Nectarine Slices Research Articles

Drying kinetics of nectarine slices in a heat pump drying system

Drying kinetics of nectarine slices in a heat pump drying system

Microstructural, biochemical and drying characteristics of dehydrated 'Sunectwentyone' nectarines as affected by sodium metabisulphite.

Nectarine fruit is highly perishable due to its high moisture content (89%) and susceptibility to decay. Continuous degradation in quality attributes due to physiological responses and ripening result ultimately in post-harvest losses. Drying of fruit offers the possibility to minimize losses and add value to fresh produce. Thus, this study evaluated the impacts of sodium metabisulphite (SMB; 10g/kg) and characterized the influence of hot air (50°C) drying on the kinetics, fruit tissue microstructure, and the physicochemical properties of dried 'Sunectwentyone' nectarines (Super star®). Out of the nine mathematical models, Logarithmic and Henderson, and Pabis models were the most suitable to predict the drying behaviour of sliced nectarines (R 2 = 0.94). Based on the microstructural analysis, prolonged drying led to higher tissue displacement/disruption in dehydrated nectarine slices. Results showed that SMB treatment was more effective in maintaining both the freshness and the color of 'Sunectwentyone' nectarine than the untreated. The online version contains supplementary material available at 10.1007/s10068-022-01039-6.

Influence of ultrasound pre‐treatment and temperature on the quality and thermodynamic properties in the drying process of nectarine slices in a hot air dryer

Influence of ultrasound pre‐treatment and temperature on the quality and thermodynamic properties in the drying process of nectarine slices in a hot air dryer

Immuno-detection and differentiation of Listeria monocytogenes and Listeria ivanovii in stone fruits.

The aim of this study was to develop a rapid detection and differentiation method for pathogenic Listeria species in stone fruits. We utilized activated charcoal enrichment media (ACM) to induce overexpression and hypersecretion of pathogenic Listeria virulence proteins which can subsequently be detected via immunoblot analysis. Plum and nectarine slices spiked with either L. monocytogenes or L. ivanovii were incubated in pre-enrichment broth followed by enrichment in ACM. Secreted proteins were precipitated and subjected to SDS-PAGE and immunoblot analysis using a combination of L. monocytogenes-specific antibody (α-listeriolysin O) and antibody specific for both L. monocytogenes and L. ivanovii (α-Internalin C). As low as 1CFU per gram of L. monocytogenes in plum and nectarine was detected, whereas a detection limit of 10CFU per gram was achieved for L. ivanovii in each food tested following a 20-h enrichment period. Nonpathogenic Listeria species and non-Listeria bacterial pathogens tested were negative. These results demonstrate the highly sensitive and specific nature of the detection method for pathogenic Listeria in stone fruits using activated charcoal enrichment as well as the capability to discriminate between L. monocytogenes and L. ivanovii. This method is the first to identify and differentiate L. monocytogenes and L. ivanovii in select stone fruit enrichments within 24h using immunological techniques. The rapidity and sensitivity of the method could aid in the reduction of exposure to the public in the event of an outbreak and expedite the administration of appropriate antibiotics to infected individuals.

Quality, sensory and volatile profiles of fresh‐cut big top nectarines cold stored in air or modified atmosphere packaging

SummarySolid‐phase microextraction (SPME) GC‐MS was used to investigate the volatile organic compound (VOC) profile of fresh‐cut ‘Big Top’ nectarine samples, stored in unsealed bags (AIR) or packed in active modified atmosphere (MAP) after 8 days of cold storage. Nectarine slices were also subjected to sensory and quality analysis after harvest and at the end of the storage. MAP preserved the overall quality, the appearance and the olfactory properties of nectarine slices during storage, while AIR samples showed symptoms of dehydration and browning. Sixty VOCs were identified in total in the headspace of the fresh nectarines and cold‐stored fruit slices samples. Principal component analysis performed on VOCs allowed to differentiate fresh nectarines from cold‐stored samples, with lactones and terpenes mainly related to fresh samples, and ester compounds positively correlated to AIR or MAP samples. Partial least square regression models allowed to identify a pool of VOC predictors of olfactory sensory descriptors.

