Bruise susceptibility in pome fruits under different loading and storage conditions

Samples of "Golden" and "Granny Smith" apples and "Conference" and "Doyenne of Cornice" pears have been tested. A great effect of storage conditions has been detected for pear but not for apple varieties. Both apple cultivars show to be equally resistant to quasi-static and to dinamic loading while pear varieties show great differences. All these effects can be quantified in order to describe mathematically species and varieties behavior.

Fruit quality sensing:Post-harvest ripeness

Firmness sensing of selected varieties of apples, pears and avocado fruits has been developed using a nondestructive impact technique. In addition to firmness measurements, postharvest ripeness of apples and pears was monitored by spectrophotometric reflectance measurements, and that of avocadoes by Hunter colour measurements. The data obtained from firmness sensing were analyzed by three analytical procedures: principal component, correlation and regression, and stepwise discriminant analysis. A new software was developed to control the impact test, analyse the data, and sort the fruit into specified classes, based on the criteria obtained from a training procedure. Similar procedures were used to analyse the reflectance and colour data. Both sensing systems were able to classify fruits w i th good accuracy.

Relationship between solar radiation on watercore on apple fruit assessed with MRI

This work is a preliminary studio of the possibility of assess a relationship between solar radiation and watercore development on apple fruit, during maturation, using a non destructive method such as Magnetic Resonance Imaging (MRI). For such purpose, several low cost solar radiation sensors were designed for the trial and placed at 2 different heights (1.5 and 2.5 m) on 6 adult ?Esperiega? apple trees, in a commercial orchard in Ademuz (Valencia). Sensors were connected along 27 days, during the end of the growth period and start of the fruit maturation process, and radiation measurements of the a-Si sensors were recorded every 1 minute. At the end of this period, fruits from the upper and the lower part of the canopy of each tree were harvested. In all, 152 apples were collected and images with MRI. A Principal Component Analysis, perfomed over the histograms of the images, as well as segmentation methods were performed on the MR images in order to find a pattern involving solar radiation and watercore incidence.

Influence of climate change on the flowering of temperate fruit trees

It is well known that winter chilling is necessary for the flowering of temperate trees. The chilling requirement is a criterion for choosing a species or variety at a given location. Also chemistry products can be used for reducing the chilling-hours needs but make our production more expensive. This study first analysed the observed values of chilling hours for some representative agricultural locations in Spain for the last three decades and their projected changes under climate change scenarios. Usually the chilling is measured and calculated as chilling-hours, and different methods have been used to calculate them (e.g. Richarson et al., 1974 among others) according to the species considered. For our objective North Carolina method (Shaltout and Unrath, 1983) was applied for apples, Utah method (Richardson et al. 1974) for peach and grapevine and the approach used by De Melo-Abreu et al. (2004) for olive trees. The influence of climate change in temperate trees was studied by calculating projections of chilling-hours with climate data from Regional Climate Models (RCMs) at high resolution (25 km) from the European Project ENSEMBLES (http://www.ensembles-eu.org/). These projections will allow for analysing the modelled variations of chill-hours between 2nd half of 20C and 1st half of 21C at the study locations.

Actual state of the mechanization of harvest of fruits and vegetables in Spain.

A review of the actual methods of harvest of fruits and vegetables in Spain is made. Special emphasis is given to the main horticultural Spanish crops that can be harvested by machines like green, beans, green peas broad beans, tomatoes, lettuces and chufas, as vegetables, and olives almonds, cherries, apples pears apricots, etc. as fruits.

Impact parameters related to bruising in selected fruits.

Impact testing with an instrumented free-fallingmass (50.4 g) device was applied to three varities of pears and two varieties of apples, forincreasing ripeness stages and impact energy (2 to 20 cm drops). Impact parameters were studied in relation to bruise and to ripeness, establishing relations between them and with the different characteristics of the fruits.

Impact bruises in pomaceae fruits: Evaluation methods and structural features.

Using a laboratory impact tester, impacts were applied to fruits of different varieties of apples and pears. The response to impact was analized, and many parameters were recorded, to be correlated to bruise susceptibility and to ripeness changes. Different methods for the detection and evaluation of the bruised Area and its features were studied, using direct observation and various reactives. Different types of bruises were established.

Impact parameters in relation to bruising and other fruit properties.

Impact response in fruits, primarily appl.es and pears (Pomaceae fruits), has been studied during the last five years. Using a laboratory impact testing device and also free-fall tests of instrumented apples, a significant body of results has been established, relative to the parameters which best characterize the impact response of these materials, and to their correlation with bruise damage, variety and ripeness level of the fruits. Bruise damage, measured as the size and/or volume of the affected fruit tissue is related primarily to applied energy (i.e. mainly drop height) for a given variety at a given ripeness stage. The relevant impact response parameters are maximum deformation (DM), permanent deformation (DP), maximum impulse (IM), maximum impact force (FM), maximum value of the force/time slope during impact (F/T) and impact time (T). The effect of ripeness differences was also studied in selected varieties of pears, being the most relevant parameters: maximum force (FM) and F/T slope.

