Fruit Juice pH Research Articles

Research Progress on Methods for the Deacidification of Small Berry Juice: An Overview

As some of the richest sources of natural antioxidants, small berry fruits have attractive colors and special tastes, with recognized benefits for human health. However, sour tastes in small berry juices result in a poor flavor and low acceptance among consumers, greatly limiting their marketability. Among the most commonly used deacidification methods, chemical deacidification methods can neutralize fruit juice via the addition of a deacidification agent, while physical deacidification methods include freezing deacidification, ion-exchange resin deacidification, electrodialysis deacidification, and chitosan deacidification. All of these methods can markedly improve the pH of fruit juice, but they introduce new substances into the juice that may have an influence on its color, taste, and stability. Biological deacidification can effectively remove malic acid from fruit juice, reducing the content from 15 g/L to 3 g/L; additionally, it maintains the taste and stability of the juice. Therefore, it is widely applied for fruit juice deacidification. On this basis, some compound deacidification technologies have also emerged, but they also present problems such as high costs and complicated working procedures. This review of deacidification methods for small berry juice provides a foundation for the industrial development of such juices.

Agronomic, Biochemical, and Physiological Responses to Magnesium (Mg) Application in Tomato (Solanum lycopersicum L.) under Greenhouse Conditions

Magnesium fertilization positively impacts various physiological processes in plants, leading to increased yield and fruit quality. In the present study, we determined the effects of the foliar application of magnesium on the yield, fruit quality, fruit biochemical content, and enzyme activity of tomato plants. The study was performed in a plastic greenhouse. The study evaluated magnesium sulfate application through drip irrigation at a single dose of 0.005 kg m2 and foliar application at rates of 0%, 0.25%, 0.5%, and 0.75%. As a consequence, the highest average fruit weight was obtained with the foliar application of 0.50% Mg. In terms of the fruit color’s a* value, the best results were again obtained with the application of 0.50% Mg. Mg applications proportionally increased the leaf chlorophyll content. Similarly, the highest leaf Mg content, the leaf relative water content, the fruits’ malic acid content, and the best fruit juice pH value were determined with the application of 0.75%. On the other hand, the application of 0.25% Mg produced the best results on the leaves’ K, Ca, and Na content, as well as in the fruits’ ascorbic acid content. Significant differences were not found in terms of the effects of the treatments on antioxidant activity, total protein amount, and enzyme activity. The application of 0.50% Mg contributed to the fruit color; 0.75% Mg application contributed to the chlorophyll, pH, and malic acid content; and the application of 0.25% Mg contributed to an increase in ascorbic acid. In conclusion, for greenhouse tomato production, a foliar application of 0.50% Mg is recommended to achieve larger, red-colored fruits. A 0.75% Mg application is suggested for increasing the chlorophyll content, lowering fruit juice pH, and enhancing malic acid content in fruits. A 0.25% Mg application is recommended to increase ascorbic acid content in fruits.

Assessment of Persian export pomegranate quality: A reliable non-destructive method based on spectroscopy and chemometrics

The present study investigated the feasibility of visible near-infrared (Vis-NIR) spectroscopy method as a low-cost, quick and reliable method for the prediction of qualitative characteristics (fruit juice percentage, soluble solids, acidity, taste index and vitamin C) of an export variety of Persian pomegranate. For this purpose, pomegranate samples were first analyzed by Vis-NIR spectroscopy, followed by destructive reference methods for quality determination. Subsequently, the data from Vis-NIR were evaluated with different pre-processing methods, among which the combination of the Savitzky–Golay (SG) smoothing model and standard normal variation (SNV) normalization model, generates the best outcomes in predicting six desired qualitative characteristics by partial least square regression (PLSR) model. Fruit juice percentage and pH presented the best prediction models with a correlation coefficient (rP) of 0.98 for both, and root mean square errors of prediction (RMSEP) equal to 0.036 and 0.041, respectively. The values of rp for all desired parameters in this study were higher than 0.95, which pointed to the excellent accuracy of the PLSR models in the prediction of pomegranate qualitative features. It can be concluded from the present study that, Vis-NIR spectroscopy using the PLSR model as a non-destructive functional approach is capable of verifying the quality of Persian export variety pomegranate as an online technique with the aim of grading products before the export phase in order to augment the product marketability.

Improving postharvest life, quality and bioactive compounds of strawberry fruits using spermine and spermidine.

