vacuum drying
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2022 ◽  
Vol 4 (3) ◽  
pp. 107
Nurwanto Nurwanto

Sari pandan merupakan hasil ekstraksi daun pandan. Sari pandan siap pakai yang beredar di Indonesia mayoritas berbentuk pasta, yang memiliki beberapa kelemahan, diantaranya mudah rusak, lengket, dan susah ditakar. Pembuatan sari pandan dalam bentuk bubuk diharapkan dapat meningkatkan mutu sari pandan. Metode yang digunakan dalam penelitian ini adalah pengeringan spray drying dan pengeringan vakum. Pengujian kadar air menunjukkan bahwa sari pandan yang dibuat dengan metode spray drying memiliki kadar air yang lebih rendah daripada metode pengeringan vakum. Pengamatan sifat fisik sari pandan dalam kondisi siap pakai menunjukkan bahwa metode spray drying menghasilkan warna dan aroma sari pandan yang lebih kuat daripada metode pengeringan vakum. Uji organoleptik menunjukkan bahwa panelis lebih menyukai warna dan aroma sari pandan yang dibuat dengan metode spray drying. Pandan extracts is made from pandan leaves. The majority of ready-to-use pandan extracts in Indonesia are in the form of pasta which has several disadvantages, including perishable, sticky, and hard to be measured. Pandan extract in powder form is expected to improve the quality of the pandan extract. The method used in this study are spray drying and vacuum drying. Water content analysis shows that pandan extract made by spray drying method has a lower moisture content than the vacuum drying method. Observation of the physical properties of pandan extract in ready-to-use form showed that the spray drying method produced stronger color and aroma than the vacuum drying  method. Organoleptic tests showed that panelists preferred the color and aroma of pandan extract made using the spray drying method.

Foods ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 112
Tea Sokač ◽  
Veronika Gunjević ◽  
Anita Pušek ◽  
Ana Jurinjak Tušek ◽  
Filip Dujmić ◽  

Valorisation of grape pomace, a by-product of the winery industry, has been pushed into the spotlight in recent years since it can enable lower environmental impact, but it can also bring an added value to the wine production process by recovering several grape pomace biologically active compounds. The first step that allows for grape pomace reuse is its drying, which should be carefully performed in order to preserve the biologically active compounds’ stability. In this study, the effects of different drying methods on the stability of polyphenols, tannins and tartaric acid in grape pomace (Vitis vinifera) cv. Graševina were investigated. In particular, vacuum drying (at different temperatures: 35, 50 and 70 °C), conventional drying at 70 °C and open sun drying were performed and the drying kinetics was described using Peleg’s model. Considering the processing time and thermodynamics, vacuum drying at 70 °C was the most convenient processing method. Polyphenols were highly stable during drying, and slight degradation occurred during vacuum drying at 35 and 50 °C. Tannins and tartaric acid were more prone to degradation depending on the drying method applied and showed the greatest stability during vacuum drying at 70 °C.

2021 ◽  
Vol 116 ◽  
pp. 111-122
Ewa Dobrowolska ◽  
Andrzej Klimczak

Temperature distribution in beech wood during vacuum drying. The temperature distribution and changes in humidity in beech wood in the form of friezes during drying in a vacuum were analysed. The intensity of the occurring phenomena of desorption and the volumetric flow of moisture through the anatomical structures of the wood, depending on the absolute pressure and the temperature of the process, was determined. It was found that the fastest temperature increase took place in the subsurface layers directly adjacent to the heating plates. The introduction of conditioning between the drying phases made it possible to even out the humidity and temperature distribution in the entire element. On the basis of the analysis of changes taking place between the volumes of the three components of wood, it was found that the volume of moisture in the form of vapor removed in the initial phase of drying is over 20 times greater than the volume of voids in wood structures, and in the following phases it decreases to 0.27. The average volume of vapour removed from 1 m3 of wood at the temperature of 55℃ is 13.9 m3/h, decreasing in the following phases to 9.1 m3/h at the drying temperature of 60℃ and then 3.1 m3/h at the temperature of 65℃. The drying rates for these phases reach the value of 0.15%/h, 0.17%/h and 0.075%/h, respectively. Direct measurements of wood moisture, made during the experimental course of the drying process at an absolute pressure of 150 hPa, follow the equivalent moisture, determined on the basis of the Hailwood-Horrobin model, taking into account the appropriate calculation factors.

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