International Journal of Food Microbiology 151 (2011) 241–246

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International Journal of Food Microbiology

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Reduction of nectarine decay caused by Rhizopus stolonifer, Botrytis cinerea andPenicillium digitatum with Aloe vera gel alone or with the addition of thymol

Diana Navarro a, Huertas M. Díaz-Mula b, Fabián Guillén a, Pedro J. Zapata a, Salvador Castillo a,María Serrano b, Daniel Valero a, Domingo Martínez-Romero a,⁎a Dept. Food Technology, EPSO, University Miguel Hernández, Ctra. Beniel km. 3.2, 03312, Orihuela, Alicante, Spainb Dept. Applied Biology, EPSO, University Miguel Hernández, Ctra. Beniel km. 3.2, 03312, Orihuela, Alicante, Spain

⁎ Corresponding author. Tel.: +34 96 6749720; fax:E-mail address: dmromero@umh.es (D. Martínez-Ro

0168-1605/$ – see front matter © 2011 Elsevier B.V. Alldoi:10.1016/j.ijfoodmicro.2011.09.009

a b s t r a c t

a r t i c l e i n f o

Article history:Received 7 July 2011Received in revised form 1 September 2011Accepted 12 September 2011Available online 17 September 2011

Keywords:NectarinesEthylenePostharvestDecayNatural antifungal activityRespiration rate

Two nectarine cultivars (‘Flavela’ and ‘Flanoba’) were treated with Aloe vera gel alone, or with the addition ofthymol, and then inoculated with Rhizopus stolonifer, Botrytis cinerea and Penicillium digitatum. Both treat-ments were effective in reducing the decay incidence caused by the 3 fungi species, although the additionof thymol did not generally improve the efficacy of Aloe vera gel on reducing the infection damage. The coat-ings were clearly effective in reducing the postharvest ripening process of both nectarine cultivars mani-fested by a delay in ethylene production and respiration rate, weight loss and softening. Interestingly,these coatings showed effectiveness on reducing decay development in inoculated fruits and thus Aloe veracould be considered as natural antifungal compound and might serve as alternative of synthetic fungicides.

+34 96 6749677.mero).

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© 2011 Elsevier B.V. All rights reserved.

1. Introduction

Nectarines arose as peach mutants, and their inheritance patternis consistent with the glabrous skin characteristic controlled by a sin-gle recessive gene (Blake, 1932). Nectarines are climacteric fruitswith physiological ripening pattern similar to peaches (Serrano etal., 2004) and they are highly perishable and deteriorate quickly dur-ing postharvest at ambient temperature (Lurie and Crisosto, 2005).

In addition nectarines are very susceptible to fungal decay, themost important postharvest fungal pathogens being Botrytis cinereaPers. ex Fr., Monilinia laxa (Ehrenb) Sacc., Penicillium spp., and Asper-gillus spp. (Eckert and Ogawa, 1988) and Rhizopus stolonifer (Erhenb.:Fr.) (Eckert and Ogawa, 1988; Gonçalves et al., 2010). The postharvestcontrol of these pathogens is quite efficiently performed by syntheticchemical fungicides (Förster et al., 2007), although consumers areaware about the use of chemical fungicides due to health implicationsand the environmental problems.

The reduced number of authorised active ingredients and growingconsumer demand for both high quality and safe fruit and vegetableshave increased efforts to develop alternative or complementary con-trol means. Among these alternative methods include ozone exposure(Palou et al., 2003), heat treatments, carbonates and bicarbonates

(Palou et al., 2002), biocontrol agents (Obagwu and Korsten, 2003),UV-light (Stevens et al., 2005), and treatmentswith natural compoundslike jasmonates or chitosan (Tripathi and Dubey, 2004). Special atten-tion has been paid to the use of essential oils as natural antimicrobialswith effectiveness being reported for carvacrol (Martínez-Romero etal., 2007), thymol, menthol and eugenol (Serrano et al., 2008; Valverdeet al., 2005a).

