Effect of harvest maturity and cold storage on correlations between fruit properties during ripening of apricot (Prunus armeniaca)

Apricots (Prunus armeniaca) were held in air storage at 0 °C and ripened at 20 °C, or ripened at 20 °C straight after harvest, and changes in fruit quality quantified using postharvest and sensory evaluations. Maturity at harvest significantly affected flesh firmness and other quality factors. Mealiness and gel formation only developed in fruit that had been stored at low (0 °C) temperatures. Mealiness did not develop until firmness dropped below approximately 20 N, whereas gel formation began to develop when firmness was as high as 35 N. Development of mealiness and loss of juiciness were correlated; however, slight mealiness was perceived when fruit were still considered juicy. Specific cultivar-related differences were evident in the changes in firmness and development of gel formation during and after cold storage. Fruit were less liked by the sensory panel when firmness dropped below 20 N, as juiciness decreased and mealiness and gel formation increased. Cell wall studies showed changes in yields of water-soluble and CDTA (trans-1,2-cyclohexanediamine tetraacetic acid)-soluble pectin. In fruit ripened after cold storage, mealiness and gel formation was accompanied by an increase in water-soluble pectin and an increase in CDTA-soluble pectin, whereas in apricots ripened straight after harvest, water-soluble pectin increased but CDTA-soluble pectin slightly decreased. All fruit, regardless of maturity or having chilling disorders or not, fitted the same correlation between firmness and uronic acid content of water-soluble pectin, but no pattern was evident for CDTA-soluble pectin. We concluded that the increasing solubilisation of pectin was a major feature of fruit softening in apricot, whereas the differences in CDTA-soluble pectin may reflect differences in strength of cell adhesion.     

Changes in postharvest physicochemical and sensory characteristics of hardy kiwifruit (Actinidia arguta and its hybrid) after cold storage under normal versus controlled atmosphere

Changes in sensory and physicochemical characteristics of fruit of Actinidia arguta and its hybrid after cold storage (1 °C and 85%RH) in air (AS) versus controlled atmosphere (CA) with low oxygen concentration (1.5%O₂ + 1.5%CO₂) were examined over a period of four and eight weeks. The investigation was carried out on two cultivars, ‘Ananasnaya’ (A. arguta) and ‘Bingo’ (Actinidia purpurea × A. arguta) harvested at two stages of maturity (6.5–8% and 8–9.5% soluble solids, respectively). During long-term storage the strongest changes in fruit characteristics were in fruit firmness and acidity. Air storage was an adequate method of refrigerated storage of fruit over a short period of 4 weeks. Application of CA can be very useful for storing hardy kiwifruit over a longer, 8 week period. The sensory characteristics of fruit stored in CA and then ripened during simulated shelf-life were similar to those of vine ripe fruit. The most significant negative change in the sensory characteristics of fruit after long-term cold storage was the increase in the intensity of their bitter taste.     

Relationships between the instrumental and sensory characteristics of four peach and nectarine cultivars stored under air and CA atmospheres

‘Big Top’ and ‘Venus’ nectarines and ‘Early Rich’ and ‘Sweet Dream’ peaches were picked at commercial maturity and stored for 20 and 40 d at −0.5 °C and 92% RH under either air or one of the three different controlled atmosphere regimes (2 kPa O₂/5 kPa CO₂, 3 kPa O₂/10 kPa CO₂ and 6 kPa O₂/17 kPa CO₂). Physicochemical parameters and volatile compounds emission were instrumentally measured after cold storage plus 0 or 3 d at 20 °C. Eight sensory attributes were assessed after cold storage plus 3 d at 20 °C by a panel of 9 trained judges, in order to determine the relationship between sensory and instrumental parameters and the influence of storage period and cold storage atmosphere composition on this relationship.A principal component analysis (PCA) was undertaken to characterize the samples according to their sensory attributes. PCA results reflected the main characteristics of the cultivars: ‘Big Top’ was the nectarine cultivar with the highest values for sweetness, juiciness and flavor; ‘Sweet Dream’ was the sweetest peach and was characterized by high values for crispness and firmness, while ‘Venus’ and ‘Early Rich’ were characterized by their sourness. To assess the influence of storage period and CA composition on sensory properties, a PLS model of the flavor of the different samples was constructed using standard quality attributes and volatile concentrations as the X-variables. The model with 2 factors accounted for more than 80% of flavor variance. PLS results indicated that the main influence on flavor perception was storage period. Atmosphere composition also had an influence on flavor perception: flavor perception decreased from samples stored in a 2/5 O₂/CO₂ atmosphere composition to those of 3/10 and 6/17. These results can be qualitatively extended to juiciness and sweetness since all these sensory properties were strongly correlated.     