Sensing physical stage of fruits by their response to non destructive impacts.

Fruits of two varieties of both apples and pears were tested in the laboratory to measure their response to a small energy impact applied by an impact tester. Samples of fruits of increasing maturity were tested during several weeks. Non-destructive impacts and other destructive and non-destructive measurements of post-harvest ripeness were applied. A new software was created to control the impact test, calculate the eleven parameters, and sort out the fruit. This software needs a data base and may create new ones. The implementation of an on-line impact device for automatic detection of texture is being designed (patent pending).

Factors influencing apple and pear physical properties and bruise susceptibility.

Fruit turgidity and firmness have shown to influence impact bruise susceptibility in apples and pears. Analysis of the impact response showed that stresses in the tissues are higher in turgid fruits, so they are more susceptible to bruising. A physical parameter, deformation at skin puncture, was able to detect fruit turgidity changes and showed to be related to bruise susceptibility.

Controlling moisture loss as a tool to reduce bruise susceptibility.

A method to reduce the bruise susceptibility of apples by controlling the moisture loss of the fruit was evaluated. Previous research indicates that reduction of the relative humidity of the storage air leads to an immediate effect on the weight loss and on skin properties and to a lower bruise susceptibility of apples. The diffusion equation is used to determine the waterpotential profile inside the fruit during storage. Characteristics of the waterpotential distribution in the fruit are related to measured bruise volumes. The results indicate how /this model can be used to control bruise susceptibility.

Influence of fruit turgidity and firmness on apple bruise susceptibility.

Bruise damage is a major cause of quality loss for apples. It would be very useful to establish a method of characterizing bruise susceptibility in order to improve fruit handling, sometimes Magness-Taylor firmness is used as an indirect guide to handling requirements. The objective of the present work was to achieve a better bruise susceptibility prediction.

Effect of impacting radius of curvature on firmness sensing of fruits in a sorting system.

Fruits of two varieties of both apples and pear were tested to measure their response to small energy impact applied by a impact tester with two spherical tips of different radious of curvature ( RA = 2.48 cm and RB = 0.98 cm) and equal mass were used. In the four varieties studied, the size of bruise was smaller with a spherical tip RA than with tip RB . The non-destructive impact test would cause less damage with a spherical impactor with a radious bigger than 0.98 cm.

Mealiness assessment in fruits using MRI techniques.

Mealiness is a sensory attribute that cannot be defined by a single parameter but through a combination of variables (multidimensional structure). Previous studies propose the definition of mealiness as the lack of crispiness, of hardness and of juiciness. Current aims are focused on establishing non destructive tests for mealiness assessment. MultiSliceMultiEcho Magnetic resonance images (MRI, 64*64pixels) have been taken corresponding to a 3ms of Echo time. Small samples of Top Red apples stored 6 months at controlled atmosphere (expected to be non mealy) and 2°C (expected to be mealy) have been used for MRI imaging. Three out of four apples corresponding to the sample maintained at controlled atmosphere did not develop mealiness while three out of four fruits corresponding to the sample stored at 2°C became mealy after 6 month of storage. The minimum T2 values/image obtained for the mealy apples shows to be significantly lower when compared with non mealy apples pointing that a more dis-aggregated structure leads to a quicker loss of signal Also, there is a significant linear correlation (r=-0.76) between the number of pixels with a T2 value below 35ms within a fruit image and the deformation parameter registered during the Magness-Taylor firmness test. Finally, all the T2 images of the mealy apples show a regional variation of contrast which is not shown for non mealy apples. This variation of contrast is similar to the MRI images of water-cored apples indicating that in these cases there is a differential water movement that may precede the internal browning.

Fruit by fruit identification of mealy peaches. Extraction of storage features.

Mealiness is a negative attribute of sensory texture, characterised by the lack of juiciness decrease in the total amount of of water content of tissues. Peach mealy textures are known as \ and leatheriness. Besides the lack of juiciness and flavour, that characterises mealy fruits, in associated with internal browning near the stone and an incapacity of ripening although there i ripe appearance. It is considered as a physiological disorder that appears in stone fruits probably < unbalanced pectolitic enzyme activity during storage. Since January 1996, a wide EC Project entitled: "Mealiness in fruits. Consumer perception and i detection" is being carried out. Within it, the Physical Properties Laboratory (ETSIA-UPM) working to develop instrumental procedures to detect mealiness in different types of fruits (s contributions by Barreiro to AgEng). The results obtained have shown to correlate well with \ measurements in apples (Barreiro et al), also we have succeeded in identifying individual mealy j the basis of instrumental measurement in peaches. The definition of these texture categories will be used in further studies as a base for new individual classification.