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Abstract

Investigations on a widely distributed variant Navel orange led to the need for reproducible, quantitative measurements of flesh firmness of orange fruits. Previous work using pressure devices on the surface of transversely-cut citrus fruits had resulted in erratic results. Whole fruit compression tests failed to show significant differences between samples of the variant and normal fruits (Table 1). In preliminary trials, dropping a pointed rod a given distance through a guide tube onto the transversely-cut fruit gave reproducible results. On the basis of the preliminary results, the present instrument, Fig. 1, was constructed and used in subsequent tests comparing variant Navel oranges with normal Navel oranges. In all plantings tested, the variant trees could be identified by means of the differences in the penetrometer measurement. The absolute values varied from planting to planting and on different sampling dates, but the differences between the two fruit types were always detectable. Results from the first plantings sampled are given in Table 1.

Open Access

The influence of photosynthetic photon flux (PPF) on peach [Prunus persica (L.) Batsch] fruit quality and the relationship between ground color and flesh firmness was studied by performing three experiments. Fruit with varying ground colors were sampled from different canopy positions with varying PPF. Fruit skin color was measured with a tristimulus colorimeter and values for L* (lightness), chroma (brightness), and hue angle (numerical values for color) were calculated for each fruit. Fruit from the canopy exterior generally were larger, had more surface area colored red, had higher soluble solids concentrations, and were darker, duller, and redder than fruit harvested from interior positions. In all three experiments, the relationship between hue angle and fruit firmness was affected by PPF, but the nature of the relationship (linear vs. curvilinear) and the influence of position was not consistent. When fruit were covered with aluminum foil or a section of the fruit surface was covered with duct tape to prevent light-induced red coloration of the skin, the relationship between hue angle and fruit firmness was similar for different canopy positions. Therefore, the relationship between ground color and fruit firmness is influenced by the light environment in which a fruit develops, and not by canopy position. Ground color does not seem to be a good indicator of fruit firmness because fruit with the same hue angle had greatly differing firmnesses.

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total). Treatments were applied to single tree plots arranged in randomized complete block design experiments with four replications. Flesh firmness was measured with a penetrometer fitted with an 11.1-mm tip (Effegi, Alfonsine, Italy) on opposite pared

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Authors: , , and

Abstract

Prior to 25 Oct., about 4-6 weeks (1983) or 3-5 weeks (1984) after the normal commercial harvest period, 1-aminocyclopropane-l-carboxylic acid (ACC), ethylene-forming enzyme (EFE), and internal ethylene concentration (IEC) in ‘Golden Delicious’ (Malus domestica Borkh.) apples attached to the tree were low. Thereafter, they began to increase rapidly. The increase in both ACC and IEC was earlier in detached preclimacteric fruit than in fruit attached to the tree. The increase of EFE coincided with that of IEC in detached fruit kept at 20°C. Attached fruit subsequently attained a higher level of ACC but a lower level of IEC as compared to the detached fruit. The results suggest that inhibitor(s) supplied from the tree not only delayed the accumulation of ACC in the fruit but also greatly inhibited its subsequent conversion to ethylene. Once the ripening process is initiated, the development of EFE precedes the development of ACC synthesis in both attached and detached fruit. Since attached fruit showed a steady loss of flesh firmness, green skin color, and starch, these changes did not appear to be related directly to the levels of ACC and internal ethylene. Detached fruit stored at 0° accumulated ACC and increased IEC slightly earlier than those stored at 20°. The magnitudes of these increases during subsequent storage at 0° were, however, smaller than those at 20°.

Open Access
Authors: , , and

Abstract

Firmness loss, increase in 1-aminocyclopropane-l-carboxylic acid (ACC) concentrations, and increase in internal ethylene concentrations were greatest in airstored fruit of ‘Golden Delicious’ apple (Malus domestica Borkh.) and lowest in controlled-atmosphere (CA)-stored fruit receiving a “rapid CA” or a “prestorage high carbon dioxide” storage procedure. Changes in apples kept in “slow CA” were intermediate. The accumulation of ACC in fruit was related closely to the subsequent flesh softening and increase in internal C2H4 concentration, and these processes were suppressed to different degrees in CA-stored fruit, depending on the storage procedures.

Open Access

, and time ( Letaief et al., 2008 ). Sensory attributes such as skin friability, skin thickness, and flesh firmness have been proposed to characterize commercial table grape cultivars ( Cliff et al., 1996 ). Recently, mechanical investigation into grape

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fruit is flesh firmness. Traditionally, this index is measured by destructive methods using a Magness-Taylor-type penetrometer. Because this technique involves penetrating the fruit flesh with a plunger, followed by recordings of maximum force, the fruit

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attributes. During fruit development, SSC at harvest is an indicator of fruit maturity, and DM content reflects the potential SSC at eating ripeness once starch reserves have been converted to sugar ( Burdon et al., 2004 ; Feng et al., 2011 ). Flesh firmness

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Authors: and

) , in which affected tissues remain firm and juicy and the disorder is distinct from senescent breakdown. This flesh browning is assumed to be a chilling injury (CI) ( Snowden, 1990 ). In ‘Empire’ apples, the disorder typically becomes apparent in May

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before applications and again after each weekly drop count. Parameters of fruit quality [flesh firmness, skin color, flesh color, soluble solids content (SSC), titratable acidity (TA), starch index (SI), and internal ethylene concentration (IEC)] were

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