Hot Water Dip Treatment Research Articles

Evaluation of Low-Input Management Methods for Plant Parasitic Nematodes in Plantain CV. Agbagba in Southwestern Nigeria

Field trial was conducted at the National Horticultural Research Institute’s experimental field between July 2003 and January 2005 to determine the effect of some cultural practices on the populations and control of plant parasitic nematodes infestation and their effect on some growth and yield attributes of plantain cv. Agbagba. The treatments included corm paring / hot water root dip, Tithonia diversifolia leaf mulch and combination of Tithonia leaf and hot water root dip. The untreated plantlets served as the control. Results showed that in all the assayed soil and root samples, the control plots recorded the highest populations of plant parasitic nematodes. They include Meloidogyne incognita, Helicotylenchus multicintus and Radopholus similis while the lowest populations occurredin plots with the treatment combination of hot water root dip and T. diversifolia mulch. Plant height, number of leaves and sucker production were significantly enhanced. in Tithonia mulch + hot water root dip- treated plantain followed by Tithonia mulch and hot water dip treatment respectively, Early flowering and fruiting as well as significant increasein bunch weight were observed in Tithonia mulch + hot water root dip - treated plantain. Similarly, the highest cumulative yield values occured in Tithonia mulch + hot water root dip - treated plantain. This practice is recommended for plantain producers in organic agriculture production system

Effect of hot water dip treatment on seedborne pathogens and germination of carrot seeds

The effect of hot water treatment of carrot seeds on seedborne pathogens (Alternaria and Fusarium spp) and seed germination was studied Carrot seeds (no fungicide) were dipped in water at 50C or 52C for 10 20 or 30 min and plated on potato dextrose agar to assess pathogen growth Treated seeds were sown in cell trays to assess germination in a glasshouse The weight of the germinated seedlings was also recorded All hot water treatments significantly (P

HOT WATER DIP AND PRECONDITIONING TREATMENTS TO REDUCE CHILLING INJURY AND MAINTAIN POST-HARVEST QUALITY OF VALENCIA AND NAVEL ORANGES DURING COLD QUARANTINE

The potential of hot water dipping (HWD) at 41±1°C for 20 min or at 50±1°C for 5 min and pre-storage conditioning (6 days at 16-18°C and 45-65% RH) treatments to control chilling injury (CI) and decay of W. Navel and Valencia Late oranges during cold quarantine at 1°C and 85–90% RH for 20 days, subsequent storage at 10°C and 85–90% RH for 20 days (as a transit period) and an additional 20 days of simulated marketing period (SMP) at 20±2°C and 40-65% RH was investigated over 2 harvest seasons (2006/2007 & 2007/2008). Untreated fruits were used as control. We studied their effects on various other postharvest quality parameters such as weight loss, juice %, soluble solids content (SSC), total acidity (TA), ascorbic acid (VC), and reducing sugars, free phenols, peroxidase (POX) and catalase (CAT) activities, and ascorbic acid oxidase (ASAO). After SMP, HWD treatments reduced the incidence of CI in W. Navel (4.2-13% versus 29–33% in control and 12-21% in conditioning treatments) and Valencia (0–27% against 60-63% in control and 60–67% in conditioning treatments). HWD treatments effectively prevented the incidence of decay in both cultivars in all storage stages, while conditioning one reduced it in W. Navel to 17-13%, against 25% in the control, although in Valencia, a very little insignificant decay % was found (3-7%). HWD treatments reduced the rate of weight loss in both cultivars, while conditioning one reduced it in Valencia, only. In addition, HWD treatments mostly increased VC content, especially in W. Navel, while reduced ASAO activity. HWD treatments increased free phenols content in both cultivars, as compared with control and conditioning treatments, although the last increased it as compared with control. HWD at 41°C for 20 min was more effective than at 50°C for 5 min in this respect. All treatments significantly increased POX and CAT activities, whether in fruit peel or juice of both cultivars as compared with control. HWD at 41°C for 20 min treatment was more effective in this respect. Generally, the reduction in chilling injury % was paralleled to higher POX and CAT activities in fruit peel and juice, and free phenols in juice, this may explain how and why the treatments reduced CI incidence. Overall, it is concluded that short postharvest HWD treatment is preferable, since it effectively induced tolerance to cold temperatures in W. Navel and Valencia Late oranges without impairing any other postharvest qualities.