<b>Investigation of the effect of temperature and pretreatment on the rehydration capacities of dried nectarine slices

In this study, the effect of temperature and pretreatment on the rehydration capacity of nectarine slices dried either with pretreatment and under ambient conditions (‘natural’) at 50°C in a cabinet dryer was investigated. Rehydration proceeded with distilled water at three different rehydration temperatures (25, 50, and 75°C). Initial rehydration rates increased with rehydration temperature for all samples and were highest for the potassium carbonate (potas)-pretreated samples. At all rehydration temperatures, the equilibrium moisture content was highest for those pretreated with potas solution. The values of Deff varied from 2.79 to 4.32x10-10, 1.72 to 2.34x10-10, and 1.86 to 2.58x10-10 m2 s-1 for potassium carbonate, citric acid, and natural samples, respectively. The activation energy values were 5.65, 6.06, and 8.29 kJmol-1 for citric acid, natural, and potassium carbonate nectarine slices, respectively. The rehydration data were fitted to Peleg and first-order kinetic models: the first order kinetic model was found to be the most appropriate model for rehydration of nectarine slices.

Fresh-cut storage of fruit and fresh-cuts affects the behaviour of minimally processed Big Bang nectarines ( Prunus persica L. Batsch) during shelf life

Abstract Nectarine can be minimally processed to successfully produce ready-to-eat fresh-cuts fruit. The aim of this work was to study the combined effect of the ripening stage of cold stored fruit before processing and the length of the storage period of fresh-cut slices after minimal processing, on the behaviour of minimally processed “Big Bang” nectarines during shelf life. ‘Big Bang’nectarine slices obtained from fruit stored at 1 ± 0.5 °C (RH = 90%) for 1 d, 10 d and 15 d were stored for 0, 3, 5, 7, 12 d. at 5 °C. At the end of each storage period, visual quality, color (L*, a* and b*), phenols and carothenoids content, TSS, TA were measured together with in-package CO2 and O2. Despite the more advanced ripening stage and the increase of polyphenol oxidase activity and ethylene production, nectarine fruit stored for 10 days were successfully processed to get fresh-cuts still marketable until 7 d after being cutting. Indeed, no difference occurred between fruit stored for 1 d before cutting and those stored for 10 d, in terms of firmness, weight loss and marketability of fresh-cut slices. The carotenoid content went descending dramatically in all samples of ‘Big Bang’ slices while in-package CO2 partial pressures were highest at 5, 7, 12 d of storage in fresh-cut to more from fruit stored for 1 d.

Effects of hot-air and hybrid hot air-microwave drying on drying kinetics and textural quality of nectarine slices

Drying and physicochemical characteristics of nectarine slices were investigated using hot-air and hybrid hot air-microwave drying methods under fixed air temperature and air speed (50 °C and 0.5 m/s, respectively). Microwave power levels for the combined hot air-microwave method were 80, 160, 240, and 320 W. Drying kinetics were analyzed and compared using six mathematical models. For both drying methods the model with the best fitness in explaining the drying behavior was the Midilli–Kucuk model. The coefficient of determination (R 2), root mean square error (RMSE) and reduced chi square (χ 2) for this model have been obtained greater than 0.999 and less than 0.006 and 0.0001 for hybrid hot air-microwave drying while those values for hot-air drying were more than 0.999 and less than 0.003 and 0.0001, respectively. Results showed that the hybrid method reduced the drying time considerably and produced products with higher quality. The range of effective moisture diffusivity (D eff ) of hybrid and hot-air drying was between 8.15 × 10−8 and 2.83 × 10−7 m2/s and 1.27 × 10−8 m2/s, respectively. The total color difference (ΔE) has also been obtained from 36.68 to 44.27 for hybrid method; however this value for hot-air drying was found 49.64. Although reduced microwave power output led to a lower drying rate, it reduced changes in product parameters i.e. total color change, surface roughness, shrinkage and microstructural change and increased hardness and water uptake.

