Blueberry Fruit Quality Research Articles

A physiological and metabolomic analysis reveals the effect of shading intensity on blueberry fruit quality.

With the advancement of blueberry industrialization, cultivation measures for obtaining high-quality fruits and technologies for obtaining high levels of the main secondary metabolites have become inevitable requirements for further development of the blueberry industry. This study applied different shading treatments and found that the FT1 shading treatment yielded the largest values for the single fruit weight, solid longitudinal diameter and transverse diameter of blueberry fruit as well as the highest solidity-acid ratio and total phenol and vitamin C contents. Moreover, 470 known metabolites were obtained from blueberry fruits. Interestingly, the differentially abundant metabolites related to ABC transporters, pyrimidine metabolism, and purine metabolism pathways were commonly identified from the three comparisons, which indicated that these three metabolic pathways in blueberry fruits are vulnerable to shading treatment. This study provides a theoretical basis for the application of summer shading to improve the quality and antioxidant substances of small berries.

Effects of melatonin on blueberry fruit quality and cell wall metabolism during low temperature storage

Melatonin is known to influence various physiological processes, including plant ripening; however, the effect of melatonin on postharvest blueberry fruit softening is unknown. Herein, the effects of melatonin at different concentrations (100, 300, and 500 μmol L-1) on the quality parameters, cell wall substances, cell-wall-degrading enzymes, and cell wall ultrastructure of blueberry fruits were investigated during low-temperature storage. Melatonin treatment was found to effectively delay the decline in fruit firmness, slow the loss of soluble solids and titratable acids, and decrease the respiration rate and decay rate of blueberry fruits. The blueberry fruits treated with 300 μmol L-1 melatonin exhibited the best quality. Melatonin treatment promoted anthocyanin accumulation, delayed ascorbic acid degradation, maintained a low relative membrane permeability in pulp, inhibited increases in lipoxygenase (LOX) activity, and reduced membrane lipid peroxidation. Moreover, melatonin controlled the formation of soluble pectin by inhibiting the activities of pectin methylesterase (PME), polygalacturonase (PG), cellulase (Cx), and β-glucosidase (β-Glu) while maintaining high contents of protopectin and cellulose. These results indicate that melatonin can effectively improve blueberry fruit quality and antioxidant capacity as well as and delay fruit softening by inhibiting the degradation of cell wall substances.

Silicon enhances production and quality of blueberry fruits (Vaccinium corymbosum L.)

The effect of silicon (Si) in the nutrient solution on the fruit development of 2-year-old blueberry plants (Vaccinium corymbosum L. cv. Ventura) was studied. Si was applied to the nutrient solution at a dose of 0.0, 0.6, and 1.2 mM. The parameters of fruit, stems and leaves growth, firmness, and biomass were measured. Fertigation in conjunction with traditional spread fertilization could improve the growth and yield of highbush blueberry to find the optimal method to control decay and prolong the quality of blueberries after harvest. The blueberry fruit has a light-blue appearance because its blue-black skin is covered with a waxy bloom. This layer is easily damaged or removed during fruit harvesting and postharvest handling. Si enhances the resistance of this layer to damage. A 2-year study was done to compare the effects of silicon fertigation and silicean sand and coir fiber as substrates on growth and availability of nutrients for blueberry plants during establishment of highbush blueberry (Vaccinium corymbosum L. “Bluecrop”). The results of experiment indicated that the application of Si had better benefit on the fruit growth of blueberry plants in coir fiber, than the effect that was observed in the sand substrate. The results should improve our understanding for better preservation of postharvest quality of blueberry fruit.

