scholarly journals Quality of Stored `Marsh' and `Ruby Red' Grapefruit after High-temperature, Forced-air Treatment

HortScience ◽  
1991 ◽  
Vol 26 (9) ◽  
pp. 1188-1191 ◽  
Author(s):  
W.R. Miller ◽  
R.E. McDonald

`Marsh' and `Ruby Red' grapefruit (Citrus paradisi Macf.) tolerated a high-temperature, forced-air, vapor heat treatment of 43.5C for 260 minutes, a treatment applied for security against the Caribbean fruit fly [Anastrepha suspensa (Loew)]. Fruit did not develop symptoms of quality deterioration during subsequent storage. With `Marsh' fruit, 99% and 96% were sound, whereas with `Ruby Red' 98% and 94% were sound after storage at 10C for 28 days or 10C for 28 days plus 7 days at 21C, respectively. Differences in means for percentage of sound fruit were not significant for cultivar or vapor heat treatment. After the final storage period, there was significantly more (2.4-fold, P ≤ 0.05) aging observed on `Ruby Red' fruit than on `Marsh', averaged over all treatments. Vapor heat did not affect aging of `Ruby Red' but increased aging of `Marsh' fruit. Decay was reduced to ≈ 22.0% in vapor heat-treated fruit from 5.0% for nontreated fruit. The efficacy of thiabendazole to control stem end rot was increased on vapor heat-treated fruit compared with nontreated fruit. After the final inspection, the appearance of `Marsh' fruit was fresher (index 2.0) than that of `Ruby Red' fruit (index 2.3), but the appearance of vapor heat-treated and nontreated fruit was similar. Peel color of `Ruby Red' fruit was not affected by the vapor heat treatment, but, after 4 weeks at 10C plus 1 week at 21C, `Marsh' fruit that were not treated were greener than those treated with vapor heat. The vapor heat treatment tested is a potentially viable quarantine procedure for Florida grapefruit that can be applied without adversely affecting fruit quality during normal storage.

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 433E-433
Author(s):  
Krista C. Shellie

Export and domestic marketing of grapefruit (Citrus paradisi Macf.) can be limited by phytosanitary barriers against fruit fly species and growth of decay organisms, especially green mold (Penicillium digitatum Sacc.), during the marketing process. The objective of this research was to identify whether the dose of high-temperature forced air that providing quarantine security against Mexican fruit fly could also beneficially control the growth of green mold during subsequent storage. `Rio Red' grapefruit were harvested four times in 1995 and nine times in 1996 and challenge-inoculated with 10 L of a 1 × 106 spores/ml spore solution (10,000 spores) of green mold before or after exposure to 46°C forced air for 300 min. Control fruit were challenge-inoculated but not exposed to the heat treatment. The growth of green mold was quantified by measuring lesion diameter after 3 days of storage at 23°C, 80% RH. Grapefruit inoculated prior to the heat treatment developed significantly smaller lesions than fruit inoculated after the heat treatment or fruit not exposed to a heat treatment. The average lesion diameter of fruit inoculated prior to the heat treatment was 2.5 and 0.9 cm, respectively, in 1995 and 1996. The average lesion diameter of fruit inoculated after the heat treatment was similar to non heat-treated, control fruit. Lesion diameter of control and post heat-challenged fruit were 6.4 and 6.1 cm in 1995 and 5.7 and 5.3 cm in 1996. Results suggest reduction in decay be attributed to alteration in the pathogenicity of green mold after exposure to the heat treatment rather than an altered resistance of the fruit to the pathogen.


HortScience ◽  
1992 ◽  
Vol 27 (5) ◽  
pp. 422-424 ◽  
Author(s):  
W.R. Miller ◽  
R.E. McDonald

`Marsh' and `Ruby Red' grapefruit (Citrus paradisi Macf.) were harvested in Florida during Oct. and Nov. 1990, degreened in an ethylene chamber, exposed to vapor heat (VH) treatment (43.5 ± 0.1C for ≈240 min), and evaluated for deterioration in quality and development of injury after various storage regimes. Symptoms of aging averaged 6% and 8% of the surface on `Ruby Red' and `Marsh' fruit, respectively, and the VH treatment had reduced the incidence of aging by 45% after 5 weeks of storage (4 weeks at 16C plus 1 week at 21C). Total decay, mostly stem-end rots (Diplodia spp. and Phomopsis spp.), remained relatively low (≈5%) in both treated and nontreated fruit after 5 weeks of storage. The VH treatment had little effect on change in peel color during treatment or subsequent storage. After the final inspection, `Marsh' fruit was higher in total soluble solids and titratable acidity than `Ruby Red' fruit, but these quality indicators and pH were not affected by the VH treatment. VH treatment did not adversely affect the quality of `Marsh' or `Ruby Red' grapefruit harvested early in the season; hence, VH should be considered as a viable quarantine treatment for Florida grapefruit.


