Postharvest Hot Water Treatments Research Articles

Influence of hot water treatment on nutritional quality attributes of cold stored apple (Malus × domestica)

The present study was carried out at ICAR-Indian Agricultural Research Institute, New Delhi during 2021–2023 to study the effect of postharvest hot water treatment (HWT) on the nutritional quality attributes of apple [Malus × domestica Borkh.] cv. Royal Delicious. Apple fruits were exposed to hot water at 48, 50, 52 and 54°C for 2, 3, 4 and 5 min. Following the treatment, the fruits were cold stored (2±1°C, 90–95% relative humidity) for 90 days and evaluated for quality changes at every 15 days interval. Our results revealed that HWT of apple fruits at 48°C and 50°C were best for optimum retention of nutritional quality of apple fruits. Exposure of fruits to HWT at 48°C/5 min and 50°C/2 min resulted in least (0.73%, 0.75%) loss of ascorbic acid and anthocyanin content (0.10%, 0.21%), respectively as compared to other temperature-time combinations. At the end of a three month storage period, under control treatment, fruits exhibited 9.56% reduction of antioxidant (AOX) activity in comparison to 0.17–2.21% reduction in HWT apples. The maximum loss in quality attributes was noticed at highest temperature-time exposure (54°C/5 min). Thus, it was observed that the right combination of temperature and time for HWT is crucial to maintain fruit quality attributes without compromising nutritional value.

Postharvest Hot Water Treatment Followed by Chitosan- and κ-Carrageenan-Based Composite Coating Induces the Disease Resistance and Preserves the Quality in Dragon Fruit (Hylocereus undatus)

ABSTRACT : Postharvest diseases and loss of freshness are major problems that cause the deterioration of dragon fruit. The present study determined the effect of hot water treatment (HWT) at 50°C for 5 min followed by 1.0% chitosan and 0.2% κ-carrageenan-based composite coating to counter the issues. The results showed that HWT followed by the composite coating-enhanced antioxidant enzyme activities and reduced accumulation of H2O2 in the peel, which demonstrated the defensive response in the tissues leading to reduce disease development. The chitinase and β-1,3-glucanase did not show a significant effect in reducing the postharvest diseases of dragon fruit. While the HWT helped to increase phenolics content and antioxidant capacity in the pulp, the composite coating was crucial to maintain green color of the bract. Therefore, we concluded that HWT combined with composite coating controlled the diseases via antioxidant defensive response and maintained the overall quality of dragon fruit for 30 days of storage at 10°C.

Effects of post-harvest hot water treatments on the fungi contamination, physiology and quality of rock melon fruit

During the postharvest management of fruits and vegetables, the losses range from 10 to 30% of the entire production. This is due to numerous causes, but the most important reason is infestation by fungi. Many synthetic fungicides are employed for postharvest treatment of fruit and vegetables throughout the world. However, fungicidal residues often represent a significant threat to human health. The current study examined the use of hot water treatments on rock melon fruit. Hot water treatments at 55℃ was arranged into four treatments of different dipping periods of 0 minutes (control), 1 minute, 2 minutes, and 3 minutes. The postharvest hot water treatments on rock melon fruit were found to increase the shelf life up to 21 days by minimizing the weight loss, maintaining firmness, preventing the damage of sucrose, retaining the rind size, maintaining the fruit appearance, and reducing fungal infection. The one-minute dip was more effective than other treatments. The treatment successfully extends the shelf life of rock melon fruit quality for the market until three weeks of storage at 21 ± 1 ℃ compared with the control, which was only stored for one week. The results showed the importance of hot water treatments as an alternative to fungicides or chemical treatments, which have a high risk to the health of consumers. Hot water treatment is economical and easier to access than the chemical treatments.

