Industrial Maltodextrin Production and Impacts on Dryer and Product Performance

Abstract

Maltodextrins are products of partial hydrolysis of starch and have been widely used in many types of processed foods. They are classified according to the degree of hydrolysis of the starch and have several properties such as sweetness, solubility, and viscosity. It also consists of a product with wide applicability, such as energy supplements. The product density is very important, since its variability may not meet the specification of some customer companies. This causes problems in the storage of the final product, causing a possible safety risk in storage. The product will not be positioned on the pallets or there will be damage to the packaging due to due storage, generating financial losses or product returns. The decision to conduct current research on maltodextrin quality control has matured after realizing that the final density has an impact on storage and on the customers’ satisfaction. This work aims to verify the influence of spray drying parameters on the apparent density of maltodextrin in six batches. After the evaluation, it was identified that the vacuum variation in the spray dryer caused deviations in the final product density. In addition, the mass and executive energy balance is calculated when drying the maltodextrin batches. The process losses and the thermal efficiency of the spray dryer were calculated in this study for future knowledge and actions. The glass transition temperature was evaluated in the spray dryer operating conditions and considerations were made for studies. The study showed that among the quantified parameters, the vacuum applied in the spray dryer that influenced the apparent density of maltodextrin and the operation of the dryer should operate with an average vacuum of 44 mmCa, since the other drying parameters presented similar values and, therefore, without influence on apparent density. The mean porosity of maltodextrin was 0.7018±0.017. According to manufacturer information (NIRO-GEA), the evaporation capacity is 1200.00 kg·h?¹ and the average of the evaporated water mass rate in the system is 876.66 kg·h?¹, which leads to the conclusion that the spray dryer was operating at 73% of the design capacity during the production phase.

The density of the liquor is 1310.62±2.81 kg·m?³. The mean mass rate of maltodextrin not recovered in the process calculated by mass balance is 269.53±122.90 kg·h?¹. The drying system showed an energy loss rate of 1,792,962 ± 55,349kJ·h?¹, which consists of a loss of 17%. The thermal efficiency of the system was 0.27±0.01, which means that 27% of the energy is used for drying the product. The value of the glass transition temperature (Tg) calculated for this drying system is between 150.0°C to 151.8°C, the output temperature of the dryer chamber between 106.12°C to 107°C and the air inlet temperature in the dryer between 192.08°C to 196.43°C. The internal operating temperature of the dryer is below the glass transition temperature of the final product. This makes it possible to classify the product as vitreous.