Hot Water Treatment Research Articles

Application of antioxidants and hot water treatments to improve shelf life of fresh-cut eggplants (Solanum melongena L.) during storage

The objective of this study was to evaluate the effect of antioxidant treatments on the conservation of cut eggplants (Solanum melongena L.), which was carried out in two stages. Initially, the effect of citric acid (CA), ascorbic acid (AA) and cysteine (Cys) solution at 0.5 and 1% on sensory attributes (general appearance and browning), and color parameters during storage were evaluated. Immersion in 1% AA was considered the best antioxidant since it maintained visual quality for 6 days. Subsequently, hot water dipping (HWD) treatments followed by the 1% AA solution were evaluated and optimized through the Response Surface Methodology (RSM). Sensory attributes, color parameters, respiration rate (RR), phenolic compounds (PhC), antioxidant capacity, as well as the activity of polyphenol oxidase (PPO) and peroxidase (POD) were assessed during cold storage. The results showed that HWD at 50 °C, 60 s and 1% AA was the optimal combination to control enzymatic browning and extend its fresh quality for up to 8 days. Furthermore, that combination of treatments reduced the PPO and POD activities and increased the PhC compared to the control (untreated), not finding significant differences between them in antioxidant capacity and RR. Therefore, the application of this combination would be the most appropriate to preserve the quality of the fresh-cut eggplants for 8 days of storage at 4 °C.

On the use of hot water treatment to control crown rot postharvest diseases of export banana fruit (Musa sp., Group AAA, subgroup Cavendish, ‘Williams’)

On the use of hot water treatment to control crown rot postharvest diseases of export banana fruit (<i>Musa</i> sp., Group AAA, subgroup Cavendish, ‘Williams’)

Improvement in heat resistance of electric heating alumite carriers

Alumite carriers were prepared by using Al/Ni-Cr-Alloy/Al clad materials with different Pore widening treatment (PWT) durations of 0, 2, 4, 6 and 8 h to observe its effect on the alumina surface structures and the overall heat resistance. Aluminum clad materials were first anodized in 298 K 4 wt% oxalic acid with 50 A/m2 electric current. Subsequently, PWT was carried out in the same oxalic acid solution at 298 K. After calcination at 623 K for 1 h, samples underwent Hot water treatment (HWT) in 358 K hot water for 2 h before lastly calcinated at 773 K for 3 h. It was found that heat resistivity improved drastically when PWT was carried out for longer than 6 h. Results also showed that alumite carriers’ surface structure changed drastically after 6 h of PWT from fragment structure into a sponge-like structure. By manipulating the PWT durations, alumite carriers produced successfully withstood up to 1223 K without needing to induce diffusion layers by preheating. Therefore, alumite carriers produced with 6 h and 8 h of PWT showed promising potential for the usage in high temperature steam reforming reactions with electric heating.

Effect of combined application of carbonate salts and hot water treatment for the management of postharvest anthracnose (Colletotrichum gloeosporioides) of papaya.

Postharvest anthracnose (Colletotrichum gloeosporioides Penz.Sacc) is the most economically important biological constraint to papaya production and consumption, which causes substantial yield loss worldwide. The effect of combined application of carbonate salts and hot water treatments on the development of postharvest anthracnose and maintenances of postharvest quality of papaya fruit was studied in completely randomized design (CRD) under laboratory condition. The results revealed that combined application of hot water treatment and carbonate salts significantly (p < .05) reduced the incidence and severity of postharvest papaya anthracnose disease. The disease incidence reached 100% 21 days after inoculation in the control treatment; this level was significantly reduced to 26.70% by dipping the fruits in NH4CO3 at 50°C and NH4CO3 at 54°C. Similarly, treatments significantly (p < .05) reduced the disease severity in different degrees from the first day of disease appearance to the date of 100% unmarketability of control fruits. Furthermore, the combined application of carbonate salt and hot water treatments significantly improves fruit marketability by 93.33%. Moreover, the treatments showed significant (p < .05) effect on maintaining pH, TSS, TA, and reducing postharvest weight loss of papaya fruit. In conclusion, postharvest treatment of papaya fruit with NH4CO3 at 54°C, NH4CO3 at 52°C, and NaCO3 at 54°C can significantly reduce anthracnose development and improve marketability of the fruits without pronounced effect on their edible qualities.

