Quality Of Blueberries Research Articles

Effect of Hydrogen Cyanamide on Bud Break, Fruit Yield and Quality of Highbush Blueberry in Greenhouse Production

Highbush blueberries need sufficient chilling exposure to induce bud break and flowering, which limits their cultivation in warm areas as well as the profitability of protected cultivation in greenhouses. Hydrogen cyanamide (H2CN2, HC), gibberellic acid (GA3), ethephon (CE), mineral oil (MO), and potassium nitrate (KNO3) are often applied to deciduous fruit trees to advance bud break and fruit set. In this study, experiments were conducted in northeast China to determine the effects of different concentrations of HC or HC in combination with GA3, CE, MO, and KNO3 on bud break, fruit quality, and fruit yield in greenhouse-grown highbush blueberry (Vaccinium corymbosum L.). The results showed that all of the treatment agents could advance bud break by at least 15 days and fruit ripening by 16 days compared to the control. In addition, all treatments could promote the development of flowers and fruits and shorten the flowering and harvest periods. Compared with the control, 0.5% HC or 0.67% HC treatment increased the fruit yield of 5-year-old and 7-year-old bushes, especially early yield. Experiments carried out over two consecutive years in two different varieties, namely ‘M7’ and ‘Brigitta’, further confirmed the positive effect of 0.67% HC application on fruit yield. The results also showed that 0.67% HC had no negative effects on fruit quality. These findings may encourage growers to consider spraying HC in greenhouses to increase fruit yield, especially early yield, in order to schedule the harvest time for a more lucrative marketing period.

Evaluation of the effects of pollination on fruit size and quality of highbush blueberry

Evaluation of the effects of pollination on fruit size and quality of highbush blueberry

Postharvest chitosan treatment on blueberry (Vaccinium corymbosum) quality during long-term cold storage

Postharvest chitosan treatment on blueberry (<i>Vaccinium corymbosum</i>) quality during long-term cold storage

Potential use of atmospheric cold plasma for postharvest preservation of blueberries

Blueberry is one of the major health foods, which is susceptible to microbial contamination during the postharvest storage period. More seriously, the gray mold caused by Botrytis cinerea (B. cinerea) is a major postharvest disease of blueberries. Atmospheric cold plasma (ACP) holds a great potential as an efficient, economical and ecofriendly method for food sterilization. Herein, this study investigated the effects of ACP treatment with different time (0, 5, 10, 15 and 20 min) on the natural decay, gray mold decay caused by B. cinerea, and postharvest quality of blueberries (Vaccinium corymbosum L.) during 10-d storage at 25 ± 2 °C. The results showed that ACP treatment inhibited the native microbial growth and natural decay of blueberries during the storage period. Meanwhile, ACP treatment also exhibited marked inhibitory effects on the spore germination and mycelial growth of B. cinerea in vitro, and gray mold decay in blueberries inoculated with B. cinerea during the postharvest storage. For the postharvest quality, the short-time ACP treatment (≤ 15 min) had minor effects on the firmness, pH, ORP and anthocyanin concentration, but darkened the color and decreased lipid peroxidation, which overall improved the postharvest quality. However, 20-min ACP treatment caused severe oxidative damage to the blueberry peels, resulting in the fruit softening and anthocyanin decrease. Taken together, these results indicate that the short-time ACP treatment may be a promising candidate for the postharvest preservation of blueberries by trading-off between the microbial decay and postharvest quality.