HortScience ◽  
1997 ◽  
Vol 32 (2) ◽  
pp. 275-277 ◽  
Author(s):  
W.R. Miller ◽  
R.E. McDonald

`Marsh' grapefruit (Citrus paradisi Macf.) produced in Florida must be certified for security against unwanted pests before entry into some domestic and export markets. Application of heat by hot water (HW) has been shown to cause severe injury to grapefruit; however, direct comparisons between forced vapor heat (VH) and HW have been lacking. Grapefruit preharvest-treated with gibberellic acid (GA) or not treated, were postharvest-treated with VH or HW such that the surfaces of fruit were exposed to the same rate of temperature increases and treatment durations. Condition and quality attributes were then compared with ambient air (AA) and ambient water (AW) controls after storage. After 4 weeks' storage at 10 °C plus 1 week at 20 °C, scald affected 5% of HW and 20% of VH-treated fruit. No scald developed on control fruit. At the end of storage, mass loss for HW and VH fruit was ≈5%. HW-treated fruit had a 5-fold higher incidence of aging than VH fruit; however, control fruit showed significantly more aging than all heat-treated fruit. Gibberellic acid (GA) and the heat treatments reduced decay relative to the control. GA-treated fruit remained greener during storage than control fruit. These findings indicate that VH and HW treatments at the temperatures and durations to control the Caribbean fruit fly (Anastrepha suspensa, Loew) will likely cause peel injury to `Marsh' grapefruit produced in Florida, regardless of treatment with GA.


HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 504A-504
Author(s):  
D.M. Obenland ◽  
F.R Ryan

Previous work by our group has demonstrated the potential feasibility of using high-temperature forced-air (HTFA) treatment for insect disinfestation of nectarines. Fruit quality of nine cultivars tested was unaffected following the application of a HTFA treatment targeted against Mediterranean fruit fly. In an extention of this work, we examined the effect of this treatment on peach and nectarine cultivars that have differing reported susceptibilities to the development of mealiness to determine if HTFA treatment has any effect on the occurrence of this disorder. Fruit were exposed to HTFA over 4 h until the fruit center registered a temperature of 47.2 °C, then stored at 5 °C for 1 to 3 weeks and 2 d at 23 °C, at which time the fruit were visually evaluated for symptoms of mealiness. `Summer Bright', `Ryan Sun', and `Elegant Lady', cultivars susceptible to the development of mealiness, showed a 66%, 24%, and 66% increase in the incidence of mealiness, respectively, due to HTFA treatment. `Summer Grand', a cultivar classified as nonsusceptible, did not develop mealiness in the absence of HTFA treatment, while 81% of the HTFA-treated fruit of this cultivar were classified as mealy following 2 weeks of storage. Enhancement of mealiness in stonefruit by heat is a very detrimental effect that must be carefully considered in the development of HTFA treatments for these commodities.


1995 ◽  
Vol 5 (1) ◽  
pp. 40-43 ◽  
Author(s):  
Krista C. Shellie ◽  
Robert L. Mangan

`Dancy' tangerines (Citrus reticulata Blanco) were harvested after color break and exposed to high-temperature forced air (HTFA) at 45C for 3.5 or 4 h to kill Mexican fruit fly [Anastrepha ludens (Loew)] larvae. Heat-treated and control fruit were stored subsequently for 2 weeks at 4C. Tangerines harvested after color break (naturally degreened) tolerated exposure to HTFA in a similar fashion as tangerines harvested before color break and degreened by postharvest exposure to ethylene. Titratable acidity (TA) was significantly lower after heat treatments. Flavor, soluble solids concentration, external appearance, incidence of decay, percent juice yield, percent weight change, and flavedo color of heat-treated fruit were not different from nonheat-treated, control fruit. Exposure to HTFA is a viable alternative to methyl bromide for disinfestation of `Dancy' tangerine.


