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.

Tomatoes for processing in the 90's: Postharvest handling.

Processing tomato industry has a high potential in Spain. Variety testing and mechanization studies and applications have been performed during the last 15 years. Many factors affect the quality and product losses during post-harvest handling which may be classified as: main or external factors: those related to the systems, procedures and devices; and fruit factors: those related to fruit properties. A research project is being carried on in the area of Vegas del Guadiana (Badajoz, Spain) to study these factors and to estimate costs, and to develop improved post-harvest handling practices.

Physical parameters in relation to physiological changes of avocado during ripening (20ºc) and cold storage (6ºc) in different conditions.

The application of the response of fruits to low energy for mechanical impacts is described, for evaluation of post-harvest ripening of avocadoes of the variety "Hass". An impactor of 50g of weight, provided with an accelerometer, and free-falling from a height of 4 cm, is used; it is interfaced to a computer and uses a special software for retrieving and analyzing the deceleration data. Impact response parameters of individual fruits were compared to firmness of the pulp, measured by the most used method of double-plate puncture, as well as to other physical and physiological parameters: color, skin puncture ethylene production rate and others. Two groups of fruits were carefully selected, stored at 6º C (60 days) and ripened at 20ºC (11 days), and tested during the storage period. It is shown that, as in other types of fruits, impact response can be a good predictor of firmness in avocadoes, obtaining the same accuracy as with destructive firmness measurements. Mathematical and multiple regression models are calculated and compared to measured data, with which a prediction of storage period can be made for these fruits.

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).

Neural bruise prediction models for fruit handling and machinery evaluation.

Some neural bruise prediction models have been implemented in the laboratory, for the most traded fruit species and varieties, allowing the prediction of the acceptability or rejectability for damages, with respect to the EC Standards. Different models have been built for both quasi-static (compression) and dynamic (impact) loads covering the whole commercial ripening period of fruits. A simulation process has been developed gathering the information on laboratory bruise models and load sensor calibrations for different electronic devices (IS-100 and DEA-1, for impact and compression loads respectively). Some evaluation methodology has been designed gathering the information on the mechanical properties of fruits and the loading records of electronic devices. The evaluation system allows to determine the current stage of fruit handling process and machinery.

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.

Study of packing lines for stone fruits and citrus using two instrumented spheres in some cooperatives in the region of Murcia (Spain).

Two instrumented spheres IS 100 were used to evaluate the quality of post-harvest operations. Results obtained from measurements made with both IS (8.8 cm 0 and 6.2 cm 0) show significant differences. Both IS measure the same values of the same variables for soft materials, but not for hard surfaces. Four packing lines belonging to different cooperatives of the region of Murcia (two for stone fruits and two for citrus) were tested. IS values obtained in transfers belonging to the tested lines lay well above 50 g's in most of them Much higher impact intensities are registered in citrus lines than in stone fruit packing lines. To study the incidence of a certain packing line on different products an interaction fruit-packing line test was perf01med. In all cases, more than 50% of fruits belonging to the post-handling sample showed some kind of damage. Bruises evolve after 48 hours storage at room temperature.

Quality assurance systems in the production and marketing of fresh peaches.

Due to the fast rate of peach post-harvest ripening, damage due to mechanical handling, externally appreciated as bruises and soft areas, is a real problem that leads to an early harvesting and poor quality of the fruits, as perceived by the consumers. More and more, the European consumer asks for good taste and freshness of fruits and vegetables, and these quality factors are not included in standards, nor in most of the producers' practices. Fruit processing and marketing centres (co-operatives) are increasingly interested in adopting quality controls in their processes. ISO 9000 procedures are being applied in some food areas, primarily milk and meat processors, but no generalised procedures have been developed until the present time to be applied to fresh product processes. All different peach and nectarine varieties that are harvested and handled in Murcia cooperatives and sold in a large supermarket in Madrid were analysed during the whole 1997 season (early May to late August). A total number of 78 samples of 25 fruits (co-operative) or 10 fruits (market), were tested in the laboratory for mechanical, optical, chemical and tasting quality. The variability and relationships between all these quality parameters are presented and discussed, and sampling unit sizes which would be advisable for quality control are calculated.

