruit firmness, browning index, respiration, ethylene release rate, soluble sugar, and vitamin C. The results showed that the quality of the mangoes was extended when treated with 12 g of KMnO4 and activated carbon per box. This treatment resulted in the lowest physiological weight losses, respiration, and ethylene release rate. Furthermore, this treatment showed the highest fruit firmness, soluble sugar, and vitamin C content, as well as the longest shelf life at the end of the storage period.

Transcriptome analysis reveals regulatory mechanism of postharvest softening in kiwiberry

BackgroundKiwiberry is an emerging edible fruit with market potential owing to its advantages of small size, thin and hairless skin, and sweet taste. However, kiwiberry is highly susceptible to softening after harvest, which poses a challenge for storage and transport. To reveal the underlying cause of kiwiberry softening, it is essential to investigate the characteristics of postharvest fruit and the molecular mechanisms that affect changes in fruit firmness.ResultsMorphological observations and analysis of physical parameters showed that the skin of kiwiberry did not change markedly from the 1st to the 7th day after harvest, while the colour of the inner pericarp gradually turned yellow. By the 9th day of room temperature storage, the kiwiberries began to rot. The hardness decreased rapidly from the 1st to the 5th day postharvest, reaching the low level on the 5th day. The starch and pectin contents of kiwiberry showed a downward trend with increasing storage time. Transcriptome sequencing and weighted gene co-expression network analysis identified 29 key genes associated with the changes in the hardness of kiwiberry after harvest. Gene Ontology enrichment analysis indicated that these 29 genes are mainly involved in pectin metabolism, starch synthesis, starch decomposition, and starch metabolism. In addition, three transcription factors, AGL31, HAT14, and ALC, were identified to be strongly positively correlated with the 29 genes that affect the hardness changes of kiwiberry after harvest, and 28 of the 29 key genes were predicted to be regulated by HAT14.ConclusionsThese results reveal the changes in morphological characteristics and physiological indicators during the postharvest ripening and softening of kiwiberry stored under room temperature conditions. Transcriptome analysis identified 29 key genes and three transcription factors that affect the firmness changes of postharvest kiwiberry. The results of this study thus provide insight into the transcriptional regulatory mechanism of kiwiberry softening during storage to improve the postharvest quality.

Effect of pullulan and pullulan-chitosan composite coating on the antioxidant activity, texture, color and shelf-life of a local cultivar of sweet cherry

This study explored the effects of pullulan and pullulan-chitosan composite edible coatings on the post-harvest quality of sweet cherries over 20 days of storage. We evaluated weight loss, total soluble solids (TSS), decay percentage, color value, texture and biochemical content, including ascorbic acid, total phenolic content (TPC), flavonoids, anthocyanins, antioxidant activity and enzyme activity. The results revealed that cherries with 3 % pullulan coating presented the lowest weight loss (25 % vs 26.33 % in the control) and decay percentage (25 % vs 47 % in the control) and maintained superior texture and stability compared with those of the control and other coatings. TSS increased less in the coated cherries than in the control cherries, with 3 % pullulan-treated cherries showing the least increase, indicating slower ripening. Pullulan coatings effectively reduced color changes, with the 3 % coating delaying darkening in cherries more than the other treatments did. Additionally, the pullulan coating preserved higher levels of ascorbic acid, phenolic compounds (TPC) and flavonoids and delayed the decrease in antioxidant activity. Notably, the 3 % pullulan-treated cherries maintained the highest antioxidant activity (88.97 %) and had the greatest TPC (2.79 mg GAE/g FW) at the end of storage. The activity of enzymes, particularly peroxidase (POD), increased less in coated cherries, highlighting the role of coatings in delaying oxidative stress. Overall, the pullulan coatings, especially at a 3 % concentration, were the most effective at extending the shelf-life and maintaining the quality of the sweet cherries. These findings suggest that the use of a pullulan-based coating is a promising approach for preserving fruit quality during storage, thereby extending shelf-life. These coatings can contribute to a reduction in food waste, improved consumer acceptability and improved economic gains by reducing postharvest losses and maintaining quality. To optimize pullulan-based coatings for commercial application, future research can focus on optimizing the formulation, consumer acceptability and scalability. Moreover, field trials to assess the effectiveness of these coatings in preserving the quality of cherry can be performed. By addressing these areas, future research can contribute to the development of sustainable options for preserving the quality and extending the shelf life of sweet cherries and other fruits.