Currently, from the 400 Aloe spp. the two most important to elabo-rate extracts for medicinal and cosmetic uses are A. vera and A. ferox(Reynolds andDweek, 1999; Reynolds, 2004). In addition, there are sev-eral reports about the antifungal activity of crude extractives of Aloe veraon human mycological diseases (Nidiry et al., 2011; Rosca-Casian et al.,2007). However, little evidence exists on the effect of Aloe extracts onfruit postharvest diseases caused by fungi, either ex vivo or in vitro. Inrecent years, there are some reports on the effect of Aloe vera gel appliedeither at pre-harvest (Castillo et al., 2010) or postharvest (Martínez-Romero et al., 2006; Valverde et al., 2005b) in controlling fruit spoilageby mould and yeasts. However, no in-depth information has beenreported on the role of Aloe in decay development in fruits previously in-oculated with fungi responsible for postharvest diseases or its relationwith quality.

Thus, the objective of the present work was to evaluate the protec-tive effects of Aloe vera gel alone or in combination with thymol onnectarine decay caused by Rhizopus stolonifer, Botrytis cinerea andPenicillium digitatum, as well as the effect of Aloe treatments and fun-gus inoculation on the changes in fruit quality and physiologicalattributes.

242 D. Navarro et al. / International Journal of Food Microbiology 151 (2011) 241–246

2. Material and methods

2.1. Plant material and experimental design

The experiment was carried out in year 2010 using 2 nectarine(Prunus persica L. var nectarine) cultivars: ‘Flavela’ and ‘Flanoba’.Both cultivars were obtained by Philippe Buffat (PSB ProducciónVegetal S.L) and cultivated on the experimental plot of “Frutas EstherSA” (Murcia, Spain). About 300 fruits for each cultivar weremanuallyharvested at commercial ripening stage (according to size, colourand soluble sugars) and immediately transferred to the laboratory.195 homogeneous fruits in colour, size and with absence of visualdefects, were selected and randomly divided into 13 lots of 15 fruits.One lot was used to analyse the fruit characteristics at harvest andthe remained were used for the following treatments: control(Non-treated), Aloe vera and Aloe vera+thymol. Before treatmentsan artificial injury (2×2 mm in length and width and 2 mm indepth) was inflicted with a sterile lancet in each fruit for fungalinoculation.

2.2. Fungus strains

The fungi used in this study were Rhizopus stolonifer CECT 2344,Botrytis cinerea CECT 2100, Penicillium digitatum CECT 2954, pur-chased from the Spanish collection of type cultures and routinely cul-tured on potato dextrose agar (PDA). The fungi spores were collectedand diluted with sterile water to 2500 CFU/mL and used as stock.

2.3. Aloe vera gel preparation

Aloe vera leaves were harvested from 3-year old plants cultivatedunder organic farming practices at the Experimental farm located atthe High Polytechnic School of Orihuela (EPSO-UMH) and immedi-ately transferred at the laboratory. Aloe vera gel (6 L) was obtainedfrom the parenchimatic tissue of 20 leaves (75% yield). The gel hadthe following characteristics: pH=5.3±0.15, °Brix=1.15±0.07,and acidity=0.053±0.02 g 100/g citric acid equivalent. The raw gelwas stabilised by lowering the pH to 3.75 using phosphoric acid, heat-ed at 80 °C for 10 s, and then cooled down to 5 °C ready for use. Fromthis gel, 3 L was used for Aloe vera treatment, and to the other 3 L thy-mol was added at concentration of 1 mL/L. Thymol (99.5% purity) waspurchased from Sigma (Sigma-Aldrich, Madrid).

2.4. Treatments and fungus inoculations

Four lots of 15 fruits were treated by dippingwith the correspondedAloe vera gel solution for 10 min and allowing to dry at room tempera-ture. Four lots of 15 fruits were used as control (Non-treated) anddipped in distilled water. After 24 h, the three lots of every treatmentwere inoculated with R. stolonifer, B. cinerea or P. digitatum by deposit-ing 20 μL of the fungi stock (50 spores) inside the artificial injury previ-ously made (2×2×2 mm of length, width and depth). One lot fromeach treatment was used as control without fungus inoculation (Non-fungus). All fruits (control or treated and inoculated or not) were incu-bated at 25 °C for 6 days with a relative humidity of 85% until analyticaldeterminations.

