Preharvest Treatments Research Articles

Preharvest and postharvest applications of 1-MCP affect umami taste and aroma profiles of mushrooms (Flammulina velutipes)

Umami-taste loss and unpleasant odor are the restrictive factors of consumer acceptance of mushrooms (Flammulina velutipes). Pre- and postharvest 1-methylcyclopropene (1-MCP) treatments were applied to evaluate the sensory score, ethylene release, respiration rate, umami taste and aroma profiles in mushrooms at 10 °C storage. The results showed that preharvest treatment resulted in a stronger inhibition of respiration and ethylene production than postharvest treatment. Preharvest treatment also had the highest sensory score and flavor 5′-nucleotides content. The EUC values of preharvest and postharvest treatments were 10.5 and 1.4 times of CK on day 0, respectively. Preharvest treatment improved overall flavor by increasing umami scores in electronic tongue analysis and maintaining volatile compounds compared with postharvest treatment. Thus, preharvest 1-MCP treatment could be considered as an alternative approach to preserve the umami taste and aroma profiles in Flammulina velutipes.

Preharvest sprays with sodium nitroprusside induce resistance in harvested muskmelon against the pink rot disease

Pink rot caused by Trichothecium roseum is an important postharvest disease of muskmelon, and caused very serious postharvest losses. In this study, sodium nitroprusside (SNP), an exogenous nitric oxide donor, was applied four times during fruit development to muskmelon. The effect of SNP sprays on pink rot in harvested fruit and the influence on the mechanism of antioxidant enzymes and the phenylpropanoid pathway were investigated. The results showed that SNP sprays significantly reduced decay incidence and lesion area of muskmelon inoculated with T. roseum. SNP sprays induced the production of H2O2 in fruit at harvest, maintained cell membrane integrity, and increased the activity of superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase during storage. In addition, SNP sprays also increased the activity of phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, and 4-coumaroyl-CoA ligase, and promoted the accumulation of total phenolic, flavonoid, and lignin content in harvested muskmelon at harvest and during storage. These results suggesting a new possible way of prevention of postharvest pathogens. Practical applications Muskmelon is an important cash crop in the world, due to its unique appearance and intrinsic quality. However, postharvest losses of the muskmelon fruit are serious. Pink rot caused by Trichothecium roseum is one of the main reasons for the postharvest losses of harvested muskmelon. SNP preharvest sprays effectively induced the resistance and reduced decay incidence and lesion area of muskmelon inoculated with T. roseum. Compared with the postharvest treatment, which involves complete exposure, preharvest sprays not only affects the fruit, but also other portions of the plants, which could indirectly affect fruit quality. In addition, the preharvest treatment operation is simple and convenient, and the control effect is better than the postharvest treatment. Therefore, this work may provide a new approach for the control of postharvest diseases of muskmelon.

Preharvest Application of Chitosan Improves the Postharvest Life of 'Garmrok' Kiwifruit through the Modulation of Genes Related to Ethylene Biosynthesis, Cell Wall Modification, and Lignin Metabolism.

The influence of the preharvest application of chitosan on physicochemical properties and changes in gene expression of ‘Garmrok’ kiwifruit during postharvest cold storage (0 °C; RH 90–95%; 90 days) was investigated. Preharvest treatment of chitosan increased the fruit weight but had no significant effect on fruit size. The chitosan treatment suppressed the ethylene production and respiration rate of kiwifruit during the cold storage. The reduction of ethylene production of chitosan-treated kiwifruit was accompanied with the suppressed expression of ethylene biosynthesis genes. Moreover, preharvest application of chitosan diminished weight loss and delayed the changes in physicochemical properties that include firmness, soluble solids content, titratable acidity, total sugars, total acids, total phenols, and total lignin. As a result, the preharvest application of chitosan delayed the maturation and ripening of fruit. Expression of genes related to cell wall modification was down-regulated during the early maturation (ripening) period, while those related to gene expression for lignin metabolism were up-regulated at the later stages of ripening. These results demonstrate that the preharvest application of chitosan maintained the fruit quality and extends the postharvest life of ‘Garmrok’ kiwifruit, possibly through the modulation of genes related to ethylene biosynthesis, cell wall modification, and lignin metabolism.

