Rheological properties of tomato concentrate were evaluated using a wide-gap rotational viscometer (Brookfield Engineering Laboratories: Model LVDV-II) at different temperatures of 20, 30, 40, 50, and 60oC, at concentration of 18, 12.18 and 8.04 % total solids, and at appropriate shear rate(1-100 RPM). The power law model was fitted to the experimental results. The values of flow behaviour index (n) were found less than unity (0.23 to 0.82) at all the temperature and the concentration indicating shear-thinning (pseudoplasticity) behaviour of the concentrate. The correlation between the observed consistency coefficient ranging from 0.09 to 65.87 Pa.sn and the inverse absolute temperature has been exhibited by Arrhenius model. Consistency coefficient increased exponentially with increase in the concentration. Statistical model was used for prediction of the consistency coefficient as a function of temperature and concentration which showed a good agreement (r2=0.99) between experimental and theoretical values. The magnitude of activation energy were found to be in the range of 8.6 to 14.08 kJ/mol.K.

Response surface methodology was used to investigate the effect of brine concentration (10% -20%) solution temperature (35˚C -55˚C), and duration of osmosis (30 -60 min) with respect to water loss (WL) and salt gain (SG). The solution to sample ratio of 5/1 (w/w) was used. The Box-Behnken design of three variables and three levels including seventeen experiments formed by five central points were used for optimizing input parameters. Linear, quadratic and interaction effects of three variables were analyzed with respect to water loss and solid gain. For each response, second order polynomial models were developed using multiple regression analysis. Analysis of variance (ANOVA) was performed to check the adequacy and accuracy of the fitted models. The response surfaces and contour maps showing the interaction of process variables were constructed. The optimum operating conditions were: solution temperature 44.89˚C, brine concentration of 16.53 per cent and duration of osmosis of 47.59 min. At this optimum point, water loss and salt gain were predicted to be 44.55 per cent and 2.98 per cent respectively.

White onions were dried using an osmo-convective drying technique. Osmotic dehydration was done by dipping the onion slices in 10, 15 and 20 brix NaCl solution at ambient temperature for one hour. The increase in the concentration of NaCl increased the water loss, solid gain and weight reduction in onion slices. The drying times of pre-osmosed onions slices at drying air temperature of 50, 60 and 70°C were 6.75, 6.00 and 5.25 h respectively. The moisture diffusivity increased with increase in air temperature and ranged between 0.83 and 0.91x10-10 m2/s. Quality of dried product in respect to flavour strength and color was superior. A lowest specific energy consumption of about 1.98 kWh/kg was found in the air drying of onions pre-treated with 20 brix NaCl solution and at air temperature of 70°C.

Rheological characteristics of pineapple juice have been investigated and rheological parameters were evaluated using rotational viscometer at temperatures 20, 30 and 40*C at concentration 26.77, 18.99 and 14 % total solids. The experimental results followed the power law model for the best fit and the values of flow behaviour index (n) was less than unity (0.08 to 0.87) at all temperatures and concentrations indicating the shear thinning (pseudoplasticity) nature of juice. An obvious correlation between consistency coefficient in the range of 0.1 - 37.16 Pa.sn and inverse absolute temperature has been exhibited by Arrhenius model. The Power equation indicated that the consistency coefficient increased non-linearly with an increase in concentration. Mathematical models were developed for prediction of the consistency coefficient as a function of temperature and concentration. A good agreement was observed between experimental and theoretical values of the consistency coefficient predicted by models. The magnitude of activation energy was found to be in the range of 3.67 to 4.62 kJ/mol.K.

In this paper features like size, shape, and external defects of agricultural products were discussed. Major steps in image processing like enhancement, morphological operations, geometric features, pattern recognition and texture features were explained. Merits and demerits of classification techniques like support vector machine, linear discriminative analysis, fuzzy k-neural network, multilayer perceptron, mahalanobis distance classifier and learning vector quantization were furnished. The overall success of attempts on apples, potatoes was discussed. This paper is concluded with the critical remarks over the performance analysis of various techniques undertaken to carry-out the algorithm efficiencies.