Amending clayey and sandy soils with nano - bio phosphorous for regulating tomato growth, biochemical, and physiological characteristics

Phosphorus is a critical nutrient that significantly enhances tomato production, so maintaining an adequate level of phosphorus plays an essential role in enhancing the growth of tomato by being present in the soil. This study assessed the impact of soil texture and phosphorus content on tomato plant properties using a factorial, complete, randomized design with four replications. Treatments included clayey and sandy soils with varying phosphorus sources: non-phosphorus (P0), calcium phosphate (CaP1 and CaP2), and nano-hydroxyapatite (PN1 and PN2), where 1 indicates a concentration of 0.12 g and 2 indicates a concentration of 0.23 g per 5-kilogram pot of fertilizer. Results indicated that treatments significantly influenced yield parameters such as average fruit weight, juice content, antioxidant activity, and fruit volume. In the clayey soil, CaP2 treatment had a superior effect on yield, average fruit weight, and shoot fresh weight. In comparison with sandy conditions, CaP2 produced a 50% increase in fruit number, 29% increase in average fruit weight, and 91% increase in fruit yield. The treatments then impacted the shoot fresh weight and root length, while the phosphorus concentration appeared to be more dependent on soil type than on phosphorus sources. Similar to the CaP1 and CaP2 treatments, the PN1 treatment in clay soil also resulted in the highest fresh and dry weights of tomato shoots when compared with the control group. Generally, the findings from this study suggest that the use of CaP2 can serve as a reliable method to improve the growth, yield, and fruit quality of tomatoes, especially in clayey soil environments. However, nano-based phosphorous sources need to be tested more to see if they can improve tomato performance in a range of soil conditions. Also, further research should look into the long-term effects of phosphorous interventions on soil health and sustainability.

Distribution characteristics of photoassimilates in walnut leaves to different organs

The understanding of photoassimilate distribution serves as the fundamental basis for scientific regulation of fruit quality. Currently, there is a scarcity of research on whole-plant scale photoassimilate distribution in walnut. In order to clarify the characteristics of leaf photoassimilates translocation to various organs in 5-year-old 'Wen185' (J. regia 'Wen185') walnut during the growing season, this study used the 13C isotope pulse labeling technique to label the whole plant of walnut trees in the growing season, temporal variations of 13C abundance (δ13C), 13C partition rate (R13C), leaf source strength and fruit sink strength were analyzed in various organs at different days after tree flowering. The findings indicated that during the periods of 30–70 days and 90–110 days after flowering, there was a higher distribution of 13C in fruits and vegetative branches. However, at 110–130 days after flowering, the predominant allocation of 13C shifted towards main trunk and roots. In-depth study of source leaves and sink fruits showed that chlorophyll content in leaves increased significantly 30–50 days after anthesis, indicating that they gradually became mature functional leaves. The increase of net photosynthetic rate led to increase of source strength, and the retention of photoassimilates in leaves was higher at this time. From 30 to 70 days after flowering, the fresh weight and volume of fruit increased rapidly, which increased the capacity of the sink and enhanced the competition ability against photoassimilates. The recovery of photosynthetic capacity of leaves from 90 to 110 days promoted the output of photoassimilates. At this time, walnut entered the oil conversion period, and the demand for photoassimilates increased. All these factors jointly promoted the unloading of photoassimilates in fruit. In summary, maintaining adequate material conditions and optimizing tree structure at 30-70d and 90-110d after anthesis are important for more efficient distribution of photoassimilates to fruit.