2.5. Analytical determinations

2.5.1. Respiration and ethylene production ratesRespiration rates andethyleneproductionweremeasured byplacing

each fruit in 0.5-L glass jars hermetically sealedwith a rubber stopper for1 h. 1 mL of the contained atmosphere was withdrawnwith a gas syrin-ge, and the ethylene was quantified using a Hewlett-Packard™ model5890A gas chromatograph (Wilmington, DE) equipped with a flameionisation detector and a 3 m stainless steel column with an inner

diameter of 3.5 mm containing activated alumina of 80/100 mesh. Thecolumn temperature was 90 °C, and injector and detector temperatureswere 150 °C. Results were themean±SE and expressed as nL/(g h). Forrespiration rate determination, another sample of 1 mL of the same at-mosphere was withdrawn and CO2 quantified using a Shimadzu™ 14Agas chromatograph (Kyoto, Japan), with a thermal conductivity detectorand amolecular sieve 5A column, 80–100mesh (Carbosieve SII. SupelcoInc., Bellefonte, USA), of 2 m length and 3 mm i.d. Oven and injectortemperature were 50° and 110 °C, respectively. Heliumwas used as car-rier gas at a flow rate of 50 mL/min. Results were the mean±SE andexpressed as mg CO2/(kg h).

2.5.2. Weight loss, firmness and infection volume measurementsCumulative weight loss was determined independently in each

fruit as percentage with respect to the recorded initial weight andexpressed as the mean±SE. For fruit firmness, a non-destructiveassay was used based on fruit deformation at 3% by using a flatprobe attached to a TX-XT2i texture analyser (Stable Microsystems,UK) according to previous reports (Martínez-Romero et al., 2007)and results (mean±SE) were expressed as N/mm.

For infection volume determination, the fruits were cut into halveslongitudinally at the infected zone, then diameter and depth infectionwere measured and volume was calculated by approximation to halfellipsoid. Data were expressed as mm3 and are the mean±SE.

2.6. Statistical analysis

Experimental data were subjected to ANOVA analysis. For eachcultivar, sources of variation were treatment, fungus type and storage.The overall least significant differences (Fisher's LSD procedure,pb0.05) were calculated and used to detect significant differencesamong fungi, treatment and storage. All analyses were performedwith SPSS software package v. 11.0 for Windows (SPSS, 2001). Statis-tical modelling were performed using linear regression and non-linear regression procedures (SigmaPlot 11.0, 2004 for Windows).The fit of the equation was evaluated by the determination of coeffi-cient R2.

3. Results

3.1. Evaluation of infection severity

After 6 days of fungi inoculation, the infection volume was clearlydifferent depending on fungal type and treatment applied (Fig. 1). Thehighest infection volume was shown for R. stolonifer in both cultivarsfollowed by B. cinerea and P. digitatum, for which this value was ca. 6-fold lower. However, the application of Aloe treatments (alone or withthe addition of thymol) led to significantly lower fungus infection vol-ume (ca. 2–3-fold) than in non-treated nectarines, although the addi-tion of thymol did not generally improve the efficacy of Aloe vera gelon reducing the infection damage.

3.2. Ethylene production and respiration rate

Ethylene production at harvest was 1.36±0.33 and 0.37±0.11 nL/(g h), for ‘Flavela’ and ‘Flanoba’ nectarine cultivars, respectively.After 6 days of incubation, an increase in ethylene production wasshown for both cultivars, although non-inoculated fruits treated withAloe vera or Aloe vera+thymol had significantly lower ethylene pro-duction than control nectarines (Fig. 2). The inoculation with the 3fungi increased significantly the ethylene production in both cultivars,with rates being higher in fruit inoculated with B. cinerea followed byP. digitatum and R. stolonifer. ‘Flanoba’ cultivar had ethylene rates over15 nL/(g h) while these rates were below 13 nL/(g h) for ‘Flavela’ nec-tarine (Fig. 2 inner).

