engleski

Ultrasound-assisted extraction of proteins and sugars from the dried pulp of Curcurbita moschata pumpkin

Pumpkin is one of the inexpensive and widely available fruits grown mainly in tropical and subtropical countries. After harvesting, pumpkins can be kept for one to three months. After that, they become susceptible to microbial spoilage, moisture loss and colour changes. To extend the shelf life of pumpkins, various drying methods such as convection and vacuum drying can be used. These methods allow the use of pumpkin powder as an excellent ingredient rich in colour and nutrients in the production of various food products. In this context, the proposed work shows the results of protein and sugar evaluation of pumpkin powder obtained after drying the pulp with hot air at temperatures of 50, 60 and 70 °C and velocity of 1.5 and 0.5 m/s. The main objective of this work was to investigate whether the parameters used affect the extraction of proteins and sugars and whether the nutritional properties of pumpkin are maintained after drying. Extraction of two analytes from dried samples was performed by ultrasound-assisted extraction (UAE) at a frequency of 37 kHz, a temperature of 50 °C, and times of 20 and 40 min for protein and sugars, respectively. The results obtained by UV/Vis spectrophotometry showed that the dried samples had a high content of proteins (9.26-10.98%) and sugars (37.97-66.07%) depending on the drying temperature and air velocity. As the results show, there is not much difference among the dried samples in terms of protein content. However, the drying parameters had a stronger influence on the sugar content. The highest protein content (10.98%) was found in a pumpkin powder dried at 70 °C at an air velocity of 0.5 m/s, while the sugar content was highest in a sample dried at 60 °C at an air velocity of 0.5 m/s. Overall, the results showed that dried pumpkin powder is rich in proteins and sugars and therefore can be considered as an acceptable and valued food ingredient due to its nutritional potential. Acknowledgements: The work was supported by the Croatian Science Foundation (research project "Hybrid drying and valorization of plant food waste and by-products" IP-2019-04-9750) - HYDRYBY.

Curcurbita moschata ; pumpkin pulp ; hot air drying ; ultrasound-assisted extraction ; protein and sugars

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