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Fresh weight of root before storage – Dry weight of root after storage) / Dryweight of root a er storage 100; then dry ma er (%) was es mated as (100 - %moisture percentage).Statistical analysis:Data were subjected to analysis of variance using GENSTATE software (version11.1.0.1575). To compare differences between means, least significant differences(LSD) at 5% were calculated according to Gomez and Gomez (1984).Correlation matrix between biochemical analysis after storage in refrigerator at(5 C/Rh 95%) and storage parameters at the 0.05 and 0.01 level (2-tailed) onPASWSta s cs18 so ware. The sign of the correla on coefficient determineswhether the correlation is positive or negative. The magnitude of the correlationcoefficient determines the strength of the correlation subjected by Evans (1996)suggests absolute r-value {0.00-0.19 (very weak), 0.20-0.39 (weak), 0.40-0.59(moderate), 0.60-0.79 (strong) and 0.80-1.0 (very strong)}.3- RESULTS3-1- Effect of bio modulators on biochemical constituents during pre- and post-harveststages:3-1-1- Total anthocyanin and ascorbic acid:All applied bio simulators increased total anthocyanin's concentration in theroots either pre- or post-harvest compared to control (Table 2). The highestanthocyanins concentrations were obtained in response to treatment with thymusoil followed by humic acid in pre-harvest stage. In roots that stored in the specifiedstorage experimental conditions, total anthocyanin concentration was decreased,either in biomodulators-treated or untreated plants compared with before storage.However, in post-harvest stage anthocyanins concentrations were highest inresponse to the treatment with peppermint oil followed by seaweed extract i.e.peppermint oil and seaweed extract caused the least decline in anthocyaninsconcentration in stored roots, in order. Data presented in table (3) show thatascorbic acid concentration in pre-stored roots was increased in response to thymeoil and seaweed extract, though the increase was insignificant in case of seaweedextract treatment. On the other hand, humic acid and peppermint oil did not affectascorbic acid concentration in the roots before storage. In stored roots, ascorbic acidconcentration was decreased either in bio modulators-treated or untreated plants.However, the magnitude of decline was lower in roots of bio modulators-treatedplants. So, after storage, ascorbic acid concentration in roots was significantly higherin all biomodulators treatments compared with control .The lowest loss percentagewas recoded in response to peppermint oil (29.7 %) followed by humic acid (31.7%).Table (2): Effect of applied bio modulators on total anthocyanin's and ascorbic acid content(mg g F.W.) in roots of Raphanus sativus L, plants before and after storage.-1Anthocyanins (mg g F.W.)Ascorbic acid (mg g F.W.)Before After Total loss % Before After Total loss %-1Seaweed extractHumic acidPeppermint 0.5020.5213.9714.0014.4242.1131.7129.71

Thyme oil8.552.6069.5937.10 22.5739.16Control7.161.4479.8920.41 9.2354.78LSD at 0.050.600.296.321.503-1-2- Total phenols and flavonoids:All applied bio modulators increased total flavonoids in roots during both preand post-harvest stages as well as total phenols only during post-harvest stage(Table 3). The only bio modulator that increased total phenols in the roots beforestorage was Peppermint oil. Both total flavonoids and phenols were decreased afterstorage, but the mantude of the decrease was lower in case of total flavonoids. Thelowest decrease in total phenols was recorded in response to Peppermint oilwhereas the least decrease in total flavonoids was recorded in response to thyme oiltreatment.Table (3): Effect of applied bio modulators on total phenols and flavonoids (mg g D.W) rootsof Raphanus sativus plants before and after storage.Total phenols (mg g F.W.) Total flavonoids (mg g F.W.)Before After Total loss% Before After Total