Investigation of the Effect of a Hybrid Drying Method on the Color Quality of Nectarine Slices and Energy Consumption

Investigation of the Effect of a Hybrid Drying Method on the Color Quality of Nectarine Slices and Energy Consumption

Effects of Edible Coatings on Quality Maintenance of Fresh-cut Nectarines

The study was conducted to investigate the effects of edible coatings, alone or in conjunction, on overall postharvest quality of fresh-cut Orion nectarine under fresh-cut commercial storage conditions. Three different coatings were used: 2% acid-soluble chitosan, 1.5% sodium alginate and a solution with 1.5% chitosan and 1% sodium alginate. Fresh-cut nectarine slices firmness, color, soluble solids content, titratable acidity and polyphenol oxidase activity were measured. Also microorganism counts of yeasts and moulds were analized. The results indicated that treatments with alginate inhibited decrease in firmness, titratable acidity and delayed browning. Chitosan coating reduced microorganism counts of yeasts and moulds compared to control treatment. Furthermore alginate inhibited the activities of PPO throughout the storage period. Our study suggests that alginate coating treatment may be a promising method of maintaining fresh-cut nectarines quality and extending their postharvest life.

Modelling of nectarine drying under near infrared - Vacuum conditions.

Drying of nectarine slices was performed to determine the thermal and physical properties in order to reduce product deterioration due to chemical reactions, facilitate storage and lower transportation costs. Because nectarine slices are sensitive to heat with long drying period, the selection of a suitable drying approach is a challenging task. Infrared-vacuum drying can be used as an appropriate method for susceptible materials with high moisture content such as nectarine slices. Modelling of nectarine slices drying was carried out in a thin layer near infraredvacuum conditions. Drying of the samples was implemented at the absolute pressures of 20, 40 and 60 kPa and drying temperatures of 50, 60 and 70°C. Drying behaviour of nectarine slices, as well as the effect of drying conditions on moisture loss trend, drying rate, effective diffusion coefficient, activation energy, shrinkage, colour and energy consumption of nectarine slices, dried in near infrared-vacuum dryer are discussed in this study. Six mathematical models were used to predict the moisture ratio of the samples in thin layer drying. The Midilli model had supremacy in prediction of nectarine slices drying behaviour. The maximum drying rates of the samples were between 0.014-0.047 gwater/gdry material·min. Effective moisture diffusivity of the samples was estimated in the ranges of 2.46·10-10 to 6.48·10-10 m2/s. Activation energy were computed between 31.28 and 35.23 kJ/mol. Minimum shrinkage (48.4%) and total colour difference (15.1) were achieved at temperature of 50°C and absolute pressure of 20 kPa. Energy consumption of the tests was estimated in the ranges of 0.129 to 0.247 kWh. Effective moisture diffusivity was increased with decrease of vacuum pressure and increase of drying temperature but effect of drying temperature on effective moisture diffusivity of nectarine slices was more than vacuum pressure. Activation energy was decreased with decrease in absolute pressure. Total colour difference and shrinkage of nectarine slices on near infrared-vacuum drying was decreased with decrease of vacuum pressure and decrease of drying temperature.

Effect of different coatings in preventing deterioration and preserving the quality of fresh-cut nectarines (cv Big Top)

Fresh-cut nectarines are very perishable product, and thus have a short shelf-life. In this study, minimally processed nectarines (cv Big Top) were treated with chitosan (20 g/L), sodium alginate (20 g/L) and Chitoplant® (20g/L), sealed in polypropylene plastic bags, and stored at 4°C for 5 days. Effects of the coatings on nectarine slices shelf-life and qualitative attributes were evaluated by investigating changes in colors, browning potential, total soluble solids content, and titratable acidity. Changes in quality parameters were lower in coated samples as compared with the control. The alginate coatings were effective on delaying the evolution of the parameters related to postharvest ripening, such as color (Hue, L*) and loss of acidity. The application of sodium alginate coating could be used to reduce deteriorative processes, maintain quality and improve the shelf-life of fresh-cut nectarine stored at 4°C.

Relationship between visual appearance and browning as evaluated by image analysis and chemical traits in fresh-cut nectarines

Consumer acceptance of fresh-cut nectarines may be related to several characteristics (freshness, overall browning) that can be measured with suitable sensors. In this paper, digital image analysis was used to assess quality and marketability of fresh-cut nectarines, stored in air for 12 d at 5 °C. Visual appearance and colour were measured using a conventional colorimeter and a computer vision system. In addition, a number of fruit were analyzed for pH, titratable acidity, total soluble solids, total phenols and antioxidant content. During storage, nectarine slices showed a loss in appearance; after 12 d slices which were brown, having lost their freshness, showed a mean 30% decrease in total phenolics and a mean 10% increase in antioxidant activity with respect to fresh slices (13.7 ± 4.3 mg gallic acid 100 g −1 f.w. and 53.5 ± 5.2 μmol TE 100 g −1 f.w.). Visual appearance correlated significantly with the browning score ( R 2 = 0.78), titratable acidity ( R 2 = 0.45) and pH ( R 2 = 0.85). Correlation of the visual appearance score with the colour parameters b * and chroma measured by the computer vision system was higher ( R 2 = 0.76) than that obtained using a colorimeter ( R 2 = 0.57). The results showed that the computer vision system was more effective than the colorimetric method. Measurements by means of the computer vision system resulted in a reliable tool to determine quality and marketability of fresh-cut nectarines in an objective and quantitative way. Moreover, the proposed computer vision system is suitable for real-time application in the food processing industry.

