Maturity assessment at harvest and prediction of softening in an early and late (original) (raw)
Related papers
Analysis and Modelling of Firmness and Juiciness of Peaches, Subjected to Chilling Injury
Acta Horticulturae, 2012
Nectarine fruit after cool storage soften normally, but become sometimes dry instead of juicy. An experiment was conducted to see if time resolved reflectance spectroscopy (TRS) could distinguish this internal disorder non-destructively. The optical parameter of absorption coefficient µ a at 670 nm of nectarine (Prunus persica 'Morsiani 90') was measured at harvest and used to sort the fruit in 15 batches so that each batch had a similar range of fruit maturity according to the value of µ a at 670 nm. Fruit were stored at 20°C after harvest or after 30 days of storage at 0 or 4°C.
Postharvest Biology and Technology, 2007
Fruit firmness measurement is a good way to monitor fruit softening and to predict bruising damage during harvest and postharvest handling. Ripening protocols traditionally utilize a destructive penetrometer-type fruit firmness measure to monitor ripening. Until recently, methods of assessing fruit texture properties nondestructively were not commercially available. The nondestructive Sinclair iQ TM firmness tester was investigated to monitor ripening and predict bruising susceptibility in stone fruit. This work was carried out on four peach, three plum, and five nectarine cultivars over two seasons. The correlations between destructive and nondestructive firmness measurements were significant (p-value = 0.0001), although too low for commercial applications as they varied from r 2 = 0.60-0.71 according to fruit type. Using a different approach, the relationship between destructive and nondestructive firmness measures was characterized in terms of segregating these fruit according to their stages of ripening. This was done by using discriminant analysis (66-90% agreement in ripeness stage classification was observed in validation tests). Discriminant analysis consistently segregated nondestructive firmness measured fruit into commercially important classes ("ready to eat", "ready to buy", "mature and immature"). These represented key ripening stages with different bruising potentials and consumer acceptance. This work points out the importance to relate nondestructive measurements directly to important commercial physiological stages rather than to correlate them with the current standard penetrometer values. Thus, destructive and nondestructive firmness measurements can be directly used to identify the stage of ripeness and potential susceptibility to bruising during postharvest changes. Further work is recommended to evaluate the performance of this nondestructive sensor in segregating fruit according to their stage of ripeness under packinghouse or processing plant conditions.
A new index based on vis spectroscopy to characterize the progression of ripening in peach fruit
Postharvest Biology and Technology, 2008
In peach fruit (Prunus persica L. Batsch), establishing the optimal harvest time is a crucial issue, since fruit shelf-life potential and quality are closely related to the ripening stage at harvest. In order to develop a non-destructive index for monitoring the progression of ripening, the difference in absorbance between two wavelengths near the chlorophyll-a absorption peak (670 and 720 nm; index of absorbance difference, I AD ) was related to the time course of ethylene production during on-tree ripening of peaches (cv. 'Fayette') and nectarines (cvs. 'Laura' and 'Stark Red Gold'). For each variety, consecutive stages of ripening, as defined according to ethylene production (pre-climacteric, climacteric, post-climacteric), occurred in the same ranges of I AD in different years (2003 and 2004). In 2005, the relationship I AD /ethylene production was used to classify fruit at harvest according to their ripening stage (class 0: pre-climacteric; class 1: onset of climacteric; class 2: climacteric). For each cultivar, the transition from class 1 to 2 was marked by increased ethylene production, and reduced flesh firmness (FF) and titratable acidity (TA). In contrast, fruit quality traits did not discriminate between fruit belonging to classes 0 and 1. In 'Stark Red Gold' nectarines, the robustness of the I AD was further corroborated by changes in transcript levels of genes which are either up-or down-regulated during peach fruit ripening. Class 0 fruit had the lowest transcript amount of the up-regulated genes and the highest of the down-regulated ones, while the opposite occurred in class 2 fruit. Moreover, mRNA abundance of some marker genes discriminated class 0 and 1 fruit. Peaches and nectarines graded at harvest according to the I AD also differed in their postharvest ripening behaviour: fruit with higher I AD produced lower amounts of ethylene, began to soften later, and maintained higher TA than those with lower I AD . Present data demonstrate that the I AD identifies physiological changes occurring during ripening regardless of the fact that they might have or not led to appreciable modifications in fruit quality. Therefore, the I AD can be regarded as a very promising tool both for practical and scientific applications, since it allows to monitor on-tree fruit ripening, to establish accurately the optimal harvest time, and to reduce the variability which is present in fruit batches.
