Residue levels and effectiveness of pyrimethanil vs imazalil when using heated postharvest dip treatments for control of Penicillium decay on citrus fruit

The influence of fungicide concentration and treatment temperature on residue levels of pyrimethanil (PYR) in comparison with the commonly used fungicide imazalil (IMZ) was investigated in orange fruits following postharvest dip treatments. The dissipation rate of PYR residues was recorded as a function of storage conditions. The fungicide efficacy against green and blue molds caused by Penicillium digitatum and Penicillium italicum, respectively, was evaluated on different citrus varieties following the fungicide application at 20 or 50 degrees C. Residue levels of PYR in Salustiana oranges were significantly correlated with the fungicide dosage, but residue concentrations were notably higher (ca. 13-19-fold) after treatment at 50 degrees C as compared to treatments at 20 degrees C. After treatment at temperatures ranging from 20 to 60 degrees C, PYR and IMZ residues in Salustiana oranges were significantly correlated with dip temperatures. Dissipation rates of PYR during storage were negligible in both Salustiana and Tarocco oranges. Results obtained on wounded, noninoculated Miho satsumas revealed that when treatments were performed at 50 degrees C, PYR or IMZ concentrations needed to achieve the complete control of decay were 8- and 16-fold less than by treatment at 20 degrees C. When fruits were inoculated with either P. digitatum or P. italicum, the application of 400 mg L(-1) PYR at 20 degrees C or 100 mg L(-1) PYR at 50 degrees C similarly reduced green and blue mold development. These results were corroborated by storage trials on Marsh grapefruits and Tarocco oranges. The lowest concentration of PYR required to achieve almost total protection of the fruit against decay accounted for 100 mg L(-1) at 50 degrees C and 400 mg L(-1) at 20 degrees C, respectively. Treatments did not affect fruit external appearance, flavor, and taste. It is concluded that postharvest PYR treatment represents an effective option to control green and blue mold in citrus fruit and that integration of fungicide applications and hot water dips may reduce the possibility of selecting fungicide-resistant populations of the pathogen, as a consequence of increased effectiveness of the treatment.     

Complexation of imazalil with beta-cyclodextrin,residue uptake,persistence, and activity against penicillium decay in citrus fruit following postharvest dip treatments

A method for the inclusion of imazalil (IMZ) in the beta-cyclodextrin (betaCD), structural characterization of the inclusion complex and its antifungal activity against Penicillium digitatum and P. italicum assessed by in vitro and in vivo tests are reported. According to the starting stoichiometry of betaCD with respect to IMZ, an equimolar ratio beta-cyclodextrin-IMZ (betaCD-IMZ) was detected by (1)H NMR. In vitro assays showed that the freshly prepared betaCD-IMZ was as effective as IMZ, although 1- and 4-day-old betaCD-IMZ mixtures were more effective. Studies on Star Ruby grapefruit showed no significant differences in residue uptake between treatments with an IMZ commercially available fungicide (Deccozil) or betaCD-IMZ when equal active ingredient (a.i.) concentrations (250 mg/L) and dip temperatures (20 or 50 degrees C) were used. By contrast, treatments of Tarocco oranges and Di Massa lemons with 250 mg/L betaCD-IMZ at 50 degrees C produced significant differences in residue uptake in comparison with 250 mg/L Deccozil treatments at 50 degrees C. The a.i. degradation rate in grapefruit during postquarantine and simulated marketing period (SMP) at 20 degrees C was not affected by the type of formulation used, whether at 20 or 50 degrees C. Conversely, IMZ in oranges and lemons had greater persistence when applied at 50 degrees C. All fungicide treatments showed a comparable efficacy against decay in grapefruit and oranges, whereas treatment in lemons at 250 mg/L a.i. of heated fungicides had higher suppressive effects against decay than unheated chemicals having equal a.i. concentrations and comparable activity at 1200 mg/L IMZ at 20 degrees C.     