Detoxification strategy of wheat straw hemicellulosic hydrolysate for cultivating Trichoderma reesei: a contribution towards the wheat straw biorefinery

The urgency for reducing the dependence on fossil-based materials is increasing the interest in the utilization of renewable feedstocks. Lignocellulosic residual biomass can be used as feedstock to produce chemicals and energy without generating food security problems. Wheat straw (WS) has a clear potential for developing sustainable processes in a circular bioeconomy context. However, the development of processes requires a strategy for utilizing the hemicellulosic, cellulosic, and lignin fractions. This work covers the utilization of the hemicellulosic fraction as the first stage of a wheat straw biorefinery. The aim was to evaluate the hydrolysis of WS by using liquid hot water (LHW) treatment, the detoxification of the produced wheat straw hydrolysate (WSH), and the cultivation of Trichoderma reesei using it as the only carbon source as proof of detoxification. LHW treatment was performed at 160 °C and 90 min and yielded a WSH rich in monomeric and oligomeric saccharides (~ 14 g/L) and containing degradation products in low concentration (furfural, HMF, and acetic acid). As part of the development of the extraction and detoxification strategy, we determined the specific inhibition thresholds for T. reesei for the mentioned degradation products. Detoxification was carried out by evaporation by modifying the % of volume evaporated and the pH of the solution. Approximately 55.9% of acetic acid and 100% of furfural were removed from the WSH. The fungal biomass obtained in the medium containing WSH was equivalent to 98% of the biomass obtained in the control medium.

Processing mediated suppression of bitterness causing compounds in ready to serve kinnow beverage

Delayed bitterness in kinnow juice affects its market value as well acceptability rate by consumers. For the purpose to enhance the shelf life of kinnow juice, RTS (ready to serve) beverage was prepared. Further, processing mediated suppression of bitterness causing compounds in ready to serve kinnow beverage was studied. Processing methods used during the study was β-cyclodextrin (2%); lye treatment (LT 1.5%); hot water treatment (HWT); Florisil® (3%), and their suitable combination. Processing significantly modulate the bitterness causing compounds. Combined treatment was observed as best due to presence of less concentration of bitter compounds and higher sensorial score. RTS prepared using different treatments were stored in glass bottles for 90 days and studied in terms of their titratable acidity, pH, TSS and antioxidant properties. Samples were stored in refrigerator at 4 °C and withdrawal after every 15 days with the aim to evaluate the storage time effect on quality and sensorial attributes. Increasing storage time deteriorate the quality attribute such as bioactive compounds, antioxidant properties, sensorial scores and other parameters (titratable acidity, pH and TSS) respectively.

Legionnaires' Disease Outbreak Associated With a Hot Tub Display at the North Carolina Mountain State Fair, September 2019.