Effects of melatonin on the components, quality and antioxidant activities of blueberry fruits

The effect of melatonin on the components, quality and antioxidant activity in blueberry fruit after harvest were evaluated. ‘Powderblue’ blueberry fruit were treated with sterile water (control) and 0.01, 0.05, 0.25 mmol L−1 melatonin. The results showed that melatonin could effectively delay decrease of fruit firmness and increase of decay incidence and weight loss rate, among which 0.05 mmol L−1 melatonin treatment showed the best blueberry quality. Melatonin treatment could maintain the contents of ascorbic acid, anthocyanin and total phenol, reduce the accumulation of reactive oxygen species and membrane lipid peroxidation. In addition, melatonin treatment also significantly promoted the activities of antioxidant enzymes such as ascorbate peroxidase (APX), glutathione S- transferase (GST) and phenylalanine ammonia-lyase (PAL) in blueberry. Among them, 0.05 mmol L−1 melatonin treatment up-regulated the expression of antioxidant genes VcAPX, VcGST and VcPAL. These findings suggested that the melatonin can improve the antioxidant activity to a certain extent and delay the senescence process of the blueberry fruit.

Wood-based biochar for small fruit production in southern Quebec, Canada

The market for small fruits (grapes, blueberries, strawberries, and raspberries) is valued at more than $100 million CAD per year in Quebec, Canada. Wood-based biochar is an amendment that improves soil quality, which may boost small fruit growth and production. The objective of this research was to determine if wood-based biochar could increase the yield and quality of grape, blueberry, strawberry, and raspberry in southern Quebec. We evaluated the fruit yield as well as the quality parameters like average fruit weight, fruit firmness, color, juice pH, total soluble solids, total phenolic content, and antioxidant activity. Field trials were established on commercial farms with grape, blueberry, strawberry, and raspberry production systems in plots that received wood-based biochar and no biochar in spring (April–May). Small fruits were harvested at their ripening stage for yield and quality evaluation in the fall (July–October). Biochar application did not improve yield and quality parameters of small fruits, except it gave a marginally higher yield of grape (3.7 vs. 4.4 t·ha−1, P = 0.08) and a higher average fruit weight of strawberry (11.9 vs. 13.2 g, P &lt; 0.05). There was no difference in the quality of the fruit from biochar-amended and control plots in the first year of biochar application, possibly because the quality parameters are affected more by weather conditions, handling, and storage than by soil quality. This work suggests that wood-based biochar (&lt;5 t·ha−1) has a limited first-year impact on small fruit yield and quality in southern Quebec, Canada.

Nondestructive detection of decayed blueberry based on information fusion of hyperspectral imaging (HSI) and low-Field nuclear magnetic resonance (LF-NMR)

Decay affects the quality of blueberry. In this paper, information fusion of hyperspectral imaging (HSI) and low-field nuclear magnetic resonance (LF-NMR) were carried out to achieve nondestructive detection of decayed blueberries. The hyperspectral images of the fruit were acquired by HSI system, multi-threshold spectral information segmentation (MT-SIS) algorithm was proposed to segment decayed region of interest (ROI). The competitive adaptive reweighted sampling (CARS) algorithm and successive projections algorithm (SPA) were used to extract the characteristic wavelengths, which were input into partial least squares discriminate analysis (PLS-DA), probabilistic neural network (PNN) and back propagation neural network (BPNN) models to detect decayed fruit. Then the carr-purcell-meiboom-gill (CPMG) sequence of the fruit was acquired by LF-NMR system. T2 relaxation information was obtained, Pearson correlation and Spearman correlation analysis were used to select parameters, which were input into the models to detect decayed fruit. Finally, information of HSI and LF-NMR was fused and input into the models to detect decayed fruit. The results showed that SPA algorithm was used to extract the characteristic wavelengths and Spearman correlation was used to extract the LF-NMR parameters, the BPNN model had the optimal effect in detecting decayed blueberries, the identification accuracy of the training set was 98.33%, and that of the test set was 97.79%. The results showed that it was feasible to fuse the information of HSI and LF-NMR to detect decayed blueberry fruit.

