•Accurate NIR calibration models were obtained for main quality indexes of apples.•Total phenolics and antioxidant activity of apples could be predicted by NIR-based models.•Classification models ...were able to discriminate apple lots on the basis of storage time.
Apples can be stored for long time under controlled temperature and atmosphere conditions, and therefore, non-destructive and rapid tools are required to assess fruit quality and to monitor changes during the postharvest period. The aim of this study was to evaluate the feasibility of NIR spectroscopy to optimize postharvest apple management and to follow changes in fruit quality during storage. An FT-NIR system operating in diffuse reflectance in the range 12,500–3600cm−1 was used to evaluate the physico-chemical (dry matter, soluble solids, colour and firmness) and some nutraceutical characteristics (total phenolics, total flavonoids and antioxidant activity) of ‘Golden Delicious’ apples, which were stored for about six months at 1°C in controlled atmosphere, over two subsequent years. Spectral data were elaborated by PLS regression and LDA classification techniques. Good correlation models between spectral data and chemical and physical parameters were obtained for soluble solids, a* colour coordinate and firmness (0.81<R2<0.90 in calibration and 0.79<R2<0.89 in cross validation). Even higher correlation values (0.89<R2<0.95 in calibration and 0.86<R2<0.92 in cross validation) were obtained for indexes correlated to the antioxidant capacity of apples. The classification technique Linear Discriminant Analysis was applied to spectral data, in order to discriminate apples on the basis of storage time. Average correct classification was higher than 93% in validation and close to 100% in calibration, indicating high potential of NIR spectroscopy for the estimation of storage time of apple lots.
In this paper, a computer vision-based algorithm for golden delicious apple grading is proposed which works in six steps. Non-apple pixels as background are firstly removed from input images. Then, ...stem end is detected by combination of morphological methods and Mahalanobis distant classifier. Calyx region is also detected by applying K-means clustering on the Cb component in YCbCr color space. After that, defects segmentation is achieved using Multi-Layer Perceptron (MLP) neural network. In the next step, stem end and calyx regions are removed from defected regions to refine and improve apple grading process. Then, statistical, textural and geometric features from refined defected regions are extracted. Finally, for apple grading, a comparison between performance of Support Vector Machine (SVM), MLP and K-Nearest Neighbor (KNN) classifiers is done. Classification is done in two manners which in the first one, an input apple is classified into two categories of healthy and defected. In the second manner, the input apple is classified into three categories of first rank, second rank and rejected ones. In both grading steps, SVM classifier works as the best one with recognition rate of 92.5% and 89.2% for two categories (healthy and defected) and three quality categories (first rank, second rank and rejected ones), among 120 different golden delicious apple images, respectively, considering K-folding with K=5. Moreover, the accuracy of the proposed segmentation algorithms including stem end detection and calyx detection are evaluated for two different apple image databases.
The quality of climacteric fruits, such as apples, depends to a great extent on the right harvesting time and appropriate storage conditions. Furthermore, it is known that the microclimate ...surrounding fruit trees influences the growth, maturation, and chemical composition of fruits. However, knowledge concerning the chemical composition of apple fruit as affected by orchard elevation is still scarce and thus the understanding of the interplay and influence of these factors on apple fruit quality needs to be improved. The overall goal of the present study was a better understanding of changes in several fruit characteristics of Golden Delicious clone B apples, derived from orchards located at different altitudes and harvested at different stages of maturity. Furthermore, it was investigated whether altitude has a statistical influence on the chemical composition of stored apples immediately after ULO storage and after six days of shelf-life. The results of the current work may lead to a better understanding of the impact of harvest date and orchard elevation on the fruit quality and storability of Golden Delicious clone B.
•Dynamic FEM simulation by defining the viscoelastic material model were performed.•the preparation of apple for SEM was used hexamethyl disilazane acid (HMDS).•The impact force-based FEM method ...offers a better estimate than the velocity-based.•Scanning electron microscopy is a reliable way to extract impact damage dimensions.•The surface temperature of bruised apple tissue is different from healthy tissue.