DERİM SONRASI SICAK SU UYGULAMALARININ CALIFORNIA WONDER TİPİ BİBER MUHAFAZASI ÜZERİNE ETKİLERİ

In this study, the effects of hot water dip treatments on the storage of California Wonder type peppers grown in greenhouse in Antalya, were investigated. In the experiment, California Wonder type peppers were dipped into hot water at 48 and 53°C for 3 minutes. After hot water dip treatments all peppers were stored at 8°C with 90-92 % relative humidity for 32 days. During the storage period, various chemical and physical analyses, weight loss, soluble solids, titretable acidity and fruit color changes were performed on the fruit by taking from cold storage at 8 days intervals. The results showed that dipping of peppers into hot water at 48 °C for 3 minutes were positively effected on controlling decays.

Effect of hot water treatments on chilling injury and heat damage in ‘satsuma’ mandarins: Antioxidant enzymes and vacuolar ATPase, and pyrophosphatase

Susceptibility of ‘satsuma’ mandarin fruit (Citrus unshiu Marc) to chilling injury limits the marketability of stored fruit. In this study, the effect of hot water dip (HWD) treatments on chilling injury tolerance, fruit quality, activity of antioxidant enzymes, and gene expression of proton transporters in the vacuole were investigated in New Zealand. Some treatments suppressed chilling injury development, but none of them could prevent it completely. The major reduction in chilling injury incidence (proportion of unacceptable fruit) and severity (level of damage) was observed in HWD at 50 °C, for 2 min. Temperatures higher than 50 °C increased fruit peel damage. Chilling injury was paralleled by higher ethylene production and respiration rate in affected fruit, and an increase in the amount of ethanol and acetaldehyde emitted in juice headspace. Afterwards, values decreased gradually with increasing chilling damage. Treatments that reduced chilling injury suppressed anaerobic products, ethylene evolution and respiration. During storage at 2 °C for 8 weeks, a decline in catalase (CAT) activity was observed, while peroxidase (POX) activity increased. This rapid increase in POX activity was associated with increased peel damage due to both chilling injury and heat damage. Decreasing chilling injury in HWD was correlated with decreased POX activity and maintenance of CAT activity during storage. Amounts of vacuolar pyrophosphatase (V-PPase) and vacuolar ATPase (V-ATPase) gene transcript in fruit peel were reduced by heat treatment. Storage periods reduced V-PPase and induced V-ATPase gene transcript level in fruit treated at 50 °C, but this was not associated with changes in the acid content in the juice. A significant induction (5–6-fold) of ATPase and V-PPase occurred in juice sacs and this may be associated with compensation for a loss of tonoplast integrity in fruit treated at 55 °C compared to those at 50 °C. We also found that V-ATPase and V-PPase transcript levels in juice sacs responded rapidly to heat treatments but were largely recovered after 8 weeks cold storage for successful (non-damaging) heat treatments. The optimal HWD treatments were 47.5–50 °C for 2 min.

Effect of Postharvest Calcium and Hot-water Dip Treatments on Catalase, Peroxidase and Superoxide Dismutase in Chilled Lisbon Lemon Fruit

Effect of Postharvest Calcium and Hot-water Dip Treatments on Catalase, Peroxidase and Superoxide Dismutase in Chilled Lisbon Lemon Fruit

EFFECTS OF POSTHARVEST STORAGE AND GENOTYPE ON QUALITY AND SHELF LIFE OF FRESH SOUTHERNPEAS [VIGNA UNGUICULATA (L.) WALP.

