Influence of parameters of drying on laser induced diffuse reflectance of banana discs

Banana discs of 1 cm thickness were immersed into different antioxidant solutions to slow down potentially disturbing discoloration during drying. Samples were randomly split into 8 groups according to the 2^p experimental design. Two antioxidant solutions with 1.66% and 4.59% ascorbic acid, two levels of drying temperature with 50°C and 80°C, two levels of drying time with 6h and 8h were used or adjusted. Laser diodes of seven wavelengths (532, 635, 650, 780, 808, 850 and 1064 nm) were selected to illuminate the surface and light penetration pattern was evaluated on the basis of radial profiles. Profiles acquired at three wavelengths (532, 635 and 650 nm) were found to respond sensitively to adjusted parameters. As a result of drying, intensity decay was observed to move closer to incident point. Significant effect (p<0.01) of temperature, drying time and their interaction was found on extracted descriptive attributes of intensity profiles: full width at half maximum (FWHM), distance of inflection point (DIP) and slope of logarithmic decay (SLD). Beyond their presence, antioxidant concentration was neutral factor without significant contribution to the model. Results were in agreement with reference spectroscopic measurements, especially with NDVI index. Promising results suggest that evaluated method might be suitable for monitoring purposes during drying of fruits.

Susceptibility of raspberry cultivars to the raspberry cane midge (Resseliella theobaldi BARNES)

During the 2004 growing season, five raspberry cultivars were evaluated in terms of their susceptibility to the raspberry cane midge (Resseliella theobaldi Barnes). The trial was carried out at Berkenye, Nógrád County, Hungary. The cultivars evaluated were ‘Rubaca’ from Germany, ‘Fertődi Zamatos’ from Hungary, ‘Tulameen’ from Canada, and ‘Autumn Bliss’ and ‘Golden Bliss’ from the United Kingdom. Every other week, twenty-five split primocanes of each cultivar were randomly collected for laboratory examination. Data recorded for each cultivar included the mean number of larvae, the mean split length, and the mean extent of bark peeling per primocane. Pearson’s linear correlation coefficients were calculated for the correlations between the annual mean number of larvae per primocane on the one hand, and the annual cumulative mean split length per primocane and annual mean extent of bark peeling per primocane on the other hand. There was a weak correlation between annual mean number of larvae and annual cumulative mean split length, and a stronger correlation between annual mean number of larvae and annual mean extent of bark peeling. Annual mean number of larvae per primocane and annual mean extent of bark peeling per primocane were both highest in ‘Rubaca’, which means that the number of larvae per cane largely depends on the extent of stem peeling, although longitudinal splitting may also play a role. Therefore, cultivars with hardly any bark peeling and few and small longitudinal splits can be presumed to be less susceptible to infestation by the raspberry cane midge. Using these criteria, the least susceptible of the five cultivars evaluated would be ‘Tulameen’ and ‘Fertődi Zamatos’. Further research is needed to confirm this conclusion and to gather data on other factors which affect cultivar choice for new plantations, including winter hardiness, and susceptibility to cane diseases.