Modified Atmospheric CO2 Levels for Maintenance of Fruit Weight and Nutritional Quality upon Long-Term Storage in Blueberry (Vaccinium corymbosum L.) ‘Liberty’

Blueberry fruits have gained consumer attention in recent years due to their good taste and high nutritional value. However, the short shelf-life of the fruit is one of the main downsides in intensive blueberry production. Therefore, optimized storage technology with a modified atmosphere is necessary to prolong blueberry fruit quality on the market. The aim of this study was to investigate long-term storage of fruit of the highbush blueberry (Vaccinium corymbosum L.) ‘Liberty’ under the air control (0.5% CO2, 19.5% O2, 80% N2) and controlled atmosphere conditions of: 5% CO2, 5% O2, 90% N2; 15% CO2, 5% O2, 80% N2; and 25% CO2, 5% O2, 70% N2. Fruit sampling was performed four times during storage (17, 30, 44, 62 days). Evaluation was carried out for fruit weight, total and individual sugar and organic acid contents, sugar-to-organic acid ratio, and individual phenolics contents. After 44 days of storage, weight loss was highest with 15% CO2 and lowest with 5% CO2, with minor variations. The greatest breakdown of total sugars was seen for the air control, and the least for 25% CO2. Organic acids were significantly reduced under all of these storage conditions. Consequently, a high sugar-to-organic acid ratio was maintained in fruit stored with 25% CO2. The contents of all of the identified phenolics significantly decreased with 15% and 25% CO2. After 62 days of storage with 5% CO2, there were small decreases in flavan-3-ols and hydroxycinnamic acids, while flavonoid and anthocyanin contents were unchanged, or for some individual phenolics, content increased. These data show that 15% CO2 or higher accelerates degradation of the phenolics. We can conclude that for maintenance of weight and nutritional quality of the blueberry fruit ‘Liberty’, the optimal controlled atmosphere under long-term storage is 5% CO2, 5% O2, and 90% N2.

De novo sequencing and analysis of the transcriptome of two highbush blueberry (Vaccinium corymbosum L.) cultivars 'Bluecrop' and 'Legacy' at harvest and following post-harvest storage.

Fruit firmness and in particular the individual components of texture and moisture loss, are considered the key quality traits when describing blueberry fruit quality, and whilst these traits are genetically regulated, the mechanisms governing their control are not clearly understood. In this investigation, RNAseq was performed on fruits of two blueberry cultivars with very different storage properties, ‘Bluecrop’ and ‘Legacy’, at harvest, three weeks storage in a non-modified environment at 4 °C and after three weeks storage at 4 °C followed by three days at 21 °C, with the aim of understanding the transcriptional changes that occur during storage in cultivars with very different post-harvest fruit quality. De novo assemblies of the transcriptomes of the two cultivars were performed separately and a total of 39,335 and 41,896 unigenes for ‘Bluecrop’ and ‘Legacy’ respectively were resolved. Differential gene expression analyses were grouped into four cluster profiles based on changes in transcript abundance between harvest and 24 days post-harvest. A total of 290 unigenes were up-regulated in ‘Legacy’ only, 685 were up-regulated in ‘Bluecrop’, 252 were up-regulated in both cultivars and 948 were down-regulated in both cultivars between harvest and 24 days post-harvest. Unigenes showing significant differential expression between harvest and following post-harvest cold-storage were grouped into classes of biological processes including stress responses, cell wall metabolism, wax metabolism, calcium metabolism, cellular components, and biological processes. In total 21 differentially expressed unigenes with a putative role in regulating the response to post-harvest cold-storage in the two cultivars were identified from the de novo transcriptome assemblies performed. The results presented provide a stable foundation from which to perform further analyses with which to functionally validate the candidate genes identified, and to begin to understand the genetic mechanisms controlling changes in firmness in blueberry fruits post-harvest.

Blueberry fruit quality and control of blueberry maggot (Rhagoletis mendax Curran) larvae after fumigation with sulfur dioxide