On September 23, 2019, the North Carolina Division of Public Health identified a legionellosis increase in western North Carolina; most patients had recently attended the North Carolina Mountain State Fair. We conducted a source investigation. Cases were fair attendees with laboratory-confirmed legionellosis and symptom onset within 2 to 14 days (Legionnaires' disease) or ≤3 days (Pontiac fever). We conducted a case-control study matching cases to non-ill fair attendees as control participants and an environmental investigation, and we performed laboratory testing (Legionella bacteria culture and polymerase chain reaction) of 27 environmental samples from fairgrounds and hot tubs and 14 specimens from case patients. We used multivariable unconditional logistic regression models to calculate adjusted odds ratios for potential Legionella exposure sources and risk factors. Of 136 people identified with fair-associated legionellosis, 98 (72%) were hospitalized and 4 (3%) died. Case patients were more likely than control participants to report walking by hot tub displays (adjusted odds ratio = 10.0; 95% CI, 4.2-24.1). Complete hot tub water treatment records were not kept, precluding evaluation of water maintenance conducted on display hot tubs. Legionella pneumophila sequence types (STs) were consistent among 10 typed clinical specimens (ST224) but distinct from the only positive environmental sample from the fair (ST7 and ST8). Hot tub displays were identified as the most likely outbreak source, making this the largest hot tub-associated Legionnaires' disease outbreak worldwide. Following the investigation, the North Carolina Division of Public Health and the Centers for Disease Control and Prevention released guidance on mitigating risk of Legionella exposure from hot tub displays. Results highlight the importance of properly maintaining equipment that aerosolizes water, including hot tubs intended for display purposes only.

N-α-Lauroyl-L-arginine ethyl ester hydrochloride combined with hot water treatment alleviates chilling injury of postharvest cucumber fruit

Postharvest cucumber fruit is prone to chilling injury (CI) under cold stress, leading to severe quality deterioration. In this study, the effects of N-α-Lauroyl-l-arginine ethyl ester hydrochloride (LAE), hot water (HW), and LAE combined with HW treatments on CI in cucumber fruit stored at 4 ± 1 ℃ were investigated. The response surface methodology (RSM) confirmed that the LAE concentration of 1.00 g L−1, HW temperature of 44 ℃, and immersion time of 10 min were the optimal condition for cucumber fruit preservation during cold storage. Further analysis revealed that LAE, HW, and LAE combined with HW treatments, all significantly mitigated chilling injury symptoms in cucumber fruit in comparison with the control, but the application of LAE combined with HW was the most effective method for enhancing cold tolerance in cucumber fruit. Moreover, LAE combined with HW treatment could reduce reactive oxygen species (ROS) accumulation, and enhance superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX) activities in cold-stored cucumber fruit. Meanwhile, the activities of arginine decarboxylase (ADC), ornithine decarboxylase (ODC), Δ1-pyrroline-5-carboxylate synthetase (P5CS), ornithine δ-aminotransferase (OAT), and glutamate decarboxylase (GAD) were also increased by LAE combined with HW treatment, while the activities of proline dehydrogenase (PDH) and γ-aminobutyric acid transaminase (GABA-T) were decreased by LAE combined with HW treatment, which contributed to maintaining higher polyamines, proline, and GABA contents. These findings suggested that LAE combined with HW treatment can reduce chilling injury in cucumber fruit via enhancing antioxidant enzymes activities, PA, proline, and GABA contents to maintain ROS homeostasis during cold storage.

Suspension of ZnO Nanostructures Synthesized by Hot Water Treatment for Photocatalytic Wastewater Treatment

Suspension of ZnO Nanostructures Synthesized by Hot Water Treatment for Photocatalytic Wastewater Treatment

Organoleptic characteristics evaluation of Diab mango fruits as affected by hot water treatments

Due to its rapid ripening after harvest, mango is a perishable fruit with a short shelf life. Organoleptic parameters such as color, flavor, texture and aroma are factors critical to consumer acceptance and the success of the fresh produce. Hot water treatments (HW) technology is gaining popularity worldwide for its potential to extend the shelf life of mango fresh produce with better fruit quality. The present study was conducted at the two successive seasons of 2019 and 2020 to evaluate the hot water dipping (HWD) treatments at 45 or 50oC for 5 and 10 min., and then stored at 8oC±2oC and 90-95% relative humidity as shipping simulation for 3 weeks and then ripened at 20oC too. The sensory characteristics score of mango fruits were measured by panelists who utilized the Hedonic test in evaluating the quality scores samples. Our results at the end of ripening storage duration (21days) appeared that the HW treatment at 50oC for 10 min showed the highest significant firm, texture, and pulp color score (3.49, 3.00 and 5.00) of mango fruits compared with untreated with lower score (1.15, 2.00 and 4.67). Moreover, the sensory score as aroma and flavor cleared gradually and showed the same trend, recording the best aroma and mango flavour score (4.67, 3.67). At the same time, control fruits have the lowest taste score (3.00 and 2.33).