Robotization of Tomato Fruits Production to Enhance Food Security

The world is facing food insecurity problem due to shortage of workforce and growing world population. Robotization of crop production will help to boost food production, through effective labour conservation. This study was carried out to optimize the performance of tomato fruits’ robotic harvesters, through field practices (pre-harvest treatments). Tomato (Cv. UC82B) was cultivated under four major field practices, which were: control, organic treatment, inorganic treatment using potassium nitrate (KNO3), and combine treatment using the combination of compost manure and KNO3. Tomato fruits were harvested at the pink maturity stage and were subjected to compression test, using the Universal Testing Machine, at three compression speeds of 15 mm/min, 20 mm/min and 25 mm/min. Results obtained from the study showed that, field practices and compression speed significantly (p ≤0.05) affected the failure parameters (failure force, failure energy and deformation) of the tomato fruits. Regardless of the compression speed, the fruits produced with combined treatment had the highest failure parameters; while the control fruits developed the least failure parameters. Tomato fruit produced using the combined treatment developed failure force, failure energy and deformation of 87.60 N, 701.97 N.mm and 16.88 mm respectively. In the terms of the compression speed, the study revealed that the ability of the fruits to absolved compression force declined significantly, as the compression speed increased from 15 mm/min to 25 mm/min, across the four treatments regimes. These results will be useful during the programming and application of automatic tomato fruits harvesting robots, to optimize their efficiency, hence improving food security condition.

Biocontrol Using Bacillus amyloliquefaciens PP19 Against Litchi Downy Blight Caused by Peronophythora litchii.

Bacillus amyloliquefaciens has been widely used in the agriculture, food, and medicine industries. Isolate PP19 was obtained from the litchi fruit carposphere and showed biocontrol efficacy against litchi downy blight (LDB) whether applied preharvest or postharvest. To further understand the underlying regulatory mechanisms, the genome of PP19 was sequenced and analyzed. The genome comprised a 3,847,565 bp circular chromosome containing 3990 protein-coding genes and 121 RNA genes. It has the smallest genome among 36 sequenced strains of B. amyloliquefaciens except for RD7-7. In whole genome phylogenetic analysis, PP19 was clustered into a group with known industrial applications, indicating that it may also produce high-yield metabolites that have yet to be identified. A large chromosome structural variation and large numbers of single nucleotide polymorphisms (SNPs) between PP19 (industrial strain) and UMAF6639 (plant-associated strain) were detected through comparative analysis, which may shed light on their functional differences. Preharvest treatment with PP19 enhanced resistance to LDB, by decreasing the plant H2O2 content and increasing the SOD activity. This is the first report of an industrial strain of B. amyloliquefaciens showing a plant-associated function and with major potential for the biocontrol of LDB.

Fertilizer type and harvest maturity index on nutritive content and proximate composition of tomato fruit

ABSTRACT There may be a link between pre-harvest treatment and the post-harvest quality traits of tomato (Solanum lycopersicum L) fruit. The experiment was undertaken to determine the relationship between year of production, fertilizer type, and fruit-ripening index on nutritive and biochemical contents of tomato fruits sourced from the Directorate of University Farms, Federal University of Agriculture, Abeokuta, Nigeria. Data were collected on: proximate content, total soluble solids (TSS), Vitamin C, lycopene, pH and β-carotene. Fruits harvested at full ripe stage had the highest ash, moisture content, crude fiber, crude protein, fat, ß-carotene, TSS and Vitamin C contents. Year of production did not affect proximate content except for crude fiber. Fertilizer type did not affect proximate content except for ash content. Harvest maturity stage influenced proximate, nutritive, and biochemical content of tomato fruit. Fertilizer type used for cultivation and the stage of maturity at harvest are important factors determining tomato fruit nutritive contents and proximate composition. Knowledge of the right stage of maturity at harvest will affect supply of good quality tomato for the fresh market and food processing.

Fruit quality of ‘Braeburn’ apple trees sprayed at post-bloom and preharvest with prohexadione-calcium and GA4+7

Abstract The objective of this study was to assess the effects of post-bloom (PB) or preharvest (PH) treatments of ‘Braeburn’ apple trees with prohexadione-calcium (ProCa; 300 mg L-1), an inhibitor of gibberellins biosynthesis, or GA4+7 (300 mg L-1) on fruit quality at harvest and after storage (four months at 0±0.5 oC, followed by five days of shelf life). PB treatments started 15 days after full bloom, with one application every week and six applications in total. PH treatments started five weeks before anticipated harvest, with one application every week and four applications in total. Control trees were sprayed with water. GA4+7 PB increased length/diameter ratio, and GA4+7 PH increased titratable acidity (TA) and flesh firmness and slightly reduced red color of the fruit at harvest. ProCa PB and PH reduced ethylene production rate, delayed starch degradation and reduced soluble solids content of the fruit at harvest, and ProCa PH maintained firmness at harvest and after storage and TA of the fruit after storage. ProCa PB or PH delayed the loss of skin green background color at harvest, while at both treatment timings reduced the development of skin red color, but with a much stronger effect when sprayed PH than PB.