Testing equipment for the improvement of mechanical devices to minimize damage to fruit in commercial packing lines.

Damages -reduced in fruit packing lines is a major cause of grace reduction and quality loos in fresh marks: fruit. Fruit must be treated gently during in sir handling to improve their qualityin order to get a good price in a competitive market. The correct post-hardvest handling in fruit packing lines is a prerequisite to cut down the heavy post-harvest losses. Fruit packing lines must be evaluated, studying their design, the impacts applied to the fruits, the characteristics of the materials, etc. This study establishes the possibility of carrying out modifications and tests in a packing line during a long period of time. For this purpose, an experimental fruit packing line has been designed and located in the Agricultural Engineering Department of the Polythecnic University of Madrid with the aim of improving mechanical devices and fruit handling conditions to minimize damage to fruit. The experimental line consists of several transporting belts, one rollers transporter, one sizer, one elevator, one singularizer, and three trays to receive the calibrated fruit. The line has a length of 6.15 m and a width cf 1.9 m. Movement of the different components is regulated by electric motors with variable velocity electronically controlled. The height of the transfer points is variable and can be easily modified. The experimental line has been calibrated using two instrumented spheres IS 100 (8.8 cm Ø and6.2cm Ø). Average acceleration values obtained in all the transfers of the experimental line lay under 80 g's, although there is big variation for some of them being some values above 100 g's.

Instrumental quality assessment of fresh peaches: Optical and mechanical parameters.

In developing instrumentation for the measurement of fruit quality, there is the need for fast and non-destructive devices, based on sensors, to be installed on-line. In the case of some fruits, like peaches, post-harvest ripeness, which is closely related to high quality for the consumer, is a priority. During ripening, external appearance (colour) and internal mechanical (firmness) and chemical (sugars and acids) quality are main features that evolve rapidly from and unripe to a ripe (high quality) stage. When considering the evolution of fruit quality in this scheme, external colour and firmness are shown to evolve in a parallel pattern, if monitored from the time of harvest to full consumer ripeness ( Rood, 1957; Crisosto et al, 1995; Kader, 1996). The visible (VIS) reflectance spectrum is a fast and easy reference that can be used to estimate quality of peaches, if we could show it to be reliably correlated with peach ripening rate during postharvest (Genard et al. 1994; Moras, 1995; Delwiche and Baumgartner, 1983; Delwiche et al. 1987; Slaughter, 1995; Lleo et al., 1998). Taste, described as an expert acceptance score, improves with ripeness (firmness and colour evolution), when considering the fruits on the tree, and also post-harvest.

Análisis de las diferencias en el crecimiento vegetativo, en los componentes del rendimiento y en la composición de las uvas y vinos del cv. cabernet sauvignon (vitis vinifera L.), producidos por el déficit hídrico durante pre-envero y post-envero