Evaluating control methods for red imported fire ant and their effects on hibiscus mealybug in citrus

AbstractThe red imported fire ant (Solenopsis invicta) may disrupt biological control of hibiscus mealybug (Nipaecoccus viridis) in Florida citrus. Controlling S. invicta may therefore be necessary for effective management of hibiscus mealybug. We evaluated four different methods to control S. invicta (ground applications of insecticide, two different insecticidal ant baits and spot‐treating ant colonies with hot water) to determine how these different treatments affected ants tending to hibiscus mealybug colonies, natural enemy abundance within hibiscus mealybug colonies and hibiscus mealybug colony abundance. While all treatments reduced the number of S. invicta colonies in treated areas compared to an untreated control, only ground applications of insecticide and the two ant baits significantly reduced the abundance of S. invicta found tending hibiscus mealybug colonies. Additionally, significantly more Brachymyrmex obscurior ants were found tending mealybug colonies in plots treated with either of the two ant baits. There was no significant effect of treatment on the abundance of natural enemies in hibiscus mealybug colonies, but significantly fewer natural enemies were found in mealybug colonies tended by S. invicta, and significantly more natural enemies were found in mealybug colonies tended by B. obscurior. Ground applications of insecticide, the abamectin ant bait Clinch and hot water treatments all reduced the overall number of hibiscus mealybug colonies compared with control areas, while the S‐methoprene ant bait Extinguish did not. Our results suggest that reducing the number of S. invicta tending hibiscus mealybug colonies can lead to higher natural enemy abundance and lower hibiscus mealybug abundance. However, methods used to control S. invicta may have different impacts on ant species like B. obscurior, leading to different outcomes with natural enemies.

Chilling injury tolerance induced by quarantine hot water treatment in mango fruit is associated with an increase in the synthesis of gallotannins in the pulp

Chilling injury tolerance induced by quarantine hot water treatment in mango fruit is associated with an increase in the synthesis of gallotannins in the pulp

Effect of hot water treatment and Timorex Gold® in the control of avocado anthracnose

Effect of hot water treatment and Timorex Gold^® in the control of avocado anthracnose

Food waste valorization applying the biorefinery concept in the Colombian context: Pre-feasibility analysis of the organic kitchen food waste processing

Food waste has been profiled as a potential source of added-value products and energy vectors. Nevertheless, the non-standard composition of food waste has been a bottleneck in proposing different biorefinery configurations. This paper aims to analyze organic kitchen food waste (OKFW) as a source of valuable products by applying the biorefinery concept. A compositional model was proposed considering seven food groups and the consumption trends in Colombia. Biogas and fermentable sugars were produced experimentally. Sugars were considered as feedstock for simulating two scenarios for producing bioethanol and polylactic acid. Finally, a techno-economic assessment was done. As a result, the liquid hot water treatment increases the crystallinity index by 30%, obtaining a fermentable sugar yield of 0.37 kg/kg of dry OKFW. The exhausted solid after saccharification produced 0.42 m3 of biogas/kg of exhausted OKFW. Ethanol and polylactic acid yields were 0.14 kg/kg of dry OKFW and 0.12 kg/kg of dry OKFW. Biogas use in cogeneration units can provide 13.49% and 4.29% of the total plant energy demand. Sugars concentration and downstream processing were the highest energy-demanding sections in the proposed scenarios. In conclusion, OKFW is a promising feedstock to produce added-value products in Colombia. However, biorefineries should be optimized to be robust regardless of the OKFW composition but considering the most representative fractions.