Small fruits such as strawberries, are a good source of natural antioxidants. In recent decades, many efforts have been made to increase the shelf life of strawberries and maintain its nutritional value in post-harvest conditions. In the present study, the effects of spermine (Spm) and spermidine (Spd) (0, 1.0 and 1.5 mM) on the post-harvest life and quality of strawberry fruits during the 3rd, 6th, and 12th days of storage, were investigated. Applications of Spm and Spd decreased the rate of weight loss, fruit decay, soluble solids content, fruit juice pH and taste index during the storage period in compared to the control. However, titratable acids and vitamin C contents, tissue stiffness, phenolic compounds and antioxidant activity increased in compared to the control. These growth regulators prevented the aging and loss of bioactive compounds of the fruit by increasing the antioxidant activity and preventing the destruction of the fruit tissue. Among the studied treatments, applications of 1.5 mM of Spm and Spd were the most effective treatments to enhance the storage life and quality characters of strawberry fruits.

Improving the Antimicrobial and Antioxidant Activity of Clove (Syzigium aromaticum L.) Essential Oil by Microencapsulation

This study aimed to investigate the effect of microencapsulation on the bioactive properties of clove essential oil (CEO). The CEO was microencapsulated into various wall materials, including maltodextrin (MD) and sodium caseinate (SC), and their combination with gum arabic (GA) and gelatin (G), through freeze-drying. The effects of wall material blend (MD-SC, MD-SC-GA, and MD-SC-G) on microencapsulation efficiency, morphology, in vitro release profile, antioxidant and antimicrobial properties were investigated. The MD-SC blend offered the best microencapsulation properties in terms of encapsulation efficiency (86.22%), ideal microcapsule shape, and maximum release rate (85.98%). Microencapsulation extended the radical scavenging time of the CEO. DPPH and ABTS scavenging activities of MD-SC microencapsulated CEO were 83.61% and 82.96% inhibition, while values were 76.37% and 80.03% inhibition for free CEO, respectively. Antimicrobial activities of microencapsulated and free CEO were investigated against eight microorganisms with in vitro (broth microdilution technique) and in-situ tests. Both free and CEO-loaded microcapsules were able to inhibit the growth of Gram-positive bacteria, except for Bacillus cereus, at the same concentration. Microencapsulated CEO exhibited weaker antimicrobial activity on Gram-negative bacteria than free CEO. The influence of the pH of fruit juices and components of milk on the antimicrobial activity of microencapsulated CEO was also evaluated. Microencapsulated CEO may have different antimicrobial effects depending on the pH and content of the food. This study showed that microencapsulation of CEO increased the application dose for antimicrobial effect in foods.

Effect of Foliar Application with Potassium Nitrate and Copper Sulfate on Fruit Yield and Quality of Pear (Pyrus communis L.) Trees

ABSTRACT Influence of foliar application of potassium nitrate and copper sulfate on the production and quality of Pear cv. Le Conte was carried out at Horticulture Research Farm and Postharvest Laboratory, The University of Agriculture Peshawar-Pakistan, during the year 2018–19. The aim of the study was to get quality pear production with minimal disease incidence. The research was carried out in a randomized complete block design with three replications. The study contained two factors, i.e., different concentrations of potassium nitrate (0%, 1%, 2%, and 3%) as Factor A, while different levels of copper sulfate (0%, 0.2%, 0.4%, 0.6%, and 0.8%) as factor B and the treatments were applied in spring season at the fruit set stage. The application of 2% potassium nitrate to the pear plants resulted in heaviest fruit (188.30 g), maximum fruit volume (203.80 cm3), fruit yield tree−1 (60.13 kg) with minimum fruit drop (8.52%) and disease incidence (5.28%), while maximum fruit firmness (7.66 kg.cm−2), total soluble solids (12.40 ○Brix), fruit juice pH (5.38), ascorbic acid content (5.56 mg.100 g−1) while minimum Titratable acidity (0.41%) were noted in fruits of plants sprayed with 3% potassium nitrate solution. However, the maximum fruit weight (192.04 g), fruit yield tree−1 (59.06 kg), minimum fruit drop (6.75%), and disease incidences (3.54%) were recorded in pear plants applied with 0.6% foliar copper sulfate solution. However, maximum fruit firmness (7.53 kg.cm−2), total soluble solids (12.38 ○Brix), fruit juice pH (5.31), ascorbic acid content (5.22 mg.100 g−1) with minimum Titratable acidity (0.42%) were noted in the plants sprayed with 0.8% copper sulfate solution. This study will provide a basis for high yield and quality fruit production, which will affect the storability of pear and other important fruit crops. Further studies should be conducted to optimize the dose, timing, and method of application of these fungicides for other pome fruits.