Use of optical coherence tomography and light microscopy for characterisation of mechanical properties and cellular level responses of ‘Centurion’ blueberries during weight loss

Postharvest blueberry softening hinders consumer acceptance and correlates with high moisture loss during storage. Such textural variations have been attributed to factors such as turgor, cell wall modifications and other microstructural changes in the outer cell layers of the fruit. This paper investigates the impact of moisture loss on blueberry quality, as well as the structure and/or function relationships associated with fruit mechanical properties during postharvest using an integrated physical and novel microstructural approach. Four different weight loss conditions [62%, 76%, 93% and 98% relative humidity (RH)] at 5.7 °C were evaluated over a three-week postharvest storage period to assess blueberry mechanical parameters using texture profile analysis (TPA), whilst simultaneously assessing microstructural changes non-destructively by optical coherence tomography (OCT) and destructively by light microscopy. Water loss affected postharvest blueberry cell morphology and resulting texture profile. Increasing weight loss resulted in a reduction in hardness, hardness slope and chewiness but an increase in cohesiveness and springiness. Blueberries stored at 98% RH also showed increasing hardness after storage, as opposed to the softening of fruit observed for the other RH conditions. The 3D OCT images revealed that the layer thickness of the top two cellular layers in the skin of blueberries increased with increasing weight loss as a result of moisture loss and had linear Pearson's correlations with TPA parameters of blueberry. Microscopy more clearly illustrated irregular cell boundaries, increased intercellular spaces, loss of cell integrity and cell collapse during moisture loss. Future work should investigate the chemical compositional changes in the epidermal and sub-epidermal layers of the blueberry stored at low water loss conditions in order to investigate the observed firming effect over the storage period. OCT has the potential to enable non-destructive real-time monitoring of the near-surface internal cellular layers of blueberries. Future work is required to validate the use of OCT as a non-destructive tool for this purpose.

Effect of Intermittent Warming on the Quality and Lipid Metabolism of Blueberry (Vaccinium corymbosum L., cv. Duke) Fruit

The change of lipid metabolism is a key point of blueberry fruit after refrigeration. This study was conducted to evaluate the effects of intermittent warming (IW) of “DuKe” blueberry fruit on its shelf life at 20 ± 0.5°C following 30 days of refrigeration. IW-treated fruit showed higher contents of phosphatidylcholine, linoleic acid, and oleic acid but lower contents of phosphatidic acid and palmitic acid compared to controls. Protective effects on the cell membrane were also reflected as inhibition of the activity of phospholipase D and lipoxygenase. The blueberry fruit showed a lower decay and pitting incidence with higher firmness than control. Interestingly, IW increased C-repeat binding transcription factor gene expression, which can induce the expression of genes related to hypothermia tolerance in plant cells at low temperature. These results indicate that IW can prevent damage to the membrane lipids, which occurs by senescence at a low temperature of blueberry fruit.

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.

Effects of different NH4 +/NO3 - ratios on the photosynthetic and physiology responses of blueberry (Vaccinium spp.) seedlings growth

Nitrogen (N) is an essential nutrient for plant growth, and ammonium (NH4 +) and nitrate (NO3 -) are two main forms of N that plants absorb from the soil. The total N concentration suitable for blueberry (Vaccinium spp.) growth is well known, but we want to know which NH4 +/NO3 - ratio is best for blueberry seedlings. We used solutions contained 3 mM N with seven NH4 +/NO3 - ratios (6/0, 5/1, 4/2, 3/3, 2/4, 1/5, 0/6) to grow Northsky half-high blueberry seedlings. Plant photosynthesis, biomass, physiological characteristics, and N content were measured after 60 days. Blueberry seedlings fertilized with the 5/1 (NH4 +/NO3 -) ratio had the longest shoot and root, the highest leaf photosynthetic rate (Pn), stomatal conductance (Gs), evaporation rate (E), and the lowest intercellular carbon dioxide (CO2) concentrations (Ci) and superoxide dismutase (SOD) activity, among the various treatments. In conclusion, the 5/1 (NH4 +/NO3 -) ratio treatment is recommended to promote the growth and improve the quality of blueberry.