Flavela

After 6 days at 25 °CRizhopus Botrytis Penicillium

Infe

ctio

n V

olu

me

(mm

3 )

0

1000

2000

3000

4000

5000

10000

12000

14000

Non-TreatedAloe veraAloe vera + Thymol

Flanoba

Rizhopus Botrytis Penicillium

Infe

ctio

n V

olu

me

(mm

3 )

0

1000

2000

3000

4000

5000

10000

12000

14000

Non-TreatedAloe veraAloe vera + Thymol

After 6 days at 25 °C

Fig. 1. Effect of Aloe vera or Aloe vera plus thymol on internal damage in nectarines by R. stolonipher, B. cinerea and P. digitatum.

243D. Navarro et al. / International Journal of Food Microbiology 151 (2011) 241–246

Moreover, this induction in ethylene production was significantlylower in those fruits treated with both coatings, without significant dif-ferenceswhen thymolwas added to the Aloe vera gel. Linear regressionswere performed between infection volume and ethylene production,and results revealed a good correlation between both parameters foreach fungi in both cultivars. For all cases, high correlations (R2=0.93–0.99) were obtained but the slopes were significantly higher (15 to20-fold) for R. stolonifer than B. cinerea and P. digitatum (Table 1).

Respiration rate at harvest for ‘Flavela’ and ‘Flanoba’ nectarine cul-tivars was ≈37 and 24 mg/(kg h), respectively. After 6 days of incu-bation, respiration rate increased in all fruits, the increase beingenhanced in the inoculated fruits, especially for R. stolonifer for bothcultivars, which had respiration rates of ≈112 and 127 mg/(kg h)for ‘Flavela’ and ‘Flanoba’, respectively (Fig. 3). For all cases, bothtreatments (Aloe vera or Aloe vera+thymol) significantly reduced

Flavela

After 6 days at 25 °C

Eth

ylen

e (n

L/(

g h

))

5

10

15

20

25

30Non-TreatedAloe VeraAloe vera + Thymol

Day 0 No Fungus Rizhopus Botrytis Penicillium

Ethylene n

0 5 10 15

Ro

t V

olu

men

mm

3

0

2000

4000

6000

8000

10000

12000 Flavela

Fig. 2. Influence of Aloe vera or Aloe vera plus thymol on ethylene production in nectarines ininternal damage volume and ethylene production for each nectarine cultivar and R. stolonif

the respiration rate although without differences attributable to theaddition or not of thymol. Interestingly, an exponential correlationwas found between infection volume and respiration rate takinginto account all data for each cultivar (Fig. 4, inner graph), although‘Flanoba’ cultivar exhibited higher respiration rate than ‘Flavela’ nec-tarine due to the produced injury by the fungi species. Moreover, foreach fungi species, linear regression was also found between infectionvolume and respiration rate (Table 1), with high correlation coeffi-cients (R2=0.99) but the slopes were significantly higher (3 to 6-fold) for R. stolonifer than B. cinerea and P. digitatum (Table 1).

3.3. Weight loss, firmness total soluble solids and total acidity

Weight loss increased during the 6 days of experiment although‘Flavela’ cultivar showed lower weight loss than ‘Flanoba’ nectarine,

Flanoba

Day 0 No Fungus Rizhopus Botrytis Penicillium

Eth

ylen

e (n

L/(

g h

))

5

10

15

20

25

30

After 6 days at 25 °C

L/(kg h)

20 25 30

Flanoba

oculated with R. stolonipher, B. cinerea and P. digitatum. Inner figure: regression betweener (−∙∙−), B. cinerea (——) and P. digitatum (− −) fungi.

Table 1Equation regression between infection volume and respiration rate or ethyleneproduction.