Postharvest fumigation of fruits and vegetables is an important tool for managing pests and diseases that can cause devastating loss if not properly controlled. Sulfur dioxide (SO2) may have promise as replacement for methyl bromide, which is expected to be phased out. However, SO2 is known to cause injury to small fruit such as table grapes (Vitis vinifera L.). We extend previous research on SO2 fumigation by focusing on an economically important fruit pest genus and through quantitative and qualitative measurements of highbush blueberry (Vaccinium corymbosum L.) fruit bleaching. This study assesses fruit damage due to SO2 fumigation at concentrations ranging 0–2.2 % (v/v) as well as the effectiveness of SO2 as a fumigant prior to cold storage for control of blueberry maggot, Rhagoletis mendax Curran. We show that fruit quality traits such as firmness, total soluble solid content, and titratable acidity are largely unaffected except at the highest SO2 concentration (2.2 %). SO2 caused bleaching and discoloration of blueberry fruit in a dose-dependent manner. Damage was also cultivar-dependent, with cv ‘Bluecrop’, and ‘Jersey’ more susceptible than ‘Draper’, ‘Elliott’, and ‘Liberty’. We show that R. mendax can be effectively controlled using a short-term (2 h), high concentration (22,000 μL L−1) SO2 fumigation followed by >14 d of cold storage at 0.5 °C. However, this treatment for control of R. mendax would likely result in damage, affecting fruit marketability.

Effect of Chitosan/Nano-TiO2 Composite Coating on the Postharvest Quality of Blueberry Fruit

Blueberries are a rich source of health-promoting compounds such as vitamins and anthocyanins and show a high antioxidant capacity. Thus, considerable commercial and scientific interest exists in prolonging its postharvest life to meet the year-round demand for this fruit. In this investigation, the effect of a chitosan-based edible coating, as well as a chitosan-based edible coating containing nanosized titanium dioxide particles (CTS-TiO2), on the postharvest quality of blueberry fruit quality was evaluated during storage at 0 °C. The blueberries were treated with a chitosan coating (CTS) and a CTS-TiO2 composite, respectively. The most suitable chitosan and nano-TiO2 fraction concentrations to be incorporated in the coating formulation were prepared based on the wettability of the corresponding coating solutions. Changes in firmness, total soluble solids (TSS), titratable acidity (TA), ascorbic acid (VC), malondialdehyde (MDA), polyphenol oxidase (PPO), and peroxidase (POD) activities, anthocyanins, flavonoids, total phenolic content, and microbiological analysis were measured and compared. This combined treatment prevented product corruption. Compared with CTS, the CTS-TiO2 composite coating application effectively slowed down the decrease in firmness, TSS, VC, and TA in the blueberries. Additionally, changes in the total polyphenol, anthocyanin, and flavonoid contents and the antioxidant capacity of CTS-TiO2 composite coating blueberry fruits were delayed. Therefore, these results indicated that the chitosan/nano-TiO2 composite coating could maintain the nutrient composition of blueberries while playing a significant role in preserving the quality of fruit at 0 °C.

Preharvest long-term exposure to UV-B radiation promotes fruit ripening and modifies stage-specific anthocyanin metabolism in highbush blueberry

Ultraviolet-B (UV-B) light (280–315 nm) is an important environmental signal that regulates plant development and photomorphogenesis, while also affecting the flavonoid pathway, including anthocyanin biosynthesis. Regarding the effects of UV-B radiation on fruits, the effects of a short-term or postharvest irradiation on fruit quality have been well-documented, but the effects of a long-term preharvest UV-B irradiation on fruit growth and coloration remain unclear. Thus, in this study, we investigated the effects of a long-term treatment involving an environmentally relevant UV-B dose on highbush blueberry (Vaccinium corymbosum) fruit. The preharvest UV-B treatment quickly promoted fruit growth and sugar accumulation, which is not commonly observed in other fruit tree species. The UV-B exposure also accelerated fruit ripening and coloration. The dual-luciferase assay proved that in blueberries, expression of VcUFGT encoding anthocyanin biosynthesis key enzyme, is positively and negatively regulated by VcMYBA1 and VcMYBC2, respectively. Throughout the fruit development stage, the UV-B treatment up-regulated VcMYBPA1 expression, which increased VcUFGT expression via VcMYBA1. In the green fruit stage, the UV-B treatment increased HY5 encoding UV receptor, which up-regulates VcMYBPA1 and down-regulates VcMYBC2, thereby promotes the accumulation of anthocyanins. On the other hand, excessive anthocyanin synthesis was inhibited by increased VcMYBC2 levels in mature fruits when exposed to UV-B light through HY5-independent pathway. In conclusion, anthocyanin-related MYB activators and repressor may coordinately balance the accumulation of anthocyanins in blueberry fruits, with UV-B treatments possibly influencing their effects in a stage-specific manner. The potential utility of preharvest UV-B treatments for improving blueberry fruit quality is discussed herein.