loss%Seaweed extract 14.49 12.0816.630.330.2912.12Humic acid13.41 10.7819.610.400.3512.50Peppermint oil14.85 12.4516.160.390.3412.82Thyme oil13.00 10.4219.850.470.446.38Control12.50 9.5123.920.310.2616.13LSD at 0.052.301.020.010.033-1-3- Total carbohydrates and total free amino acids:Generally, total carbohydrates concentration in roots before storage wasincreased in response to bio modulators treatments, though the increase wasinsignificant (Table 4). In addi on, roots of bio modulators-treated plants afterstorage contained higher concentrations of total carbohydrates compared withcontrol roots, though the differences did not reach the significance level. In alltreatments, total carbohydrates concentrations were decreased after storage, withthe least decrease in response to seaweed extract followed by Peppermint oiltreatment.Total free amino acids concentrations in roots treated with all bio modulatorsbefore storage were not significantly different than that in control roots (Table 4).On the other hand, roots of bio modulators-treated plants after storage containedsignificantly higher concentrations of total free amino acids compared with control.Storage caused a decrease in total free amino acids concentrations in roots of biomodulators-treated as well as control plants. In stored roots of seaweed extracttreated plants, the decrease in concentration of total free amino acids was the least,followed by thyme oil.Table (4): Effect of applied biomodulators on total carbohydrates (mg g D.W.) and free aminoacids (mg/100 g D.W.) in dried roots of Raphanus sativus plants before and afterstorage.-1-1-1-1Total carbohydrates(mg g D.W.)Befor AfterTotaleloss%127. 104.17.80-1SeaweedTotal free amino acid (mg/100 gD.W.)BeforeAfterTotal loss%12.095.6453.35

extractHumic acid50127.03Peppermint oil 126.60Thyme oil112.12Control110.90LSD at 2.033.3072.57-3.730.49-3-1-4- Concentration of potassium and sulphur:Roots of biomodulators-treated plants either before or after storage containedhigher concentrations of both potassium (K) and sulphur (S) compared with controlroots (Table 5). However, the recorded increase in S concentra on before storagewas insignificant in response to all biomodulators treatments. In roots ofbiomodulators-treated as well as control plants, concentrations of both potassium Kand S were decreased after storage. The decrease was of the least magnitude inresponse to seaweed extract treatment in case of K and in response to peppermintoil in case of S.Table (5): Effect of applied biomodulators on potassium concentra on (mg g D.W.) andSulphur percentage in dried roots of Raphanus sativus plants before and afterstorage.-1ControlPotassium (mg gD.W.)Befor Afte Totalerss%12.48 11.0 11.86013.00 10.0 23.08013.64 10.0 26.03913.26 10.0 24.06712.37 9.00 27.24LSD at 0.050.15 0.71-1Seaweed extractHumic acidPeppermint oilThyme oil-Sulfur (%)Befo Aftreer1.43 0.931.20 0.901.50 1.151.29 1.011.10 0.500.48 0.35Totalloss%34.9725.0023.3321.7154.55-3-1-5- Activity of peroxidase and polyphenol oxidase:In roots of biomodulators-treated plants, the activity of peroxidase (POD) wasincreased either before or after storage compared with that in roots of controlplants. A similar trend in the activity of polyphenol oxidase (PPO) was recorded inroots after storage. On the other hand, before storage, PPO activity in roots wasincreased in response to seaweed extract and peppermint oil treatments whereasdecreased in response to humic acid and thyme oil treatments. Storage affected theactivity of both POD and PPO, but in different manner. Where POD activity wasdecreased a er storage, PPO ac vity was increased (Fig. 5). The least decrease in