Effects of Plant Growth Promoting Rhizobacteria on Growth, Yield and Fruit Quality of Pomegranate (Punica granatum L.)

This study was carried out in a commercial pomegranate garden in Denizli, in 2017-2018 in order to determine the effects of Pseudomonas sp. HV 5 and Micrococcus luteus GC- subgroup B MFDV3 bacterial strains, which are potentially capable of improving plant yield and development, on plant growth, yield and quality. The effects of bacterial application on shoot diameter, fruit width, fruit size, fruit juice content, pH, acidity and yield per tree were statistically in significant but the effects on fruit weight, fruit volume and fruit juice C vitamins were found to be significant. Concomitant use of HV5 and MFDV3 bacteria resulted in increased fruit weight, volume, and amount of vitamin C in fruit juice compared to control. According to the results of the research, it was concluded that the bacterial strains used had a positive effect on fruit juice and vitamin C only, so that different application forms and doses should be tested.

Nickel toxicity pretreatment attenuates salt stress by activating antioxidative system and ion homeostasis in tomato (Solanum lycopersicon L.): an interplay from mild to severe stress.

Plants antioxidative system is the first line of defense against oxidative stress caused secondarily by toxic ions under salinity. Plants with pre-activated antioxidative system can better adapt to salinity and can result in higher growth and yield. The current experiment was conducted to assess the adaptation of two tomato genotypes (Riogrande and Green Gold) with pre-activated antioxidative enzymes against salt stress. Tomato seedlings were exposed to mild stress (Ni: 0, 15 and 30mgL-1) for three weeks to activate the antioxidative enzymes. The seedlings with pre-activated antioxidative enzymes were then grown under severe stress in hydroponics (0, 75 and 150mMNaCl) and soil (control, 7.5 and 15 dSm-1) to check the adaptation, growth and yield. The results showed that Ni toxicity significantly enhanced activities of antioxidant enzymes (SOD, CAT, APX and POX) in both the genotypes and reduced growth with higher values in genotype Riogrande than Green Gold. The seedlings with pre-activated antioxidant enzymes showed better growth, low Na+ and high K+ uptake and maintained higher antioxidative enzymes activity than non-treated seedlings after four weeks of salt stress treatment in hydroponics. Similarly, the results in soil salinity treatment of the Ni pretreated seedlings showed higher yield characteristics (fruit yield per plant, average fruit weight and fruit diameter) than non-treated seedlings. However, Ni pretreatment had nonsignificant effect on tomato fruit quality characteristics like fruit dry matter percentage, total soluble solids, fruit juice pH and titratable acidity. The genotype Riogrande showed better growth, yield and fruit quality than Green Gold due to higher activity of antioxidant enzymes and better ion homeostasis as a result of Ni pretreatment. The results suggest that pre-activation antioxidant enzymes by Ni treatment proved to be an effective strategy to attenuate salt stress for better growth and yield of tomato plants.

Evaluating the Influence of Deficit Irrigation on Fruit Yield and Quality Indices of Tomatoes Grown in Sandy Loam and Silty Loam Soils