Postharvest storage of southernpeas is crucial in the production process. Governed by consumer demands, farmers strive for a product that is high in quality and freshness, and has an appropriate texture and appealing color. Improper storage of southernpeas results in their premature deterioration, lack of acceptance, and possible loss of profit. Therefore, an appropriate storage facility and temperature should be devised that will benefit both farmer and consumer. In an effort to prevent potential losses of southernpeas, a study was conducted to determine the best environmental condition at which to store and to potentially extend shelf life. In 2004, two experiments were conducted on the University of Arkansas Agriculture Research and Extension Center, Fayetteville, Ark., to determine the best genotype and storage environmental condition to maintain a quality marketable prod-uct. In the first experiment, a screening of 23 southernpea genotypes was conducted from single plots to determine which genotypes could maintain their appearance the longest in a refrigerated environment. In the second experiment, two separate plantings were made of five southernpea genotypes in a randomized block design in two separate fields. Upon maturity, 12 mature green pods of each genotype were subjected to a sweated and unsweated treatment. After shelling, seeds were subjected to one of three different environmental conditions: cool regime, room temperature, and ambient air, evaluating each on the basis of changes in physical appearance; a hot water dip treatment was also examined. A refrigerated environment at or near 37 to 41 °F was the best environment to store southernpeas for nearly 2 weeks. The sweated treatment also aided in the shelling process and appeared to maintain the appearance of each genotype longer.

Codling Moth (Lepidoptera: Tortricidae) Larval Survival under Heated Anaerobic Conditions

Quarantine regulations of importing countries are designed to prevent the introduction of exotic arthropod pests. A popular procedure is to use thermal treatments such as vapor heat, forced hot air, and hot water dips to disinfest fresh agricultural commodities (Sharp, 1994; Hallman and Armstrong, 1994; Neven, 2003). Other potential treatments involve controlled atmosphere thermal treatment systems (CATTS) (Neven and Mitcham, 1996) and radio frequency exposures in water baths (Ikediala et al, 2002; Wang et al, 2001). Wang et al. (2002) used a heating block system to determine the temperatures and exposure times required for efficacious use of heat against codling moth larvae, Cydia pomonella (L.) (Lepidoptera: Tortricidae). The predicted treatments have been verified for infested sweet cherries, Prunus avium (L.) L. (Rosaceae), by using various hot water baths (Hansen et al, 2004). Although heat is the major component for all these thermal treatments, many other abiotic factors can influence efficacy (Hansen and Sharp, 1998,2000). An obvious condition that impacts insect survival is any impediment to the vital respiration of the pest, such as in the CATTS or hot water dip treatments. However, few studies have compared treatment efficacy between aerobic and anaerobic systems. Knowledge of the contribution of asphyxiation would improve the efficacy of postharvest treatments and refine the precision of the mathematical mortality models. The objective of this study was to compare the efficacy of a thermal treatment under different oxygen-poor atmospheres by using codling moth larvae. This information would aide in the development of efficacious heat treatments.

Evaluation of the integrated application of two types of modified atmosphere packaging and hot water treatments on quality retention in the litchi cultivar ‘McLean’s Red’

SummaryThe efficacy of modified atmosphere packaging (MAP), Xtend® (XF) or biorientated polypropylene (BOPP), and hot water dip treatments on quality retention in the litchi cultivar ‘McLean’s Red’ was evaluated as an alternative to SO2-fumigation. Fruits were dipped in hot water at different temperatures and time regimes [50°C 2 min; 55°C 1 min; or 60°C 1 s] and packed in XF or in BOPP. The XF bags were closed with rubber bands, while the BOPP bags were heat-sealed to modify the atmosphere around the fruit. Packed fruits were placed in commercial cardboard cartons and stored at 2°C and 95% RH for 34 d to simulate commercial export conditions. Commercial SO2-fumigation, and fruit without any hot water dip treatment packed in XF or BOPP were included as controls. Weight loss, firmness, pericarp browning, severity of decay, Hunter colour values, titratable acidity, fruit pH and soluble solids concentrations were determined after storage. Sensory analysis was carried out to determine colour retention of the pericarp and aril, flavour qualities, taste, odour, juiciness and overall consumer acceptability. Fruit packed in BOPP showed reduced weight loss, colour deterioration and decay, and retained excellent eating quality during long-term storage due to the high RH and higher O2 concentrations (17%) around the fruit. Hot water dip treatments at 50°C for 2 min, or at 55°C for 1 min, caused deleterious effects on pericarp colour, surface structure and quality parameters.