Control of apple surface microflora for fresh-cut produce by post-harvest hot-water treatment

Growing interest in a healthy and convenient diet causes a strong increase in the consumption of packaged fruit salads. Frequently, apple slices are a microbial problematic component. Apples are processed with their peel, which increases the consumers health risk and decreases the shelf life of fruit salads. Consequently, specific preprocessing sanitizing efforts directly during fresh fruit salad production are indispensable. Therefore, the study focused on the effective reduction of the microbial load of apples, particularly concentrating on human pathogens. Short-term hot-water treatment (HWT) actually controlled the microflora of apple surface if applied directly before processing. A HWT of 55 °C for 0.5 - 2 min efficiently reduced the natural microflora and artificial inoculated microbes on the apple peel for 2 - 3 log steps (i.e. 100 - 1000-fold) and yielded the best balance between preservation of the fruit and sanitation effect. Simply washing off the microorganisms (MOs) could be excluded as mechanism of hot-water disinfection. Due to complete waiving of any chemicals, short-term HWT is not only an efficient but also very gentle method to improve safety and shelf-life of fresh fruit salads. In addition, the proposed system could be easily and cost-effective integrated in existing production lines.

Effect of post-harvest treatments on black spotting, infestation and organoleptic quality of mango cv. Amrapali during ambient storage

This experiment was conducted during the year 2011–12 to study the effect of post-harvest hot water treatment and wax coating on occurrence of black spotting and infestation of insects like fruit fly during storage of Amrapali mango fruits under ambient condition. Black spots on fruits skin during ripening and storage are mainly due to the infection of Anthracnose and Stem-end rot are the major post-harvest diseases of mango fruits. In the present experiment, fruits were harvested at green mature stage and treated with four post-harvest treatments, viz., T1 (Hot water treatment at 52 ± 2°C for 5 minutes), T2 (Wax coating of 6% wax emulsion), T3 (Hot water treatment + Wax coating) and T4 (Water was taken as control). Treated fruits were packed in CFB boxes and stored under ambient condition. Observations were recorded at 3 days intervals during storage. Results revealed that the treatment of (HWT + Wax coating) was found to be best to minimize the black spotted and infested fruit per cent in mango during storage. Treated fruits retained the maximum fruits firmness and highest organoleptic score with acceptability up to 15 days, while 6 days in untreated fruits during the ambient storage. Treatments of (HWT +Wax coating) was also improved the shelf life of mango fruits up to 15 days with lowest PLW per cent against only 9 days was recorded in control.

Chilling injury incidence and antioxidant enzyme activities of Carica papaya L. ‘Frangi’ as influenced by postharvest hot water treatment and storage temperature

The effect of double-dip hot water treatment (42°C for 30min and 49°C for 20min) with two different storage temperatures (6 and 12°C, 85–90% RH) and storage durations (0–3 weeks) on peel and pulp chilling injury incidence and antioxidant enzyme (catalase, ascorbate peroxidase, superoxide dismutase) activities of Frangi papayas, were investigated, with untreated fruit as controls. Peel and pulp chilling injury (CI) incidence was reduced in the treated fruit, especially in fruit stored at 6°C, which was accompanied by increased ascorbate peroxidase activity. Thus, hot water dips followed by low storage temperature could prolong the storage life and reduce CI incidence of Frangi papaya.

Epidemiology and management of brown rot on stone fruit caused by Monilinia laxa

Stone fruit is attacked by various pathogens, of which brown rot disease is one of the important diseases. There are three Monilinia species mainly responsible for the brown rot disease: Monilinia fructicola is mainly found in North America and Australasia, and M. laxa and M. fructigena mainly in Europe. Both M. fructicola and M. laxa can infect flowers, resulting in blossom blight, as well as both healthy and wounded fruit, resulting in brown rot. On the other hand, M. fructigena can only infect wounded fruit. Compared to the two other species, M. fructicola has been extensively studied, whereas the equally important M. laxa has had less attention. This paper addresses this imbalance and reviews research on the biology, epidemiology and management of M. laxa on stone fruits. Due to EU regulations, the number of fungicides available for controlling plant diseases has been steadily decreasing, particularly in the post-harvest environment. This has placed much more emphasis on alternative control methods, a focus of the present review. Numerous physical and biological approaches to control have achieved successful outcomes but often in small-scale trials and in isolation from integrated strategies. Promising physical control methods include removal of mummified fruit in orchards and post-harvest hot-water treatment. Many micro-organisms have been shown to have biocontrol potential against brown rot but only a few have been commercially formulated. It is generally agreed that the use of biocontrol agents needs to be integrated with other measures. Current research focuses on disease management from flowering to post-harvest period. Recent results have suggested that reducing overwintering inoculum should be considered as one of key aspects of integrated management of brown rot on stone fruit. Finally, we make recommendations about future research and development on integrated pest management strategies for control of M. laxa, especially on strategic deployment of biocontrol agents and interactions among brown rot pathogens.