Factors affecting the synergy of thiabendazole, sodium bicarbonate, and heat to control postharvest green mold of citrus fruit

The efficacy of thiabendazole (TBZ) to control postharvest decay caused by Penicillium digitatum of citrus fruit can be enhanced by co-application with sodium bicarbonate (SBC) and/or heat treatment. The impact of these treatments was investigated in citrus fruit, as a function of TBZ and SBC concentration and temperature, and were related to the amount of TBZ residues in fruit (total residues), in fruit surface, in the cuticular wax, and in the inner fruit. The residue levels of TBZ were determined in 'Valencia' oranges following a 1 min dip in an aqueous mixture of SBC at 0.5, 1, or 2 wt %/vol and TBZ at 600 or 400 mg/L (active ingredient, a.i.) at 20 or 40 degrees C and after 0 and 20 days at 17 degrees C and 90% relative humidity. The influence of SBC and heat on the TBZ residue concentration on the fruit surface, in cuticular wax, and on the inner cuticle tissue was determined in 'Salustiana' oranges after a 1 or 3 min dip in TBZ alone at 600 mg/L and 20 or 50 degrees C or for 1 min in TBZ at 600 mg/L and SBC at 2% and 20 degrees C. The efficacy of heat treatments with water, SBC, and TBZ, applied separately or in combination, was investigated on artificially inoculated 'Nova' mandarins and 'Valencia' oranges for the control of postharvest green mold caused by a TBZ-sensitive (TBZ-s) or TBZ-resistant (TBZ-r) isolate of P. digitatum. The residue levels of TBZ in fruit, evaluated as total residues, were not affected by the co-application of SBC in most samples. While TBZ residues in the fruit surface were not significantly affected by the dip temperature or by co-application of SBC, the rates of diffusion and penetration of TBZ into cuticular wax markedly increased in the presence of SBC or when TBZ was applied in combination with heat. TBZ residues in the inner tissue of fruits treated at 20 degrees C were not dependent upon the dip time or by the presence of SBC and were similar to those found in fruit treated with TBZ at 50 degrees C for 1 min, whereas significantly higher values were recorded in samples treated with TBZ at 50 degrees C for 3 min. When TBZ at 600 mg/L and 20 degrees C was applied in the presence of SBC at concentrations of 1-2 or 0.5-2%, it effectively reduced decay caused by the TBZ-resistant isolate of green mold in 'Nova' mandarins and 'Valencia' oranges. This treatment was also significantly more effective than TBZ alone to control green mold caused by a TBZ-s isolate in 'Valencia' oranges. The combination with SBC and mild heat (40 degrees C) and TBZ at 400 mg/L generally improved the control of a TBZ-r isolate of green mold with respect to the combined treatment at 20 degrees C. TBZ efficacy was also improved when applied at reduced rates (200 mg/L) and 50 degrees C, significantly suppressing green mold caused by a TBZ-s isolate of P. digitatum and effectively controlling a TBZ-r isolate. The rate of weight loss of 'Valencia' oranges was significantly increased by SBC treatment and was positively dependent upon the concentration of SBC used in the treatment, while the temperature of the treatment solution had little influence on later weight loss.     

Residue levels and storage responses of nectarines, apricots, and peaches after dip treatments with fludioxonil fungicide mixtures