Influence of pre-harvest sprays on flower quality and vase life of Alstroemeria

Alstroemeria, commonly known as Peruvian Lily, has high demand in the global market. The flowers are popularly known for their wide range of colours. Short postharvest life is a significant problem in Alstroemeria flowers. The objective of the study is to extend the vase life of flowers by application of pre-harvest foliar sprays. Foliar spray of Salicylic acid (50, 100 & 150 µM), Benzyl Adenine (50, 100 & 150 µM) and Gibberellic acid (200, 250 & 300 ppm) were applied twice during 2 weeks and 1 week before flower harvest with distilled water as control. The harvested flowers were placed in conical flasks containing distilled water as vase solution, and parameters like relative fresh weight, vase solution uptake, floret diameter, total chlorophyll content, ethylene evolution and vase life were recorded. The results showed that pre-harvest treatment of flowers with Gibberellic acid @ 300 ppm showed a significant increase in floret diameter (7.6 cm), total chlorophyll content (0.72 mg g-1 of fresh leaf), high relative fresh weight (88.50%) and high uptake of vase solution (2 g stem-1 day-1). Treatment with Benzyl adenine @ 150 µM has given favourable result by increasing the vase life of the flower up to 8 days followed by Gibberellic acid @ 300 ppm (7 days). Treatment with Salicylic acid did not show any favourable result. There was no significant difference in ethylene evolution pattern among treatments. From this experiment, it is concluded that pre-harvest treatment of flowers with Gibberellic acid @ 300 ppm and treatment of flowers with Benzyl adenine @ 150 µM showed positive results with treatment using Gibberellic acid @ 300 ppm as the best treatment.

Effect of pre-harvest treatment of GA3 on physiological behaviour in Mango

Mango (Mangifera indica L.) is one of the most important fruit crops of many tropical and sub-tropical countries of world which belongs to the family Anacardiaceae (Nakasone and Paul 1998 and Purseglove 1972). The experiment was carried out in Horticulture Garden of Bihar Agricultural College, Sabour during Rabi season with the objectives focused in this direction on the effect of GA3 application on physiological regulation of flowering and maturity in mango [Mangifera indica L.] cv. Langra. A critical analysis of data revealed that wide range of observation was observed on physiological traits. The traits such as photosynthetic rate (8.71 µmol/m2/sec) and internal CO2 concentration (283.80 ppm) was recorded with gibberellic acid @ 200 ppm while Stomatal conductance of leaf (0.163 µmol/m2/sec) was recorded at the time of stone formation stage. A wide range was observed with application of gibberellic acid on Physiological parameters.

Effect of pre-harvest treatments on growth and yield characters of multiplier onion (Allium cepa L. var. aggregatum Don.) cv. CO-5

Onion (Allium cepa L.) belongs to the family Alliaceae,is a bulb crop and one of the important vegetables of theworld. India stands first in sharing 8% of the worldproduction with an average cultivated area of 1.06 millionhectare and an average annual production of 15.18 milliontonnes (NHB 2014-15). Small onions are also known ascountry onion, shallots, multiplier or aggregatum onion.This onion is produced only in southern states of Indiaviz., Tamil Nadu, Andhra Pradesh and Karnataka (Kaveriand Thirupathi 2015). In Tamil Nadu, aggregatum onionis cultivated in 0.04 million hectares with a totalproduction of 0.47 million tonnes (NHB 2014-2015).Storage loss of onion is caused by sprouting, rottingand physiological loss in weight. According to Biswaset al. (2010) reported that storage losses in onion couldbe as high as 66%. Onion is highly perishable

Effects of methyl jasmonate on the monoterpenes of Muscat Hamburg grapes and wine.