Sustained carbon import supports sugar accumulation and anthocyanin biosynthesis during fruit development and ripening in blueberry (Vaccinium ashei)

Fruit ripening is a highly coordinated process involving molecular and biochemical changes that collectively determine fruit quality. The underlying metabolic programs and their transitions leading to fruit ripening remain largely under-characterized in blueberry (Vaccinium sp.), which exhibits atypical climacteric behavior. In this study, we focused on sugar, acid and anthocyanin metabolism in two rabbiteye blueberry cultivars, Premier and Powderblue, during fruit development and ripening. Concentrations of the three major sugars, sucrose (Suc), glucose (Glc), and fructose (Fru) increased steadily during fruit development leading up to ripening, and increased dramatically by around 2-fold in ‘Premier’ and 2- to 3-fold in ‘Powderblue’ during the final stage of fruit ripening. Starch concentration was very low throughout fruit development in both cultivars indicating that it does not serve the role of a major transitory carbon (C) storage form in blueberry fruit. Together, these patterns indicate continued import of C, likely in the form of Suc, throughout blueberry fruit development. Concentrations of the predominant acids, malate and quinate, decreased during ripening, and may contribute to increased shikimate biosynthesis which, in-turn, allows for downstream phenylpropanoid metabolism leading to anthocyanin synthesis. Consistently, anthocyanin concentrations were highest in fully ripened blue fruit. Weighted gene co-expression network analysis (WGCNA) was performed using a ‘Powderblue’ fruit ripening transcriptome and targeted fruit metabolite concentration data. A ‘dark turquoise’ module positively correlated with sugars and anthocyanins, and negatively correlated with acids (malate, quinate), was identified. Gene Ontology (GO) enrichment analysis of this module identified transcripts related to sugar, acid, and phenylpropanoid metabolism pathways. Among these, increased transcript abundance of a VACUOLAR INVERTASE during ripening was consistent with sugar storage in the vacuole. In general, transcript abundance of the glycolysis pathway genes was upregulated during ripening. The transcript abundance of PHOSPHOENOLPYRUVATE (PEP) CARBOXYKINASE increased during fruit ripening and was negatively correlated with malate concentration, suggesting increased malate conversion to PEP, which supports anthocyanin production during fruit ripening. This was further supported by the co-upregulation of several anthocyanin biosynthesis-related genes. Together, this study provides insights into important metabolic programs, and their underlying gene expression patterns during fruit development and ripening in blueberry.

Enhancing Soil-Grown Strawberry Fruit Quality through the Synergistic Influence of Beneficial Microorganisms and Digestate

Enhancing Soil-Grown Strawberry Fruit Quality through the Synergistic Influence of Beneficial Microorganisms and Digestate

Flowering and fruiting characteristics of Kokum [Garcinia indica (Thouars) Choisy] germplasm collected for Industrial Use from the Konkan Region of India

Abstract Kokum [Garcinia indica (Thouars) Choisy] is a multi-purpose tree with culinary, cosmetics and pharmaceutical uses found popular in Konkan region of India. ICAR-NBPGR Regional Station, Thrissur made a systematic exploration and collection missions on kokum over a period from 1987–2004 and collected 31 accessions from various parts of Konkan region to characterize them using morphological characters and also to investigate their flowering and fruiting behaviour. Totally, 85 trees planted in Field Gene Bank in which only 67 trees (23 accessions) survived during field establishment. Among them, 32 (47.8%) were male and remaining 25 identified as female (37.3%) and 10 as co-sexual (14.9%). Fruit bearing ability noticed only in both female and co-sexual trees with huge variation in fruits. Morphological characterization of 33 trees with fruiting (23 accessions) for 35 morphological traits revealed presence of considerable amount of variation among them on basis of CV%. Highest positive correlation observed between fresh seed weight and fresh kernel weight (0.92). Cluster analysis formed four major clusters with Cluster I and II comprising male/bisexual genotypes and Cluster III and IV with female genotypes and it clearly distinguished male/bisexual genotypes from female ones. PCA analysis accounted 65.6% of genetic variation present among accessions by first three most informative PCs. Superior accessions identified for important traits will be more useful in industrial aspects of preparing kokum butter and juice. Further, seasonal difference identified in fruiting and maturity of fruits well-before onset of monsoon may be exploited by kokum industries for drying and processing of fruits.

