Obtenção e caracterização de hortelã em pó em spray dryer

Abstract

The spearmint (Mentha Spicata L.) is a typical herbaceous plant that belongs to Lamiaceae Family, possessing numerous varieties. Their leaves can be used fresh to produce tea, in cooking for preparation of sauces, in the production of candies and beverages, in the tobacco industry to aromatization of cigarettes and can be used as raw material to obtain menthol for pharmaceutical purposes. The dried leaves possess a high humidity chemical moisture composition, enabling microbial growth and making it perishable. Therefore, the drying of aromatic plants, such as spearmint, is an alternative to increase their shelf life. This procedure aims to remove a certain percentual of free water, avoiding the enzymatic and microbiological degradation processes, providing the conservation and extending their durability. Therefore, this work aims to obtain powder spearmint, with or without thermal pre-treatment, using spray dryer and to evaluate the physicochemical characteristics of the powder obtained. The pre- treatment used was the blanching process. Thereby, in addition to the effect of using or not the blanching process, the influence of temperature, drying air flow rate, and solution feed flow were also investigated. The results showed that the particulate material obtained with the blanching process presented, in general, a lower moisture value when compared to the particulate material obtained without going through the blanching process. Besides, the samples submitted to blanching process in the experiments with the lower temperature associated with lower feed flow and drying air flow also resulted in a less hygroscopic particulate material. As for color, the samples submitted to pre-treatment (blanching process) showed minor loss of color, resulting in greener particles with greater luminosity. The lowest bulk density results of the powder obtained with and without blanching were in conditions of higher entry drying temperatures. Blanching contributed to greater retention of carotenoid pigments and high levels of chlorophyll and total phenolics. The highest yield value observed was 50.24%, for the powder obtained with blanching produced at lower temperatures associated with high solution feed flow. Regarding the average diameter, the highest value mentioned for the powders with and without blanching was 3.018 μm. It is evident that the blanching powders presented spherical and smooth structures, with shorter wetting times.