The importance of monoterpenes in grape and wine aroma has compelled researchers to focus on developing methods to increase their abundance. Recent research has revealed that exogenous elicitors can increase the contents of these compounds. This study determined the effects of methyl jasmonate (MeJA) preharvest treatments on the monoterpene profiles of Muscat Hamburg grapes and wine. A total of 27 monoterpenes were identified for Muscat Hamburg grapes and wine. The contents of most of the monoterpenes (free and glycosylated forms) in the grapes and wine increased in response to MeJA. An analysis of the expression of the genes in the terpenoid biosynthesis pathway indicated that the related biosynthetic pathways were activated by MeJA. The transcript levels of some genes were consistent with monoterpene production, including VviCSLinNer, VviGwbOciF, VviPNRLin, VviGT14 and VviUGT85A1L1. The developmental expression patterns of the VviPP2B1 and VviMYB24 transcription factor genes were positively correlated with monoterpene accumulation in ripening grapes. Our results suggest that MeJA may be useful for improving the aroma quality of grapes and wines.

Pre-Harvest Treatments On Canino Apricot Trees to Improve Yield, Fruit Quality at Harvest and During Storage

The present study was conducted on eighteen years old Canino apricot trees grown in a private orchard at Motobus, Kafr El-Sheikh governorate, Egypt in 2019 and 2020 seasons to evaluate the effects of preharvest foliar treatments of potassium sulphate at 1.5% and calcium chloride at 2% individually or in combination in addition to Control (tap water) on yield, fruit quality at picking date and during cold storage at 0±1°C with 90 – 95 % RH. Canino apricot trees were sprayed three times starting after full bloom, fruit setting and finally ten days before harvest with one of the abomination treatments. The results showed that all treatments increased yield and improved fruit weight, size, height and width compared to control. Application of 1.5% K2SO4 produced the highest vitamin C content and SSC% after 7, 14 and 21 days of cold storage in both seasons. While, Application of 2% CaCl2 showed the lowest fruit decay % and SSC %, and maintained fruit firmness until 28 days of cold storage in both seasons. The combination between 1.5 % K2SO4 and 2% CaCl2 treatment produced the highest vitamin C content and acidity% and maintained fruit weight loss% and SSC/acid ratio in lowest values until 21 and 28 days of cold storage in both seasons. Finally, it could be recommend to spray K2SO4 at 1.5% and CaCl2 at 2% on Canino apricot trees three times to increase yield and improve physical and chemical fruit quality and maintains characteristics of fruit under cold storage.

Effect of pre-harvest treatments with salicylic and methyl salicylic acid on the chemical profile and activity of some phenylpropanoid pathway related enzymes in apple leaves

The effects of single and multiple sprayings with salicylic acid (SA) and methyl-salicylic acid (MeSA) on the composition of phenolic compounds in apple leaves of the 'Topaz' cultivar were investigated by combined analysis of phenolic compounds by HPLC-MS and measurements of the activities of selected enzymes of the phenylpropanoid pathway (phenylalanine ammonia lyase (PAL), chalcone synthase (CHS)/chalcone isomerase (CHI), flavanone-3β-hydroxylase (FHT) and dihydroflavonol 4-reductase (DFR)). The results showed that SA and MeSA in general can stimulate the activity of the above-mentioned enzymes, which led to an increase in certain proven antifungicidal phenolics, such as catechin, chlorogenic acid and phloridzin. MeSA increased the catechin content in apple leaves by up to 48 %, chlorogenic acid by up to 55 % and it also increased the content of phloridzin (1.7-fold higher content in comparison with the control). The content of some phenolic groups, such as hydroxycinnamic acid, flavanones and flavanols, increased with the number of sprayings with MeSA.

Preharvest Application of Oxalic Acid Improved Pomegranate Fruit Yield, Quality, and Bioactive Compounds at Harvest in a Concentration-Dependent Manner

The effects of oxalic acid (OA) applied in preharvest on pomegranate crop yield and quality properties have not yet been investigated. Pomegranate trees were treated with OA at 1, 5, and 10 mM along the developmental growth cycle during 2016, from full blossom until harvest, and the fruit diameter was recorded monthly. The yield was significantly higher in OA-treated pomegranate trees, the on-tree ripening process being promoted in a concentration-dependent manner. With respect to quality traits, OA at 10 mM showed better results in terms of firmness, external color due to a red color enhancement, and respiration rate and sensory attributes. Then, a second-year experiment was performed with OA at 10 mM, and crop yield and fruit quality results were confirmed. In addition, an increase in glucose and total acidity, specifically malic and ascorbic acids, was observed in OA 10 mM-treated pomegranate fruit. Bioactive compounds were also higher in OA-treated fruit than control, the 10 mM concentration being the most effective in increasing total phenolics, total anthocyanins, and total antioxidant activity. Overall, results suggest that OA applied at 10 mM as preharvest treatment could be an effective tool to enhance pomegranate crop and quality and to improve the content of health-related compounds.