Apple fruit is affected by operations such as harvesting, packing, grading, storage, and transportation on the way from the garden to the sales centers. During these stages, the products are subjected to several static and dynamic loads applied to each product, damaging them. The aim of this study was to determine the dynamic deformation behavior using finite element simulation and to investigate the surface temperature changes of Golden Delicious apple cultivar due to impact loads. For this purpose, the physical, mechanical and rheological properties of the internal components of apples were determined in three parts: skin, flesh and core. A viscoelastic material model was defined for more accurate simulation. Scanning electron microscope is used to measure the volume of damage and a thermal camera is used to measure the surface temperature of the product. To collect valid data in the dynamic loading section, the pendulum impact test was performed in the form of a factorial design. In this test, the independent variables included impact levels at 3 levels, product temperature at 2 levels and product radius of curvature at 2 levels, and dependent variables included bruising volume and surface temperature difference. The simulation results showed that the difference in bruise volume in the force-time and velocity-time methods with the bruise volume in the experimental test was 14.12% and 18.53%, respectively, and the maximum difference in reaction force was 9.36% and 15.97%. Therefore, in dynamic simulation based on pendulum impact test results, the use of force-time data offers better results than velocity-time data. The results of surface temperature measurements showed that with a gradual increase in apple temperature, the surface temperature of the bruised area is lower than the temperature of the healthy area. The highest surface temperature difference was observed in 30 minutes after impact and in the third impact level (33 N) equivalent (0.4 °C). Also, the results of the experimental pendulum impact test showed that all three factors of impact level, product temperature and radius of curvature had significant differences in bruising volume. Thus, the volume of bruising is directly related to the impact surface and the radius of curvature and inversely related to the apple temperature.
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Apple skin russeting naturally occurs in many varieties, particularly in "Golden Delicious" and its pedigree, and is regarded as a non-invasive physiological disorder partly caused by excessive ...deposition of lignin. However, the understanding of its molecular mechanism is still limited. In this study, we used iTRAQ (isobaric tags for relative and absolute quantitation) and RNA-seq to detect the changes in the expression levels of genes and proteins in three developmental stages of russeting formation, in russeted (non-bagging) and non-russeted (bagging) skin of "Golden Delicious" apple. 2856 differentially expressed genes and 942 differentially expressed proteins in the comparison groups were detected at the transcript level and protein level, respectively. A correlation analysis of the transcriptomics and proteomics data revealed that four genes (MD03G1059200, MD08G1009200, MD17G1092400, and MD17G1225100) involved in lignin biosynthesis are significant changed during apple russeting formation. Additionally, 92 transcription factors, including 4 LIM transcription factors, may be involved in apple russeting formation. Among them, one LIM transcription factor (MD15G1068200) was capable of binding to the PAL-box like (CCACTTGAGTAC) element, which indicated it was potentially involved in lignin biosynthesis. This study will provide further views on the molecular mechanisms controlling apple russeting formation.
•Preharvest sodium nitroprusside (SNP treatment increased the NO content in ‘Golden Delicious’ apples.•Preharvest SNP treatment inhibited ethylene metabolism.•Preharvest SNP treatment promoted the ...accumulation of sucrose.•Preharvest SNP treatment might be a potential measure for ripening control.
In order to examine the influence of preharvest nitric oxide (NO) treatment on ethylene biosynthesis and soluble sugar metabolism in ‘Golden Delicious’ apples, apple trees were sprayed with 50μM sodium nitroprusside (SNP) (a donor of NO) 14 days before harvest. The results indicated that preharvest SNP treatment can increase the NO content and the NOS activity in apple fruit, therefore, delay the accumulation of ethylene due to its inhibition on the activities of 1-aminocyclopropane-1-carboxylate synthase (ACS) and 1-aminocyclopropane-1-carboxylate oxydase (ACO). Fructose is the main sugar in ‘Golden Delicious’ apple. The synthesis of sucrose was stimulated and the decomposition of sucrose was inhibited by this treatment, thus causing the accumulation of sucrose. We can draw a conclusion that pre-harvest SNP (50μM) treatment can increase the NO content of fruit during storage, while higher NO content can further regulate fruit ripening through its effect on ethylene and sugar metabolism in ‘Golden Delicious’ apple fruit during storage at 18°C.