Synergistic Influence of Pre-Harvest Calcium Sprays and Postharvest Hot Water Treatment on Fruit Firmness, Decay, Bitter Pit Incidence and Postharvest Quality of Royal Delicious Apples (<i>Malus x domestica</i> Borkh)

Experiments were conducted to observe the effect of pre-harvest calcium (Ca) applied as calcium chloride (1% W/V) and postharvest hot water treatment (HWT) on “Royal Delicious” apples. For this, apples were divided in 4 lots viz., untreated (neither Ca nor HWT), Ca alone (pre-harvest 3 sprays of CaCl2 (1.0% w/v) in the orchard), HWT (42℃ for 2 h). Apples of all four lots were stored in cold storage maintained at 0℃ ± 1℃ and 90% - 95% relative humidity for 6 months. After storage, fruits were removed to ambient conditions for 5 days, and then observations on decay area and incidence, bitter pit incidence, fruit Ca content, lipoxygenase (LOX) and antioxidant (AOX) activity, fruit firmness and fruit quality parameters were recorded. After 6 months in cold storage plus 5 day at 22℃ ± 2℃ and 70% + 4% RH, apples, which received Ca as pre-harvest spray or those which received postharvest hot water treatment or Ca + HWT had significantly lesser decay area (decay lesions) caused by Penicillium expansum or Botrytis cinerea than untreated ones (control). Ca + HWT treatment was significantly more effective on B. cinerea than P. expansum. Untreated apples exhibited higher incidence of bitter pit (18.2%) than those treated with Ca or HWT or both. Fruit Ca content (2.92% DM) were significantly lower and conversely the LOX activity (6.9 μmoles min–1×g–1FW) was higher in untreated apples. Similarly, total phenolics and AOX activity were also lower in the untreated apples than Ca or HWT treated. HWT or Ca treated apples have beneficial effects on fruit firmness, peel colour and quality parameters like TSS and ascorbic acid content. Thus, it is concluded that pre-harvest sprays of calcium chloride with postharvest HWT is highly useful for “Royal Delicious” for reducing decay loss, maintaining firmness, high levels of antioxidants and fruit quality.

Quality response of table grapes (Vitis vinifera L.) during cold storage to postharvest cap stem excision and hot water treatments

SummaryBerry quality, total phenol, sensory characteristics and decay incidence of grapes (V. vinifera cvs. Müşküle and Red Globe) as affected by prestorage hot water immersion with or without cap stem excision treatments were investigated with 7‐day interval during storage at 1 °C for 21 days. Weight loss occurred mainly up to the second week and was more pronounced for the untreated control samples subjected to the stem excision. In Müşküle, the least weight loss value was obtained from hot water–treated grapes (0.62%), while the highest loss occurred in control grapes of stem‐excised berries (0.96%). Immersion of stem‐retained grapes in hot water was the best applications for maintenance of overall storage quality for both cultivars. According to panellist scores, it is evident that hot water has positive effect on maintaining the minimally processed table grapes without altering the flavour and taste of the commodity. Stem‐retained berries of hot water treatment had the highest score for both Müşküle and Red Globe, with their values 3.8 and 4.2, respectively, while the least values were obtained from stem‐excised berries of untreated control group of both the cultivars (1.9 and 3.0, respectively). At the end of three‐week storage, the least decay rates were determined in stem‐retained berries that received hot water treatment (5.3% for Müşküle and 1.1% for Red Globe). Attenuate influence of brief high temperature exposure on ripening parameters (SSC, TA, MI, pH) was also observed. Postharvest hot water treatment may be used as a nonchemical means to extent storage life of minimally processed grapes with its alleviating effect on physiological disorders. Cap stem retaining in minimal processing can be recommended to maintain the quality of grapes.