Effects of cold storage and shelf-life on sensory quality and consumer acceptance of ‘Abate Fetel’ pears

Fruit products certified by quality labels should guarantee high levels of consumer acceptance, despite the unavoidable variability arising from growing conditions and postharvest responses. The quality of ‘Abate Fetel’ pear (Pyrus communis L.) fruit was studied, after short or long cold storage, by analysis of physicochemical, texture and flavour traits, to investigate factors affecting consumer acceptance. Fruit from three orchards differing in location and design, monitored during 10 d of ripening at 20 °C, softened progressively to reach and exceed firmness adequate for consumption. Change in colour, in particular hue angle, paralleled softening. Sensory traits were investigated by evaluating fruit of three different firmness levels within the range of acceptable eating quality. Firmness differences were clearly perceived both by expert judges and by consumers, but did not influence the degree of liking. ‘Abate Fetel’ pear can maintain acceptable eating quality at 20 °C for 4–8 d after 13 weeks storage at ?1 °C, or 2–6 d after 23 weeks storage at ?1 °C. Changing texture parameters were perceived at eating, without compromising overall quality. Production system affected intrinsic quality parameters such as total soluble solids concentration, but did not influence consumer acceptance. In consumer tests conducted after 13 weeks of cold storage, high scores were recorded, with a 86% acceptance frequency and more than 40% of scores reflecting “like very much” or “like extremely”. After 23 weeks of cold storage a decrease in degree of liking was observed. The overall value of ‘Abate Fetel IGP Emilia-Romagna’ quality label was confirmed by consumer evaluations. However, the decrease in consumer acceptance after 23 weeks of cold storage indicates that caution should be used in using long storage durations.     

Volatile profiles of ripening West Indian and Guatemalan-West Indian avocado cultivars as affected by aqueous 1-methylcyclopropene

Separate experiments were conducted with three major commercial avocado (Persea americana Mill.) cultivars grown in Florida: ‘Simmonds’ (early-season, West Indian race); ‘Booth 7’ (mid-season, Guatemalan-West Indian hybrid); and ‘Monroe’ (late-season, Guatemalan-West Indian hybrid). Fruit were harvested at preclimacteric stage and left untreated (Control) or treated 24 h after harvest with aqueous 1-methylcyclopropene (1-MCP) at 1.39 (treatment M1) or 2.77 μmol L⁻¹ a.i. (treatment M2) (75 or 150 μg L⁻¹) for 1 min at 20 °C. Whole fruit ripening was monitored at 20 °C/92% ± 3% R.H. and based on whole fruit firmness, respiration and ethylene evolution. Fruit volatiles were assessed at preclimacteric (24 h after harvest), mid-ripe (half of initial fruit firmness) and ripe maturity stages, from 100 g of chopped pulp using a purge and trap system. Untreated, firmer fruit ‘Monroe’ (268 N at harvest) ripened within 12 d of harvest while softer fruit ‘Simmonds’ (118 N) ripened within only 6 d. 1-MCP treatment extended ripening time from 33% (M1) to 83% (M2). All fruit softened normally, indicating the potential benefits of aqueous 1-MCP as a postharvest treatment for avocado when applied at these concentrations. Volatile profiles differed among the three cultivars with several compounds detected in only one cultivar, results that may contribute to a potential identification of the origin of the cultivar based on fruit volatile composition. The West Indian cultivar ‘Simmonds’ had much higher emission of hexanal (preclimacteric fruit) and cis-3-hexenal and cis-3-hexen-1-ol (ripe fruit) than the Guatemalan-West Indian hybrids ‘Booth 7’ and ‘Monroe’. On the other hand, these latter hybrids had much higher levels of alkanes than ‘Simmonds’. Treatment with 1-MCP increased emissions of alkanes during ripening of ‘Booth 7’ and ‘Monroe’. Total volatiles of avocado decreased during ripening mainly due to the significant reduction of sesquiterpenes, the main group of volatiles in all cultivars at harvest (‘Simmonds’, 53%; ‘Booth 7’, 78%; ‘Monroe’, 66%). β-Caryophyllene was the major compound at harvest, but decreased to less than 2% in ripe fruit, at which point most sesquiterpenes were not detected. Among the 10 sesquiterpenes commonly found in the avocado cultivars in this study, only α-Copaene had significantly higher emissions in mid-ripe fruit treated with the higher concentration of 1-MCP (2.77 μmol L⁻¹ a.i.), suggesting that ethylene participates in the regulation of this sesquiterpene.     