In vitro germination and regeneration of Senna artemisioides, a valuable leguminous ornamental shrub

Τhis research was carried out at the prospect of introducing new ornamental species in the floriculture industry concerning the use of valuable plants. A leguminous species native to Australia was the object of the present study. Seeds of Senna artemisioides established in a private botanical garden were chosen as the starting material for both germination and in vitro studies. Hot water treatment at 90 °C, for 10 min was applied to interrupt the seed-coat dormancy. Incubation was conducted in vitro in Petri dishes, at seven different temperatures ranging from of 5.0 to 35.0 °C, involving three separate treatments of incubation at 5.0 °C, for 0, 30 and 60 days. The seeds germinated at 25 °C (56.0%). Node explants derived from produced seedlings were cultured in vitro onto Murashige and Skoog media (MS), hormone free (Hf) or containing 6-Benzyladenine (BA). The establishment of initial cultures was successful being higher on MS supplemented with BA at the range 0.1-1.0 mg L-1 media. The multiplication phase followed on MS media containing the same range of a total of four cytokinins widely used in in vitro experimentation, i.e BA, Kinetin (KIN), N6-Isopentenyladenine (2IP) and Zeatin (ZEA). 1-Naphthaleneacetic acid (NAA) was tested in conjunction with the higher concentration of the four cytokinins. MS media supplemented with BA at 0.5 mg L-1 led to a satisfactory proliferation rate; 2.4 shoots/explant were formed. Rooting phase had moderate efficiency, being higher for media with 4.0 mg L-1 IBA. Acclimatisation was successful for all rooted plantlets, promising an effective method for exploitation of this new ornamental species of high value.

Hot water treatment improves peach fruit cold resistance through PpHSFA4c-mediated HSF-HSP and ROS pathways

Peach fruit is cold-sensitive and susceptible to chilling injury (CI), and hot water (HW) treatment can reduce their CI. However, the mechanism of HW treatment reduced CI has not been characterized. In this study, HW treatment suppressed the increases in CI index, electrolyte leakage, and malonaldehyde (MDA) content in peach fruit during cold storage. It also decreased reactive oxygen species (ROS) accumulation and increased the activity of ROS-scavenging enzymes. Transcriptome analysis indicated that HW treatment might contribute to the crosstalk between the heat shock factor-heat shock protein (HSF-HSP) and ROS pathways during cold storage. PpHSFA4c was a key transcription factor and could up-regulate defense genes to alleviate the CI of peach fruit during storage. Furthermore, PpHSFA4c could activate the expressions of PpHSP18.5, PpHSP70, PpHSP83, PpAPX1, and PpAPX3 by interacting with their promoters. These studies indicated that HW treatment alleviated the CI, increased antioxidant activity, and maintained ROS homeostasis of peach fruit through the PpHSFA4c-mediated HSF-HSP and ROS pathways. This study provides novel insights into the regulatory mechanisms of HW treatment alleviating CI in postharvest peach fruit, and expands the theoretical basis for commercial application of HW treatment technology to maintain quality and reduce CI in cold-sensitive fruit.

An Eco-Friendly Modification of a Walnut Shell Biosorbent for Increased Efficiency in Wastewater Treatment

Herein, we report the performance of some low-cost biosorbents developed by environment-friendly modification of walnut shells. Two types of biosorbents were prepared by ecological modification of walnut shell surfaces: (1) biosorbents obtained by hot water treatment (WSH2O) and (2) biosorbents produced by mercerization (WSNaOH). Different techniques were used to evaluate the morphological, elemental, and structural modification of the biosorbents, by comparison with raw materials. These characterization techniques involved scanning electron microscopy (SEM) coupled with energy-dispersive X-ray analysis, and Fourier-transform infrared spectroscopy (FTIR). The biosorbents were employed for the removal of methylene blue (MB) and crystal violet (CV) cationic dyes (as model organic pollutants) from aqueous solutions. The kinetic adsorption data mainly followed the pseudo-first-order model. The maximum adsorption capacities of the produced biosorbents ranged from 102 to 110 mg/g and were observed at 330 K. Equilibrium data for adsorption were fitted to Langmuir and Freundlich isotherm models. The calculated values of thermodynamic parameters suggested that the investigated adsorption processes were exergonic (ΔG &lt; 0) and exothermic (ΔH &lt; 0). In addition, a possible valorization of the cost-effective and eco-friendly spent biosorbents was tested by performing secondary adsorption of the anionic dyes.

