Textural Quality Assessment for Fresh Fruits and Vegetables

Effect of post-harvest cold plasma treatment on physicochemical properties and inactivation of Penicillium digitatum in Persian lime fruit

Cold atmospheric plasma (CAP) treatment is used in this study to inactivate Penicillium digitatum in lime fruit at post-harvest. Limes were inoculated manually withP. digitatum spore (106 CFU/fruit) and then were treated with CAP at 30, 60, 90, and 120 s and compared with untreated samples. The results showed that increasing the exposure time of CAP reduced spores to less than 7 CFU/fruit in 120 s on the lime peel. In the treated samples, antioxidant activity had an upward trend. In addition, phenolic compounds, vitamin C, density, soluble solid content (SSC), color, and pH of the lime juice were increased (P < 0.05). Compared to the control sample, no significant changes were observed in the juice yield percentage, texture, acidity, chlorophyll, and carotenoid (P > 0.05). The best exposure for CAP treatment was 60 s since it increased phenolic compounds, antioxidant activity, and vitamin C content in the lime juice.

Rapid evaluation of the texture properties of melon (Cucumis melo L. Var. reticulata cv. Green net) using near infrared spectroscopy

The near infrared (NIR) spectroscopy as the rapid nondestructive method was aimed to be applied for determination of the texture properties of melon intact fruit and pulp including initial firmness, rupture force, average firmness, rupture distance, toughness, average penetrating force and penetrating energy. The data from the reference method of texture analyzer were correlated with the NIR spectral data. The result showed that, only the two properties including rupture force and penetrating force in pulp could be predicted by NIR spectroscopy technique. The determination coefficient of validation (r2 ) for prediction of rupture force and penetrating force in the pulp of melon using intact fruit spectra were 0.850 and 0.845, respectively. The r2 , for prediction of rupture force and penetrating force in the pulp of melon using pulp spectra were 0.813 and 0.778, respectively. This indicated that the NIR spectroscopy protocol developed here was useful for research works such as breeding and postharvest research, the melon processing factory and also the import and export of melon.

PRACTICAL APPLICATIONS

The near infrared spectroscopy protocol developed for determination of rupture force and penetrating force in pulp using intact fruit spectra as a nondestructive method will be useful for research works such as breeding and postharvest research, the melon processing factory and also the import and export of melon. There are also the protocol developed using pulp spectra can be used for texture determination of fresh-cut melon.

Influence of harvest day on changes in mechanical properties of grape berries

Changes in the composition, physical and mechanical properties occur in grape berries during the ripening process, but the heterogeneity of the grapes harvested at different ripening stages affects the reliability of the results obtained. The characterization of the mechanical properties of grape berries seems to be an important parameter for understanding grape ripening. In this work, these changes were studied in seven grapevine varieties (Riesling, Blaufränkisch, Pinot Noir, Cerason, Malverina, Laurot, and Hibernal) harvested during six consecutive weeks. Mechanical behaviour was measured using compression and puncture tests using of TIRATEST 27025 testing machine. Skin mechanical properties were evaluated using a puncture test carried out on the equatorial side. The dependence of these properties on the chemical composition has been evaluated. These parameters of force/time curves were studied by puncture test: the berry skin break force, the needle displacement at the skin break and the berry skin break energy. The crushing force, the plate displacement at the crushing strength and the berry crushing energy were studied from force/time curves by compression test. Results of the puncture test shows that there the skin break strength and the acidity content are monotonic functions of the time. A comparison of different varieties from the point of the value of the crushing force was obtained by vertical and transversal loading. The crushing force is monotonically decreasing function of the harvesting time like the break force evaluated at the puncture test. The correlation between the skin break strength and the sugar content is significant namely for the varieties: Hibernal, Riesling, Malverina, and Cerason.

Cell wall polysaccharide chemistry of peach genotypes with contrasted textures and other fruit traits

Cell wall composition, pectin, and hemicellulose fine structure variation were assessed in peach and related genotypes with contrasted texture and fruit shape. Cell walls were prepared from four commercial peaches, eight genotypes from the Jalousia × Fantasia peach cross, and six genotypes from the Earlygold peach × Texas almond cross. Sugar composition was determined chemically while fine structure of homogalacturonan pectin and xyloglucan hemicellulose were assessed by coupling pectin lyase and glucanase degradation, respectively, with MALDI-TOF MS analysis of the degradation products. The results indicate clear compositional and structural differences between the parents and their related genotypes on the basis of pectin versus cellulose/hemicellulose content and on the fine structure of homogalacturonan and xyloglucan. A relation between methyl- and acetyl-esterification of pectin with fruit shape is revealed in the Fantasia × Jalousia peach genotypes.