Quantitative determination of flesh mealiness in peach [Prunus persica L. (Batch.)] through paper absorption of free juice

A simple and rapid method was developed for quantitative determination of juiciness in peach flesh based on the absorption of free juice with ordinary absorbent paper after a flesh sample is squeezed by two metallic rolling cylinders. Juiciness data were compared with trained panel determinations on three peach cultivars kept at 4 °C and 90% RH for 7, 14 and 21 d plus a ripening period at 20 °C and 65% RH until the flesh reached 19.6 ± 9.2 N. There was a high correlation between panel judgment and paper absorption (r² = 0.75 in ‘Elegant Lady’, 0.77 in ‘O’Henry’ and 0.93 in ‘Ross’). A sub-sample of the juiciest and the mealiest fruit also were sorted after 14 and 21 d in cold storage. ‘Ross’, a non-melting peach cultivar, did not develop flesh mealiness during any evaluation period. During storage, there was a reduction in juiciness reaching 15% less after 21 d. Mealy fruit were exclusively observed with melting cultivars exposed to cold storage. The proposed method for determining juice content is easily executed and shows a high association with human perception of juiciness and mealiness in peach.     

Use of equilibrium modified atmosphere packaging for preservation of ‘San Antonio’ and ‘Banane’ breba crops (Ficus carica L.)

The purpose of this work was to study the effect of equilibrium modified atmosphere packaging on the stability of ‘San Antonio’ and ‘Banane’ breba fruit during postharvest cold storage by the use of three different microperforated films (1/50 mm, 1/30 mm, and 1/10 mm; ø = 100 μm). Gas composition in the wraps, weight loss, % disorder, and microbial counts were monitored during cold storage for 21 days. The tested microperforated films allowed the extension of cold storage time for brebas, minimizing weight loss and delaying the disorders due to fungal proliferation, especially M50 (1/50 mm). Total soluble solids (TSS), titratable acidity (TA), pH, firmness, and sensory quality were also evaluated. Among the tested microperforated films, M50 showed the best performance in terms of delaying physicochemical senescence processes of fruit. The breba cultivar had an important impact on the extension of cold storage. For ‘San Antonio’ and ‘Banane’ cultivars packaged with microperforated M50, the optimal time of cold storage was 14 and 21 days, respectively.     

Integrated ethylene and temperature conditioning for induction of ripening capacity in ‘Anjou’ and ‘Comice’ pears

‘Anjou’ and ‘Comice’ pears from three harvest dates were conditioned to develop ripening capacity by exposure to 100 μL L⁻¹ ethylene at 20 °C for 0, 24, 48, or 72 h, followed by varying durations of temperature conditioning at −0.5 or 10 °C. Ripening capacity was tested by measuring fruit firmness after 7 d at 20 °C after completion of conditioning treatments. Fruit firmness was also measured after conditioning but before ripening, and was designated “shipping firmness”, indicative of the potential for the fruit to withstand transport conditions without physical injury. Ripening capacity in both cultivars developed more rapidly with later harvest date, increasing duration of ethylene conditioning, and increasing duration of temperature conditioning. Ripening capacity developed much more rapidly at 10 °C than at −0.5 °C. Useful durations of temperature conditioning at 10 °C were limited by fruit softening below acceptable values of shipping firmness. However, sequential combinations of ethylene and temperature conditioning at both −0.5 and 10 °C were identified wherein post-conditioning shipping firmness was acceptable.     