1993 ◽  
Vol 118 (4) ◽  
pp. 481-485 ◽  
Author(s):  
Krista C. Shellie ◽  
Michael J. Firko ◽  
Robert L. Mangan

Early season degreened `Dancy' tangerines (Citrus reticulata Blanco) were size graded and subjected to high-temperature, moist, forced-air (HTMFA) treatments using air at 45, 46, or 48C for 0, 1, 2, 3, or 4 hours. The phytotoxic response of fruit to the beat treatments was evaluated immediately after treatment and weekly during 3 weeks of cold (4C) storage. Mortality of nonfeeding, third instar Mexican fruit fly [(Anastrepha ludens (Loew)] larvae was estimated for each time-temperature heat treatment combination in water baths that simulated the heating and cooling profiles of heat-treated fruit. Unacceptable phytotoxic symptoms, such as inferior flavor and darkened flavedo tissue, were observed when fruit was treated at 46 or 48C. Fruit heated with 45C forced moist air had flavedo color change(ΔL*)percent juice yield, soluble solids concentration, and flavor ratings that were statistically similar to ratings for unheated, control fruit. An HTMFA treatment of 3 or 4 hours at 45, 46, or 48C and subsequent cooling was sufficient to kill 100% of naked larvae in water baths. Market quality of fruit was maintained after a 4-hour HTMFA treatment at 45C, and 100% mortality of naked larvae occurred after 3 hours at 45C.


2020 ◽  
Vol 7 (1) ◽  
pp. 191539 ◽  
Author(s):  
Takamasa Ishigaki ◽  
Yusuke Nakada ◽  
Naoki Tarutani ◽  
Tetsuo Uchikoshi ◽  
Yoshihiro Tsujimoto ◽  
...  

Nano-size EVONIK AEROXIDE ® P25 titanium dioxide, TiO 2 , powder was heat-treated at temperatures, 700–900°C, in air. An X-ray diffraction study showed that the P25 powder is composed of approximately 20 and approximately 80 mass% of rutile and anatase phases, respectively. It was also shown that the transformation from anatase to rutile induced by high-temperature heat treatment was almost completed at 750°C, whereas a small amount (less than 3 mass%) of anatase phase was still left even in the powder heat-treated at 900°C. The transformation behaviour was consistent with results obtained by Raman scattering spectroscopy. Raman experiments also indicated that high-temperature heating induced the formation of oxide ion vacancies. Powders were dispersed in methyl orange (MO) aqueous solution, and the bleach rate of MO was measured to evaluate photocatalytic activity under ultraviolet (UV)- and visible-light irradiation. After the heat treatment, the UV-light photocatalytic performance sharply deteriorated. Interestingly, visible-light photocatalytic activity was enhanced by high-temperature heating and reached the highest performance for an 800°C-heated sample, indicating that the P25 powder obtained high visible-light photocatalytic performance after heat treatment. Even after 900°C heat treatment, the photocatalytic performance was higher than that of as-received powder. Enhancement of photocatalytic activities was discussed in relation to visible light absorption and charge carrier transfer.


2020 ◽  
Vol 100 (1) ◽  
pp. 165-174 ◽  
Author(s):  
Piotr Micek ◽  
Katarzyna Słota ◽  
Paweł Górka

The aim of this study was to determine the effect of heat treatment alone or in combination with the addition of lignosulfonate (LSO3) on canola cake protein, lysine, and methionine degradation in the rumen. Cold-pressed canola cake was left untreated, heated at 90, 110, 130, or 150 °C, or processed with 5% of LSO3 (in dry matter) and then heated. Effective rumen degradability of crude protein (CP), lysine, and methionine was less for treated than untreated canola cake (P < 0.05) and decreased with increased temperature of heating, but particularly when canola cake was heated at 150 °C (quadratic, P < 0.01). In general, effective rumen degradability of CP, lysine, and methionine was less for canola cake heated at 130 °C in combination with LSO3 compared with canola cake heat treated only (quadratic × LSO3 interaction, P ≤ 0.07). Results of this study indicate that high temperature heating (130 °C or greater for 60 min) may be necessary to protect canola cake protein from degradation in the rumen, and the combination of heat treatment and LSO3 may be more effective in protecting canola cake protein, lysine, and methionine from degradation in the rumen than the use of heat treatment only.


2013 ◽  
Vol 212 ◽  
pp. 229-236
Author(s):  
Marek Cieśla ◽  
Franciszek Binczyk ◽  
Marcin Mańka

mpact of heat treatment on durability has been evaluated in this study in conditions of high-temperature creep of castings made from nickel superalloy MAR-247 post production rejects. Castings made in the processes of modification and filtration when pouring into moulds were subject to solubilization (1185°C/2 h) with subsequent ageing (870°C/20 h). It has been found on the basis of performed tests that in conditions of high-temperature creep at temperature 980°C with stress σ = 150 MPa the resistance of specimens of coarse-grain structure was significantly higher when compared to fine-grain material. The conditions of initiation and propagation of cracks in these specimens were analysed with consideration of morphological properties of material macro-, micro-and substructure. Moreover, it has been proven that creep resistance of heat treated MAR-247 superalloy significantly improves when compared to its condition after the process of modification only. Macrostructural changes in the MAR-247 superalloy that determine the increase of superalloy creep resistance after solubilization and ageing, as observed in the tests, were also examined.


Sign in / Sign up

Export Citation Format

Share Document