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

Combined effect of heat treatment and modified atmosphere packaging on the color development of cherry tomato

Abstract Mature green cherry tomato ( Lycopersicon esculentum , cv. Coco) fruit was dipped in hot water (39 °C for 90 min) and subsequently stored in plastic films with various O 2 but similar CO 2 permeabilities at 15 °C. Changing gas composition within the films and color development of the fruit was evaluated during a storage period. Results showed that individually both the hot water dip treatment (HWT) and low O 2 modified atmosphere in films delay color development. The combination of HWT and lower O 2 had a more substantial effect in delaying color development.

Catalase enzyme activity is related to tolerance of mandarin fruits to chilling

The effect of a postharvest hot-water dip treatment (HWT) at 53°C for 3 min and a 3-day heat-conditioning treatment at 37°C with air (HAT) at 90–95% RH on chilling tolerance and catalase (CAT) activity was compared in ‘Fortune’ mandarins. The HWT treatment increased CAT activity in the fruit, but after they were removed from high temperature to cold storage a rapid decline in CAT activity was associated with increased chilling injury. Greater chilling tolerance and CAT activity was induced when fruits were conditioned for 3 days at 37°C and 90–95% RH. The CAT activity in fruits exposed to HAT was higher than in the dipped and the non-heated fruits over the storage period at 2°C. An inhibitor of CAT activity, 3-amino-1,2,4-triazole (AT), caused peel damage in HAT ‘Fortune’ mandarins and in the chilling-tolerant ‘Clementine’ and ‘Clemenules’ cultivars stored at 2°C but not at 12°C (non-chilling temperature). CAT activity was reduced about two to three times by AT upon cold storage in the cultivars studied. Little difference was found in the activity of ascorbate peroxidase (APX), glutathione reductase (GR) and superoxide dismutase (SOD) between AT-treated and non-treated fruits. The data indicate that CAT may be a major antioxidant enzyme involved in the defence mechanism of mandarin fruits against chilling stress. Our results also suggest that the different effectiveness of the heat-conditioning treatments in increasing chilling tolerance of ‘Fortune’ mandarins may be related to induction of CAT activity during heating and on its persistence during cold storage.

Seasonal Susceptibility of Tarocco Oranges to Chilling Injury As Affected by Hot Water and Thiabendazole Postharvest Dip Treatments

Susceptibility of Tarocco (blood) oranges (Citrus sinensis Linn. Obsek) to chilling injury (CI) was investigated with fruit harvested from December through April. The fruit was subjected to a 3 min dip in water with and without thiabendazole (TBZ) at 200 ppm (50 °C) or 1200 ppm (19 °C, room temperature) and then stored at 3 °C and 90-95% relative humidity (RH) for 6 weeks followed by 1 additional week at 20 °C and approximately 80% RH to simulate a marketing period (SMP). CI development was significantly affected by the age of the fruit, decreasing later in the season. Water dips at 50 °C reduced CI. However, dip efficacy was significantly influenced by picking date and storage duration. Treatments with 1200 ppm TBZ at 19 °C also ameliorated CI but had no better effect than water at 50 °C. Treatments with 200 ppm TBZ at 50 °C significantly suppressed CI development on fruits harvested throughout the season. TBZ accumulation on fruits following 200 ppm dips at 50 °C was not significantly dependent on fruit age, while 1200 ppm TBZ at room temperature resulted in significantly higher TBZ uptake in fruits harvested late (April) rather than early (December), with intermediate concentrations of fungicide in fruits harvested from January through March. Residue concentrations in fruits after treatment with 200 ppm TBZ at 50 °C were not significantly different from those found following 1200 ppm TBZ dipping at 19 °C throughout the season. We concluded that postharvest treatments with 1200 ppm TBZ at room temperature or 200 ppm TBZ at 50 °C produced similar TBZ uptake in Tarocco oranges, but TBZ treatments at 50 °C water gave the most effective reduction of CI symptoms.