Hot water treatments reduce leaf yellowing and extend vase life of Asiatic hybrid lilies

The vase life of Asiatic lilies can be limited by leaf yellowing, which can be caused by exposure to low light or temperature during winter growth or in storage. We examined the use of postharvest hot water treatments (HWTs) as a means of reducing leaf senescence in stored (4 °C for 2 weeks) and non-stored Asiatic hybrid lily ‘Elite’ ( Lilium sp.). A range of HWTs (45–55 °C for 2.5 or 5 min) was applied to leaves on cut lily stems (but not flowers). Higher temperatures and the longer duration resulted in heat damage, but treatments of 50 °C for 5 min and 52.5 °C for 2.5 min were found to be optimal for minimising leaf yellowing with trace levels of heat damage for both non-stored and stored stems. The onset of yellowing was delayed by 3–4 d, and the occurrence of an unacceptable level of yellowing eliminated for up to 12 d (compared with <6 d for control stems). The physiological effects of these optimal HWTs were examined in terms of water uptake, chlorophyll fluorescence and chlorophyll degradation. Water uptake for optimal HWTs during shelf life was reduced by more than 50% of the control stems. Chlorophyll fluorescence of leaves on control stems showed a reduction in yield ( F v/ F o) over time, which was more marked in lower than upper leaves (thus correlating with yellowing, which was more severe in the lower leaves). Although both optimal HWTs resulted in an initial reduction in yield, there was a recovery over time resulting in a yield that, by 12 d, was as high or significantly higher than control leaves (particularly for the lower leaves). All treatments showed a reduction in chlorophyll content (total, chlorophyll a and chlorophyll b), but control leaves had significantly lower levels after 7 d. HWTs show potential as a non-chemical, simple means of delaying leaf yellowing of Asiatic lilies and thus increasing vase life.

ORGANIC MANGO PRODUCTION IN MEXICO: STATUS OF ORCHARD MANAGEMENT

Eight percent of total planted area in Mexico is in the process to change from conventional to organic system mainly in the Pacific Coast under tropical dry and wet conditions. Mango cultivars in organic systems are ‘Tommy Atkins’, ‘Kent’, ‘Ataulfo’ which are demanded by market and early or late season of harvest. Cultivars are grafted on local polyembrionic rootstock well adapted to different soil types, they remain vigorous but tolerance to soil diseases has not been proved yet. Information of better combinations of rootstocks and cultivars appropriated for organic production and adapted to variable soil conditions, is needed. Plant densities range 100 to 200 trees ha-1, but are rapidly changing to higher tree densities. Either, tillage practices or cover crops are used to avoid herbicides to control weeds in between tree rows. Pruning of trees is a very important activity applied by growers to control tree size, avoid pest and diseases and promote better light conditions in internal canopy to improve fruit color. Many diseases affect tree foliage, flowering and fruits and are properly controlled using permitted products listed by IFOAM. However organic and more efficient alternatives are needed in order to control the wide diversity of diseases in the field. In addition to field applications, anthracnose damage on fruits is controlled by means of postharvest hot water treatments. Fruit flies are important pests, but they are kept under control with integrated management program applied to different regions according to population levels. Several organic products are used to fertilize orchards, but beneficial impact on fruit production and quality remain to be thoroughly clarified.

Influence of a post-harvest hot water treatment on the development of green mould [Penicillium digitatum (Pers.:Fr.) Sacc.] and on the quality of ‘Mandora’ fruit [Citrus reticulata Blanco Citrus sinensis (L.) Osbeck

SummaryThe effect of a post-harvest hot water treatment (HWT) at 56° – 65°C for 1 – 3 min on the development of green mould [Penicillium digitatum (Pers.:Fr.) Sacc.] on inoculated ‘Mandora’ fruit [Citrus reticulata Blanco × Citrus sinensis (L.) Osbeck], and on rind colour and juice quality, were evaluated during post-treatment storage at 8.5°C and 90% relative humidity. Treatment duration was more influential than treatment temperature on the incidence of green mould (IGM) during post-treatment cold storage. ‘Mandora’ fruit demonstrated a relatively high thermal tolerance to HWT. Treatment for up to 3 min at 56°C did not result in any symptoms of rind discolouration or heat damage after 16 d of storage, while it reduced the IGM by 98.2%, 60.9%, and 16.2% after 8, 12, and 16 d of cold storage, respectively. The loss in fresh weight (FWL) for fruit treated at 56°C for 3 min was 15.7% higher than in untreated control fruit after 16 d of cold storage. The titratable acidity and soluble solids content of the juice were not affected by HWT, and no sensory defects were detected after storage. Post-harvest HWT may constitute a valuable, stand-alone application to control the IGM on organically produced ‘Mandora’ fruit, or as a pre-treatment for conventionally produced fruit. However, HW-treated fruit were prone to an increased FWL, indicating caution during the commercial application of HWT.