Linear equation R2

Infection volume (mm3) vs respiration rate (mg/(kg h))Rizhopus inoculated in Flavela Y=455.56X−38712.19 0.99Rizhopus inoculated in Flanoba Y=256.14X−22114.42 0.99Botrytis inoculated in Flavela Y=125.09X−9018 0.99Botrytis inoculated in Flanoba Y=100.39X−7859.91 0.99Penicillum inoculated in Flavela Y=75.06X−5109.03 0.89Penicillum inoculated in Flanoba Y=44.50X−2580.61 0.99

Infection volume (mm3) vs ethylene production (nL/(g h))Rizhopus inoculated in Flavela Y=3196.07X−9326.67 0.98Rizhopus inoculated in Flanoba Y=1554.76X−20891.12 0.98Botrytis inoculated in Flavela Y=241.37X−800.57 0.99Botrytis inoculated in Flanoba Y=73.09X−674.99 0.99Penicillum inoculated in Flavela Y=115.18X+357.36 0.93Penicillum inoculated in Flanoba Y=114.33X−1558.36 0.99

244 D. Navarro et al. / International Journal of Food Microbiology 151 (2011) 241–246

withfinal losses ofweight of 6.84±0.12 and 10.70±0.36%, respectivelyin non-treated fruits (Fig. 4). Both treatments (Aloe or Aloe+thymol)were significantly effective in reducing the fruit weight losswith no dif-ferences due to the inoculation or the inoculated fungal type.

With respect to fruit firmness, control fruits showed a decrease offruit firmness during storage from their initial values (14.74±0.29and 15.37±1.01 N/mm, for ‘Flavela’ and ‘Flanoba’ nectarines, respec-tively) with percentages of firmness losses of about 80% after 6 daysof storage at 25 °C (Fig. 5). The application of both treatments led topositive effects on reducing the softening process, since at the end ofthe experiment all treated nectarines had a 10% higher firmness valuesthan non-treated ones. Again, the inoculation process or the addition ofthymol did not affect significantly to the firmness retention.

4. Discussion

In a previous paper, commercial Aloe vera gel could reduce the my-celium growth of B. cinerea and P. digitatum on PDA plates, the efficacybeing higher for P. digitatum than for B. cinerea (Castillo et al., 2010).

Flavela

After 6 days at 25 °C

Day 0 No Fungus Rizhopus Botrytis Penicillium

CO

2 (m

g/(

kg h

))

20

40

60

80

100

120

140

160

Non-TreatedAloe VeraAloe vera + Thymol

60 70 80 90

Ro

t V

olu

me

mm

3

0

2000

4000

6000

8000

10000

12000Flavela Y = 3,77e0

Flanoba Y =19,68e

Fig. 3. Influence of Aloe vera or Aloe vera plus thymol on respiration rate in nectarines inocinternal damage volume and respiration rate for ‘Flavela’ (−∙−) and ‘Flanoba’ (——) nectar

In this work it has been demonstrated that the gels from Aloe vera(alone or with the addition of thymol) obtained from plants cultivatedunder organic farming at the EPSO-UMH, were effective on reducingfruit decay in two nectarine cultivars inoculated with R. stolonifer, B.cinerea and P. digitatum. Although the fungal growth rate was differentfor each fungi species, the effects of both Aloe gels were similar in termsof reduction in rot incidence (between 50 and 70% depending on nec-tarine cultivars and fungus species). Accordingly, postharvest applica-tion of commercial Aloe vera gel to table grapes (Valverde et al.,2005b) and sweet cherry (Martínez-Romero et al., 2006) was effectivein reducing microbial spoilage (lower counts of mesophilic aerobicsand moulds and yeasts) and decay occurrence. Recently, Nidiry et al.(2011) have reported that the predominant anthraquinones (aloinand aloe-emodin) could be important antifungal moieties.