Effect of mechanical vibration on postharvest quality and volatile compounds of blueberry fruit

The objective of the study was to investigate the effect of mechanical vibration on postharvest quality and volatile compounds in blueberries (Vaccinium spp. Berkeley). Ethylene production, respiratory rate, firmness, decay incidence, soluble solids content (SSC), titratable acid content (TAC), flavonoid content, total phenols content (TPC), enzyme activity and volatile compounds of blueberry fruit were determined. Results showed that mechanical vibration resulted in the increase of ethylene production, respiratory rate, decay incidence and the decrease of firmness, enzyme activity, SSC, TAC, flavonoid content, TPC in blueberries comparing with the control. Moreover, mechanical vibration improved the relative content of alcohols and decreased the relative content of esters in comparison with the control group. In conclusion, the effect of transport vibration on blueberry quality was conspicuous. The quality of blueberry fruit gradually decreased with the extension of vibration time during the transportation, which seriously reduced storage life and commodity value of blueberries.

Pathway Analysis to Determine Factors Contributing to Overall Quality Scores in Four Berry Crops

Abstract Fruit quality attributes are influenced by environmental, agronomic and genetic factors; both cultivars and growing conditions can vary substantially between UK production and imported fruit. This study aimed to record and dissect the most relevant fruit quality traits for berries imported into the UK in the winter months. Blackberry, blueberry, raspberry and strawberry fruit were imported from 11 countries into a Kent-based packhouse (UK) or purchased from major retailers between December 2018 and March 2019. Multiple fruit quality components were assessed for relative contribution towards a high “overall assessment” fruit quality score. It was found that strawberry and blackberry overall scores were affected by sweetness perception, whereas blueberry and raspberry organoleptics are more complex, with overall scores influenced by flavor perception. Multiple raspberry and strawberry fruit quality traits were found to be associated with genotypic differences, indicating a promising potential for genetic improvement through breeding. By contrast, the study findings suggest that there is less potential for genetic improvement in blueberry, and that the environment may have a large effect on blueberry fruit quality traits.

Study of the Quality Attributes of Selected Blueberry (Vaccinium corymbosum L.) Varieties Grown under Different Irrigation Regimes and Cultivation Systems

Quality parameters are always of major importance in fruit sensory perception and they are influenced by the agriculture and environmental strategies of water-use efficiency that in the last few years are being developed due to water scarcity. Blueberry fruit quality depends on several factors, such as variety, water availability or cultivation system. The purpose of this work was to determine the effect of deficit irrigation and cultivation systems on the quality of three blueberry cultivars along two consecutive seasons. Three blueberry varieties (‘Rocio’, V2 and V3) were subjected to two irrigation regimes (100% and 80% crop evapotranspiration) and grown under two cultivation systems (open field and plastic tunnels). Their quality attributes (color, sugars, acidity, firmness, size and weight) were evaluated over two consecutive seasons (2011–2012). The application of deficit irrigation did not significantly affect the quality parameters, except for an increase in firmness. The cultivation system used influenced the quality attributes of blueberries cultivated under plastic tunnels in both seasons, increasing the soluble solids content and decreasing the titratable acidity. All the studied quality parameters were significantly affected by genetic factors. The V2 cultivar was the most influenced by the cultivation system. In conclusion, the use of deficit irrigation and plastic tunnels in blueberry cultivation is a good alternative to obtain fruits with enhanced quality features.

Combination of beneficial bacteria improves blueberry production and soil quality.

