Resumen de Determinacion de la fecha optima de cosecha mediante metodologias de referencia y no destructivas en manzanas 'royal gala' y 'golden smoothee'
The aim of this work was to establish a better criterion in the selection of the optimum harvest period for 2 apple cultivars in Catalonia (Spain). The optimum harvest period was defined as the period giving the best consumer evaluation and quality, measured using reference and non destructive tests as well as some antioxidant compounds were evaluated as possible objective measures. For this purpose, quality of #Royal Gala# and #Golden Smoothee# apples, by reference and non destructive tests, was evaluated at harvest and after 8 months of cold storage in a controlled atmosphere with ultra low oxygen (CA-ULO, 0.5ºC; 1% O2; 1% CO2) during 2002, 2003, and 2004. The apples studied were obtained from 12 different orchards and harvested on a weekly basis during 6 weeks for each year. In parallel, consumer tests were carried out at two different locations in Spain (Girona and Lleida) after storage. Two complementary assays were carried out on #Golden Smoothee# apples. First, antioxidant compounds and ethylene production in relation to temperature were evaluated, during 2003 and 2004, to propose a biochemical marker to follow quality changes during the harvest period. The second assay was carried out in 2004 to compare the capability of non destructive techniques (Acoustic Firmness Sensor (AFS), IQ # Sinclair and lateral impact LPF-UPM) to follow quality changes, and to study the influence of harvest dates, turgidity before and after a dehydration treatment and ripening after different storage periods on the readings using these non destructive techniques.
For #Royal Gala# apples, intermediate harvest dates (harvest dates, 3 and 4) received the best consumer scores, while for #Golden Smoothee#, later harvest dates (5 and 6) received the best scores. For both cultivars, the De Jager index appeared to be the most appropriate for differentiating between harvest dates within a given harvest period. The models proposed were able to estimate consumer expectations for both cultivars and most of the parameters involved in the estimation of consumer expectations could be measured non destructively. Ascorbate level and catalase activity were interesting markers to follow changes in maturity exhibited by #Golden Smoothee# apples. Catalan consumers preferred firm, less acidic and less sweet #Royal Gala# apples while they preferred firm, more acidic and sweeter #Golden Smoothee# apples. AFS was only able to follow changes during harvest for #Royal Gala# apples but during storage changes for both cultivars could be followed. The correlation between M.T. firmness and acoustic parameters was significant for #Royal Gala# apples both at harvest and postharvest while for #Golden Smoothee# apples no correlation was found at harvest nor postharvest. For #Golden Smoothee# apples, acoustic firmness seemed not to be correlated with IQ#Sinclair, lateral impact LPF-UPM, puncture nor ball compression texture test. Acoustic parameters seemed to be more appropriate to predict consumer satisfaction for #Royal Gala# than #Golden Smoothee# apples.