Volatile compounds,quality parameters and consumer acceptance of ‘Pink Lady®’ apples stored in different conditions

Standard quality parameters, consumer acceptance, and volatile compound emission of ‘Pink Lady^®’ apples (Malus × domestica Borkh.) were measured at harvest and after 14 and 25 weeks of cold storage in three different atmospheres. After storage, fruit were left to ripen for 1 and 7 days at 20 °C before instrumental and sensory measurements were performed. Data were subjected to principal component analysis (PCA) and partial least square regression (PLSR). PLSR results indicated that the parameters positively influencing acceptability were soluble solid content, titratable acidity, background colour, and emission of hexyl 2-methylbutanoate, hexyl hexanoate, hexyl propanoate, butyl 2-methylbutanoate, 2-methylbutyl acetate and butyl propanoate. Results of sensory analyses revealed the treatments considered in this work could be split into two levels of acceptability.     

Effects of postharvest treatments on gene expression in Prunus persica fruit: Normal and altered ripening

Peach (Prunus persica) fruit have a short shelf-life, and the most common method employed to delay ripening and increase their postharvest life is cold storage. However, after extended storage at low temperature some cultivars have alterated ripening processes, resulting in a lack of juice and a woolly texture. To improve our understanding of the molecular mechanisms involved in the responses of peach fruit to cold storage we determined gene expression changes of fruit (cv. O’Henry) under different postharvest conditions: ripening (5 days at 21 °C), cold storage (21 days at 4 °C) and induction of woolliness (21 days at 4 °C followed by 5 days at 21 °C).Cluster analyses of genes differentially expressed between treatments revealed unique patterns associated with biological processes that operate during postharvest treatments. Genes up-regulated during postharvest ripening and woolliness include components of ethylene, and aroma biosynthesis as well as oxidative stress response. During cold storage treatment and woolliness, several genes linked to the oxidative stress response increased in abundance, suggesting changes in redox status. Quantitative RT-PCR analysis showed a sequential increase levels of mRNAs encoding key components of cellular stress response. Moreover, after 21 days of cold storage, expression of genes encoding oxidoreductase, catalase, superoxide dismutase and gluthatione reductase was still significantly higher than before cold treatment, suggesting that fruit cells were able to respond to the increased production of ROS that was induced by extended cold storage. In the woolly fruit, up-regulation of stress response genes was accompanied by down-regulation of key components of metabolic pathways that are active during peach ripening. The altered expression pattern of these genes might account for the abnormal ripening of woolly fruit.     

Changes in bioactive compounds and response to postharvest storage conditions in purple eggplants as affected by fruit developmental stage

Fruit maturity stage at harvest influences the response to postharvest storage conditions and bioactive compounds content. In this work fruit from two purple eggplant cultivars (Monarca and Perla Negra) were harvested at 12, 15, 18, 20 and 23 d after fruit set (designated as stages I through V) and changes in size, dry weight, calyx area, cell wall material (AIR, alcohol insoluble residue), firmness, respiration, and antioxidants (peel anthocyanins and pulp carotenoids, ascorbic acid, phenolics and chlorogenic acid) were determined. In a second set of experiments the postharvest performance of fruit harvested at stages I (“baby” eggplants), III and IV (traditional harvest stages) during storage at 0 or 10 °C was assessed. Fruit growth continued until late ripening in contrast to calyx expansion and peel anthocyanin accumulation, which were relatively earlier events. Fruit dry weight decreased between stages I and III, remaining constant afterwards. “Baby” eggplants had higher antioxidant capacity, chlorogenic acid (ChA), carotenoids and ascorbic acid contents than late-harvested fruit. ChA predominated in pulp placental tissues at stage I, spreading throughout the fruit core at as ripening progressed. No marked differences in dry mass, antioxidant capacity or responses to postharvest storage regimes were found between fruit harvested at stages III and IV. Late pickings increased yields and led to less dense fruit, which had lower respiration rates. Within this harvest window, storage at 10 °C maximized quality maintenance. In contrast “baby” eggplants stored better at 0 °C. Understanding the developmental changes in bioactive compounds and postharvest performance may help in the maximization of fruit antioxidant properties as well as in the selection of the optimal handling conditions for each ontogenic stage.     