Effects of Nonthermal Plasma-Activated Water on the Microbial Sterilization and Storage Quality of Blueberry

Effects of Nonthermal Plasma-Activated Water on the Microbial Sterilization and Storage Quality of Blueberry

Evaluation of Pressurized Inert Gas Treatments on the Postharvest Quality of Blueberries

This study investigated the efficacy and mechanism of pressurized inert gas treatment for the quality preservation and shelf life extension of fresh blueberries. The change of physiological metabolisms and surface microbial attributes of pressurized gas-treated blueberries during 4 °C storage were measured over a 12-day period. Compared with the control group (without treatment), the pressurized inert gas treatments with argon, carbon dioxide, and nitrogen could effectively suppress the rate of respiration and ethylene production, reduce the water loss, and avoid softening and anthocyanin degradation in the blueberries. Meanwhile, the surface color, citric acid content, and soluble solid content in the blueberries were well maintained during the storage. Pressurized inert gas-treated blueberries carried significantly (P < 0.05) less microbial populations (yeast, mold, and bacteria) than those without the treatments. The findings from this study indicated that pressurized inert gas treatment could effectively preserve the quality and potentially be applied for the shelf life extension of fresh blueberries.

Evaluation of the effects of immersion thawing methods on quality of blueberries

AbstractThe changes on food quality during thawing process has attracted significant attention of the frozen food industry. The effects of immersion thawing on the quality changes of blueberries were investigated. Blueberries were stored in freezing temperature for 3 days after quick freezing, and then, they were thawed using four methods: water immersion thawing (WIT), sugar immersion thawing (SIT), ultrasound‐assisted water immersion thawing (UAWIT), and ultrasound‐assisted sugar immersion thawing (UASIT). Later, texture profile, physiochemical characteristics, and sensory evaluation analysis were conducted to evaluate quality changes of blueberry after thawing. The thawing procedure employed significantly affected the quality of fruits. The shortest duration for total thawing was observed for the UASIT process. The anthocyanins and total solid content were better retained when blueberries were thawed using SIT and UASIT processes. There was no benefit of using UASIT with respect to protecting the blueberry tissue structure. However, the consumer acceptability of blueberries was not significantly difference among the four thawing conditions. Each method had advantages and disadvantages, and we should choose the suitable means according to consumer and production demand.Practical applicationThis work was aimed at determining if there were any changes on the quality of blueberries when subjected to various thawing treatments. The sugar immersion thawing could be beneficial to nutrient retention in the freezing and thawing processing of fruits.

Changes of the Aroma Composition and Other Quality Traits of Blueberry 'Garden Blue' during the Cold Storage and Subsequent Shelf Life.

The changes of volatile composition and other quality traits of blueberry during postharvest storage were investigated. Blueberries were packaged in vented clam-shell containers, and stored at 0 °C for 0, 15 and 60 days, followed by storage at room temperature (25 °C) for up to 8 days for quality evaluation. The firmness, pH, and total soluble solids increased by 8.42%, 8.92% and 42.9%, respectively, after 60 days of storage at 0 °C. Titratable acidity decreased 18.1% after 60 days of storage at 0 °C. The volatile change was monitored using headspace–solid-phase microextraction–gas chromatography–quadrupole time-of-flight–mass spectrometry (HS-SPME-TOF-MS) and off-odor was evaluated by sensory panel. Volatile compounds generally showed a downward trend during cold storage. However, the subsequent shelf life was the most remarkable period of volatile change, and was represented by the strong fluctuation of ethyl acetate and the rapid decrease of terpenoids. Extending storage from 15 to 60 days under cold condition still resulted in an acceptable odor. However, subsequent storage at higher temperature resulted in a quick deterioration in sensory acceptability. The results proved that cold storage was a reliable way to maintain the quality of blueberry, and flavor deterioration during subsequent shelf life was more fatal to the blueberry flavor.