It iswell known that in climacteric fruits, such asnectarines, ethyleneproduction and respiration rate are physiological parameters related toripening and quality attributes (Serrano et al., 2004). In non-treatedfruits, ethylene production and respiration rate increased during the6 days at 25 °C and the application of Aloe vera gel (alone orwith the ad-dition of thymol) led to lower rates of both physiological traits, in accor-dance with previous reports in which reduced respiration rate has beenobserved in Aloe vera gel coated-sweet cherry and table grapes, bothnon-climacteric fruits (Martínez-Romero et al., 2006; Valverde et al.,2005b). In ‘Arctic Snow’ nectarines, Ahmed et al. (2009) also observedreductions in ethylene production and respiration rate at ambient tem-perature. The reduced respiration rate in ‘Flavela’ and ‘Flanoba’ nectar-ines could be attributed to the fact that coating could increaseresistance of fruit skin to gas diffusion and the creation of a modified in-ternal atmosphere, since it is known thatMAP could reduce the ethyleneproduction and respiration rate due to high CO2 and low O2 gas insidethe tissues (Valero and Serrano, 2010).

When nectarines were inoculated with the 3 fungi, the increase ofboth ethylene production and respiration was higher than non-injured fruits, especially for ‘Flanoba’ cultivar, which could be attrib-uted to the fact that injury induced a stimulation of ethylene biosyn-thesis and respiration rate. Similarly, in table grapes inoculated withB. cinerea, ethylene and respiration rate also increased (Martínez-Romero et al., 2007) as a consequence of the fungal growth. We

Flanoba

Day 0 No Fungus Rizhopus Botrytis Penicillium

CO

2 (m

g/(

kg h

))

20

40

60

80

100

120

140

160

Non-TreatedAloe veraAloe vera + Thymol

After 6 days at 25 °C

100 110 120 130

,0724X r2= 0.98

0,05X r2= 0.97

ulated with R. stolonipher, B. cinerea and P. digitatum. Inner figure: regression betweenine cultivars.

Flavela

After 6 days at 25 °C

Wei

gh

t L

oss

(%

)

2

4

6

8

10

12

Non-TreatedAloe veraAloe vera + Thymol

Flanoba

No Fungus Rizhopus Botrytis Penicillium No Fungus Rizhopus Botrytis Penicillium

Wei

gh

t L

oss

(%

)

2

4

6

8

10

12

Non-TreatedAloe veraAloe vera + Thymol

After 6 days at 25 °C

Fig. 4. Effect of Aloe vera or Aloe vera plus thymol on weight loss in nectarines inoculated with R. stolonipher, B. cinerea and P. digitatum.

245D. Navarro et al. / International Journal of Food Microbiology 151 (2011) 241–246

have found that for each fungus a positive linear relationship wasfound between internal damaged volume and ethylene productionor respiration rate. Moreover, taking into account all data from thevolume of damage, an exponential relationship was obtained be-tween rot volume and respiration rate for both nectarine cultivars.

Postharvest storage of fruit is accompanied by quality losses mani-fested by weight loss and reduction of firmness, among other parame-ters. Non-injured control fruits had the highest weight loss after 6 daysat 20 °C while those fruits treated with Aloe significantly reduced thephysiological weight loss, even in those artificially inoculated fruits. Onthe other hand, Aloe vera treated nectarines maintained fruit firmnessduring storage independent ofwhether fruitswere orwere not inoculat-ed with 3 fungi. Aloe vera, as an edible coating, was also effective in re-ducing the transpiration process and softening in sweet cherry and

Flavela

After 6 days at 25 °C

Fir

mn

ess

(N/m

m)