Phenolic content and antioxidant capacity versus consumer acceptance of soaked and vacuum impregnated frozen nectarines

Nectarines (Prunus persica L. cv. Maria Laura) were manually selected, cut in slices and divided into four groups: fresh, untreated frozen, soaked in osmotic solution and subsequently frozen, and vacuum impregnated (VI) and subsequently frozen. This investigation was focused on evaluation of consumer acceptance with respect to treated versus untreated frozen nectarine slices. In a preliminary acceptance test of untreated frozen nectarine slices, fruits were generally rejected on the basis of a darkened appearance and “oxidized” taste. These negative attributes were probably linked to the activity of polyphenol oxidase (PPO) and depletion of phenols due to cell rupture during freeze–thaw procedures. For these reasons, in order to evaluate the tendency of fruit to oxidation, several analyses were performed: the antioxidant capacity of phenolic fraction and the o-diphenol content were estimated by spectrophotometric assays, whereas the hydroxycinnamic acid (chlorogenic and neochlorogenic acids) composition was evaluated by high performance liquid chromatography (HPLC). Phenolic content and antioxidant capacity were found to correlate well with the acceptance level of frozen nectarine slices. In this regard a higher phenolic content associated with a higher acceptance level of nectarine samples.

Quality Changes in Fresh‐cut Peach and Nectarine Slices as Affected by Cultivar, Storage Atmosphere and Chemical Treatments

ABSTRACTThe shelf‐life of slices from 13 cultivars of peaches and 8 cultivars of nectarines, varied (between 2 and 12 days at 0°C). Controlled atmospheres of 0.25 kPa O2 and/or 10 kPa or 20 kPa CO2 extended the shelf‐life at 10°C of ‘O'Henry’ or ‘Elegant Lady’ peach slices by 1–2 days beyond the air control. Low (0.25 kPa) O2 acted synergistically with CO2 levels of 10 and 20 kPa to induce fermentative metabolism as indicated by ethanol and acetaldehyde production. A 2% (w/v) ascorbic acid + 1% (w/v) calcium lactate postcutting dip resulted in limited reduction of cut surface browning and tissue softening in ‘Carnival’ peach slices.

Effects of Fruit Ripeness and Storage Temperature on the Deterioration Rate of Fresh-cut Peach and Nectarine Slices

The effects of fruit ripeness and postcutting storage temperature on the deterioration rate of fresh-cut `Flavorcrest' peaches and `Zee Grand' nectarines [Prunus persica (L.) Batsch] were investigated. Based on visual quality, peach and nectarine slices from mature-green fruit (>40-53 N flesh firmness) had the longest shelf-life (8 days at 0 °C for peaches and 8 d at 0, 5, or 10 °C for nectarines). However, slices from mature-green peaches and nectarines as well as partially ripe peaches (>27-40 N flesh firmness) failed to soften to acceptable eating quality when held at 0 or 5 °C. Slices from overripe peach and nectarine fruit (0-13 N flesh firmness) were organoleptically acceptable at the time of cutting, but based on visual quality had a shelf-life of only 2 days or less (peach) or 3 to 6 days (nectarine) when stored at 0, 5, or 10 °C. The optimal ripeness for preparing fresh-cut peach slices was the ripe (>13-27 N flesh firmness) stage and these slices at 0 °C and 90% to 95% relative humidity (RH) had a shelf-life of 6 days, while retaining good eating quality. The optimal ripeness for preparing fresh-cut nectarine slices was the partially ripe (>27-49 N) or ripe (>13-27 N flesh firmness) stages and these slices at 0 °C and 90% to 95% RH had a shelf-life of 8 days, while retaining good eating quality.