Mature apricots (Prunus armeniaca), nectarines [Prunus persica var. nectarine (Ait.)], and peaches [P. persica (L.) Batsch.] were subjected to a 2 min dip treatment with warm water at 48 degrees C or with fludioxonil (FLU) at 100 mg L-1 and 20 degrees C or at 25 mg L-1 FLU and 48 degrees C and then stored at 5 degrees C and 90-95% relative humidity (RH) for 1 week plus 1 additional week at 18 degrees C and approximately 80% RH. Fruit residue uptake was determined as a function of fungicide concentration, dip temperature, treatment time (only on nectarines), and fruit storage conditions. FLU residue level was closely related to fungicide concentration and treatment temperatures and was dependent on fruit species. FLU residues showed great persistence over both storage and shelf life. Fruit dipping in water at 48 degrees C effectively reduced decay development in cvs. 'May Grand' nectarines and 'Pelese' apricots but was ineffective in cvs. 'Red Top' and 'Sun Crest' nectarines during 7 days of storage compared with nontreated fruit. Decay rates in cvs. 'Glo Haven' peaches and 'Fracasso' apricots were very low in fruit dipped in water at both 20 and 48 degrees C. Fungicide treatments at 20 and 48 degrees C resulted in the total or almost total suppression of decay in all cultivars. During shelf life, fruit became very prone to decay, averaging 25.7-100% depending on the cultivar. Fruit dipping in hot water effectively reduced decay in 'Pelese' and 'Fracasso' apricots, 'Sun Crest' peaches, and 'May Grand' nectarines as compared to control, but was ineffective in 'Glo Haven' and 'Red Top' peaches. Fungicide treatments at 20 degrees C were more effective than hot water in most cultivars. The combination of FLU with water at 48 degrees C further improved the fungicide performance. Indeed, reduced levels (a fourth) of active ingredient were required to achieve a control of decay comparable to that for treatment at 20 degrees C. Residue levels in fruit after treatment with 100 mg L-1 FLU at 20 degrees C or with 25 mg L-1 FLU at 48 degrees C averaged approximately 0.6-2 mg kg-1, which were notably lower than the maximum residue limit (5 mg kg-1) allowed in the United States for stone fruit.     

Sodium carbonate treatment induces scoparone accumulation, structural changes, and alkalinization in the albedo of wounded citrus fruits

Following sodium carbonate treatment, accumulation of scoparone (6,7-dimethoxycoumarin) but not scopoletin (6-methoxy-7-hydroxycoumarin) was found in the albedo of wounded fruit from different Citrus sp. and cultivars. Treating wounded mandarin fruit cv. Fairchild with 5% Na(2)CO(3) (SC) lead to a scoparone accumulation in the albedo of 310, 361, and 382 microg g(-1) fresh weight after 7, 10, and 15 days, respectively. Scoparone accumulation was associated with a decrease in decay severity. When oranges cv. Biondo comune wounded and treated with 5% SC were inoculated with Penicillium digitatum or Penicillium italicum conidia 3 days posttreatment, the decay percentage as compared to untreated wounds was reduced by 97.2 and 93.9%, respectively. Observations by scanning electron microscopy of wounded Citrus fruits treated at 20 degrees C with 2, 3, 4, or 5% (w/v) solutions of sodium carbonate showed structural modifications to the albedo as well as damage to 24-48 h old mycelia of P. digitatum, the cause of citrus green mold. Modifications were more evident in orange, lemon, and grapefruit as compared to mandarin fruit. The efficacy of the treatment was strictly related to the SC interaction with the albedo tissue that, in addition to structural changes, significantly increased tissue pH, affecting P. digitatum pathogenicity. The SC remaining as a film on unwounded flavedo had no effect in preventing contact infection by the Penicillia.     

Factors affecting imazalil and thiabendazole uptake and persistence in citrus fruits following dip treatments.

The effect of concentration, temperature, and length of treatment with imazalil (IMZ) and thiabendazole (TBZ) was studied with application to citrus fruit. The amount of residues retained by fruit after "home" washing was also monitored. IMZ uptake in citrus fruit was related to treatment duration, whereas TBZ residues was not. Residues of IMZ or TBZ fungicides were significantly correlated with dip temperature (r = 0.943 for IMZ; r = 0.911 for TBZ). Treatment at 50 degrees C produced a deposition approximately 8 and approximately 2.5 times higher than when treatments were carried out at 20 degrees C in IMZ and TBZ, respectively. No significant differences in terms of IMZ deposition were detected after treatments carried out alone or in combination. Uptake of the two fungicides was associated with their physicochemical characteristics as well as different formulation types. IMZ residues showed a great persistence during storage when applied separately, and >83% of active ingredient was present after 9 weeks of storage. IMZ residues increased with dip length, doubling when dip time increased from 0.5 to 3 min. In contrast, TBZ residues did not change with the different dip times. Following postharvest dip treatments of citrus fruit at 20 or 50 degrees C, home washing removed approximately 50% of the IMZ and approximately 90% of the TBZ.     