EFFECTS OF POSTHARVEST HOT WATER TREATMENT ON PHYSIOLOGICAL AND BIOCHEMICAL PROPERTIES OF 'EKSOTIKA' PAPAYA DURING RIPENING

Effects of postharvest hot water treatment (HWT) on the 'Eksotika' papaya fruit quality during ripening were investigated. HWT is a method for fruit fly disinfestation which is a quarantine requirement for the papaya exportation industries. Fruit were harvested at maturity stage Index 2 (green with a tinge of yellow). One group was treated with hot water at 47±1°C for 10 min and another group was untreated. Fruit were left to ripen at ambient temperature (25°C) and were taken into experiment at Index 2 (Harvest Index), Index 4 and Index 5. Physiological changes including peel colour, weight loss, fruit firmness, total soluble solids (TSS) and pH were determined at the three different ripening indices. Biochemical changes including total sugars and total reducing sugars were also investigated. From the results, both treated and untreated fruit showed normal ripening. There were also no significant differences in weight loss, TSS and pH value between the untreated and treated fruit at the three ripening indices. However, the peel colour changes in untreated fruit were delayed by approximately 1-2 days. At Index 5, the treated fruit was firmer than the untreated fruit. The total sugars and total reducing sugars contents showed no significant difference between the two groups at the three different ripening indices. The reducing sugar content was increased and attained highest value at Index 4. Conversely, the non reducing sugar content was decreased during ripening. Although HWT hastened degreening (of peel), cause slightly firmer fruit when ripe, fruit sweetness was remained unchanged and maintained at a good quality. This suggests that postharvest hot water treatment at the selected temperature can maintain postharvest quality of 'Eksotika' papaya fruit and at the same time prevent it from insect infestation.

The Influence of Postharvest Treatment and Type of Packaging on Quality and Storage Ability of Cauliflower (Brassica oleracea L. var. botrytis)

The Influence of Postharvest Treatment and Type of Packaging on Quality and Storage Ability of Cauliflower (Brassica oleracea L. var. botrytis) The influence of postharvest hot and cold water treatments on the quality and storage ability of cauliflowers were studied. Also the usefulness of different type of unit packaging for cauliflower storage was compared. The cauliflower heads of Fremont F1 cultivar, after different treatments, were stored at 0°C for six weeks. Postharvest hot water treatment with temperature 38-54°C has not influenced on the storage ability of cauliflower. The heads treated with water of temperatures 50°C and 54°C have shown after six weeks of storage higher rooting, greater compactness loss and colour changes than not treated heads. Postharvest cooling of heads with ice water has not affected quality after storage. It was found that the type of packaging influenced on cauliflower quality after storage. The best quality of cauliflowers after 28 and 42 days of storage was maintained in P-Plus film bags and PE film bags with perforation (8 holes ϕ0.04 cm). The satisfactory quality was maintained also in case of heads wrapped in stretch film and stored for 42 days. The unsatisfactory quality due to heads darkening was found for cauliflowers kept in tightly sealed PE film bags.

HOT WATER TREATMENT FOR DISEASE CONTROL AND EXTENSION OF SHELF LIFE OF ´KESAR´ MANGO (MANGIFERA INDICA L.) FRUITS

The present investigation was undertaken to study the effect of post harvest hot water treatment for disease control and extension of shelf life of 'Kesar' mango fruits grown under arid zone. For this purpose, the mango fruits were harvested at proper stage of maturity and given hot water treatments at 52°C for 10 minutes either alone or in combination with fungicidal dips viz., Bavistin (0.1%) and Captan (0.2%). The mango fruits were then packed in corrugated fibre board box and then stored in two storage environments viz., at room temperature (28.12 to 36.18°C temperature and 46.18 to 71.25% RH) and in zero energy cool chamber (21.47 to 27.10°C temperature and 91 to 95% RH). It was observed that hot water treatment combined with Bavistin (0.1%) was found to be the best in controlling the incidence of anthracnose and stem-end rot.[...]