Reduction in microbial load on buffalo meat by hot water dip treatment

Buffalo meat cuts from shoulder and leg portions were subjected to hot water treatment (70 and 80 °C for 30 and 60 s). Meat cuts dipped in water at ambient temperature served as control. The surface samples were analysed for microbial load, visual score for colour and numerical values of colour parameters (a ∗, b ∗, L ∗, W). Control samples of shoulder and leg meat had a mean total plate count (TPC) of 4.15 log CFU cm −2 and 3.81 log CFU cm −2 and enterobacteriaceae counts of 2.33 log CFU cm −2 and 2.26 log CFU cm −2, respectively. Treatment of meat cuts with hot water reduced the TPC significantly ( p < 0.001)with a highest reduction of 1.60 log in leg meat and 1.80 log in shoulder meat at 80 °C. Hot water treatment of meat eliminated enterobacteriaceae. Although, there was discolouration of meat by hot water treatment, the colour regained during storage of meat at refrigerated temperature (4 ±1 °C). Hot water treatment of meat resulted in loss of redness (a ∗), increase in lightness (L ∗) and whiteness (W). After storage, a ∗ increased and L ∗ and W decreased. The results suggested that the dip treatment with hot water reduces the initial bacterial load substantially and improves the microbiological quality of buffalo meat without causing any permanent discolouration.

Temperature and duration of water dips influence chilling injury, decay and polyamine content in `Fortune' mandarins

Late-ripening mandarin (Citrus reticulata, Blanco, cv. `Fortune') is appreciated for its quality, but the high sensitivity of this cultivar to chilling injury (CI) limits its marketability. In this study, the effect of postharvest hot-water dip (HWD) treatments on chilling tolerance and polyamine (PA) induction in flavedo tissue was investigated. After HWD treatments (44°C for 3, 9 and 15 min; 47°C for 3, 6 and 9 min; and 50° and 53°C for 3 min), fruits were stored for 45 days at 2° or 12°C, and CI development, decay, weight loss, and PA content were evaluated. After 45 days at 2°C, the major reduction in CI was found in fruit dipped for 6 min at 47°C or 3 min at 53°C. Under these treatments, the CI index was 0.8 and 0.75, respectively, as compared with 1.5 in untreated fruit. Fruit stored at 12°C did not develop any CI symptoms. The different HWDs also reduced fruit decay, but did not alter the rate of water loss during cold storage at both temperatures. Immediately after HWDs, PA content increased in flavedo with temperature and exposure time. The most important relative increase occurred in spermine (spm), despite being the minor PA. The HWD-induced spm content decreased about two-fold after 28 days of cold storage. Spermine reduction was more important than that observed in spermidine (spd) and putrescine (put). This pattern of change in PA content does not appear to be related to the HWD-induced cold tolerance.

Effect of gamma irradiation combined with hot water dip and transportation from Thailand to Canada on biochemical and physical characteristics of Thai mangoes (Nahng Glahng Wahn variety)

Two lots of mangoes of the Nahng Glahng Wahn variety from Thailand were irradiated at the Thai Irradiation Center (TIC) at 0.49 to 0.77 kGy. Following this, one batch was retained in Thailand (TIC) while the other was shipped to the Canadian Irradiation Center (CIC) for investigation of the same variables during storage. This way, it was hoped to compare the effects of gamma radiation with hot water dip (HWI) or without (I) before and after transportation, on the respiratory activity, rotting, texture, ph, titratable acidity and on the total soluble solids in mangoes. Irradiation stimulated carbon dioxide (CO 2) production early in the study but delayed ethylene (C 2H 4) production which peaked later. The production of CO 2 and C 2H 4 occurred later at CIC than at TIC. The I and particularly HWI treatments also delayed the rotting of the mangoes. The texture of the mangoes declined earlier and more rapidly during storage in Thailand than in Canada. The irradiated samples developped a softer texture early during storage and the rise in pH was less marked than the controls. The control showed lower values of total soluble solids during the first 10 days of storage but increased later.