Residue levels and storage decay control in Cv. Star Ruby grapefruit after dip treatments with azoxystrobin

Cv. Star Ruby grapefruit (Citrus paradisi Macf.) were subjected to a 3-min dip in water at room temperature (20 degrees C) or at 50 degrees C with or without 25, 50, or 100 mg/L azoxystrobin (AZX). Then, the fruits were subjected to cold quarantine at 2 degrees C and 90-95% relative humidity (RH) for 3 weeks and then stored for 5 weeks at 8 degrees C and approximately 85% RH and for another 2 weeks at 20 degrees C and 80% RH to simulate a 2-week marketing period (SMP). No AZX residues were detected in the albedo and pulp following treatments at 20 or 50 degrees C, the total amount of residues being recovered from the flavedo tissue. There was a relationship between the AZX uptake in fruit and the amount of fungicide employed at 20 or 50 degrees C. When AZX was applied to the fruit at 25 mg/L at 20 degrees C, the residue level averaged 0.11 mg/kg (active ingredient, whole fruit basis). This residue concentration increased by 50 and 75% when the application rate increased from 25 to 50 or 100 mg/L, respectively. A similar pattern of accumulation was detected in fruit subjected to treatments at 50 degrees C. However, treatments at 50 degrees C produced residue levels higher than the treatments at 20 degrees C, with increases ranging from 63 to 84%, for the same concentration. Storage conditions did not affect the amount of AZX residues in the fruit. Treatment at 50 or 100 mg/L at 20 degrees C reduced the incidence of moderate to severe chilling injury (CI). Water dips at 50 degrees C reduced the incidence and severity of CI to a very low extent, with no additional advantages when hot water was used in combination with AZX. Treatments with 50 or 100 mg/L of AZX at 20 degrees C produced beneficial effects in decay control similar to those of 25 mg/L AZX at 50 degrees C or hot water alone. Better results were achieved with 50 or 100 AZX at 50 degrees C, providing complete control of decay during cold storage and with negligible decay after SMP. It was concluded that when AZX was applied at 50 degrees C, low doses of fungicide and minimal residue levels in fruit were required to control the postharvest decay of grapefruit. This treatment does not impair fruit quality and offers very interesting prospects for large scale application, due to the reduced potential toxicity of AZX to nontarget organisms and to the environment.     

Residue uptake and storage responses of Tarocco blood oranges after preharvest thiabendazole spray and postharvest heat treatment

Tarocco blood oranges (Citrus sinensis Linn. Obsek) were subjected to a single preharvest spray with thiabendazole (TBZ) at a concentration of 1% active ingredient (ai) in water and harvested 2 weeks after fungicide application or heated at 37 degrees C for 48 h under saturated humidity after harvest. The two treatments were also combined before cold quarantine (3 weeks at 2 degrees C), subsequent storage (3 weeks at 8 degrees C), and simulated marketing period (SMP) (1 week at 20 degrees C). Fruit not treated with TBZ and unheated were used as controls. The residue levels of TBZ (active ingredient, whole fruit basis) after spray were approximately 6.3 and 5.4 mg x kg(-1) before fruit storage respectively, a level close to the tolerance limit set by the European Community. TBZ showed a high persistence during quarantine, storage, and SMP. TBZ spray significantly reduced the incidence and severity of chilling injury (CI) and decay during the postquarantine period and SMP. Heat treatment (HT) produced beneficial effects in controlling CI, especially during SMP, when applied in combination with TBZ. However, HT remarkably promoted the development of secondary fungal infections such as Phytophthora rots and adversely affected fruit flavor and taste. The occurrence of off-flavor and off-taste was found to be perceptible after heating.     