Inactivation of Listeria innocua on blueberries by novel ultrasound washing processes and their impact on quality during storage

We explored the efficacy of ultrasound in combination with carvacrol and carbonated water as a treatment to decontaminate fresh produce using blueberries as a model system. We also evaluated its impact on the quality of blueberries during refrigerated storage. Blueberries inoculated with Listeria innocua, a model pathogen, were washed in presence of individual treatments by either 20 kHz ultrasound at (20 kHz), 1 MHz ultrasound at (1 MHz), 2 mM carvacrol (CR), or carbonated water (CW) as well as their combinations at 20 °C for 10 min. Individual treatments resulted in around 2 log CFU/g L. innocua reductions on the blueberries' surface with 3–4 log CFU/mL viable bacteria remaining in the wash water. Comparatively, both 20 kHz + CR and 1 MHz + CR + CW led to significantly lower (P < 0.05) bacterial counts on blueberries’ surface (~1 log additional reduction) with 2.6 and 2.9 log CFU/mL in the washed water. 20 kHz + CR and 1 MHz + CR + CW treatments were selected to further investigate their effects on blueberry quality compared to washing with sodium hypochlorite (SH) containing 100 ppm free chlorine, or water during subsequent 4 °C storage for up to 20 days. Unwashed blueberries were used as control. Blueberries washed by selected treatments had equal or lower (P < 0.05) total aerobic and total mold and yeast counts compared to those treated by water, SH and the control. There was no influence of ultrasound washing processes on the total phenolic content and total anthocyanin content of blueberries, however, a significant impact on color and texture was observed. The findings showed that washing blueberries with novel combined ultrasound washing processes have the potential to enhance the safety and shelf-life of ready-to-eat blueberries.

Development of a Novel Phenotypic Roadmap to Improve Blueberry Quality and Storability.

Improved fruit quality and prolonged storage capability are key breeding traits for blueberry (Vaccinium spp.) fruit. Until now, breeding selection was mostly oriented on the amelioration of agronomic traits, such as flowering time, chilling requirement, or plant structure. Up until now, however, the storage effect on fruit quality has not been extensively studied, mostly because objective and handy phenotyping tools to evaluate quality traits were not available. In this study we are proposing a novel phenotyping protocol to support breeding selection and quality control within the entire blueberry production chain. Volatile organic compounds (VOCs) and texture traits, were measured by Proton Transfer Reaction- Time of Flight- Mass Spectrometry (PTR-ToF-MS) and a texture analyzer respectively, taking into consideration the influence of prolonged storage. The exploitation of the genetic variability existing within the investigated blueberry germplasm collection (including both southern and northern highbush, hybrids, and rabbiteyes) allowed the identification of the best performing cultivars, based on texture and VOCs variability, to be used as superior parental lines for future breeding programs. The comprehensive characterization of blueberry aroma allowed the identification of a wide array of spectrometric features, mostly related to aldehydes, alcohols, terpenoids, and esters, that can be used as putative biomarkers to rapidly evaluate the blueberry aroma variations related to genetic differences and storability. In addition, this study revealed a lack of straightforward relationship between harvest and postharvest quality features, that might be genotype-dependent.

Concentración de la solución nutritiva y su relación con la producción y calidad de arándano azul