1

2

3

4

14

16 Non-TreatedAloe VeraAloe vera + Thymol

Day 0 No Fungus Rizhopus Botrytis Penicillium

Fig. 5. Effect of Aloe vera or Aloe vera plus thymol on fruit firmness in n

table grapes during storage, and thus lower weight loss and higherfruit firmness were obtained (Martínez-Romero et al., 2006; Valverdeet al., 2005b). Several mechanisms have been proposed to explain thelower weight loss and firmness maintenance in fruits, including reduc-tion in gas diffusion through the fruit skin (Banks et al., 1993) and thedelay of fruit metabolism by reducing respiration rate and ethylene emis-sion (Valero and Serrano, 2010). Changes in fruit texture are due tochanges in the chemistry of middle lamella and primary cell wall compo-nents, which are accompanied by degradation of pectic polysaccharidesby enzymes capable of altering cell wall texture, such as pectinmethyles-terase, endo- and exo-polygalacturonase, cellulose andß-galactosidase. Inthis sense, the effect of Aloe vera coating on reducing the activity of theseenzymes could not be discharged, although further studies are necessaryto confirm this hypothesis.

Flanoba

Day 0 No Fungus Rizhopus Botrytis Penicillium

Fir

mn

ess

(N/m

m)

1

2

3

4

14

16Non-TreatedAloe veraAloe vera + Thymol

After 6 days at 25 °C

ectarines inoculated with R. stolonipher, B. cinerea and P. digitatum.

246 D. Navarro et al. / International Journal of Food Microbiology 151 (2011) 241–246

The addition of thymol to the Aloe vera gel did not improve thefinal results in terms of fruit quality and physiological parameters,contrarily to what occurred when an active packaging was developedby combining modified atmosphere and thymol (Serrano et al., 2008).In this case the thymol vapour was in permanent contact on the fruitduring all postharvest storage. However, in this work, thymol was incontact only during the treatment, and then the essential oil could beevaporated and lower effectiveness was obtained.

In conclusion, it has been demonstrated that Aloe vera gel could beconsidered as a good tool to alleviate the decay in nectarine caused byRhizopus stolonifer, Botrytis cinerea and Penicillium digitatum. In addi-tion, the coatings were effective in reducing the ripening process by asignificant delay in respiration rate, ethylene production, weight lossand softening. In future, research should be focused on the determi-nation of the specific compounds responsible for the antifungal activ-ity of Aloe vera gel during postharvest storage of fruits.

Acknowledgments

This work has been co-funded by the MICINN (Spanish Ministry ofScience and Innovation) through project AGL2009-10857 and Euro-pean Commission with FEDER funds.

References

Ahmed, M.J., Singh, Z., Khan, A.S., 2009. Postharvest Aloe vera gel-coating modulatesfruit ripening and quality of ‘Arctic Snow’ nectarine kept in ambient and cold stor-age. International Journal of Food Science and Technology 44, 1024–1033.

Banks, N.H., Dadzie, B.K., Cleland, D.J., 1993. Reducing gas exchange of fruits with sur-face coatings. Postharvest Biology and Technology 57, 183–188 3, 269–283.

Blake, M.A., 1932. The J.H. Hals as a parent in peach crosses. Proceedings of the Amer-ican Society for Horticultural Science 29, 131–136.

Castillo, S., Navarro, D., Zapata, P.J., Guillén, F., Valero, D., Serrano,M.,Martínez-Romero, D.,2010. Antifungal efficacy of Aloe vera in vitro and its use as a preharvest treatment tomaintain postharvest table grape quality. Postharvest Biology and Technology 57,183–188.

Eckert, J.W., Ogawa, J.M., 1988. The chemical control of postharvest diseases: deciduousfruits, berries, vegetables, and rot/tuber crops. Annual Review of Phytopathology26, 433–469.

Förster, H., Driever, G.F., Thompson, D.C., Adaskaveg, J.E., 2007. Postharvest decaymanage-ment for stone fruit crops in California using the “reduced-risk” fungicides fludioxoniland fenhexamid. Plant Disease 91, 209–215.

Gonçalves, F.P., Martins, M.C., Junior, G.J.S., Lourenço, S.A., Amorim, L., 2010. Postharvestcontrol of brown rot and Rhizopus rot in plums and nectarines using carnauba wax.Postharvest Biology and Technology 58, 211–217.

Lurie, S., Crisosto, C.H., 2005. Chilling injury in peach and nectarine. Postharvest Biologyand Technology 37, 195–208.