Postharvest hot water treatment for the control of Thielaviopsis black rot of pineapple

Abstract Black rot of pineapple (Chalara paradoxa (De Seyen.) Sacc.) is a common postharvest problem in many countries. Consumer resistance to the use of fungicides has precipitated the need for alternative means of controlling the disease. In vitro studies on heat-treated (50 °C for 3 min) spores of the pathogen showed a mean colony count of 11 ± 0.7, following 48 h incubation at 28 °C, while plates with heat-treated spores at 54 and 58 °C showed a mean colony count of 1 ± 1.0 and 1 ± 0.7, respectively. Pineapples inoculated with 104 spores/ml, C. paradoxa, followed by a hot water dip treatment at 54 °C for 3 min were free of disease when stored at 10 °C for 21 days followed by 48 h at an ambient temperature (28 ± 2 °C). Inoculated dip-treated fruit held at 28 ± 2 °C for 6 days also remained healthy. However, characteristic symptoms of the disease were observed in fruit that were inoculated and held as controls under similar storage conditions, with no hot water dip treatment. No significant difference occurred between hot water dip-treated and untreated controls with respect to flesh and shell colour of fruit, ascorbic acid levels and titratable acidity. Mean ascorbic acid level was 18.8 mg/100 g in fruit stored at 10 °C compared with 9.3 mg/100 g in fruit stored at 28 ± 2 °C, irrespective of whether they were inoculated or non-inoculated fruit. A significant difference (p

An integrated method to control postharvest diseases of banana using a member of the Burkholderia cepacia complex

Abstract Banana ( Musa acuminata ) is a perishable fruit subjected to anthracnose, crown rot and blossom end rot at the postharvest stage. The present study focused on developing an integrated method to control postharvest diseases of banana by combining antagonistic bacteria occurring naturally in the fructosphere with hot water treatment. Twenty-five temperature and exposure time combinations were tested for their ability to control anthracnose and crown rot and their influence on postharvest quality parameters such as peel colour, hardness and Brix value of fruit. Optimum temperature and exposure time for postharvest hot water treatment of banana were determined to be 50 °C and 3 min, respectively. Temperatures higher than 50 °C reduced the colour of fruit peel and gave a pale appearance to fruit even after ripening. Exposure times longer than 5 min substantially reduced the Brix value. A member of the Burkholderia cepacia complex, isolated from the fructosphere of banana was effective as an antagonist of postharvest pathogens even after 5 years of storage in sterile distilled water at ambient temperature. The isolate of B. cepacia used was different from the already identified species of the B. cepacia complex. The most effective concentration of B. cepacia was determined to be 10 10 CFU/ml for in vivo control of anthracnose and crown rot. The most effective control was achieved by repeated dipping of bananas in bacterial solution or by adding a wetter (Tween 20) to the bacterial solution. Combining hot water treatment with the bacterial antagonist also gave more effective control of anthracnose, crown rot and blossom end rot than using the two treatments individually. Higher efficacy of this integrated method was confirmed further by its greater control of artificially infected anthracnose. The present study provides valuable options for non-chemical control of postharvest diseases of banana using an antagonistic bacterium and hot water treatment either individually or together.

Conditioning `Kensington' Mango with Hot Air Alleviates Hot Water Disinfestation Injuries

In an effort to develop an inexpensive alternative to vapor-heat insect disinfestation of `Kensington' mango (Mangifera indica Linn.), the effect of postharvest hot water treatments (HWT) on fruit quality was determined. Fruit were given 46C HWT for 30 minutes at a fruit core temperature of 45C either 24 hours after harvest or after various conditioning treatments of 4 to 24 hours at 39 ± 1C in air. Fruit were compared to nontreated fruit after a subsequent 7 days at 22C. The HWT increased fruit softening and reduced chlorophyll fluorescence and disease incidence. The longer conditioning times produced softer fruit. Conditioning reduced damage to the fruit caused by HWT. Preconditioning for ≥8 hours resulted in &lt;1% of fruit being damaged as shown by cavities, skin scald, and starch layer formation. The quantitatively measured higher mesocarp starch content paralleled the visible starch layer injury. Skin yellowing increased in response to HWTs that were not damaging to the fruit. Fruit ripening changes were unequally affected by HWT and by conditioning before HWT; thus, the sequence and extent of these changes must be determined to establish a reliable and useful hot water disinfestation treatment.