The most important biotic stress factor impacting tomato crop biophysical, biochemical, physiological, and morphological features is water stress. A pot experiment was undertaken in a greenhouse to study the drought responsiveness of tomato (Solanum lycopersicum) yield and quality indices in sandy loam and silty loam soils. For both sandy loam and silty loam soils, the water supply levels were 70–100% FC, 60–70% FC, 50–60% FC, and 40–50% FC of ETo (crop evapotranspiration) from the vegetative stage to the fruit ripening stage, calculated using the Hargreaves–Samani (HS) model compared to the time-domain reflectometer (TDR) values calibrated using volumetric water content (VWC). The experiment was conducted as a 2 × 4 factorial experiment, arranged in a completely randomized block design, with four treatments replicated four times. In this study, we examined how sandy loam and silty loam soils at different % FC affect the total marketable yield and quality components of tomatoes, concentrating on total soluble solids (Brix), fruit firmness, dry fruit mass, pH, titratable acid (TA), ascorbic acid (Vit. C), and carotenoid composition. Lycopene and β-Carotene were estimated using the UV spectroscopy method, with absorption spectra bands centered at 451 nm, 472 nm, 485 nm, and 502 nm. The results revealed that even though there were some limitations, TDR-based soil moisture content values had a strong positive correlation with HS-based evapotranspiration, with R2 = 0.8, indicating an improvement whereby TDR can solely be used to estimate soil water content. Tomato plants subjected to 40–50% FC (ETo) water stress in both sandy loam and silty loam soils recorded the highest total soluble solids, titratable acidity, ascorbic acid content, and β-carotene content at an absorption peak of 482 nm, and lycopene content at an absorption peak of 472 nm, with lower fruit firmness, fruit juice content, and fruit juice pH, and a reduced marketable yield. Similarly, tomato plants subjected to 60–70% FC throughout the growing season achieved good fruit firmness, percent juice content, total soluble solids, titratable acidity, ascorbic acid content, and chlorophyll content (SPAD), with minimum fruit juice pH and high marketable yield in both soil textural types. It is concluded that subjecting tomato plants to 60–70% FC (ETo) has a constructive impact on the marketable yield quality indices of tomatoes.

A dual-functional flexible sensor based on defects-free Co-doped ZnO nanorods decorated with CoO clusters towards pH and glucose monitoring of fruit juices and human fluids

Herein, ZnO nanorods were doped with Co and decorated with CoO clusters through an in situ technique to create a CoO/Co-doped ZnO (CO/CZO) heterostructure at low temperatures (150 °C) on a flexible PET substrate. In the CO/CZO heterostructure, the Co dopant has a low energy barrier to substitute Zn atoms and adsorb over oxygen atoms and their vacancies. Therefore, it decreased the charge density (ND = 2.64 × 1019 cm−3) on non-active sites of ZnO and lowered the charge transfer resistance (317 Ω) at Co-doped-ZnO/electrolyte interface by suppressing the native defects and reducing the Schottky barrier height (− 0.35 eV), respectively. Furthermore, CoO clusters induced a p-n heterostructure with Co-doped ZnO, prevented corrosion, increased the active sites for analyte absorption, and increased the ultimate tensile strength (4.85 N m−2). These characteristics enabled the CO/CZO heterostructure to work as a highly sensitive, chemically stable, and flexible pH and glucose oxidation electrode. Therefore, CO/CZO heterostructure was explored for pH monitoring in human fluids and fruit juices, demonstrating a near-Nernst-limit pH sensitivity (52 mV/pH) and fast response time (19 s) in each human fluid and fruit juice. Also, it demonstrated high sensitivity (4656 µM mM−1 cm−2), low limit of detection (0.15 µM), a broad linear range (0.04 mM to 8.85 mM) and good anti-interference capacity towards glucose-sensing. Moreover, it demonstrated excellent flexibility performances, retained 53% and 69% sensitivity of the initial value for pH and glucose sensors, respectively, after 500 bending, stretching, and warping cycles.Graphical

Effect of different levels and sources of calcium on post harvest physiology of hybrid tomatoes (Solanum lycopersicum)

Due to high respiration and ethylene production, tomato (Solanum lycopersicum) is highly perishable horticulture produce that deteriorates faster during the post-harvest storage period. Calcium nutrition is important to overcome these losses as it helps in retarding ripening process during storage and improve the post-harvest quality tomatoes. Hence a field experiment was conducted with different calcium sources and levels viz., Calcium sulphate, Calcium Nitrate, Calcium silicate, Poultry manure and Pressmud applied at 0, 20, 40, 60 and 80 kg Ca ha-1. A storage study was conducted in a factorial completely randomized block design (FCRD) to ensure the effective role of calcium in post-harvest quality of hybrid tomato. Tomatoes were analyzed for pH of fruit juice, firmness, titratable acidity, total soluble solids, moisture content and physiological loss at five days intervals upto 15 days. The results revealed thatCalcium sources and levels had highly significant impacts on the quality of tomato fruits. The tomatoes harvested from the plot applied with poultry manure at 80 kg Ca ha-1 retained the highest fruit firmness(3.76 N m-1), moisture content (88.2%) and the lowest weight loss (8.82%) in fruit, highertitratable acidity (0.41%), lesser pH (3.61)andtotal soluble solids (4.23 ˚Brix). Hence the application of poultry manure at 80 kg Ca ha-1was beneficial in improving the quality and extending the storage life of hybrid tomatoes.

