•Cuticle and scar permeance of fruit varied two- and three-fold among breeding lines.•Scar area was 0.19–0.74% of berry surface, leading 39–67% of whole fruit water loss.•Scar sealing increased ...firmness retention but benefit was less at 0°C than 20°C.•Influence of the stem scar on water loss increased as temperature declined.•Some lines have much lower water loss via the stem scar than predicted.
The role of fruit scar on water loss from fresh harvested, fully blue highbush blueberry (Vaccinium corymbosum L.) fruit was studied on three germplasm lines from each of three half-sib families at University of Talca, Chile. The stem scar of half of the harvested fruit was sealed using nail polish and weight loss of sealed and non-sealed fruit determined daily at 20°C (5 d storage) and bi-weekly at 0°C (15 d storage). Fruit firmness was determined at the end of the storage period. The stem scar accounted for approximately 40% of the moisture lost at 20°C, but percentages varied considerably between lines. While the stem scar covered 0.19% to 0.74% of the fruit surface area, its rate of transpiration was 170-times higher than for the cuticle at 20°C. The larger the fruit scar area, the greater was the absolute rate of water loss, but scar size scar did not affect the rate of weight loss expressed on a per gram fruit basis. Higher levels of water loss were associated with a greater loss in firmness; fruit having a large scar had a greater rate of water loss and were less firm than those having medium or small scars. The water permeance of the fruit cuticle varied two-fold and the apparent permeance of the scar varied three-fold among the 9 lines evaluated when held at 20°C. Interestingly, one line exhibited a 75% lower rate of water loss from its stem scar than the other lines than would be predicted based on its scar diameter. Storage at 0°C reduced the rate of water loss by 90% but the cuticle permeance was not affected by temperature. Sealing the stem scar increased fruit firmness retention at 0°C and 20°C, but provided less benefit at 0°C vs. 20°C. The highly variable nature of water loss through the stem scar and the cuticle in this study suggests that large gains in reductions in water loss are possible for the highbush blueberry once the mechanisms for transpiration are better understood.
Fresh blueberries are very susceptible to mechanical damage, which limits postharvest life and firmness. Softening and susceptibility of cultivars "Duke" and "Brigitta" to developing internal ...browning (IB) after mechanical impact and subsequent storage was evaluated during a 2-year study (2011/2012, 2012/2013). On each season fruit were carefully hand-picked, segregated into soft (<1.60 N), medium (1.61-1.80 N), and firm (1.81-2.00 N) categories, and then either were dropped (32 cm) onto a hard plastic surface or remained non-dropped. All fruit were kept under refrigerated storage (0°C and 85-88% relative humidity) to assess firmness loss and IB after 7, 14, 21, 28, and 35 days. In general, regardless of cultivar or season, high variability in fruit firmness was observed within each commercial harvest, and significant differences in IB and softening rates were found. "Duke" exhibited high softening rates, as well as high and significant
between firmness and IB, but little differences for dropped vs. non-dropped fruit. "Brigitta," having lesser firmness rates, exhibited almost no relationships between firmness and IB (especially for non-dropped fruit), but marked differences between dropping treatments. Firmness loss and IB development were related to firmness at harvest, soft and firm fruit being the most and least damaged, respectively. Soft fruit were characterized by greater IB development during storage along with high soluble solids/acid ratio, which could be used together with firmness to estimate harvest date and storage potential of fruit. Results of this work suggest that the differences in fruit quality traits at harvest could be related to the time that fruit stay on the plant after turning blue, soft fruit being more advanced in maturity. Finally, the observed differences between segregated categories reinforce the importance of analyzing fruit condition for each sorted group separately.
•Cumulative frequency distributions suggest E side would produce softer fruit.•E side of the plant produced more blue fruit at harvest and more total fruit production.•Six days of harvest delay ...increased the amount of soft and very soft fruit.
For blueberry, harvest readiness is based on skin color, with fruit being considered ready to pick when the berry skin reaches 100% blue coverage. The extended bloom period for the blueberry inflorescence and uneven developmental rates can yield fully blue fruit that are widely different in physiological maturity, at any given harvest date. The objective of this study was to determine the inherent variability in the firmness of a synchronized cohort of blueberry fruit and the effects of harvest delay and position within the canopy on fruit characteristics at harvest and after refrigerated storage. During two consecutive seasons, the harvest canopy of ‘Duke’ and ‘Brigitta’ was divided into two regions as east (E) and west (W) sides. Fruit of a specific developmental stage from each side were either harvested when reaching 100% blue coverage (ripe fruit: B100) or allowed to stay on the plant for six additional days (over-ripe fruit: B100+6). Despite the narrow period of time elapsed between harvests of ripe and over-ripe fruit, variation in firmness was extensive, with decreases up to 24%, depending on year and cultivar. The six days of additional development were enough to increase the amount of soft and very soft fruit at harvest and after storage, demonstrating the importance of frequent harvests to improve firmness at final destinations. Both the percentage of blue fruit at each harvest date and total fruit produced were higher on the E side of the plant. Year-to-year variation in firmness exceeded that caused by the imposed treatment, which highlights the need to understand the environmental factors contributing to fruit softening. This is the first report on in-plant fruit variability for blueberry and its effect on postharvest performance.
