The main objective was to investigate the effect of ultrasound‐assisted osmotic dehydration (UOD) pretreatment on the dehydration kinetics and the physicochemical properties of pomegranate seeds using a response surface methodology, in order to optimize the process. Quality attributes of seeds were estimated through the assessment of physical and thermal characteristics. Results showed a good correlation of experimental values with the model. The optimum conditions used for UOD and osmotic dehydration (OD) were found to be 240 min, 60°Brix, 41°C, and 240 min, 29°Brix, 50°C, respectively. UOD pretreatment led to a higher mass transfer rate than the OD process. UOD‐treated seeds reached the optimal moisture content (10%) and water activity (aw < 0.650) faster than both fresh seeds and OD‐treated seeds. Differential scanning calorimetry revealed that UOD pretreatment induced the loss of an important amount of water. X‐ray diffraction analysis showed that ultrasound pretreatment did not affect the amorphous characteristics of pomegranate seed powder during drying.
Practical applications
Ultrasound‐assisted osmotic dehydration could be a novel approach for food preservation and processing, due to the combined effect of osmotic pressure gradient and ultrasonic effect on the surface of the food material. Ultrasound pretreatment can be implemented as an alternative pretreatment to reduce drying time and, consequently, processing costs. Ultrasound‐assisted osmotic dehydration is gradually gaining attention as a pretreatment method due to its advantages which include preservation of antioxidant properties and bioactive compounds. This study provides information on the application of response surface methodology for the optimization of ultrasound‐assisted osmotic dehydration of pomegranate seeds.
Cite this articleSebii H, Karra S, Bchir B, et al. Physico-chemical, surface and thermal properties of date palm pollen as a novel nutritive ingredient. Adv Food Technol Nutr Sci Open J. 2019; 5(3): 84-91.
BackgroundDate palm pollen (DPP) is a natural product well-known in folk medicine in the Arab world. It is used to improve the fertility of human beings and studies have tested this activity on rabbits and rats. In the region of Sfax from Tunisia, a huge quantity of DPP could be discarded. Taking into account of the richness of this typical product of different components and of the trend of producing food supplements that could be sold at medium price comparing with the existing product, DPP was analyzed on the basis of physical and chemical properties in order to promote its use as a techno-functional ingredient in the agri-food and pharmaceutical field.
ResultsX-ray diffraction showed that DPP is characterized by an amorphous structure which leads to better techno-functional properties while stored in a water-air-tight container. Findings proved that DPP is capable to reduce the surface tension. Collected data from thermal analysis proved that DPP is thermally stable during storage and in different food systems.
ConclusionThe present study demonstrated that DPP could be used in the agri-food and pharmaceutical field. The obtained results help to define the suitable storage conditions of DPP and to predict its behavior when used as an ingredient. DPP can be used as a whole in food formulations or after extracting protein which is the main responsible agent for surfactant property. DPP proteins might be used as a food supplement in commercial sports nutrition products that can be sold at medium prices compared to some existing products.
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