Thiabendazole uptake and storage performance of cactus pear [Opuntia ficus-indica (L.) Mill. Cv Gialla] fruit following postharvest treatments with reduced doses of fungicide at 52 degrees C

The storage response of cactus pears [Opuntia ficus-indica Miller (L.) cv. Gialla] was investigated over 6 weeks at 6 degrees C, plus an additional week of simulated marketing period (SMP) at 20 degrees C, after a 3-min dip treatment with thiabendazole (TBZ) at 1000 mg/L at 20 degrees C or 150 mg/L TBZ at 52 degrees C. Untreated fruits were used as control. Following TBZ treatments at 20 and 52 degrees C, total residues were recovered from the peel of cactus pear, as the concentration of residues in the pulp was negligible. Treatments with 1000 mg/L TBZ at 20 degrees C resulted in a 2.82 mg/kg residue uptake (active ingredient, whole-fruit basis), whereas treatment at 150 mg/L TBZ left 1.09 mg/kg. TBZ showed great persistence over both storage and SMP: on average, in the fruits treated at 20 and 52 degrees C, over 72 and 68%, respectively, of TBZ was still present after SMP. Postharvest treatments with 1000 mg/L TBZ at room temperature did not affect the expression of slight-to-moderate chilling injury (CI), but reduced severe CI by approximately 50% and decay development by 63.4% in comparison to those of untreated fruit after SMP. The effectiveness of TBZ was much higher with the treatment at 150 mg/L TBZ at 52 degrees C, providing 91% control of severe CI and approximately 89% suppression of decay; no treatment damage occurred during storage and SMP. External appearance was better in fruit treated with 150 mg/L TBZ at 52 degrees C. Respiration rate, titratable acidity, soluble solids concentration, and acetaldehyde in the flesh were not significantly influenced by treatments. Ethylene production rate and ethanol levels in the flesh were significantly higher in the TBZ-treated fruit as opposed to those in the untreated control fruit.     

川芎提取液对脐橙的防腐保鲜效果

为了开发植物源脐橙贮藏保鲜技术,该文研究了川芎提取液在离体和活体条件下对采后脐橙的主要致腐菌意大利青霉和指状青霉的抑制作用,以及对贮藏期脐橙品质和生理生化的影响。结果显示:在离体条件下,川芎提取液对2种供试菌种有显著的抑制作用(P0.05),最低抑菌质量浓度均为25.00 mg/m L;在活体条件下,川芎提取液能有效抑制2种病原菌在脐橙上的生长,且质量分数为4%效果较好,与体积分数为50%乙醇处理的对照相比,差异显著(P0.05);在脐橙采后贮藏中,川芎提取液对脐橙的防腐保鲜效果与其质量分数相关,其中质量分数为4%的效果较好,与蒸馏水处理的对照相比,能够显著(P0.05)降低采后脐橙的腐烂率、失重率和丙二醛含量,延缓总酸的下降,以及诱导过氧化物酶活性上升,有利于维持可溶性固形物和总糖质量分数,而对维生素C和果皮色泽的变化无显著影响(P0.05)。结果表明,川芎提取液用于脐橙贮藏保鲜切实可行,研究结果为脐橙天然保鲜剂的开发及脐橙在贮藏、运输和销售期间防腐保鲜提供参考。     

Storage temperature effects on blood orange fruit quality.

Orange fruits of two blood varieties (Tarocco and Moro) were stored at 8 degrees C and 22 degrees C for 85 and 106 days, respectively, and analyzed periodically for standard quality parameters (total soluble solids, total acidity, ascorbic acid, juice yield, and rind color) and sensory influencing parameters (anthocyanins, and total and free hydroxycinnamic acids). A decrease in total acidity (TA) and juice yield during storage was observed for both cultivars; total soluble solids (TSS) increased only in the Tarocco oranges stored at 8 degrees C. The increase in TSS observed for Tarocco and the simultaneous decrease in TA in both varieties resulted in a higher maturity index (TSS/TA) for the two cultivars. No loss of vitamin C was noted in Tarocco orange at either temperature, whereas a sharp reduction in vitamin C occurred in the first 50 days of storage for Moro. A significant increase in anthocyanin content was observed in Tarocco and Moro stored at 8 degrees C. Overlong storage induces extensive hydrolysis of hydroxycinnamic derivatives to free acids in Moro orange and these, in turn, could develop the malodorous vinylphenols.     