Controlled atmosphere storage of rabbiteye blueberries enhances postharvest quality aspects

Blueberries are highly perishable and therefore it is necessary to develop strategies to increase their storage life. Two rabbiteye cultivars (‘Centurion’ and ‘Maru’) were stored at 1.5 °C in either regular air or controlled atmosphere (2.5 kPa O₂ + 15 kPa CO₂) for up to 6 weeks. Measurements of firmness, soluble solids content, titratable acidity, weight loss, shrivel and blemishes were combined with determinations of antioxidant activities and total phenolic content. Weight loss and shrivel were not affected by storage atmosphere or storage duration. After 28 days, controlled atmosphere storage resulted in only half as much blemished fruit compared with storage in regular air. Additionally, fungal development in ‘Maru’ fruit was minimised by controlled atmosphere storage.Water-soluble extracts from ‘Centurion’ fruit had higher antioxidant activities and total phenolic content than those from ‘Maru’ fruit at harvest and after storage in regular air and controlled atmosphere. The highest increases in antioxidant activity and total phenolic content occurred during the additional 6 days of shelf-life at 20 °C.     

Comparative studies on nanostructures of three kinds of pectins in two peach cultivars using atomic force microscopy

Firmness is an important postharvest quality property of fruit. To investigate the reasons for firmness differences between soft and crisp fruit cultivars, two peach (Prunus persica L. Batsch) cultivars (soft and crisp) were selected to compare the nanostructures of pectins. Water-soluble pectin (WSP), chelate-soluble pectin (CSP) and sodium carbonate-soluble pectin (SSP) were extracted and nanostructures were conducted and analyzed using atomic force microscopy (AFM). The results show that SSP chain lengths were different between the two cultivars with average SSP lengths of 249 nm and 57 nm for fruit of the crisp and soft cultivars, respectively, while the WSP and CSP chain lengths were not much different. There were no statistical differences for chain heights and widths in the three kinds of pectins between fruit of the two cultivars. All the chain heights were about 1–5 nm. The results indicate that neutral sugar-rich pectins from the primary cell wall of peach flesh might be the cause of the main differences in pectin nanostructures between the two cultivars. The neutral sugar-rich pectins in primary cell walls of peach might also be the reason for firmness differences.     

Induction of ripening capacity in ‘Packham's Triumph’ and ‘Gebhard Red D’Anjou’ Pears by temperature and ethylene conditioning

Methods were tested for rapid induction of ripening capacity in ‘Packham's Triumph’ and ‘Gebhard Red D’Anjou’ pears in order to facilitate early marketing. Fruit of each cultivar were harvested at the onset of maturity and conditioned to develop ripening capacity by exposure to 100 μL L⁻¹ ethylene at 20 °C for 0, 24, 48, or 72 h, followed by varying durations of temperature conditioning at −0.5 or 10 °C. Ripening capacity was tested by measuring fruit firmness after 7 d at 20 °C after completion of conditioning treatments. Fruit firmness was also measured after conditioning but before ripening, and was designated “shipping firmness,” indicative of the potential for the fruit to withstand transport conditions without physical injury. With temperature conditioning at −0.5 °C only, ‘Packham's Triumph’ pears needed 45 d to develop ripening capacity, while ‘Gebhard Red D’Anjou’ pears were not capable of fully ripening after 60 d, the longest duration tested. Using ethylene only, 72 h exposure was necessary to develop full ripening capacity in both cultivars, and adequate shipping firmness was maintained. Using temperature conditioning at 10 °C, ripening capacity in ‘Packham's Triumph’ and ‘Gebhard Red D’Anjou’ developed within 10 and 20 d, respectively, but shipping firmness in ‘Gebhard Red D’Anjou’ was compromised at 20 d. In both cultivars, 24 or 48 h in ethylene followed by 5 d at 10 °C induced ripening capacity while maintaining adequate shipping firmness.     