Improving Yield and Quality of ‘Balady’ Mandarin Trees by Using Shading Techniques and Reflective Materials in Response to Climate Change Under Flood Irrigation Conditions

Considering climate change predictions, it is logical to anticipate detrimental effects on the mandarin tree, an essential citrus crop. Therefore, scientists should promptly focus on developing methods to enhance its resistance to climatic stress effects such as sunscald. This study assesses the strategies employed in ‘Balady’ mandarin trees when covered by shading nets of varying colors and percentages (white 50%, green 50% or 63%, black 50% or 63%), as well as the application of reflective materials (kaolin at 4% and CaCO3 at 3%) on the micro-climate of orchards, leaf, and fruit surface temperatures, fruit sunburn%, productivity, and fruit quality. The results indicated that shade nets effectively reduced temperature and enhanced humidity, especially during the period from June to September, when compared to open-field treatments. Black shade nets, particularly those with a shading level of 63%, demonstrated the most notable decrease in canopy temperature and an elevation in humidity, surpassing the performance of green and white shade nets. The present study found that shade nets and reflecting materials like kaolin and calcium carbonate significantly reduced fruit sunburn. Trees without shade had a sunburn rate of 8.74%, while those with shade treatments suffered no sunburn. Kaolin foliar spray at a concentration of 4% and calcium carbonate at a concentration of 3% reduced sunburn incidence to 3.64% and 7.32%, respectively. These treatments also reduced the intensity of sunburn. All treatments increased fruit yield % compared to the control and yield efficiency (kg/m2), especially the trees covered with white shade net of a 50% shading rate provided the highest values (43.70 and 40.17%) and (5.24 and 5.47 kg/m2) compared to other treatments in both seasons, respectively. Trees covered with a white shade net of a 50% shading rate, followed by a green shade net of 50% and a 63% shading rate, as well as a black shade net of 50% and a 63% shading rate, tended to improve the physical and chemical fruit properties. Therefore, it could be recommended that trees be covered with a white shade net of a 50% shading rate or a green shade net of a 50 and 63% shading rate in summer months due to its beneficial impact on mitigating fruit sunburn damage and enhancing the productivity and quality of ‘‘Balady’’ mandarin trees. Hence, shade nets can be a beneficial technology to protect citrus fruits from sunburn without affecting fruit quality in commercial citrus farms.

Assessment of heat tolerance and identification of miRNAs during high-temperature response in grapevine.

With global warming, heat stress has been recognized as a significant factor limiting grapevine development and fruit quality. MicroRNAs (miRNAs) are a class of small non-coding RNAs known to play crucial regulatory roles in stress resistance. Hence, there is an immediate requirement to cultivate and identify grapevine varieties that are resistant to heat and explore miRNA-mediated heat stress defense mechanisms. In this study, we assessed the thermal resistance of 38 grape germplasm resources and identified a series of miRNAs involved in heat stress resistance. The CK (25°C) and HS (45°C) groups of "Shenyue" cuttings of grapes were used as experimental materials for next-generation sequencing and construct libraries of small RNAs. A total of 177 known and 20 novel miRNAs were detected in the libraries. Differential expression analysis identified 65 differentially expressed miRNAs (DEMs) using the DE-Seq procedure. Furthermore, RT-qPCR validation confirmed complementary expression profiles of eight DEMs and their target genes between the HS and CK groups. Heterologous transformation further identified the function of Vvi-miR3633a downregulated under heat stress in Arabidopsis. In the heterologous expression lines, the survival rate was reduced by high temperature treatment indicating the ability of Vvi-miR3633a to regulate heat resistance. Assessing the heat resistance of grape species and the expression patterns of miRNA in response to high temperatures may reveal the molecular processes of heat resistance regulation mediated by miRNA in grapes under heat stress.