Blueberry is an important agricultural crop with high nutritional, health, and economic value. Despite the well‐studied blueberry cultivation methods and soil requirements, little is known about how beneficial bacteria function in organic blueberry cultivation systems and their effects on acidic soils. In this study, a single bacteria Bacillus amyloliquefaciens JC65 and three biocontrol bacteria consortiums containing JC65 were applied to organic system. The effect of bacteria to blueberry growth, yield, fruit quality, and soil quality was investigated. A consortium of three mixed Bacillus (B. amyloliquefaciens JC65, B. licheniforims HS10 and B. subtilis 7ze3) showed the highest growth improvement efficiency. The bacterial inoculation increased blueberry leaf chlorophyll content, net photosynthetic rate by 21.50%, 13.21% at 30 days, and increased average plant height by 2.72% at 69 days. Compared with the control, the inoculated plants showed an increased yield of 14.56%. Interestingly, blueberry fruit quality was also improved with supplement of the bacterial consortium. Fruit anthocyanin, soluble sugar, vitamin C, soluble solids, and soluble protein content were increased by 5.99%, 4.21%, 17.31%, 2.41%, and 21.65%, respectively. Besides, beneficial bacterial consortium also enables sustainable agriculture by improving soil ammonium nitrogen and organic matter by 3.77% and 2.96% after blueberry planting. In conclusion, the combination of beneficial bacteria showed a synergistic activity in organic system to promote the blueberry yield, fruit quality, and soil nutrient preservation.

Effect of edible coatings on quality of blueberry fruits under supermarket storage conditions

Blueberry is a nutrient-rich fruit having very high antioxidant activity due to anthocyanin and phenolic compounds. However, its shelf-life is 7-8 days at ambient conditions. Thus, there is an urgent need for extending its shelf-life and availability. In order to increase blueberries shelf-life the most economic and environment friendly technique such as edible coatings stand first. In the present experiment, four edible coatings were used to evaluate their effects on shelf-life and nutrient status of blueberries. Edible coatings such as carboxymethylcellulose (CMC 1%), xanthan gum (0.3%), guar gum (0.75%) and gum Arabic (10%) were coated on the Misty blueberry fruits and then packed in punnet boxes and stored at supermarket condition (18°C and 85-90% RH). During storage, different physical and quality parameters were observed up to 18 days. Our results revealed that, all the coatings were effective in extending storage-life of coated blueberry fruits. Among the coatings, the CMC-coated Misty blueberry fruits exhibited highest score for fruit firmness (2.53 N), total soluble solids (17.52°B) and sensory evaluation score (7.79), and exhibited lowest fruit decay (1.06 %) and lipoxygenase (LOX) activity (3.34 μmoles/min/g FW). Therefore, it can be concluded that CMC (1%) was the most effective coating as it increased the shelf life of Misty blueberry from 9 days (noncoated fruits) to 18 days.

Pollination Efficiency of Managed Bee Species (Apis mellifera and Bombus pauloensis) in Highbush Blueberry (Vaccinium corymbosum) Productivity

Abstract Understanding how bees use the resources provided by crops of massive flowering is essential to develop meaningful agricultural management of plans to maximize the potential of pollination service. We assessed the effect of the pollination carried out by native species Bombus pauloensis and Apis mellifera on the production and quality of blueberry fruits. In this context, we tested the prediction that pollinator assemblages benefit fruit yield. Four treatments were performed: open pollination, B. pauloensis pollination, A. mellifera pollination, and autogamy. For each treatment, the frequency of floral visitors, fruit setting, yield, and quality were evaluated. The results showed that Vaccinium corymbosum L. ‘Emerald’ is highly dependent on entomophilous pollination to obtain optimal production and high-quality fruit, and that pollination with A. mellifera generated the highest proportion of fruit setting (0.80 ± 0.03). The highest seed number was found in open pollinated fruits. This study highlights the effect of the interactions among wild and managed pollinators on the productivity of commercial blueberry fields, and is the first report of B. pauloensis use in blueberry pollination.