POD activity was recorded in response to thyme oil treatment, whereas the highestincrease in PPO activity was achieved in response to humic acid treatment.Fig. (5): Effect of applied bio s mulators on the ac vity (U g F.W.) of Peroxidase (POD) andPolyphenoloxidase (PPO) in roots of Raphanus sativus plants before and after storage.-13-2- Effect of biomodulators on post-harvest quality parameters of stored roots:After two months-storage, stored roots had visible decay symptoms manifestedby rotting, water stains and unusual smell due to growth of bacteria and fungus onroots. However, quality parameters of stored roots were differed betweenbiomodulators treatments and control. All applied biomodulators decreased weightloss and post-harvest decay percentages hence, roots of biomodulators-treatedplants contained higher dry matter compared with the roots of untreated plants.Weight loss as well as post-harvest decay percentage was minimum in response topeppermint treatment, followed by thyme oil treatment. Nevertheless, dry matterpercentage in stored roots was highest due to seaweed extract followed by humicacid treatments (Fig. 6).Fig. (6): Quality parameters of stored roots of Raphanus sativus plants after storage for threemonths in refrigerator at 5 C and 95% rela ve humidity as affected by biomodulatorstreatments.3-3- Pearson's correlation matrix between roots biochemical analyses after storageand their post-harvest quality parametersIn table (8) showed the output of Pearson's correlation matrix betweenbiochemical analysis a er storage in refrigerator at (5 C/Rh 95%) for three monthsand storage parameters of radish plants in first season 2015. Dry ma er and post-

harvest decay showed very strong significant negative as follow (-0.90 and -0.99)respec vely rela onship with sulfur concentra on at the 0.05 and 0.01 level. Totalanthocyanin revealed very strong significant posi ve as follow (0.98 and 0.92)rela onship with total phenols and carbohydrates at the 0.05 and 0.01 level.Ascorbic acid, total phenols, flavonoids and anthocyanin recorded very strongsignificant posi ve as follow (0.95, 0.97, 0.89 and 0.91) respec vely rela onship withtotal flavonoids at the 0.05 and 0.01 level.Table (8): Pearson's correlation matrix between roots biochemical analyses after storageand their post-harvest quality arameters.DM PDP% WLP T.A ASA T.P%%T.F T. T.ACKS PO PPD ODM%PDP 0.88%WLP -0.61% 0.30T. A-0.83 0.720.83ASA-0.69 0.00 0.210.57T. P-0.77 0.79 0.98 0.10.73**1T. F-0.660.14 0.9 0.020.520.025*T.C-0.66 0.85 0.92 - 0.97 0.57* 0.00 ** 0.12T.A-0.70 0.66 0.46 0.6 0.51 0.4 0.0.3527 56K-0.72 0.78 0.71 0.3 0.77 0.1 0. 0.90.4889 83 1*S0.61 0.86 0.6 0.79 0.6 0. 0.6 0.0.90* 0.99**32 67 3 67POD -0.81 0.20 0.45 0.7 0.31 0.8 0. 0.3 0. 0.0.7489* 13 5 21 82PPO ٠.٦٤- ٠.٥٧ ٠.٨٦ - ٠.٨١ ٠.٠ ٠. ٠.٠ ٠. ٠. 0.٠.٧٢٠.٠٤٥ ٧٠ ٥ ٢٩ ٧١ 49*Correla on is significant at the 0.05 level (2-tailed).**Correla on is significant at the 0.01 level (2 tailed)DM, dry matter; PDP, post-harvest decay; WLP, weight loss; TA, total anthocyanin's; AsA, TP, totalphenols; ASA, ascorbic acid; TF, total flavonoids; TC, total carbohydrates; TA, total amino acids; K,potassium; S, sulphur; POD, peroxidase; PPO, polyphenoloxidase.DISCUSSIONCold storage and post-harvest quality of plant products:Senescence is the most important internal factor that causes damage tovegetables whereas low temperature is the best way to delay post-harvestdeterioration of fruits and vegetables. In this context, Bayomi (2008) concluded thatthe higher post-harvest decay percentage in late harvesting stage of fruits is due tohigher rate of respiration, more skin permeability for water loss and highsusceptibility to decay. Dry matter acts an index to evaluate the fruit quality due to