Yield and Quality of Table Grapes cv. Flame Seedless as affected by Bud Break and Pre-Harvest Treatments

This study was carried out during the two successive seasons of both 2018 and 2019 on 5-year-old Seedless grapevines in a private vineyard located at Kom Hamada - Beheira Governorate, Egypt. The trees were spaced at 1.5 x 3 m apart and irrigated by drip irrigation system and received similar cultural practices adapted in the orchard. The present investigation aimed at study yield and quality of table grapes cv. Flame seedless as affected by bud break and pre-harvest treatments. This experiment consisted of sixteen treatments arranged in factorial experiment in Randomized Complete Block Design (RCBD) with four replicates for each treatment and one tree for each replicate. The experiment consisted of 16 treatments (Control, Garlic oil at 1 %, Urea at 2 %, Dormex at 4 %, Abscisic acid at 400 mg/ l, Ethrel at 250 mg/ l, Gibberelic acid 250 mg/ l, Garlic oil at 1 % + ASA at 400 mg/l , Garlic oil at 1 % + Ethrel at 250 mg/l, Garlic oil at 1 % + GA3 at 250 mg/l, Urea at 2 % + ASA at 400 mg/l, Urea at 2 % + Ethrel at 250 mg/l , Urea at 2 % + GA3 at 250 mg/l, Dormex at 4 % + ASA at 400 mg/l , Dormex at 4 % + Ethrel at 250 mg/l and Dormex at 4 % + GA3 at 250 mg/l . Results revealed that spraying dormex at 4%, recorded the best values of cluster weight and yield/plant, physical characters i.e. (berry length, berry diameter, weight of100 berry, size of 100 berry and fruit firmness), and all chemical compositions i.e. (total sugars, reducing sugars, anthocyanin content and vitamin c), also, abscisic acid 400 mg/l gave the highest mean values of cluster weight, yield/plant and anthocyanin content, while Ethrel at 250 mg/l recorded the maximum values of physical characters i.e. (berry length, berry diameter, weight of100 berry, size of 100 berry and fruit firmness), and all chemical compositions i.e. (total sugars, reducing sugars, and vitamin c), as compared with the control treatment which recorded the minimum values of this studied characters, during both seasons.

Vine Removal Prior to Harvest, and Curing Duration and Temperature Affect the Incidence and Severity of Internal Necrosis in ‘Covington’ Sweetpotato

Internal necrosis (IN) is a physiological disorder that affects Covington, the most commonly grown sweetpotato (Ipomoea batatas) cultivar in North Carolina. Because IN affects the quality of sweetpotato storage roots, studies have been conducted since the first report of IN in 2006. Field studies (three in 2016 and two in 2017) were conducted to evaluate preharvest and postharvest treatments on the occurrence of IN in ‘Covington’ storage roots. Four preharvest treatments consisted of combinations of high chlorine or minimal chlorine potash fertilizer and mowing vs. not mowing before harvest. For postharvest treatments, 30 storage roots were obtained at harvest from each preharvest treatment plot and immediately cured in 75 and 85 °F rooms for a duration of 0.5, 1, 2, 3, and 5 weeks in 2016, and 0.5, 1, and 2 weeks in 2017. Shorter curing durations (0.5 and 1 week) coincided with industry recommendations while longer durations mimicked the challenges that some commercial facilities face when cooling down temperatures of rooms after curing is supposed to be concluded. Once curing temperature and curing duration treatments were completed, roots were placed in a 58 °F storage room at 85% relative humidity until cut. A control comparison was included in which harvested roots were placed in a 58 °F storage room (no curing) immediately after harvest. The storage roots from all temperature treatments were then cut 49 to 80 days after harvest, and incidence and severity of IN visually rated. Preharvest potash fertilizer treatments had minimal or no effect on occurrence of IN. However, mowing vines before harvest in several studies reduced IN incidence when roots were cured for more than 0.5 week at temperatures of at least 75 °F. Lower temperature (75 vs. 85 °F) and shorter curing duration (0.5 vs. 1, 2, 3, or 5 weeks) resulted in reduced IN occurrence in ‘Covington’ sweetpotato.

Seasonal Variation of Health-Promoting Bioactives in Broccoli and Methyl-Jasmonate Pre-Harvest Treatments to Enhance Their Contents.