Effects of Ripeness and Blending Speed on the Extraction Yield and Physical Chemical Properties of Low Viscosity Banana Juice

Low viscosity banana juice can be extracted from banana by blending and pressing the resulted semi-solid pulp to separate the juice. This juice extraction technology is relatively new and further studies to understand key parameters for juice release is vital for scaling up production and commercialisation. This study, investigated the influence of blending speed and ripeness stage on banana juice yield using two banana cultivars; the East African highland banana (Mbile) and the exotic banana (Pisang awak). Types of sugars and organic acids in the juice were analysed using an HPLC. Changes with ripening of fruit firmness, juice pH and soluble solids were also examined. The juice yield increased significantly (p < 0.05) with increasing blending speed and ripeness stage for all cultivars. The Mbile cultivar from Kagera had the highest juice yield of 82.35%, followed by Mbile cultivar from Kilimanjaro with 75.30% and Pisang awak cultivar with juice yield of 62.50%. The highest juice yield for all cultivars was achieved at 3500 rpm blending speed and ripeness stage 5. Fructose and glucose sugars increased significantly (p < 0.05) with ripeness, while sucrose showed insignificant changes. Malic and citric acids were observed to increase significantly (p < 0.05) during ripening in all banana cultivars.
 Keywords: East African highland banana, Banana juice extraction, Blending speed, Low viscosity banana juice.

Performance of two terms exponential model on the drying kinetics of solar-dried tomatoes (Lycopersicum esculentum L.) treated with and without chemical preservatives

Open sun drying of horticultural produce results in contamination due to microbial and fungal attacks and could also be damaged by insects, pests, and rodents. Solar drying through solar collectors is, therefore, an important technique used for the preservation of foods and to extend the shelf life of produce, thereby reducing microbial attack and contamination. Therefore, an experiment was carried out to study the response of the drying kinetics of solar-dried tomatoes to the thin layer of preservatives on the drying and quality attributes. The tomato fruits were treated with natural preservatives (honey and aloe vera) and chemical preservatives (citric acid, sodium benzoate, and potassium meta-bisulfate). The tomato fruits were then kept at three (40, 45, and 50oC) different temperatures using a parabolic trough solar air heater for drying purposes. Both the drying temperature and preservative levels significantly (P< 0.001) affected the drying and quality traits of tomato slices. At a temperature of 50 oC and with citric acid as a preservative, the tomato attained the best average results for moisture lost hr-1, drying time, drying rate, total soluble solids (TSS) °Brix, fruit juice pH, titratable acidity (%) and vitamin C. Based on the average maximum results, 50°C temperature and citric acid as a coating material could be considered for attaining better quality attributes of dried tomatoes. A two-term exponential model on the moisture ratio of tomatoes was found to fit for correlation and regression.

Influence of Scion/Rootstock reciprocal effects on post-harvest and metabolomics regulation in stored peaches

Peach is an important stone fruit crop cultivated at commercial scale in Pakistan. While, appropriate selection of rootstock has significant impact on the quality of peach fruit. Therefore, in the current study the influence of three rootstocks viz. ‘GF-677′, ‘Peshawar Local’ and ‘Swat Local’ were evaluated on the quality of ‘Flordaking’ peaches following cold storage during two consecutive years. The fruit from these rootstocks were kept at 0 °C for five weeks were studied for various fruit physical (weight loss, colour, firmness) and biochemical (pH, soluble solids content (SSC), titratable acidity (TA), SSC:TA ratio, fruit juice pH, sugars (total, reducing and non-reducing sugars), ascorbic acid (vitamin C) and free radicals scavenging activities) were evaluated. During both years, fruit harvested form trees grafted on ‘GF-677′ exhibited reduced fruit weight loss, changes in Chroma (C*) and highest fruit firmness, Lightness (L*), ascorbic acid contents and radical scavenging activities as compared to fruit harvested from tree grafted on other rootstocks. In conclusion, the post-harvest quality of scion ‘Flordaking’ peach fruit was significantly influenced and best quality can be obtained when it is grafted on ‘GF-677′ rootstock.