Mode of action of hot-water dip in reducing decay of lemon fruit

A hot-water dip for 2 min at 52-53 degrees C prevented decay for at least one week in lemon fruit inoculated with Penicillium digitatum. The mode of action of hot water in reducing decay was investigated by studying the effects of this treatment on the pathogen and on the resistance mechanisms of the fruit. The hot-water dip had a transient inhibitory effect on the pathogen, arresting its growth for 24-48 h. During this lag period, the combined effects of the pathogen and the hot-water dip induced the build up of resistance in the peel. Lignin production in the inoculated sites began within 24 h after inoculation or wounding. When inoculation was followed by the hot-water dip, lignin accumulation continued for a week. Inoculated lemons that were not dipped in hot water rotted completely within 3 days after inoculation and their lignin content did not rise or even decreased. The scoparone concentration in the inoculated sites of hot dipped fruit started to rise 24 h after treatment and reached a level sufficient to inhibit the pathogen within 2 days after treatment. Parallel to scoparone accumulation, scopoletin was detected in inoculated and heat-treated lemons. Without the pathogen challenge or wounding, heat treatment by itself was not able to induce any of the above-mentioned defensive effects. Our data do not support the involvement of ethanol-extractable aldehydes, associated in the literature with wound gum, or of citral in decay inhibition in hot-water dipped lemons.     

Gas chromatographic determination of fenpropimorph residues in citrus fruit

A rapid gas chromatographic method for determining fenpropimorph residues in citrus fruit is reported. The fungicide is extracted with hexane after pH adjustment of the fruit homogenate. A short liquid-liquid partitioning process is performed before gas chromatography on an OV-17 column with nitrogen-phosphorus specific detection. The limit of detection of the method was 0.01 mg/kg, based on a 25 g sample. Recovery was always higher than 70%. Fenpropimorph residues in "Washington Navel" oranges and "Hernandina" clementine fruits dipped in a 1500 mg/L fungicide solution were determined. The fungicide remains mainly in the peel, with levels less than 0.1 mg/kg in the pulp. Fungicide residues in the peel decrease during storage, mainly in Washington Navel peel, where values decreased from 5.2 to 2.8 mg/kg.     

Comparative study of antimicrobial peptides to control citrus postharvest decay caused by Penicillium digitatum

The objective of this study was to investigate and compare the in vitro efficacy and in vivo potential of eight distinct short antimicrobial peptides to control the postharvest green mold disease of oranges caused by the fungus Penicillium digitatum. The L-amino acid versions of the four peptides PAF26, PAF38, PAF40, and BM0, previously obtained by combinatorial approaches, were examined. The study included two antibacterial peptides formerly identified by rational design, BP15 and BP76, and it is demonstrated that they also have in vitro antifungal properties. The natural antimicrobial peptides melittin and indolicidin were also selected for comparison, due to their well-known properties and modes of action. In vitro and in vivo results indicated differential behaviors among peptides, regarding the inhibitory potency in growth media, selectivity against distinct microorganisms, fungicidal activity towards nongerminated conidia of P. digitatum, and efficacy in fruit inoculation assays. Interestingly, a high in vitro inhibitory activity did not necessarily associate with an effective control of fruit infection by P. digitatum. The short tryptophan-rich cationic peptides PAF26, PAF38, PAF40, and BM0 were lethal to conidia of P. digitatum, and this property is correlated with better protection in the decay control test.     