Broccoli is a source of bioactive compounds that provide an important nutritional value. The content of these compounds can vary depending on agronomic and environmental conditions, as well as on elicitation. In this study, three crop trials were carried out to evaluate the effects of the cultivation season, the application of different dosages of methyl-jasmonate (MeJA) on the overall quality and on the total content of bioactive compounds of ‘Parthenon’ broccoli cultivated under the field conditions of southeastern Spain. Color parameters, chlorophyll content, total phenolic compounds, total flavonoids and antioxidant activity were measured to evaluate the overall quality. Moreover, individual carotenoids, phenolic compounds and glucosinolates were evaluated by high performance liquid chromatography with diode array detection (HPLC-DAD) and high performance liquid chromatography equipped with diode array detector coupled to mass spectrometer using electro spray ionization (HPLC-DAD-ESI/MSn). The content of total carotenoids, phenolic compounds and glucosinolates were higher in autumn compared with spring, showing increases of 2.8-fold, 2-fold and 1.2-fold, respectively. Moreover, a double application of MeJA increased the contents of total carotenoids, phenolic compounds and glucosinolates by 22%, 32% and 39%, respectively, relative to the untreated samples. Considering our results, the controlled and timely application of 250 µM MeJA to the aerial parts of the plants four days before harvest, on two consecutive days, seems to be a valid agronomic strategy to improve the health-promoting capacity of Parthenon broccoli, without compromising its overall quality.

Enhancement of antioxidant and storability of Hollywood plum cultivar by preharvest treatments with moringa leaf extract and some nutrients

BackgroundPlum fruit has a short shelf life with a rapid deterioration in quality after harvest. The main aim of this study was to evaluate the effect of preharvest treatments by moringa leaf extract (MLE), boric acid (B), and chelated calcium (Ca EDTA) on Hollywood plum fruit quality attributes bioactive compounds and antioxidant activity during cold storage. Plum trees were sprayed twice: at full bloom stage and 1 month later with T1, 5% MLE + 1% B + 2% Ca EDTA; T2, 5% MLE + 2% B + 3% Ca EDTA; T3, 10% MLE + 1% B + 2% Ca EDTA; T4, 10% MLE + 2% B + 3% Ca EDTA; and T5, water only as control. At maturity stage, fruits were harvested and stored at 0 ± 1 °C and RH 85–90% for 8 weeks.ResultsAt the end of storage, all studied treatments exhibited significantly higher sensory quality: firmness, color, soluble solid content:titratable acidity ratio, total anthocyanin content, total flavonoids content, total phenolic content, and antioxidant activity than control.ConclusionsIt could be concluded that preharvest treatment with moringa leaf extract, boric acid, and chelated calcium could be a safe and eco-friendly to improve and maintain plum quality attributes and especially their content of antioxidant compounds during cold storage periods.

Enhancing antioxidant systems by preharvest treatments with methyl jasmonate and salicylic acid leads to maintain lemon quality during cold storage

The effects of preharvest treatments with 0.1 mM methyl jasmonate (MeJA) and 0.5 mM salicylic acid (SA) on quality parameters of lemon fruit and their relationship with antioxidant systems, gene expression and bioactive compounds at harvest and during cold storage were evaluated. Results showed that total antioxidant activity, total phenolic content and the major individual phenolics (hesperidin and eriocitrin) were always higher in treated fruit than in controls. The activity of the antioxidant enzymes catalase, peroxidase and ascorbate peroxidase was also increased at harvest by SA and MeJA treatments, especially the last enzyme, for which the expression of its codifying gene was also enhanced. In addition, treated fruit had lower weight and firmness losses, respiration rate and production of ethylene than controls. Moreover, sugars and organic acids were maintained at higher concentration in flavedo and juice as a consequence of preharvest SA and MeJA treatments, showing an effect on maintaining fruit quality properties.

Effect of pre-harvest inactivated yeast treatment on the anthocyanin content and quality of table grapes

Due to the global warming, more and more often the red-pink grape varieties grown in the Mediterranean basin reveal an insufficient accumulation of anthocyanins and thus a scarce coloration. Nowadays, this is becoming an important technological issue, which may result in the reduction of the fresh market value of table grape. This study aimed at assessing the effect of the pre-harvest treatment by specific inactivated yeasts (YE) on the qualitative parameters and anthocyanin pattern of three red table grape varieties, which typically present poor and/or incomplete coloration during warm years. An increment of anthocyanins level up to almost seven folds corresponding to an improvement of red skin appearance was observed in all the treated table grapes, which was preserved after cold storage, too. While, no significant influence on chemical composition and berry texture and dimensions was found, meaning that YE did not cause appreciable taste changes in grapes.