Effect of gamma irradiation on the physico-chemical and visual properties of mango (Mangifera indica L.), cv. ‘Dushehri’ and ‘Fazli’ stored at 20 °C

The effect of γ-irradiation doses (0.3, 0.5, 0.7, 1.0, 6.0, 10.0 kGy) on different physico-chemical and visual properties of two Indian cultivars of mango, cv. ‘Dushehri’ and ‘Fazli’ was observed during storage at 20 °C for the evaluation of delayed ripening and extension of shelf-life. Visually all the irradiated fruit showed greener peel and lighter pulp throughout the storage, however, radiation injuries were present in ‘Dushehri’ treated with 6–10 kGy and in ‘Fazli’ with 1–10 kGy. Loss of fruit due to rotting was less in the irradiated samples, treated up to 1 kGy of both the cultivars. Irradiated fruit of both the cultivars at high doses (6–10 kGy) showed increased sugar content from 0 d, however, all the treated fruit registered a slower rate of increase of sugars with storage compared to the respective controls and those treated with the lower doses of 0.5 and 0.7 kGy attained peak sugar concentration later. Significant (p ≤ 0.05) textural deterioration could be detected immediately after irradiation, in ‘Dushehri’ at doses ≥1 kGy and in ‘Fazli’ at doses ≥0.7 kGy. However, low dose treated fruit (0.3–1 kGy) of both the cultivars softened at a considerably slower rate during storage and registered significantly greater fruit firmness (compression strength) throughout the storage period. Similarly, ‘Dushehri’ treated with 0.3–0.7 kGy and Fazli treated with 0.7 kGy registered significantly greater flesh firmness (shear strength). ‘Dushehri’ treated with 0.3–1 kGy and ‘Fazli’ with 0.5–1 kGy also registered significantly harder and tougher peel, as determined by puncture test, throughout the storage. Scanning electron microscopy (SEM) performed on 3rd and 2nd d of storage of ‘Dushehri’ and ‘Fazli’ respectively, revealed microstructural breakdown at and above 1 kGy in both cultivars. Cell separation could be observed in ‘Fazli’ even at 0.7 kGy. SEM also revealed that the control fruit were in a more advanced stage of ripening than the low dose treated fruit. The study showed the feasibility of low dose γ-irradiation on ‘Dushehri’ (0.3–0.7 kGy) and ‘Fazli’ (0.5 and 0.7 kGy) that induced useful delay in ripening and extension of shelf-life by a minimum of 3 and 4 d, respectively.     

Effect of antifungal hydroxypropyl methylcellulose-beeswax edible coatings on gray mold development and quality attributes of cold-stored cherry tomato fruit

Edible composite coatings based on hydroxypropyl methylcellulose (HPMC), beeswax (BW), and food preservatives with antifungal properties, were evaluated on cherry tomatoes during cold storage. Food preservatives selected from previous research work included sodium propionate (SP), potassium carbonate (PC), ammonium phosphate (APh) and ammonium carbonate (AC). Cherry tomatoes artificially inoculated with Botrytis cinerea were coated and stored up to 15 d at 5 °C followed by 7 d of shelf-life at 20 °C. All antifungal HPMC-BW coatings significantly reduced gray mold development on inoculated and cold-stored cherry tomatoes, the SP-based coating being the most effective. Analytical and sensory fruit quality was also evaluated after cold storage and shelf-life. The AC-based coating was the most effective to control weight loss and maintain the firmness of coated cherry tomatoes. Respiration rate, firmness, color, sensory flavor, off-flavor, and fruit appearance were not adversely affected by the application of the antifungal coatings. Overall, the application of HPMC-BW edible composite coatings containing AC could be a promising treatment to extend the postharvest life of cherry tomatoes. Further studies should focus on the modification of some physical characteristics of the coatings in order to enhance the general performance and provide higher peel gloss.     