Identification of Candidate Genes Associated with Flesh Firmness by Combining QTL Mapping and Transcriptome Profiling in Pyrus pyrifolia

Flesh firmness is an important quality of pear fruits. Breeding cultivars with suitably low flesh firmness is one of the popular pear breeding goals. At present, SNP markers related to pear flesh firmness and genes affecting flesh firmness are still uncertain. In this study, a QTL analysis was performed, and the result showed that the position of 139.857 cM in lineage group 14 (LG14) had the highest average logarithm of odds (3.41) over two years. This newly discovered locus was identified as a flesh firmness-related QTL (qFirmness-LG14). The ‘C/T’ SNP was found in corresponding Marker1512129. The ‘C’ genotype is the high-firmness genotype, which is a dominant trait. The average firmness of fruits with genotype C is 21.4% higher than genotype without the C genotype. Transcriptome profiling was obtained between ‘Zaoshengxinshui’ and ‘Qiushui’ at five time points. Three candidate genes in the interval of qFirmness-LG14 might affect firmness. A gene of xyloglucan endotransglucosylase 1 (PpXTH1) was upregulated in ‘Qiushui’ at all five time points. Two transcription factors (PpHY5 and PpERF113) were upregulated in ‘Zaoshengxinshui’, which might be negative regulatory genes for high flesh firmness. The transcriptome results also isolated a large number of cell wall-related genes (e.g., Pectate lyase, Pectin acetylesterase, Pectin methylesterase, and 4-coumarate-CoA ligase) and transcription factors (e.g., ERF, WRKY). These genes are all potential upstream and downstream genes related to flesh firmness. In conclusion, this study provides valuable insights into the QTLs and molecular mechanisms associated with fruit firmness in Pyrus pyrifolia.

Assessment of quality and antioxidant capacity of peach in response to different UV-C dose irradiation.

The effects of different doses of UV-C irradiation (0, 0.5, 1.0, 2.0, and 4.0kJ m-2) on the quality and antioxidant capacity of peach fruit were examined. Results showed that irradiation at 2.0kJ m-2 led to higher firmness and total soluble solids, as well as lower weight loss and decay index. Additionally, peach fruits irradiated with 2.0kJ m-2 UV-C exhibited increased production of reactive oxygen species, which in turn stimulated the synthesis of total phenolics and total flavonoids and enhanced the activities of superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase. Overall, the best abiotic stress effect was observed with 2.0kJ m-2 UV-C irradiation, resulting in improved shelf quality and increased antioxidant capacity of peach fruits during storage. PRACTICAL APPLICATION: This study provides a theoretical basis for the application of UV-C irradiation in peach fruit preservation.

Induced Resistance in Fruit and Vegetable Enhancing Host Defence to Curve Post-harvest Diseases

