Effect of Temperatures on Drying Kinetics, Extraction Yield, Phenolics, Flavonoids, and Antioxidant Activity of Phaleria macrocarpa (Scheff.) Boerl. (Mahkota Dewa) Fruits

Abstract

Phaleria macrocarpa or ‘Mahkota Dewa’ is a popular plant found in Malaysia as it is a valuable source of phytochemicals and therapeutic properties. Drying is an essential step in the storage of P. macrocarpa fruits at an industrial level to ensure their availability for a prolonged shelf life as well as preserving their bioactive compounds. Hence, this study evaluates the effect of different temperatures on the drying kinetics, extraction yield, phenolics, flavonoids, and antioxidant activity of P. macrocarpa fruits. The oven-drying process was carried out in this study at temperatures of 40 °C, 50 °C, 60 °C, 70 °C, and 80 °C. Six thin-layer drying models (i.e., Lewis, Page, Henderson and Pabis, two-term exponential, Logarithmic, and Midilli and Kucuk models) were evaluated to study the behaviour of oven-dried P. macrocarpa fruits based on the coefficient of determination (R2), root mean square error (RMSE), and chi-square (χ2). The quality of the oven-dried P. macrocarpa fruits was determined based on their extraction yield, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl) using ultrasound-assisted extraction. The results showed that the time for moisture removal correspondingly increased in the oven-dried P. macrocarpa fruits. Apparently, the Midilli and Kucuk model is the most appropriate model to describe the drying process. The range of effective moisture diffusivity was 1.22 × 10−8 to 4.86 × 10−8 m2/s, and the activation energy was 32.33 kJ/mol. The oven-dried P. macrocarpa fruits resulted in the highest extraction yield (33.99 ± 0.05%), TPC (55.39 ± 0.03 mg GAE/g), TFC (15.47 ± 0.00 mg RE/g), and DPPH inhibition activity (84.49 ± 0.02%) at 60 °C based on the significant difference (p < 0.05). A strong correlation was seen between the antioxidant activity, TPC, and TFC in the oven-dried P. macrocarpa fruits. The current study suggests that the oven-drying method improved the TPC, TFC, and antioxidant activity of the P. macrocarpa fruits, which can be used to produce functional ingredients in foods and nutraceuticals.

A High-Efficiency Radio-Frequency-Assisted Hot-Air Drying Method for the Production of Restructured Bitter Melon and Apple Chips

“…value of HAD at 60 °C was consistent with previous publications [39,40], ranging from 3.210 × 10 −9 to 2.840 × 10 −8 m 2 /s for the drying of tomato and P. macrocarpa fruits with similar geometries. Furthermore, the Deff value of the RFHAD method were 1.67 times higher compared to that of HAD, which demonstrated that the moisture transfer efficiency of the RFHAD process was much higher than that of HAD.…”

“…As expected, the higher D eff values were obtained for RFHAD (6.889 × 10 −9 m 2 /s) and RFHAD + EAR (6.062 × 10 −9 m 2 /s), whereas the lower D eff values were obtained for HAD (4.124 × 10 −9 m 2 /s) and HAD + EAR (3.218 × 10 −9 m 2 /s). The D eff value of HAD at 60 • C was consistent with previous publications [39,40], ranging from 3.210 × 10 −9 to 2.840 × 10 −8 m 2 /s for the drying of tomato and P. macrocarpa fruits with similar geometries. Furthermore, the D eff value of the RFHAD method were 1.67 times higher compared to that of HAD, which demonstrated that the moisture transfer efficiency of the RFHAD process was much higher than that of HAD.…”

Changes in the Physical Properties and Volatile Odor Characteristics of Shiitake Mushrooms (Lentinula edodes) in Far Infrared Radiation Drying

“…As the drying temperature increases, the drying rate accelerates, leading to a reduction in the drying time. Similar results have been reported by Stephenus et al for Phaleria macrocarpa (Mahkota Dewa) fruits [18] and by Xie et al for wolfberry [12]. The penetrating heat of FID prevents the surface hardening of the material, consequently enhancing the rate of moisture migration.…”

“…The moisture ratio (MR) of shiitake mushrooms during the thin-layer drying experiments is determined using the following equation [18]:…”

Drying kinetics and mathematical modeling of seeds of two mango varieties at different temperatures and with different pretreatments

“…Drying temperature has a significant impact on the quality (chemical composition) and can cause physical damage to fruit seeds unless properly optimized. 45,46 In this regard, five different temperatures (313, 323, 333, 343, and 353 K) were selected and used for the drying experiment in a heating furnace. The seed samples were also weighed at specific time intervals to measure the effect of time on the moisture content of the sample.…”