La producción, calidad y concentración nutrimental foliar del arándano azul (Vaccinium corymbosum L.) cv. Biloxi de bajo requerimiento de frío fue evaluada en cultivo hidropónico, empleando diferentes concentraciones de solución nutritiva. El ensayo se realizó en un invernadero tipo semitúnel, con cubierta de plástico, sistema de ventilación pasivo con apertura cenital y lateral, y sin control climático. Se emplearon plantas de arándano de un año de edad, provenientes de cultivo in vitro, y fueron colocadas en contenedores de plástico flexible de 15 L de capacidad con roca basáltica volcánica roja como sustrato, con un marco de plantación de 2 m entre hileras y 0,5 m entre plantas. El diseño experimental fue completamente al azar, con cuatro tratamientos y cinco repeticiones, y cada repetición tuvo cuatro plantas, lo que dio un total de ochenta plantas. Se evaluaron cuatro concentraciones de solución Steiner modificada (0,5; 1,0; 1,5 y 2,0 dS/m). Las variables evaluadas fueron producción y calidad de fruto, y se consideró tamaño, pH, sólidos solubles totales y firmeza, así como la concentración foliar de macronutrimentos en cada etapa fenológica. Se concluyó que el arándano azul cv. Biloxi es sensible a la salinidad del medio de crecimiento. Se determinó que, cuando el valor de conductividad eléctrica (CE) es mayor a 1,0 dS/m, afecta el crecimiento, producción y calidad del arándano; sin embargo, se puede utilizar una solución nutritiva con CE entre 0,5 y 1,0 dS/m sin afectar el rendimiento y la calidad de fruto, ni los niveles de concentración nutrimental foliar en cultivo hidropónico.

Effects of 5-ALA on Fruit Quality of Blueberry Cultivated in Different Modes

This experiment used southern highbush blueberry as material to study the effects of different concentrations (0, 2000, 2500, 3000 times) of 5-ALA on fruit quality of blueberry grown in three different modes at fruit bearing period. The results showed that: (1) Rain-proof cultivation and greenhouse cultivation could significantly increase the yield of blueberry, but reduce the intrinsic fruit quality of blueberry; (2) The fruit quality of blueberry was affected by the interaction of cultivation mode and concentration of 5-ALA amino acid water-soluble fertilizer.

Influence of sulfur dioxide-emitting polyethylene packaging on blueberry decay and quality during extended storage

Abstract Blueberries are highly susceptible to decay after harvest and application of sulfur dioxide (SO2) has been shown to effectively control decay during extended storage. Box liners are in commonly used with other commodities to reduce water loss. In 2017 three varieties, ‘Emerald’, Jewel’ and ‘Misty’, were obtained from commercial packing houses. They were contained in plastic clamshells with 12 clamshells per box. We examined: 1) two liners that continuously emitted SO2 from sodium metabisulfite incorporated into the liner film. These ventilated with holes that comprised 0.3 % or 0.9 % of the liner surface area; 2) two solid, non-ventilated liners designed to develop a modified atmosphere (MA) during storage, either alone or with SO2 emitting sheets inside the packages within the liners; 3) control packages without liners. After packaging the fruit were placed into storage for either 3 or 6 weeks and then evaluated for decay and fruit quality. The effect on decay was determined both by assessing natural decay and by determining the spread of decay from berries inoculated with Botrytis cinerea. In 2018 two varieties, ‘Draper’ and ‘Duke’ were tested in a similar manner, except a 0.1 % vented liner replaced the 0.9 % liner, which performed poorly in 2017, and the SO2-emitting sheets were not included as a treatment. In 2018 we measured concentrations of SO2 and atmospheric gases were monitored within the packages. Results from both years indicated that the SO2-emitting liners were effective in reducing natural decay and the spread of aerial mycelial growth of B. cinerea from inoculated berries compared to treatments without SO2. Treatments that combined SO2 and MA (SO2/MA) were the most effective. MA alone did not consistently control decay. The high level of effectiveness of the SO2/MA treatment in controlling decay may be due to higher humidity levels within the packages that would enhance SO2 activity, because SO2 concentrations did not differ among the liner types and concentrations of CO2 in the MA packaging were too low to have had much effect. Weight loss was significantly less in packaging with liners with less vent area, with the least being in the MA packaging, regardless of the presence of SO2. Less weight loss was associated with reduced shrivel, although firmness was not always greater. SO2 concentrations measured in 2018 did not exceed 10 μL L-1 and bleaching of the berries did not occur in either year. SO2-emitting liners are an effective means of preserving blueberry quality during extended storage, particularly when combined with MA. The simplicity of assembling a package with a single liner versus using a conventional liner followed by a SO2-emitting sheet could be of benefit to blueberry packers.