endure prolonged storage (Jackson and Harker, 1997). Generally, low temperaturecan maintain organic matter and vitamins levels in short and long term storagebecause most enzyme activities decrease and the expression of many genesinhibited during cold storage. Low temperature markedly delays senescence ofbroccoli during storage (Javanmardi and Kubota, 2006). In addition, Shen et al.(2013) reported that refrigeration can reduce deterioration and extend shelf life offresh fruits by delaying the metabolic processes. Dry matter production represents abalance between photosynthesis and respiration. Respiration rate, which has longbeen used to measure metabolic process in stored produce (Scholz, 1962; Ki ockand Law, 1968), is governed by water availability, temperature, O concentration,microbial contamination, mechanical damage, among other factors. Porter et al.(2003) reported that respira on rate of chinese cabbage was higher at 20 C than atlower temperatures.Effect of essential oils on post-harvest quality parameters:Synthetic chemicals are commonly used in the controldiseases of stored plant products however; these chemicals maycause toxic residues in treated plants (Isman, 2000).Alternatively, the use of natural products like herbalextracts and essential oils can reduce harm to public healthand preserve the environment from pollution. These ecofriendly plant-derived products generally possess a broadspectrum of activity against several pathogens and pests(Bakkali et al., 2008). Essential oils are natural complexcompounds with a strong smell and produced as secondarymetabolites in aromatic plants. In nature, essential oils actsas antibacterial, antivirus, antifungal and insecticides. Itcontains compositions of terpenes, sesquiterpenes, aldehydes,ketones and phenolic compounds (Burt, 2004). The main chemicalcomponents of thyme oil are thymol, carvacrol, α- pinene, βpinene, borneal, linalool, β-simine and camphene (Dew et al.,1984). The composition of volatile oil of M. piperita ismenthol, monoterpene and methofuran (Dew and Evans, 1984).These constituents act as inhibitor for pathogens growthduring cold storage and reduce senescence in treated plants.In the current investigation, thyme as well as peppermint oil decreasedweight loss and post-harvest decay percentages hence, preserved roots dry matterduring cold storage (Fig.6). These findings are in harmony with those of previousstudies (Aminifard and Mohammed, 2013; Janparval et al., 2014; AliKhani et al.,2009b; Geransayeh et al., 2015; Abd EL-Wahab, 2015; Amin, 2016).Biomodulators-induced enzymatic, non-enzymatic antioxidants and theirrelationship with post-harvest quality:Antioxidants play an important role in scavenging reactive oxygen species(ROS) that appear during storage-related senescence of vegetables (Hounsome etal., 2009). Antioxidant capacity is directly correlated with phenolic compounds(Tavarini et al. 2008; Koh et al. 2009). Therefore, plants with enhanced levels ofantioxidants can resist oxidative damage (Navarro et al., 2006). The results of thepresent investigation revealed that generally, the applied biomodulators diminishedthe decline in concentrations of anthocyanins, ascorbic acid, phenols and flavonoids2

as well as in the activity of the antioxidant enzyme, peroxidase. This implies thatstored roots of biomodulators-treated plants contained higher levels of antioxidantscompared with roots of untreated plants. Similar conclusions were made based onthe results of previous studies (Wang et al., 2008; Znidarcic and Pozrl, 2006; DelNobile et al., 2009; Kramchote et al., 2012; Pirthiviraj et al., 2014). How elevatedlevels from these constituents preserve roots quality during storage could bediscussed as follows:AnthocyaninsAnthocyanin's belong to flavonoids group and located in a cell vacuole(Timberlake, 1981). It plays important role as an antioxidant. The anthocyaninpigment inhibits active oxygen radicals formed by exposure to stress conditions thatoccur during storage periods due to pathological injures i.e., enzymatic browning,molds and water stains on fruits. The results of some in vitro experiments indicatedthat anthocyanin pigments scavenge superoxide, active oxygen radicals (Yamasaki etal., 1996) and hydrogen peroxide (Leng and qi, 2003). On the other hand,anthocyanin pigment is affected by the amount of sugar due to a lower wateractivity Hubbermann et al. (2006). Lopez-Andreu et al. (1988) reported thatanthocyanins