Induced resistance (IR) is an emerging, environmentally friendly strategy to manage post-harvest diseases in fruits and vegetables by enhancing the plant’s innate immune system. This approach leverages the plant's natural defense mechanisms, including the activation of defense-related enzymes like chitinases, glucanases, and peroxidases, accumulation of secondary metabolites such as phytoalexins and phenolics, and the strengthening of cell walls to prevent pathogen invasion. Additionally, the production of reactive oxygen species (ROS) plays a crucial role in both signaling and direct pathogen inhibition. Despite its potential, the effectiveness of IR varies across different crops and pathogens, and its success is heavily influenced by environmental factors, such as humidity, temperature, and light. There are also concerns regarding possible trade-offs, such as reduced yield or changes in fruit quality due to the diversion of energy towards defense responses. However, the integration of IR with other disease management strategies, including the use of biological control agents and conventional fungicides, has shown promising results in reducing post-harvest losses. Case studies in fruits like apples, tomatoes, and citrus, as well as vegetables like potatoes and peppers, demonstrate the practical applications of IR in commercial agriculture. Advances in genetic engineering are opening new pathways for enhancing IR by manipulating key genes involved in defense pathways, while new formulations and precision agriculture technologies offer greater control and efficiency in IR applications. These innovations, along with optimized post-harvest handling and storage practices, hold the potential to make IR a more reliable and sustainable solution for managing post-harvest diseases. However, ongoing research is necessary to address the variability in effectiveness and to explore long-term sustainability, especially as pathogens evolve and environmental conditions change. Induced resistance, when integrated with a comprehensive disease management approach, offers a significant step forward in reducing post-harvest losses and improving food security globally.

Current insights into yeast application for reduction of patulin contamination in foods: A comprehensive review.

Patulin, a fungal secondary metabolite with multiple toxicities, is widely existed in a variety of fruits and their products. This not only causes significant economic losses to the agricultural and food industries but also poses a serious threat to human health. Conventional techniques mainly involved physical and chemical methods present several challenges include incomplete patulin degradation, high technical cost, and fruit quality decline. In comparison, removal of mycotoxin through biodegradation is regarded as a greener and safer strategy which has become popular research. Among them, yeast has a unique advantage in detoxification effect and application, which has attracted our attention. Therefore, this review provides a comprehensive account of the yeast species that can degrade patulin, degradation mechanism, current application status, and future challenges. Yeasts can efficiently convert patulin into nontoxic or low-toxic substances through biodegradation. Alternatively, it can use physical adsorption, which has the advantages of safety, high efficiency, and environmental friendliness. Nevertheless, due to the inherent complexity of the production environment, the sole utilization of yeast as a control agent remains inherently unstable and challenging to implement on a large scale in a practical manner. Integration control, enhancement of yeast resilience, improvement of yeast cell wall adsorption capacity, and research on additional patulin-degrading enzymes will facilitate the practical application of this approach. Furthermore, we analyzed the feasibility of the yeast commercial application in patulin reduction and provided suggestions on how to enhance its commercial value, which is of great significance for the control of mycotoxins in food products.

Effect of lemongrass and chili pepper oils on the quality of ripe tomato fruits stored under tropical ambient temperature

Postharvest quality of tomato (Solanum lycopersicum L.) fruits treated with lemongrass (Cymbopogon citratus L.) and chili pepper (Capsicum annuum L.) oil was evaluated. Tomato variety Roma fruits of uniform size and weight at the red stage of ripening were overlaid with lemongrass oil only (L1P0), chili pepper oil only (L0P1), or mixtures in a ratio 1:1 (L1P1), and 1:2 (L1P2 and L2P1). Control (L0P0) was not treated with any oil. Treated and untreated fruits were stored at 280±20C and 46%±2 RH for 12 days. Treatments L1P0 and L2P1 oil inhibited postharvest tomato fruit rot for 12 days, whereas L1P2, L0P1, and L1P1 oil and the control showed rot within the range of 86.6% - 100% in 12 days. L1P0 and L2P1 also slowed fruit softening and significantly reduced weight loss, though L1P0 was the most protective. Total soluble solid content of fruit was not affected by both L1P0 and L2P1 throughout storage, but the parameter reduced significantly (p<0.05) in fruits treated with L1P1, L1P2, L0P1 and in control. Reduction in titratable acidity during storage was least in fruits treated with L1P0 followed by L2P1, compared to that in other treatments and the control. This study showed that lemongrass oil applied as surface coating preserved tomato fruit quality in tropical ambient storage conditions for 12 days.