The effects of normal (NA) and controlled atmosphere (CA) storage and postharvest treatment with 1-methylcyclopropene (1-MCP) before CA storage for 5 months on the volatilome, biochemical composition ...and quality of ‘Golden Delicious’ (GD) and ‘Red Delicious’ (RD) apples were studied. Apples stored under NA and CA maintained and 1-MCP treatment increased firmness in both cultivars. NA storage resulted in a decrease of glucose, sucrose and fructose levels in both cultivars. When compared to CA storage, 1-MCP treatment caused a more significant decrease in sucrose levels and an increase in glucose levels. Additionally, 1-MCP-treated apples exhibited a significant decrease in malic acid content for both cultivars. All storage conditions led to significant changes in the abundance and composition of the volatilome in both cultivars. GD and RD apples responded differently to 1-MCP treatment compared to CA storage; higher abundance of hexanoate esters and (E,E)-α-farnesene was observed in RD apples treated with 1-MCP. While 1-MCP was effective in reducing (E,E)-α-farnesene abundance in GD apples, its impact on RD apples was more limited. However, for both cultivars, all storage conditions resulted in lower levels of 2-methylbutyl acetate, butyl acetate and hexyl acetate. The effectiveness of 1-MCP is cultivar dependent, with GD showing better results than RD.
•We find that the endogenous chlorogenic acid levels were closely related with fruit russet index.•When exogenous CA was treated, fruit russeting of Golden Delicious apple was blocked.•CA treatments ...affect enzyme activities and regulate gene expression in phenylpropanoid route.•CA treatment regulates secondary metabolism of apple peels which is related with russet formation.
Analysis of the secondary metabolites in apple peels showed that the levels of total flavonoids and chlorogenic acid (CA) during 15–60 days after full bloom (DAFB) were significantly higher in cultivar ‘Feng Shuai’, a spontaneous non-russeting mutant of ‘Golden Delicious’ apple, than in its maternal plant, which indicated higher level of endogenous CA may be associated with the inhibition of russet formation. Application of 0.5mmolL−1 exogenous CA solution to ‘Golden Delicious’ fruits at 30 DAFB effectively inhibited fruit russet formation. It also increased the levels of CA and total flavonoids in fruit peels at the 7th day after treatment, but depressed the lignin content. Furthermore, CA treatment induced the activity of phenylalnine ammonialyase (PAL) and cinnamate-4-hydrolase (C4H), but depressed activity of polyphenol oxidase (PPO) and peroxidase (POD). These effects were further supported by RT-PCR, where the expressions of PAL, C4H, 4CL, CHS, and CHI were up-regulated while those of CAD, POD and PPO were down-regulated by CA treatment. Interestingly, the up-regulated genes are involved in the biosynthesis of chlorogenic acid and flavonoids while the down-regulated ones are involved in lignin biosynthesis. Therefore, it can be deduced that the inhibition of russet formation in ‘Golden Delicious’ apple by CA is associated with the inhibition of lignin biosynthesis, not the enhancement of total flavonoids biosynthesis.
Purpose: Apple fruit widely suffers from different damages every year including post-harvest diseases such as blue mold (caused by Penicillium expansum). Recent studies have shown the role of ...hormones in different signaling pathways after a pathogen attack. Hormones may trigger different the expression of genes involved in the resistance mechanism and thus activating the immune system in plants. Findings: qRT-PCR results showed an increase in the expression of PR5, ERF1 and CHIB genes after treatment with BABA in both Golden Delicious and Fuji cultivars. ACC treatment also significantly increased the expression of ERF1 and CHIB genes after challenged with fungal spores. The expression of PR5 and ERF1 was relatively very similar in both cultivars after treatment with BABA and ACC, respectively. In contrast, the expression of CHIB was different in two cultivars, thus showing a 4 times higher expression in Golden delicious in compared to Fuji. Originality/Value: Using of new insecticides with new and widespread mode of action can be recommended against postharvest pest in the practical entomology. Research limitations: No limitations were found. Originality/value: The results of this study can be important in breeding studies and to select genes involved in the resistance mechanism. In addition, hormones with a positive impact to provide resistance to fungal diseases can be considered as a possible alternative to fungicides.
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