‘Frontenac’ Grape Response to Canopy Management in North Dakota

Experiments were conducted in 2013 and 2014 to evaluate the effects of training system and leaf removal treatments on yield and quality for ‘Frontenac’, an interspecific hybrid wine grape, at a research vineyard located near Absaraka, North Dakota. The experiment was structured as a randomized complete block design with a split-plot arrangement including four training system treatments (Geneva Double Curtain (GDC), High Cordon (HC), Vertical Shoot Positioned (VSP), Four-Arm Kniffin (4AK)), and four-leaf removal timing treatments (bloom, post-bloom, veraison, and a control, no removal) with eight replicates. In 2013, 1428 growing degree days (GDDs) accumulated in the 155 days between frost events. In 2014, 1156 GDDs accumulated in the 121 days between frost events, 272 GDDs less than the year prior. Even with the large GDD differences between years, there was no significant interaction between trellis type and leaf removal, and the main factor of leaf removal did not influence any of the fruit variables where data were collected. Combined data analysis showed no significant differences in fruit juice total soluble solids (TSS) or titratable acidity (TA). The fruit juice pH in 2013 was greater when grapes were grown in the VSP system compared to grapes grown in the other trellis systems. In 2014, live nodes and total shoots were greater for grapes grown on GDC and 4AK systems compared to grapes grown on the HC and VSP systems. Additionally, in 2014, grapes grown on the GDC system had a greater cluster number and yield when compared to grapes grown on the 4AK or VSP systems. These findings suggest that ‘Frontenac’ fruit TSS accumulation and TA were not affected by leaf removal or trellis system in North Dakota vineyards and that yield gains may be reached due to the training system without negatively affecting fruit quality.

Gibberellic Acid and Boron Enhance Antioxidant Activity, Phenolic Content, and Yield Quality in Pyrus Communis L.

Foliar application of micronutrients and plant growth regulators (PGRs) is one of the strategies of plant-feeding direct through leaves to allow rapid uptake irrespective of soil condition. This is the best way to enhance nutrient balance and its accumulation in the crops that, in turn, lead to improved crop yield and quality. This research studied the effect of boron (0, 25, 50, 75, and 100 ppm) and gibberellic acid (GA3; 0, 20, 40, and 60 ppm) on quality fruit production of pear. Fruit weight, yield (kg/tree), minimum fruit drop (%) and disease incidence (%) were significantly enhanced in fruit sprayed with 75 ppm boron while fruit firmness (kg/cm), total soluble solids (° Brix), fruit juice pH, ascorbic acid content, and minimum titratable acidity (%) significantly increased in pear fruit sprayed with 100 ppm boron. The highest contents of phenols, flavonoids, and antioxidants (%) were observed in pear fruit sprayed with 100 ppm of boron and 60 ppm of GA3. Maximum fruit firmness, total soluble solids (° Brix), fruit juice pH, ascorbic acid with minimum titratable acidity (%) were recorded in plants sprayed with 60 ppm GA3. Boron (100 ppm) and GA3 (60 ppm) could be applied at the fruit set stage to obtain the quality fruit production of pear.

Component Analysis of Tooth Surface Caused by Fruit Juice using Energy Dispersive X-ray Spectroscopy

Dental erosion is the irreversible loss of dental hard tissue by acids not by bacteria. The prevalence rate of dental erosion is on the rise these days, and the consumption of acidic beverages is recognized as one of the main risk factors. Therefore, in this study, pH of certain commercial fruit juices was measured to determine whether they cause enamel corrosion of teeth, and the changes in calcium (Ca) and phosphorous (P) were evaluated by quantitative analysis using energy dispersive X-ray spectroscopy (EDS). As the pH decreased, the solubility of Ca increased, and as the exposure time increased, the loss of Ca was greater. Ingestion of fruit juice with a low pH affects the risk of dental erosion, and the retention time of the juice in oral cavity should be shortened as long-term contact with the juice may cause the tooth damage.