2006
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 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 R 2 = 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. (P.E. Zerbini). different wavelengths. Absorbance is related to light attenuation in the fruit, and it is affected by both light absorption and light scattering. To separate these two effects, timeor frequency-resolved methods are required. Time-resolved reflectance spectroscopy (TRS) is a non-destructive method for complete optical characterization of highly diffusive media, such as biological tissues and fruit (Cubeddu et al., 2001a,b). In TRS, a short laser light pulse is injected into the medium to be analyzed and the temporal distribution of re-emitted photons is detected and fitted with a theoretical model of light propagation, allowing the absorption coefficient µ a and the reduced scattering coefficient µ s to be measured simultaneously. In fruit such as apples, pears and nectarines the typical values of the optical parameters in the 600-1000 nm spectral range 0925-5214/$ -see front matter
Nirs Evaluation of Peach and Nectarine Fruit Quality in Pre- and Post-Harvest Conditions
V International Peach Symposium, 2002
Fruit quality at harvest is usually determined on the external appearance while internal fruit characteristics, which may better meet consumer expectations, are traditionally determined in a destructive manner on a given number of fruits. In the last few years, non-destructive methods using near-infrared spectroscopy (NIRS) to evaluate parameters for estimating maturity were applied to different fruits species so as to check ripening status directly on the tree or to grade fruits in the packing house. The present study reports the results recorded with two NIRS instruments, one portable and one stationary, used to estimate soluble solids content, flesh firmness, dry matter content and total titratable acidity in peach and nectarine fruits. The prediction of the considered quality parameters was similar to that based on data collected destructively, which were recorded as reference measures in both field and packing house conditions. The results showing the best fit were soluble solids.
A Spectroscopy-Based Approach for Automated Nondestructive Maturity Grading of Peach Fruits
IEEE Sensors Journal, 2015
This paper presents an automated approach for peach fruit maturity grading that, by exploiting fiber-optic spectroscopy-based sensors and multivariate processing techniques, minimizes the operator intervention while reducing discharge and waste. The use of a spectroscopic sensor complies with the socalled non-destructive measurement method, which enables fast repeated measurements to be performed at the single fruit level while avoiding fruit damage and loss. Maturity grading is accomplished by retrieving estimates of the fruit flesh firmness by means of multivariate retrieval techniques applied to the reflectance spectra acquired with the spectrometer and by processing the retrieved values within the framework of a maturity fuzzy classifier. A decision support system is developed to provide the user with maturity category decision and associated reliability. Experimental results show that the approach is effective for automated maturity grading of peach fruits affected by a high degree of variability. This work lays the foundations for the realization of easy-to-use sustainable automated maturity grading systems.
Assessing harvest maturity in nectarines
Postharvest Biology and Technology, 2007
The maturity at harvest of nectarines can be assessed with the novel technique of time-resolved reflectance spectroscopy (TRS) measuring the light absorption at 670 nm in the fruit flesh. A kinetic model was developed that links this absorption coefficient (μ a ), expressed as the biological shift factor, to firmness decrease during ripening. The model thus includes the variations in maturity at harvest of the individual fruit. In non-linear regression analyses of data from four different seasons, the explained part ranged from 81 to 92% for cv 'Spring Bright'. The kinetic parameters values obtained were highly similar in different seasons. The results suggest that in nectarines the degreening of fruit flesh, expressed as TRS absorption at 670 nm, is synchronised with the softening. The distribution of μ a was skewed, but that of the biological shift factor, derived from μ a , was normal. By measuring the colour of fruit flesh with the non-destructive and very rapid TRS technique, and applying the model parameters, individual fruit can be graded at harvest into classes of usability, selecting fruit with different ripening stages for different market segments and predicting their softening time, thereby guaranteeing sufficient firmness to transport the fruit and sufficient ripening potential to reach good eating quality upon arrival in the receiving regions or countries. Consumers therefore will be more satisfied, encouraging them to repeated purchase. Retailers and wholesalers will be more satisfied since fruit unfit for sale not longer needs to be transported.