Preharvest application of methyl jasmonate (MeJA) in two plum cultivars. 1. Improvement of fruit growth and quality attributes at harvest

Two plum (Prunus salicina Lindl.) cultivars ‘Black Splendor’ (BS) and ‘Royal Rosa’ (RR) were treated with methyl jasmonate (MeJA) at 3 concentrations (0.5, 1.0 and 2.0 mM) along the on-tree fruit development: 63, 77 and 98 days after full blossom (DAFB). On a weekly basis, fruit samples were taken for measuring fruit size and weight and parameters related to quality. Results revealed that MeJA was effective in increasing fruit size and weight, the 0.5 mM being the most effective for BS cultivar and 2.0 mM for RR. At harvest, those fruit treated with 0.5 mM MeJA had the highest firmness and colour Hue values. Total acidity was also generally higher in MeJA-treated fruit than in controls, while the content of total soluble solids remained unaffected. In addition, total phenolics and total antioxidant activity were found at higher concentrations in 0.5 and 2.0 mM MeJA-treated than in control fruit over at last 3 weeks of fruit development for BS and RR cultivars, respectively. Overall results suggest that MeJA could be a promising preharvest tool to increase plum size and quality with enhanced bioactive compounds and antioxidant activity, although the optimum concentration is cultivar dependent.     

The aroma development during storage of Castlebrite apricots as evaluated by gas chromatography,electronic nose,and sensory analysis

One of the most important factors limiting apricot quality is the loss of flavor during storage, particularly overall aroma. To characterize fruit aroma, several techniques have been used, including both instrumental- and sensory-based methodologies. Despite the importance of aroma in fruit quality, limited information is available regarding the effects of long-term cold storage and ripening on the apricot’s volatile compound profile. The objective of this research was to characterize the aroma of two lots of Castlebrite apricots at different stages of initial maturity using gas chromatography–mass spectrometry (GC–MS), electronic nose (e-nose) analysis, and a sensory panel. GC measurements were performed on both intact fruit and ground fruit tissue. Evaluations were performed at harvest, after 15 or 30 d of cold storage at 0 °C under a normal air atmosphere and also after a simulated shelf-life period at 20 °C. Among the volatiles identified by GC–MS, aldehydes and esters were the primary constituents of Castlebrite apricot aroma, and differences in volatile aroma profiles were observed between intact and ground fruit. Only the concentrations of aldehyde compounds, primarily hexanal, were different between maturity stages. Furthermore, the e-nose was able to successfully differentiate between the two different stages of fruit maturity examined, but only after simulated shelf-life storage. Interestingly, despite the changes detected by GC and the e-nose, the sensory panel could not identify any differences between apricots at different stages of maturity.     

A model for the softening of nectarines based on sorting fruit at harvest by time-resolved reflectance spectroscopy

Time-resolved reflectance spectroscopy (TRS), allows for the complete optical characterization (in terms of the absorption and scattering coefficients) of diffusive media such as fruit, in the spectral range 600–1100 nm, probing a volume to a depth of about 2 cm. The hypothesis was made that the absorption coefficient at 670 nm (μ_a), near the chlorophyll peak, could be an index of fruit maturity at harvest. The aim of this research was to model nectarine softening for fruit of different maturity at harvest, as assessed by μ_a. Nectarine fruit of two sizes (A and B) were picked in 2002, 2003 (cv ‘Spring Bright’) and 2004 (cv ‘Ambra’), measured by TRS at harvest on two opposite sides and ranked by decreasing μ_a averaged per fruit (increasing maturity). Fruit were stored at 0 °C for 3, 10 and 6 days, then at 20 °C for 79, 120 and 117 h in 2002, 2003 and 2004, respectively. Firmness was measured by pressure test (8 mm tip) during shelf life, on two sides of each fruit, and then averaged. Softening at 20 °C followed a logistic model as a function of μ_a at harvest and of time at 20 °C (adjusted R² = 0.85 in ‘Spring Bright’ and 0.75 in ‘Ambra’). The effects of fruit size and cold storage were negligible. The absorption coefficient μ_a explained 13–34% of the variation of firmness. Fruit with different μ_a at harvest softened with the same sigmoidal pattern in time, which was shifted earlier in low μ_a fruit, and later in high μ_a fruit. μ_a accounted for the time shift in softening of individual fruit within the same batch. The value of μ_a can be regarded as an index of the biological age of fruit. By using this model, it is possible to predict individual fruit softening rates at 20 °C.