Mitigation the adverse effect of salinity stress on the performance of the tomato crop by exogenous application of chitosan

BackgroundIn recent years, ecofriendly compounds such as chitosan has been used to alleviate the destructive effects of salt stress. Chitosan is a natural biodegradable compound with no toxicity in nature and act as a stress tolerance inductor involved in physiological processes and prevent water loss through transpiration. Tomato cv. Rio Grande grown in pots was subjected with salinity stress in the form of 4 levels (0, 50, 100 and 150 mM) whose effect was mediated by treating it with different concentration of chitosan (0, 50, 100 and 150 mg L−1).ResultsThe data revealed that various application of salinity had a negative effect on almost all the studied parameters. Tomato plants treated with distilled water having no salinity (control) recorded maximum plant height (cm), average number of compound leaves plant−1, leaf area (cm2), stem diameter (mm), number of fruits plant−1, fruit firmness (kg cm−2), leaf chlorophyll content (SPAD), fruit juice pH, yield plant−1 (kg) and minimum total soluble solids (Brix°). Whereas, minimum plant height (cm), average number of compound leaves plant−1, leaf area (cm2), stem diameter (mm), number of fruits plant−1, fruit firmness (kg cm−2), leaf chlorophyll content (SPAD), fruit juice pH, yield plant−1 (kg) and maximum total soluble solids (Brix°) were found in plants treated with salinity level of 150 mM. Chitosan concentration of 150 mg L−1 significantly mediated the effect of salinity stress and recorded maximum plant height (cm), average number of compound leaves plant−1, leaf area (cm2), stem diameter (mm), number of fruits plant−1, fruit firmness (kg cm−2), leaf chlorophyll content (SPAD), total soluble solids (Brix°) and yield plant−1 (kg) with minimum fruit juice pH.ConclusionIt is concluded that foliar application of chitosan at the rate of 150 mg L−1 and salinity stress 150 mM could have positive impact on performance of tomato.

Effect of postharvest edible coatings on fruit quality of guava cv. Sufaid Gola under ambient and zero-energy cool Chamber storage conditions

Investigations were made to evaluate the effect of different edible and chemical coatings on quality and shelf life of guava (Psidium guajava L.) cv. Sufaid Gola fruits stored under ambient (20 ± 3 °C) and zero energy cool chamber (ZECC) conditions (15 ± 3 °C). The fruits were subjected to different coating treatments, i.e., control (uncoated fruits, T0), fruits coated with 1% CaCl2 (T1), 2% CaCl2 (T2), 10% Aloe vera gel (T3) and 15% Aloe vera gel + 1.5% Ascorbic acid (T4). The studied quality attributes included weight loss, total soluble solids (TSS), pH of fruit juice and fruit skin colour. As the storage period increased, weight loss, juice TSS and pH values significantly increased. Fruit skin colour also changed depending on the coating treatment, storage conditions and duration. Fruits stored at ZECC conditions had lower weight loss with lesser juice TSS and pH values and resulted in prolonged shelf life than ambient storage conditions. The fruits coated with 15% Aloe vera gel + 1.5% Ascorbic acid and 10% Aloe vera gel resulted in lower weight loss as compared to other treatments. Fruit coated with 15% Aloe vera gel + 1.5% Ascorbic acid and 2% CaCl2 had better shelf life with lower juice TSS and pH values as compared to other treatment combinations.

Chitosan-based foliar application modulated the yield and biochemical attributes of peach (Prunus persica L.) cv. Early Grand

BackgroundPeach fruits are highly perishable leading to many pre- and post-harvest problems, which adds to the reduction in the potential yield and productivity. Chitosan is a natural polysaccharide, produced after alkaline chitin deacetylation. It is one of the most preferred biopolymers due to its biocompatibility, antioxidant, anticancer, biodegradability, antimicrobial, and non-toxic properties as well as being an economical material. A pre-harvesting experiment was carried out based on the problems of peach and the importance of chitosan.ResultsPeach trees were foliar sprayed with different concentrations of chitosan (0, 0.50, 0.75, and 1.0%) at different times (30, 50, and 70 days after full bloom) to elucidate the effect of chitosan to peach yield and fruit quality. The results showed that foliar application of chitosan (1%) caused significant increases in fruit weight, volume, tree yield−1, fruit firmness, titratable acidity, and ascorbic acid content but caused significant decreases in total soluble solid fruit juice pH and disease incidence of peach fruit. Similarly, foliar application of chitosan after 50 days of full bloom increased fruit weight, volume, yield tree−1, firmness, titratable acidity, and ascorbic acid content with the number of fruit kg−1, total soluble solids, juice pH, and disease incidence as compared to other application times.ConclusionsIt is concluded that chitosan at 1% applied after 50 days of full bloom improved most of the peach attributes studied compared to the other concentrations of chitosan at 0.50 and 0.75, and control for the production of quality peach fruit.