Bitter pit (BP) is one of the most relevant post-harvest disorders for apple industry worldwide, which is often related to calcium (Ca) deficiency at the calyx end of the fruit. Its occurrence takes ...place along with an imbalance with other minerals, such as potassium (K). Although the K/Ca ratio is considered a valuable indicator of BP, a high variability in the levels of these elements occurs within the fruit, between fruits of the same plant, and between plants and orchards. Prediction systems based on the content of elements in fruit have a high variability because they are determined in samples composed of various fruits. With X-ray fluorescence (XRF) spectrometry, it is possible to characterize non-destructively the signal intensity for several mineral elements at a given position in individual fruit and thus, the complete signal of the mineral composition can be used to perform a predictive model to determine the incidence of bitter pit. Therefore, it was hypothesized that using a multivariate modeling approach, other elements beyond the K and Ca could be found that could improve the current clutter prediction capability. Two studies were carried out: on the first one an experiment was conducted to determine the K/Ca and the whole spectrum using XRF of a balanced sample of affected and non-affected 'Granny Smith' apples. On the second study apples of three cultivars ('Granny Smith', 'Brookfield' and 'Fuji'), were harvested from two commercial orchards to evaluate the use of XRF to predict BP. With data from the first study a multivariate classification system was trained (balanced database of healthy and BP fruit, consisting in 176 from each group) and then the model was applied on the second study to fruit from two orchards with a history of BP. Results show that when dimensionality reduction was performed on the XRF spectra (1.5 - 8 KeV) of 'Granny Smith' apples, comparing fruit with and without BP, along with K and Ca, four other elements (i.e., Cl, Si, P, and S) were found to be deterministic. However, the PCA revealed that the classification between samples (BP vs. non-BP fruit) was not possible by univariate analysis (individual elements or the K/Ca ratio).Therefore, a multivariate classification approach was applied, and the classification measures (sensitivity, specificity, and balanced precision) of the PLS-DA models for all cultivars evaluated ('Granny Smith', 'Fuji' and 'Brookfield') on the full training samples and with both validation procedures (Venetian and Monte Carlo), ranged from 0.76 to 0.92. The results of this work indicate that using this technology at the individual fruit level is essential to understand the factors that determine this disorder and can improve BP prediction of intact fruit.
Firmness is the most relevant attribute in blueberries and softening is the main obstacle for long distant shipments (>45 d). The main cause of softening is dehydration, which occurs through the ...stem-scar and the cuticle of the fruit. The evolution of firmness during postharvest depends on the sum of the environmental conditions (E) and the agronomic managements (M) occurring along growth and development of the fruit, interacting with the genotype (G). This results in an interrelationship (G×E×M) that impacts postharvest softening, being E×M in the case of blueberries, as relevant as G. Specially, because the asynchrony in fruit set and ripening implies that any stimulus, (E or M) will have a different impact, depending on the stage of development of each fruit within the cluster. Finally, given the harvest index based on color, fruit of similar appearance may have different physiological maturity. All this results in a great variability of firmness within a lot, which, together with a random distribution of the berries into the clamshell (different proportion of exposed epidermis and stem-scars inside the commercial unit), would prevent firmness at harvest from being a good predictor of the final condition at destination. Considering the close association between water loss and softening in storage, and the relevance of the pedicel scar in dehydration of fruit until consumption, this article reviews the elements that support a change in the paradigm of the relevance of firmness values at harvest, both for the industry and researchers. The main argument is that by measuring the rate of dehydration, a better estimate of fruit behavior in storage could be obtained. Consequently, different patterns of water loss would be expected when fruit are exposed at various RH, assuming that the rate of dehydration at each RH would be a simplified characterization of the in-season impact of G×E×M on final postharvest condition. Over the seasons, a history of G×E×M can be constructed to make decisions, of the best destination to be reached with a required firmness, by an early estimation of the maximum potential water loss.
•Blueberry firmness is not enough to estimate postharvest softening.•Great variability of firmness within a clamshell•GxExM makes it difficult to predict a pattern of firmness loss
Fresh blueberries are prone to softening and dehydration during postharvest, which limits their competitiveness when reaching the final markets. Commercial cultivars ‘Duke’ and ‘Brigitta’ exhibit ...contrasting softening patterns. Although ‘Duke’ berries usually show higher firmness levels at harvest as compared to ‘Brigitta’, they display higher softening and weight loss rates after cold storage. The aim of this study was to evaluate the physicochemical changes and modifications in cuticle composition of ‘Duke’ and ‘Brigitta’ blueberries across five developmental stages: green (G), 25 and 50% pink (25P, 50P), and 75 and 100% blue (75B, 100B), to determine those characters with the most influence on their postharvest behavior. For each developmental stage, maturity parameters, respiration, and ethylene production rates were assessed, and cuticular wax and cutin were analyzed. Principal component analysis (PCA) revealed that ‘Duke’ berries were characterized by higher respiration and ethylene production rates, while ‘Brigitta’ showed higher contents of oleanolic acid and α-amyrin over total waxes. The results suggest that larger surface/volume ratios and higher amounts of ursolic acid and lupeol in ripe fruit may underlie higher weight and firmness loss rates of ‘Duke’ berries as compared to ‘Brigitta’.