Foliar Nourishment with Different Potassium Sources to Maximize Yield Through Improving Nutrient Uptake in Citrus Aurantifolia Trees Grown in Potassium-Deficient Soil

AbstractPurpose: Based on its crucial regulatory role in several biochemical processes, potassium (K) is considered to greatly influence fruit yield and quality. Methods: Two field experiments were carried out in two seasons (2021 and 2022) to explore the response of lemon (Baladi cv.) trees grown in K-deficient soil to four different K fertilizer sources applied individually as a foliar spray. K citrate (KC1 = 1.3 vs. KC2 = 2.6 g L− 1), K nitrate (KN1 = 1.5 vs. KN2 = 3.0 g L− 1), K tartrate (KT1 = 1.5 vs. KT2 = 3.0 g L− 1), and K thiosulfate (KS1 = 1.25 vs. KS2 = 2.5 g L− 1) were applied three times, and the treated trees were compared with untreated trees. This study was established with a randomized complete block design (RCBD) using four replicates. Results: The findings revealed that the KC treatment, regardless of dosage, showed clear superiority in terms of the values for the leaf phosphorus (%), manganese, and zinc contents (mg kg− 1), as well as fruit firmness, fruit dry matter, and total soluble solids in both seasons. In second place was the KT treatment, which yielded the best values for fruit length and width in 2021, the best values for leaf nitrogen and iron contents and fruit weight and volume in 2022, and the best values regarding variable fluorescence by maximum fluorescence, relative chlorophyll content (SPAD readings), the photosynthetic performance index, total acidity, and vitamin C in both seasons. Furthermore, the highest total lemon yield and leaf potassium contents were achieved with the KN treatment in both seasons. The heat map illustrating that most of the studied characteristics were positively and significantly correlated with total lemon yield (TLY). Conclusions: The KN treatment, closely followed by the KC treatment, is regarded to be the best treatment for most of the studied trails.

Multispecies Trichoderma in Combination with Hydrolyzed Lignin Improve Tomato Growth, Yield, and Nutritional Quality of Fruits

The application of biological pesticides as alternatives to chemical phytosanitary products is a natural and innovative method to improve environmental protection and sustainable agricultural production. In this work, the compatibility between Trichoderma spp. and a commercial lignin extract was assessed in vitro and in vivo. The beneficial effects of lignin in combination with different Trichoderma consortia were evaluated in terms of improved growth and quantitative and qualitative tomato productivity. T. virens GV41 + T. asperellum + T. atroviride + lignin formulation was the most effective in growth promotion and increased root and stem dry weight compared to control (45.4 and 43.9%, respectively). This combination determined a 63% increase in tomato yield compared to the control, resulting in the best-performing treatment compared to each individual constituent. Consistent differences in terms of lycopene, GABA, ornithine, total, essential, and branched-chain amino acids were revealed in fruits from tomato plants treated with Trichoderma–lignin formulations (T. asperellum + T. virens GV41 + lignin) or with the microbial consortia (T. asperellum + T. virens GV41, T. atroviride + T. virens GV41). The developed bioformulations represent a sustainable biological strategy to increase yield and produce nutritional compound-enriched vegetables.

Long-term effects of combining reclaimed and freshwater on mandarin tree performance

The current scenario of water scarcity leads to a seek for new irrigation strategies that maintain agricultural productivity while reducing the pressure on freshwater resources, especially in the Mediterranean region, which has a structural deficit of water sources. In this study, the effects of irrigation with water from different origins were assessed over six consecutive years in soil salinity indicators, tree physiology and yield of mandarin trees in south east Spain. The following treatments were considered: i) freshwater from the “Tagus-Segura” water-transfer canal (TW or Control); ii) reclaimed water from a wastewater-treatment plant (RW); iii) irrigation with TW, except in stage II of fruit development when RW was used (TWc); and iv) irrigation with RW except in stage II when TW was used (RWc). Soil salinity indicators increased in all treatments with respect to Control, except for TWc in winter. However, this increase only led to reductions in net photosynthesis and stomatal conductance in the RW treatment, while gas exchange parameters of trees from TWc and RWc were not negatively affected. Tree vegetative growth was only affected in the long-term, with trees from the RWc treatment having greater canopies. Yield was increased in the TWc and RWc treatments by 23.1 % and 29.5 %, respectively; while it was reduced by 23.5 % in RW when compared to TW. Likewise, differences among treatments in fruit quality traits were also detected. Our results suggest that combining water from different sources could be a viable alternative for irrigating mandarin trees under semiarid conditions with savings of approximately 50 % of fresh water, although the sustainability of soil health should be ensured. In addition, further research is needed to adapt these strategies to other species and cultivar-rootstock combinations.