La presente Tesis Doctoral se realizó con el fin de estimar conjuntamente la respuesta agronómica y fisiológica de la vid (Vitis vinifera L.), así como los efectos sobre la evolución de la maduración, composición y la calidad de la uva y del vino, bajo la aplicación de diferentes déficit hídricos en pre-envero y post-envero, dentro de un marco de referencia de cambio climático. La variación climática que prevén los estudios sobre el cambio climático, resulta un factor decisivo en la eficiencia del uso del agua en la vid. En zonas cálidas, las estrategias de cultivo del viñedo frente al cambio climático deben de ir dirigidas a atenuar sus efectos sobre el crecimiento y el desarrollo de la vid, haciéndose imprescindible el estudio pormenorizado del déficit hídrico como factor decisivo en la obtención de las uvas adecuadas, ya que son la clave indispensable para el éxito en la elaboración del vino, y de forma muy especial en los vinos enfocados a un sector de alta calidad. El ensayo se llevó a cabo en un viñedo comercial de Bodegas Licinia, en la Comunidad de Madrid, durante los años 2010 y 2011. La variedad estudiada fue Cabernet sauvignon / 41 B, plantada a un marco de plantación de 3 m x 1 m, con un guiado vertical de la vegetación. El dispositivo experimental fue totalmente al azar, y se establecieron 4 tratamientos experimentales con 4 grados de disponibilidad hídrica, déficit moderado continuo (T0,45-0,6), déficit severo continuo (T0-0,3), déficit severo después de envero (T0,45-0,3) y déficit severo antes de envero (T0-0,6). En cada tratamiento se distribuyeron 3 repeticiones. El año 2010 fue el más lluvioso de los años de ensayo, con 478 mm de precipitaciones anuales, lo que supuso 146 mm más que en el año 2011. Su distribución a lo largo del ciclo fue más homogénea en el año 2010, mientras que en 2011 las precipitaciones contabilizadas en el período de maduración de la uva fueron nulas. La temperatura media subió 0,9ºC en 2011, respecto a 2010 y en cuanto a la integral térmica eficaz, en 2011 se acumularon, desde el 1 de abril hasta el final de ciclo, 217 grados•día más que en 2010. El déficit hídrico en pre-envero, modificó notablemente el crecimiento vegetativo y la producción de cosecha de la parcela de ensayo, no así la fertilidad de las yemas. El tratamiento con mayor disponibilidad hídrica (T0,45-0,6) obtuvo el mayor peso de baya, y los tratamientos con menor déficit hídrico en pre-envero (T0,45-0,6 y T0,45-0,3) registraron los mayores rendimientos de cosecha, mientras que las menores tasas de cuajado correspondieron al tratamiento con un déficit severo continuo (T0-0,3). La parcela de ensayo se caracterizó por un exceso de vigor y un alto crecimiento vegetativo. El pH del mosto se vio afectado por el déficit hídrico, disminuyendo su valor en el tratamiento de déficit hídrico severo antes de envero (T0-0,6). Organolépticamente, no se percibieron diferencias significativas en los vinos elaborados en función del déficit hídrico, y respecto a su composición físico-química, solo existieron diferencias en la concentración de ácido L-Málico, con mayores concentraciones en los tratamientos sin déficit hídrico en pre-envero, T0,45-0,6 y T0,45-0,3. El déficit hídrico modificó notablemente el color del vino, aumentando los valores de las coordenadas CIELAB a* y b*, la luminosidad (L*), croma (C*) y tonalidad (H*), para los tratamientos con un déficit severo en pre-envero (T0-0,3 y T0-0,6) y disminuyendo estas en el tratamiento con mayor disponibilidad hídrica (T0,45-0,6). Del mismo modo, mediante el análisis de color por métodos tradicionales, IPT e IC de los vinos, aumentó en los tratamientos con mayor déficit hídrico en pre-envero (T0-0,3 y T0-0,6), respecto a los tratamientos de mayor disponibilidad (T0,45-0,6 y T0,45-0,3). La concentración de taninos de la baya en vendimia, no se vio afectada por el déficit hídrico, aunque sí estuvo relacionada positivamente con el tamaño de las bayas. Organolépticamente, los hollejos del año 2011 resultaron con menor frescura, acidez, afrutado, sensación herbácea e intensidad tánica, aunque con mayor astringencia respecto a 2010. Las pepitas fueron más astringentes y aromáticas pero menos crujientes, sin llegar a los niveles de madurez del año 2010. El catador relacionó los taninos con la calidad del vino, asociándolos con un mayor cuerpo, acidez, intensidad, equilibrio gustativo, amargor y menor astringencia en la fase gustativa. La concentración de taninos en los vinos