concentration was decreased at the end of the cold storage period,which imply that they are consumed in scavenging storage-related ROS.Phenolic compoundsPost-harvest stresses e.g. mechanical injuries andothers during storage led to enzymes activity that responsiblefor phenolic compounds deterioration (Yang et al., 2011).Phenolic compounds and enzymes do not interact with each nsequently, shelf life of vegetables and fruits isincreased. However, when membranes are damaged, destructionand oxidation of phenolic compounds are initiated, causingbreakdown of defense line in the cell against free radicals(Toor and Savage, 2006; Yang et al. 2011). Similar conclusionswere made by Wang et al. (2008) and Abd EL-Wahab (2015).Flavonoids are the most important group of phenolic compoundsin plants (Hounsome et al., 2009) that assist in scavengingfree radicals and inhibiting oxidative stress, therebydecreasing cell membrane deterioration during long storage(Koh et al., 2009).Ascorbic acidAscorbic acid is a major component of the plant defense system (Hodges andForney, 2000) that protect biological processes of the plant from ROS generatedduring biotic and abiotic stresses (Foyer and Noctor, 2011). In addition, it has apivotal role in eliminating H O through the glutathione-ascorbate cycle that operatesin the cytosol, mitochondria, plastids and peroxisomes where it involves ascorbate,glutathione, NADPH and the enzymes linking these metabolites during long termstorage. Since glutathione, ascorbate and NADPH are present in high concentrationsin plant cells it is assumed that the glutathione-ascorbate cycle plays a key role forH O detoxification. Peroxidases also contribute to H O removal in plants. Thedestruction of ascorbic acid is one of the most serious problems facing plants under222222

stress conditions, whether in the soil or when storing in the short or long term(Emese and Nagymate, 2008). The oxidized form of ascorbic acid is more prone todecomposition during storage in low temperature. Ascorbic acid decreases duringstorage due to its consumption in the ROS-detoxification process especially attemperature above 0 C (Ajibola et al., 2009) through oxidation in the presence ofascorbate oxidase enzyme, and changes back to its active form (Lee and Khader,2000). The antioxidant role of ascorbic acid in mitigating stress-related metabolicabnormalities was evident from the results of other studies (Wang et al., 2008;Aminifard and Mohammed, 2013; Serrano et al., 2005; Alkhani et al., 2009b;Raafat et al., 2012).REFERENCESAjibola, V.O., Babatunde, O.A. and Suleiman, S. (2009). The effect of storage method on thevitamin C content in some tropical fruit juices. Tr. App. Sci. Res. 4(2):79-84.Alikhani, M.; Sharifani, M.;Mousavizadeh, S.J. and Rahimi, M. (2009b). Increasing shelf life andmaintaining quality of strawberries (Fragaria ananassa L.) with application ofmucilage edible coa ng and plant essen al oil. J. Agric. Sci. Nat. Resour. 16 (2):1–10(in Persian).Alikhani, M.; Sharifani, M.;Mousavizadeh, S.J. and Rahimi, M. (2009b). Increasing shelf life andmaintaining quality of strawberries (Fragaria ananassa L.) with application ofmucilage edible coa ng and plant essen al oil. J. Agric. Sci. Nat. Resour. 16 (2):1–10(in Persian).Amin, A.(2016). Determination of Some Essential Oils Effects on the Quality Traits of theEgyp an Anna Apple Fruit During its Shelf Life. . Hor . Sci.& Ornam. Plants 8 (1): 3545.Aminifard, M.H. and Mohammadi, S. (2013). Essential oils to control Botrytis cinerea in vitroand in vivo on plum fruits. Journal of the Science of Food and Agriculture. 93(2):348–353.A

* Botany Department, Faculty of Agriculture, Mansoura University, Mansoura, Egypt, ** Post harvest and handling vegetables Res. Dept., Hort. Res. Inst., Agric. Res .Center, Giza, Egypt ABSTRACT This study was carried out to assess the effect of certain biomodulators, namely seaweed extract, humic acid, peppermint and thyme oils, on quality-related