Bio synthesis of chitosan from shrimp shell chitin using Streptomyces griseoincarnatus RB7AG:Characterization and application as coating material to enhance shelf life of tomatoes (var. Ruby pusa) in post-harvest storgae condition

In this investigation, chitosan was successfully obtained from shrimp shell chitin through microbial degradation by Streptomyces griseoincarnatus RB7AG. The resulting chitosan showcased remarkable characteristics, including high solubility, a high degree of deacetylation, a well-defined crystalline structure, and a rough surface with minimal pores. The application of chitosan as a coating material for tomatoes demonstrated significant preservation benefits compared to commercially available chitosan. The chitosan coating proved effective in minimizing weight loss, reducing the production of reactive oxygen species (ROS), and preserving essential compounds such as anthocyanin content and antioxidant enzymes in tomatoes. Firstly, the chitosan coating served as a physical barrier, preventing moisture loss and maintaining the tomatoes' structural integrity. Secondly, the antimicrobial properties of chitosan hindered the growth of spoilage-causing microorganisms, extending the shelf life of the tomatoes. Additionally, the chitosan coating exhibited antioxidant properties, scavenging ROS and preserving the natural antioxidants in tomatoes. Furthermore, the chitosan coating facilitated controlled gas exchange, allowing optimal levels of oxygen and carbon dioxide to maintain the freshness of the tomatoes without accelerating the ripening process. With the help of the above-mentioned mechanisms, the potential of the microbially synthesized chitosan to enhance the shelf life of the tomatoes can be explained which was found better than the commercially synthesized chitosan coating. This research underscores the potential of microbially synthesized chitosan as an effective coating material but also provides insights into the intricate mechanisms involved in preserving tomatoes. The findings pave the way for innovative applications of chitosan-based coatings in the food industry, ensuring prolonged freshness and nutritional quality of perishable fruits and vegetables.

Effect of Tapioca and Tragacanth based edible coatings on the physiological, chemical, microbial, and phytochemical quality of Tomato fruits

AbstractIn recent years, edible coatings have emerged as a promising solution to extend the shelf life, and maintain the quality of fruits and vegetables. The purpose of the study was the development and application of gum Tragacanth and Tapioca‐based edible coatings to extend the storability and quality of tomato (Solanum Lycopersicum L). Different treatments were prepared with combinations of Tragacanth gum (0.5, 1, 1.5 g) and Tapioca (1, 1.5, 2 g). Parameters such as weight loss, sugars, decay percentage, pH, titratable acidity, total soluble solids, antioxidant capacity, phenolic and flavonoid contents, microbial counts, and sensory evaluation were measured during 14 days storage. Results revealed that the application of gum Tragacanth and Tapioca‐based coatings significantly reduced weight loss, decay percentage, and microbial counts of treated tomatoes as compared to the control group. The coated tomatoes exhibited improved sensory features, with a slower rate of softening, during the storage. There was a significant increment in total phenolic and flavonoid contents and antioxidant capacity of coated fruits during 7 days of storage. The observed improvements in the postharvest quality attributes suggest that the gum Tragacanth and Tapioca‐based edible coatings have the potential to retain and enhance the nutritional and bioactive contents and shelf life of tomato.