Effects of organic manure application on blueberry fruit quality and soil condition

The present study investigated organic manure of southern highbush blueberry cultivated in southwestern China. We studied the efficiency of three organic fertilizers produced from locally accessible resources, namely rapeseed residue (RS-R), cattle manure (Cat-M), and chicken manure (Chi-M). Fruit quality, and soil chemical properties were analyzed. Rapeseed residue at the highest concentrations (2 or 3 kg RS-R plant−1) improved fruit sweetness (total soluble sugar and water-soluble sugar contents) and anthocyanin content, and depressed soil pH.

Improved Postharvest Quality of Cold Stored Blueberry by Edible Coating Based on Composite Gum Arabic/Roselle Extract

The present work aimed at evaluating the efficacy of gum Arabic–based edible coating enriched with red and white roselle extracts, on the postharvest quality of blueberry fruits during storage at 4 ± 0.5 °C. Physicochemical, phytochemicals, antioxidant capability, decay percent, and microbiological analyses of coated and uncoated blueberries were performed. The change rates of polyphenol oxidase (PPO) and guaiacol peroxidase (POD) activity were also measured. The coatings (gum Arabic with or without roselle extract) inhibited the growth of microbes (yeast and mesophilic aerobic bacteria) and enzyme activities (POD and PPO) of blueberries, reduced the degradation of anthocyanins and total phenolic as well as the weight loss and decay, and improved the firmness of blueberries. In comparison with gum Arabic coating, the gum Arabic enriched with roselle extract coating showed better performance on reducing microbes, enzyme activities, and anthocyanins degradation while enhancing the total phenolic content and decreasing the decay percentage. No significant differences were observed between the coated and uncoated blueberries in terms of their antioxidant capacities and pH values (p > 0.05). In conclusion, the combination of gum Arabic and roselle extract as edible coating materials can be used to conserve the quality of blueberry.

Effects of Hot-Air Treatments on the Quality of Blueberry Fruits during Storage

Blueberry 'Tifblue' fruits were hot-air treated at 40, 50, and 60℃, with the aim of extending their storage periods. The effects of different hot-air treatments on the appearance, sugar content, acid concentration, and peel anthocyanin content of the fruits were investigated. The disappearance of the bloom and shriveling of the fruit skin during storage were suppressed by hot-air treatments at 40 and 50℃ for 30 minutes. Changes in the sugar and acid content of the blueberry fruit treated with hot air at 40 and 50℃ were similar to those in control fruits during storage. The anthocyanin content was maintained at the initial value during the storage period by hot-air treatments, while in the control the anthocyanin content decreased during storage. These results suggested that hot-air treatment after harvest was effectively able to extend the storage periods of blueberry 'Tifblue' fruits.

Effect of Forced-air Cooling, Hydrocooling, or their Combination on Fruit Quality of Two Southern Highbush Blueberry Cultivars