Effect of gamma irradiation with or without hot water dip and transportation from Thailand to Canada on nutritional qualities, ripening index and sensorial characteristics of Thai mangoes (Nahng Glahng Wahn variety)

Two lots of mangoes of the Nahng Glahng Wahn variety from Thailand were irradiated at the Thai Irradiation Center (TIC) at 0.49 to 0.77 kGy. Following this, one batch was retained in Thailand while the other was shipped to the Canadian Irradiation Center (CIC) for investigation of the same variables during storage. This way, it was hoped to compare the effects of gamma radiation with hot water dip (HWI) or without (I) before and after transportation on the ripening, vitamin C and vitamin A content and sensory qualities of mangoes. The results indicate that the I and HWI treatments delayed the ripening of the mangoes. The irradiated groups appeared to have a slightly higher content of ascorbic acid on the first day after irradiation than their corresponding controls. The sensory evaluation indicates that the panelists mostly favoured the I and HWI irradiated groups for the overall appearance and texture of whole mangoes and pulp and in taste and palatability of the pulp alone. Transportation stress did not appear to have much of an effect on the ascorbic acid and dehydroascorbic acid levels and the sensorial tests. The mangoes stored and studied in Canada appeared to have a lower vitamin A content.

Hot water dips for the control of pathological decay in sweet potatoes

Hot water dip treatments in the range 40–100°C for 2–240 s were investigated for the control of pathological decay in sweet potatoes ( Ipomea batatus (L.) Lam cultivar ‘L0323’). It was found that dipping roots at 90°C for 2 s, 80°C for 2, 4 or 10 s, 70°C for 10 s or 40°C for 120 s substantially delayed the time to initial rot without affecting respiration rate or weight loss.

Heat treatments for the control of sprouting of potatoes during storage

SUMMARYPotatoes were given hot water dip and vapour heat treatments at temperatures ranging from 50 to 80°C and 60 to 70°C respectively for various durations to control sprouting.Hot water treatment at its effective temperatures and durations resulted in undesirable physical damage to tubers. On the other hand, vapour heat treatment at 60°C with 95 ° 5 r.h. for 60 min suppressed sprouting, when given to tubers at the sprout emergence stage, without causing any deleterious side effects. The treatment, when repeated after 3 wk further reduced sprout yield during storage at ambient conditions (22–35°C, 50–80 r.h.).Comparative studies on the efficacy of vapour heat treatment and manual de‐sprouting showed that vapour heat was superior to manual de‐sprouting.

Radiation preservation of foods of plant origin. III. Tropical fruits: bananas, mangoes, and papayas.

The current status of research on the use of ionizing radiation for shelf life improvement and disinfestation of fresh tropical fruits like bananas, mangoes, and papayas are reviewed. The aspects covered are influence of maturity and physiological state of the fruits on delayed ripening and tolerance to radiation; varietal responses; changes in chemical constituents, volatiles, respiration, and ethylene evolution; biochemical mechanisms of delayed ripening and browning of irradiated fruits; and organoleptic quality. The efficacy of the combination of hot water dip and radiation treatments for control of postharvest fungal diseases are considered. The immediate potential of radiation as a quarantine treatment, in place of the currently used chemical fumigants, for disinfestation of fruit flies and mango seed weevil are discussed. Future prospects for irradiation of tropical fruits are discussed in the light of experience gained from studies conducted in different countries.