Martínez-Romero, D., Alburquerque, N., Valverde, J.M., Guillén, F., Castillo, S., Valero, D.,Serrano, M., 2006. Postharvest sweet cherry quality and safety maintenance byAloe vera treatment: a new edible coating. Postharvest Biology and Technology39, 93–100.

Martínez-Romero, D., Guillén, F., Valverde, J.M., Bailén, G., Zapata, P., Serrano, M., Castillo,S., Valero, D., 2007. Influence of carvacrol on survival of Botrytis cinerea inoculated intable grapes. International Journal of Food Microbiology 115, 144–148.

Nidiry, E.S.J., Ganeshan, G., Lokesha, A.N., 2011. Antifungal activity of some extractivesand constituents of Aloe vera. Research Journal of Medicinal Plant 5, 196–200.

Obagwu, J., Korsten, L., 2003. Integrated control of citrus green and blue molds usingBacillus subtilis in combination with sodium bicarbonate or hot water. PostharvestBiology and Technology 28, 187–194.

Palou, L., Usall, J., Muñoz, J.A., Smilanick, J.L., Viñas, I., 2002. Hot water, sodium carbon-ate, and sodium bicarbonate for the control of postharvest green and blue molds ofclementine mandarins. Postharvest Biology and Technology 24, 93–96.

Palou, L., Smilanick, J.L., Crisosto, C.H., Mansour, M., Plaza, P., 2003. Ozone gas penetra-tion and control of the sporulation of Penicillium digitatum and Penicillium italicumwithin commercial packages of oranges during cold storage. Crop Protection 22,1131–1134.

Reynolds, T., 2004. Aloes: the genus Aloe. CRC Press.Reynolds, T., Dweek, A., 1999. Aloe vera leaf gel: a review update. Journal of Ethnophar-

macology 68, 3–37.Rosca-Casian, O., Parvu, M., Vlase, L., Tamas, M., 2007. Antifungal activity of Aloe vera

leaves. Fitoterapia 78, 219–222.Serrano, M., Martínez-Romero, D., Castillo, S., Guillén, F., Valero, D., 2004. Effect of

preharvest sprays containing calcium, magnesium and titanium on the qualityof peaches and nectarines at harvest and during postharvest storage. Journalof the Science of Food and Agriculture 84, 1270–1276.

Serrano, M., Martínez-Romero, D., Guillén, F., Valverde, J.M., Zapata, P.J., Castillo, S.,Valero, D., 2008. The addition of essential oils to MAP as a tool to maintain theoverall quality of fruits. Trends in Food Science and Technology 19, 464–471.

SPSS, 2001. VERSION 11.0 for Windows. SPSS Inc, Chicago, IL.Stevens, C., Khan, V.A., Wilson, C.L., Lu, J.Y., Chalutz, E., Droby, S., 2005. The effect of fruit

orientation of postharvest commodities following low dose ultraviolet light-Ctreatment on host induced resistance to decay. Crop Protection 24, 756–759.

Tripathi, P., Dubey, N.K., 2004. Exploitation of natural products as an alternative strategy tocontrol postharvest fungal rotting of fruit and vegetables. Postharvest Biology andTechnology 32, 235–245.

Valero, D., Serrano, M., 2010. Postharvest Biology and Technology for Preserving FruitQuality. CRC Press-Taylor & Francis, Boca Raton.

Valverde, J.M., Guillén, F., Martínez-Romero, D., Castillo, S., Serrano, M., Valero, D., 2005a.Improvement of table grapes quality and safety by the combination ofmodified atmo-sphere packaging (MAP) and eugenol, menthol or thymol. Journal of Agricultural andFood Chemistry 53, 7458–7464.

Valverde, J.M., Valero, D., Martínez-Romero, D., Guillén, F., Castillo, S., Serrano, M.,2005b. Novel edible coating based on Aloe vera gel to maintain table grape qualityand safety. Journal of Agricultural and Food Chemistry 53, 7807–7813.