Blueberry is widely grown around the world, and the United States is the leading producer. A strategy to maintain fruit quality during commercial handling is rapid cooling using the forced-air system. Hydrocooling (HY) is an effective cooling method widely used for many crops and has potential as a cooling method for blueberry. The objective of this study was to compare the cooling efficiency of conventional forced-air cooling (FA), the current commercial method, with immersion HY alone or HY in combination with FA (HY + FA), and to determine effects on blueberry fruit quality during subsequent cold storage. ‘Emerald’ and ‘Farthing’ southern highbush blueberry were commercially harvested and packed into plastic clamshell containers. FA was accomplished by simulating commercial conditions using a small-scale unit within a cold room at 1 °C/80% relative humidity (RH) until 7/8 cooling was achieved (27 minutes). For HY, fruit in clamshells (125 g) were immersed in chlorinated ice water (200 ppm free Cl−1, pH = 7.0) and 7/8 cooling occurred in 4 minutes. For HY + FA, fruit were 7/8 hydrocooled then transferred to FA for 30 minutes to remove free water from the fruit. After the cooling treatments, clamshells were evaluated weekly for selected quality parameters during 21 days storage at 1 °C. For HY treatment, the 1/2 cooling time was 1.13 minutes for ‘Emerald’ and 1.19 minutes for ‘Farthing’, whereas for FA treatment, the 1/2 cooling times were 4.5 and 6.8 minutes, respectively. For ‘Farthing’, cooling method did not affect fruit firmness; after 21 days, there was a slight softening in fruit from all treatments. However, ‘Emerald’ fruit cooled by HY + FA were softer than those from either HY or FA after 14 days of storage. For all cooling methods ‘Emerald’ was less acidic (0.3% citric acid) and was sweeter [10.2% soluble solids content (SSC)] than ‘Farthing’ (0.6% citric acid, 9.4% SSC). There were no differences in bloom among cooling methods. Bloom ratings for ‘Emerald’ remained >4.5 (70% to 80% coverage) whereas that for ‘Farthing’ cooled by HY or HY + FA was 3.7. Anthocyanin concentration in ‘Emerald’ fruit from HY + FA cooling method decreased by 33% during 21 days of storage, whereas that for ‘Farthing’ remained constant (8.3 mg cyanidin-3-Glicoside/g) irrespective of treatment during storage. Compared with ‘Farthing’, ‘Emerald’ was more sensitive to HY, where ≈15% of fruit developed visual skin breaks (split) after 7 days storage. HY shows potential as an alternative method to rapidly and thoroughly cool southern highbush blueberries such as ‘Farthing’, thus, maintaining fruit quality, while introducing a rinsing and sanitizing treatment. HY needs to be tested on commercial cultivars to determine the incidence of fruit splitting.

Vegetative Growth and Quality of Blueberry Fruit Cultivated in Chihuahua, Mexico

The aim of this investigation was to evaluate the vegetative growth and some physicochemical quality parameters in fruits of different varieties of blueberries grown with amendments applied to the soil. The experimental design was completely randomized according to factorial treatments with nine replications. Length and number of shoots, flower buds number, total soluble solids (TSS), pH, color, total anthocyanins (TA), total phenols (TP) and antioxidant capacity (AC) were evaluated. The application of gypsum, sulphur and compost increased the shoots number in the varieties ‘Bluejay’ and ‘Duke’ with values from 15 and 17.5, respectively. The ‘Duke’ variety was the latest with regard to the flowering stage, evading the problem of frost. Among varieties, ‘Bluejay’ and ‘Blueray’ stood out for presenting fruits with greater acidity and antioxidant capacity (89.1 and 91.5% DPPH inhibition, respectively), however, the TP was higher in ‘Bluejay’ (701.6 mg gallic acid 100 g-1). The use of gypsum, sulphur and compost allows obtaining fruits with high soluble solids content (9.8 °Brix), however, the antioxidant capacity was similar when pine peel was included, with AC values from 91.4 and 88.8% DPPH inhibition, respectively. The amendments such as gypsum, sulphur and compost incorporated into the soil allow an adequate vegetative growth and the obtaining of blueberry fruits with physicochemical quality characteristics acceptable for their commercialization.

Changes in Cuticular Wax Composition of Two Blueberry Cultivars during Fruit Ripening and Postharvest Cold Storage.

Cuticular wax plays an important role for the quality of blueberry fruits. In this study, the cuticular wax composition of two blueberry cultivars, 'Legacy' ( Vaccinium corymbosum) and 'Brightwell' ( Vaccinium ashei), was examined during fruit ripening and postharvest cold storage. The results showed that wax was gradually deposited on the epidermis of blueberry fruits and the content of major wax compounds, except that for diketones, increased significantly during fruit ripening. The total wax content was 2-fold greater in 'Brightwell' blueberries than that in 'Legacy' blueberries during fruit ripening. The total wax content of both cultivars decreased during 30 days of storage at 4 °C, and the variation of cuticular wax composition was cultivar-dependent. The content of diketones decreased significantly in 'Legacy' blueberries, while the content of triterpenoids and aliphatic compounds showed different fold changes in 'Brightwell' blueberries after 30 days of storage at 4 °C. Overall, our study provided a quantitative and qualitative overview of cuticular wax compounds of blueberry fruits during ripening and postharvest cold storage.