Orthophenylphenol and phenylhydroquinone residues in citrus fruit and processed citrus products after postharvest fungicidal treatments with sodium orthophenylphenate in California and Florida

Sodium orthophenylphenate (SOPP) has been used extensively for >40 years to control postharvest diseases of citrus fruits. Studies of the metabolism of [(14)C]SOPP have identified orthophenylphenol (OPP) as the major metabolite with phenylhydroquinone (PHQ) as a minor metabolite. The whole-fruit tolerance in the United States for OPP is 10 ppm. This study was conducted to quantify terminal OPP and PHQ residues in whole Navel oranges, grapefruit, and lemons following SOPP applications at maximum application rates and following commercial application and fruit storage practices. OPP and PHQ residues also were determined in products processed from treated Navel oranges. OPP residues in lemons, Navel oranges, and grapefruit treated with SOPP using foamer wash and shipping wax applications remained below the 10 ppm tolerance, and PHQ residues were all < or =0.439 ppm. PHQ residues in whole fruit increased with time in commercial storage. OPP residues in all Navel orange matrices except oil remained relatively stable with time in commercial storage; residues in oil declined substantially while in storage.     

Enantioseparation of imazalil residue in orange by capillary electrophoresis with 2-hydroxypropyl-beta-cyclodextrin as a chiral selector

Chiral resolution of imazalil, a fungicide, was performed by capillary electrophoresis (CE) using 2-hydroxypropyl-beta-cyclodextrin as a chiral selector. Factors affecting the chiral resolution and migration time of imazalil were studied. The optimum running conditions were found to be 5 mM ammonium dihydrogenphosphate-50 mM phosphate buffer (pH 3.0) containing 4 mM 2-hydroxypropyl-beta-cyclodextrin with an effective voltage of +25 kV at 20 degrees C using direct detection at 200 nm. Under these conditions, the resolution (Rs) of racemic imazalil was approximately 6. The extraction of imazalil from orange samples was done with acetonitrile under basic conditions. The extract was purified with a solid-phase extraction cartridge (Sep-Pak plus PS-2) and was analyzed by the above CE method. Eight orange samples were analyzed, and imazalil was detected in seven samples. In four of these seven oranges, the level of (-)-imazalil was the same as that of (+)-imazalil, but in the other three oranges, the level of (-)-imazalil was found to be lower than that of (+)-imazalil, suggesting that (-)-imazalil was degraded more quickly than (+)-imazalil in oranges.     

Chemical composition, antioxidant properties, and thermal stability of a phytochemical enriched oil from Acai (Euterpe oleracea Mart.)

Phenolic compounds present in crude oil extracts from acai fruit ( Euterpe oleracea) were identified for the first time. The stability of acai oil that contained three concentrations of phenolics was evaluated under short- and long-term storage for lipid oxidation and phenolic retention impacting antioxidant capacity. Similar to acai fruit itself, acai oil isolates contained phenolic acids such as vanillic acid (1,616 +/- 94 mg/kg), syringic acid (1,073 +/- 62 mg/kg), p-hydroxybenzoic acid (892 +/- 52 mg/kg), protocatechuic acid (630 +/- 36 mg/kg), and ferulic acid (101 +/- 5.9 mg/kg) at highly enriched concentrations in relation to acai pulp as well as (+)-catechin (66.7 +/- 4.8 mg/kg) and numerous procyanidin oligomers (3,102 +/- 130 mg/kg). Phenolic acids experienced up to 16% loss after 10 weeks of storage at 20 or 30 degrees C and up to 33% loss at 40 degrees C. Procyanidin oligomers degraded more extensively (23% at 20 degrees C, 39% at 30 degrees C, and 74% at 40 degrees C), in both high- and low-phenolic acai oils. The hydrophilic antioxidant capacity of acai oil isolates with the highest phenolic concentration was 21.5 +/- 1.7 micromol Trolox equivalents/g, and the total soluble phenolic content was 1252 +/- 11 mg gallic acid equivalents/kg, and each decreased by up to 30 and 40%, respectively, during long-term storage. The short-term heating stability at 150 and 170 degrees C for up to 20 min exhibited only minor losses (<10%) in phenolics and antioxidant capacity. Because of its high phenolic content, the phytochemical-enriched acai oil from acai fruit offers a promising alternative to traditional tropical oils for food, supplements, and cosmetic applications.     