se vio favorecida con el déficit hídrico en pre-envero y post-envero. Los tratamientos con mayor déficit hídrico en pre-envero, T0-0,6 y T0-0,3, obtuvieron las menores concentraciones de potasio en mostos y vinos. Las relaciones entre la concentración de potasio, ácido L-Málico y el porcentaje de color rojo puro (dA(%)) resultaron altamente significativas, de modo que las mayores tasas de potasio en el vino se asociaron a los valores más bajos de color rojo y a los mayores de ácido L-Málico. ABSTRACT The present Doctoral Thesis has been done in order to estimate the grapevine (Vitis vinifera L.) agronomic and physiologic performance or response as well as the impact in the grape and wine maturity, composition and quality evolution, with different water deficits. The variation in climate that the global warming studies for seen is a key factor for the grapevine water use efficiency. In warm areas the farming vineyards strategy to face the climatic change, should be focused on diminish the effects on the grapevine growth and development, so that the water deficit detailed analysis becomes decisive to obtain the appropriate grapes, that are the main subject for a successful wine production and especially for top quality wines. The trial was carried out in a commercial vineyard in Chinchón (Madrid), Licinia winery, during the 2010 and 2011 seasons. The grape variety studied was Cabernet Sauvignon grafted onto 41B with a vine spacing 3m x 1m trained as VSP. Experimental design consisted on 4 irrigation treatments with 3 replications totally randomized. Irrigation treatments were: moderate regulated deficit (T0,45-0,6), severe continuous deficit (T0-0,3), severe post-veraison deficit (T0,45-0,3) and severe pre veraison deficit (T0-0,6). The 2010 was rainier year than the 2011; Total annual rain in 2010 was 478 mm, which resulted in 146 mm more than in 2011. The distribution along the vine cycle was more homogeneous in the 2010, whereas precipitations in 2011 along the grape maturity period were nonexistent. The average temperature in 2011 was 0,9ºC higher than that of the 2010 and regarding to the thermal integral, in the 2011 from 1st April to the end of the growing cycle, was 217 degrees•day higher than that in 2010. Water deficit significantly modified the vegetative growth and yield but, it did not modified bud fertility. The treatment with the highest water availability (T0,45-0,6) got the highest berry size, the lowest berry set rates were found in the severe continuous deficit treatment (T0-0,3). The plot studied in this trial was characterized by both excessive vigour and vegetative growth. Water deficit modified the pH must by, reducing it in the severe water deficit during pre-veraison (T0-0,6). There were not differences in wine tasting between the water deficits treatments. Regarding to the physical-chemical composition, it only existed differences in the L-malic acid concentration, resulting higher concentrations in the water deficit pre-veraison treatments: T0,45-0,6 y T0,45-0,3. Water deficit significantly modified wine colour by, increasing the CIELAB coordinates a* and b*, the brightness (L*), croma (C*) and tonality (H*), in the lower water availability pre-veraison treatments (T0-0,3 y T0-0,6), and reducing them in the in the moderate continuous water deficit ones (T0,45-0,6). By means of traditional wine colour parameters analyses, red colour percentage, TPI, they became higher in the lower water availability pre-veraison treatments (T0-0,3 y T0-0,6), than in those with higher availability (T0,45-0,6 y T0,45-0,3). At harvest, berry tannins concentrations was not affected by the water deficit although it did in a positive way, in the berry size. Berry tasting in 2011, resulted in a lower freshness, acidity, fruity, herbaceous flavour and tannic intensity, but with higher astringency respect to the 2010 season. Seeds, in 2011, were more astringent and aromatic as in the 2010, but less crunchy, without getting to the point of maturity. The taster linked the tannins to wine quality, associating them with a higher bodiest wine, acidity, intensity, taste balance, bitterness and with a lower astringency in the tasting stage. Treatments with a higher water deficit up to veraison T0-0,6 y T0-0,3 got less musts and wines potassium concentration. The relation between L-malic acid and the full red color percentage (dA(%)), were highly related, resulting the higher potassium content the lower wine quality.