Comparative Proteomic Analysis Provides New Insights into the Molecular Basis of Thermal-Induced Parthenogenesis in Silkworm (Bombyx mori).

Artificial parthenogenetic induction via thermal stimuli in silkworm is an important technique that has been used in sericultural production. However, the molecular mechanism underlying it remains largely unknown. We have created a fully parthenogenetic line (PL) with more than 85% occurrence and 80% hatching rate via hot water treatment and genetic selection, while the parent amphigenetic line (AL) has less than 30% pigmentation rate and less than 1% hatching rate when undergoing the same treatment. Here, isobaric tags for relative and absolute quantitation (iTRAQ)-based analysis were used to investigate the key proteins and pathways associated with silkworm parthenogenesis. We uncovered the unique proteomic features of unfertilized eggs in PL. In total, 274 increased abundance proteins and 211 decreased abundance proteins were identified relative to AL before thermal induction. Function analysis displayed an increased level of translation and metabolism in PL. After thermal induction, 97 increased abundance proteins and 187 decreased abundance proteins were identified. An increase in stress response-related proteins and decrease in energy metabolism suggested that PL has a more effective response to buffer the thermal stress than AL. Cell cycle-related proteins, including histones, and spindle-related proteins were decreased in PL, indicating an important role of this decrease in the process of ameiotic parthenogenesis.

DIFFERENT POST-HARVEST TREATMENTS ON PHYSICOCHEMICAL PROPERTIES AND SHELF LIFE OF TOMATO (SOLANUM LYCOPERSICUM CV. PUSA RUBY) FRUITS

A well-known vegetable of the Solanaceae family that is grown all over the globe is the tomato (Solanum Lycopersicum). In Nepal, post-harvest tomato losses of up to 50% have been observed. This study examined the effects of several post-harvest procedures to lengthen the shelf life of tomatoes stored at room temperature. The experiment had a completely randomized design (CRD) and included six treatments that were repeated four times. The freshly picked tomato was waxed, given a hot water treatment, wrapped in low-density polyethylene, treated with calcium chloride, and then given a control treatment. Weight loss, shelf life, total soluble solids, and titratable acidity were the subjects of data collection. Analysis of data was done through Microsoft- Excel, R- Studio, and Analysis of Variance (ANOVA). This study discovered that tomato fruit dipped in 8% CaCl2 had no positive impact on the fruit’s quality reserves or shelf life. The polyethylene wrapping of tomato fruits produced better results than all other treatments in terms of weight loss, maximum TSS content (3.880 Brix), titratable acidity, and maximum extension of the storage period of tomato fruits (25 days). As a result, it can be used to store light red tomato fruits for up to 25 days at room temperature.

Large-Scale Amide Coupling in Aqueous Media: Process for the Production of Diazabicyclooctane β-Lactamase Inhibitors

Herein, the amide coupling of six primary amines with the sodium salt of diazabicyclooctane acid in an aqueous medium without an additional base/surfactant or organic solvent is described. The product was efficiently isolated from the reaction through simple filtration and recrystallized using hot water treatment as a swift and cost-effective process. The methodology was implemented on a kilogram scale to produce penultimate intermediates for synthesizing β-lactamase inhibitors such as zidebactam, relebactam, and nacubactam. The comparison of green metrics for several previously reported amide coupling methods was discussed. The developed procedure avoids using hazardous organic solvents and provides a simple isolation method at the operational level with high purity and efficiency.