Inhibitory effect of monogalactosyldiacylglycerol, extracted from spinach using supercritical CO2, on mammalian DNA polymerase activity

We investigated the effective extraction of monogalactosyldiacylglycerol (MGDG) from dried spinach (Spinacia oleracea) using supercritical fluid carbon dioxide (SC-CO(2)) with a modifier/entrainer. The yield of MGDG in the SC-CO(2) extract was not influenced by increasing temperature at a constant pressure, although the total extract yield was decreased. The total extract yield and MGDG yield in the extract from commercially purchased spinach (unknown subspecies), were greatly influenced by lower pressure. In a modifier (i.e., ethanol) concentration range of 2.5-20%, both the extract and MGDG yield increased as the ethanol concentration rose. The highest total extract yield (69.5 mg/g of spinach) and a good MGDG yield (16.3 mg/g of spinach) were obtained at 80 degrees C, 25 MPa, and 20% ethanol. The highest MGDG concentration (76.0% in the extract) was obtained at 80 degrees C, 25 MPa, and 2.5% ethanol, although the total extract yield under these conditions was low (5.2 mg/g of spinach). The optimal conditions for the extraction of MGDG were 80 degrees C, 20 MPa, and 10% ethanol. Of the 11 subspecies of spinach tested under these conditions, "Ujyou" had the highest concentration of MGDG. The total extract yield and MGDG concentration of Ujyou were 20.4 mg of the extract/g of spinach and 70.5%, respectively. The concentration of MGDG was higher in the SC-CO(2) extract than in the extract obtained using solvents such as methanol and n-hexane. The extract of Ujyou, which was the optimal subspecies for the extraction of MGDG, inhibited the activity of calf DNA polymerase alpha with IC(50) values of 145 microg/mL but was not effective against DNA polymerase beta.     

Investigations into inhibitor type and mode, simulated gastrointestinal digestion, and cell transport of the angiotensin I-converting enzyme-inhibitory peptides in Pacific hake (Merluccius productus) fillet hydrolysate

Fish protein hydrolysate (FPH) produced by incubation of Pacific hake fillet with 3.00% Protamex at pH 6.5 and 40 degrees C for 125 min demonstrated in vitro ACE-inhibitory activity (IC50 = 165 microg/mL), which was enhanced by ultrafiltration through a 10 kDa molecular weight cutoff membrane (IC50 = 44 microg/mL). However, after simulated gastrointestinal digestion, FPH and ultrafiltrate had similar ACE-inhibitory activity (IC 50 = 90 microg/mL), indicating that FPH peptides act as "pro-drug type" inhibitors and that enrichment by ultrafiltration may be unnecessary. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry confirmed that the molecular weights of major peaks were <1 kDa regardless of ultrafiltration. ACE-inhibitory activities of digested hydrolysates were not significantly affected by preincubation with ACE ( P > 0.05) and exhibited a competitive inhibitory mode. A permeability assay using fully differentiated colorectal adenocarcinoma (Caco-2) cells showed an apical to basolateral transport of peptides that ranged from approximately 2 to 20% after 2 h at 37 degrees C. Pacific hake fillet hydrolysates are a potentially bioavailable source of ACE-inhibitory peptides awaiting further in vivo study.     

Development of apple superficial scald, soft scald, core flush, and greasiness is reduced by MCP.

1-Methylcyclopropene (MCP) was used to evaluate the role of ethylene in development of apple (Malus x domestica Borkh.) physiological disorders during storage. Granny Smith, Red Chief Delicious, and Fuji apple fruit were treated with MCP at a concentration of 1 microL L(-)(1) for 12 h at 20 degrees C. For all varieties stored at 0 degrees C, ethylene production and respiration rates were reduced for several months following MCP treatment, and firmness and titratable acidity of treated fruit were higher compared to controls. Apples treated with MCP did not develop superficial scald or peel greasiness through 6 months storage plus ripening at 20 degrees C for 7 days. Core flush was not observed in MCP-treated fruit until 6 months after treatment when the incidence was still lower compared to control fruit. MCP delayed the rise in production of alpha-farnesene and reduced accumulation of its oxidation products.