Applications of N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU) can increase blueberry (Vaccinium corymbosum L.) yield and fruit size, but their impact on postharvest is unknown. We studied repeated CPPU ...applications effects on yield and quality (harvest, postharvest), over 2 yr on mature 'Duke' plants in South-Central Chile. The first year, 5 or 10 mL L^sup -1^ CPPU was applied at 3, 10, and/or 17 d after full bloom (DAFB) plus a non-sprayed control. The second year, 5 or 10 mL L^sup -1^ CPPU were sprayed 10 and 17 DAFB plus a control. The first year, only 10 mL L^sup -1^ CPPU sprayed 3+17 DAFB increased yield (32.5% > control); 10 mL L^sup -1^ CPPU applied 10 or 3+17 DAFB had highest fruit diameter; and 10 mL L^sup -1^ CPPU at 17 DAFB or at 3+10+17 DAFB had highest soluble solids. Overall, 10 mL L^sup -1^ CPPU applied 3+17 DAFB, was the best treatment for year one, since it increased fruit yield and diameter, while soluble solids and postharvest weight loss were similar to control. The second year, 10 mL L^sup -1^ CPPU reduced fruit coloration (blue color coverage index: BCCI) and soluble solids, but not firmness at harvest. This rate increased berry weight (24.2%) and fruit wax (59% > wax coverage index: WCI) at harvest. Harvest and postharvest WCI increased consistently as CPPU rate increased. CPPU reduced fruit rotting (15% at 45+5 evaluation). During storage, CPPU-treated-fruit had a slower decrease in firmness (30.5% < control at 30+1), but no difference at 30+5. CPPU-treated-fruit usually had higher post harvest soluble solids. Ten mL L^sup -1^ CPPU retarded color evolution at harvest and at 30+1, but not at 30+5, 40+1 or 40+5.
The goal of this research was to evaluate the effect of different doses of peroxyacetic acid on the productivity of watercress (Nasturtium officinale R. Br.) cultivated hydroponically using a ...constant nutritive solution. Green chemistry in protected horticulture seeks compatibility with the environment through the creation of biodegradable byproducts. In hydroponics, appropriate doses of peroxyacetic mixtures deliver these byproducts while also oxygenating the roots. Watercress producers who recirculate the nutritive solution can use these mixtures in order to increase oxygenation in the hydroponic system. The experiment took place between August and December 2009, beginning with the planting of the watercress seeds and concluding with the completion of the sensory panels. A completely random design was used, including three treatments and four repetitions, with applications of 0, 20 and 40 mg L(-1) of the peroxyacetic mixture. Measured variables were growth (plant height, leaf length and stem diameter), yield (weight per plant and dry matter) and organoleptic quality (color and sensory panel). The application of 40 mg L(-1) of the peroxyacetic mixture had a greater effect on the growth and development of the plants, which reached an average height of 29.3 cm, stem diameter of 3.3 mm and leaf length of 7.6 cm, whereas the control group reached an average height of only 20.2 cm, stem diameter of 1.9 mm and leaf length of 5.7 cm. The application of the peroxyacetic mixtures resulted in an improvement in growth parameters as well as in yield. Individual weights achieved using the 40 mg L(-1) dose were 1.3 g plant(-1) in the control group and 3.4 g plant(-1) in the experimental group (62% yield increase). Sensory analysis revealed no differences in organoleptic quality.
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•First report characterizing blueberry fruit cuticular triterpenes.•Ursolic acid was positively correlated to weight loss and softening after storage.•Lupeol was the main triterpene, ...while α-amyrin was only present in Briggita.•Duke, firmer at harvest, was highly affected by harvest delay compared to Brigitta.
Chilean fresh blueberries take 20–50days to arrive by boat to the Northern hemisphere, softening and dehydration being the main defects upon arrival. The effect of maturity at harvest (75% blue, 100% blue, and overripe) on cuticular triterpene content, and the possible associated impacts on firmness and weight loss after cold storage were explored for ‘Duke’ and ‘Brigitta’ fruit, both non-bagged or bagged in macro-perforated low-density polyethylene bags. Softening and weight loss varied with cultivar and maturity stage: ‘Duke’ fruit softened faster and were more prone to dehydration than ‘Brigitta’ samples, whereas overripe fruit were less firm after storage. This is the first report characterizing the triterpenoid fraction in cuticles of fresh blueberries, which may play a role in their postharvest behavior. Weight loss and softening rates were highly correlated to ursolic acid contents at harvest; further research will be required for a better understanding of these relationships.
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