Gh. Chegini, B. Ghobadian, M. Barekatin,
Volume 7, Issue 4 (winter 2004)
Abstract
The difficulties in the storage of fruit juice and the use of juice powder in various food processing industries has made the juice powder attractive to consumers and producers. Making powder from fruit juice is one of the most complex methods of fruit processing.The hygroscopic nature of fruit juice component and its thermoplastic properties has caused the drying time control and the transportation of the product from the drying zone to the next stage to become very difficult. In this investigation with laboratory spray dryer, the effective parameters on orange juice powder deposit on the wall of the spray dryer was studied. The results indicate that the powder can not be made without the use of additives. Using liquid glucose as an additive to orange juice concentration increased the dryer performance and reduced the wall deposit considerably. With the help of liquid glucose additive, spray dryer optimum conditions were obtained with a feed flow rate of 15 ml/min, inlet air temperature of 130oC and outlet air temperature of 85oC. The results from the statistical analysis of the experimental data show that the parameters of inlet air temperature and feed flow rate have significant effects on the dryer yield and wall deposit both individually and jointly. By increasing inlet air temperature and feed flow rate, the dryer yield decreased but wall deposit increased. In spite of using suitable additives, the wall deposit was still in the range of 14 to 65 %. The results of experiments indicate that the main cause of wall deposit can be attributed to the wall high temperature. It is, therefore, necessary to keep the wall temperature below the orange powder sticky point temperature to prevent rising temperature in wall deposit. For the orange powder containing 2% moisture, the sticky point temperature is 44oC. To control the wall temperature, a dryer with double partition wall chamber and a cooling system is proposed.
Homa Chegini, Chooghi Bairam Komaki, Majid Owneq, Hamidreza Asgari, Khalil Ghorbani,
Volume 30, Issue 1 (spring 2026)
Abstract
This study aimed to analyze the spatial–temporal correlation between the Vegetation Health Index (VHI) and climatic variables, including precipitation, potential evapotranspiration (PET), and mean temperature, in Golestan Province during the period 2000–2024. MODIS satellite products were used for vegetation and land surface temperature data, while the TerraClimate dataset provided precipitation and PET variables. After spatial–temporal alignment, the Cross-Correlation Function (CCF) was applied to identify optimal time lags, and the Random Forest model was employed to assess the relative importance of the climatic drivers. Turning to the results, increasing trends in mean temperature and PET were observed, alongside a significant decrease in precipitation, which led to intensified climatic stress and reduced VHI across the province, especially during summer in croplands and rangelands. The relationship between VHI and precipitation was positive (maximum correlation of 0.299 in croplands), negative with PET (−0.287), and non-linear with temperature (0.275). Notably, VHI responded to precipitation with short-term lags (0–1 month), whereas PET and temperature effects emerged with longer lags (2–4 months). The Random Forest analysis highlighted precipitation as the most influential factor on VHI, followed by PET and temperature, achieving strong predictive performance (R² = 0.78, RMSE = 0.09). Overall, these findings emphasize precipitation as the immediate driver of vegetation health, while PET and temperature act as secondary, cumulative stressors. The results provide valuable insights for developing climate adaptation and sustainable resource management strategies in agriculture and natural ecosystems of Golestan Province.
