Comparison of pulsed vacuum and ultrasound osmotic dehydration on drying of Chinese ginger (Zingiber officinale Roscoe): Drying characteristics, antioxidant capacity, and volatile profiles

Abstract

The effects of pulsed vacuum osmotic dehydration (PVOD) and ultrasound osmotic dehydration (USOD) on drying characteristics and quality attributes of ginger were investigated. PVOD was subjected to pulsed vacuum at 13 kPa for 30 min, and USOD was subjected to ultrasound with the frequency of 40 kHz for 30 min. After PVOD and USOD treatments, the samples were then dried at intermittent microwave & air‐drying oven with an output of 700 W and temperature of 60°C to the final moisture content of 0.12 g water/g d.w. The results showed PVOD and USOD treatments could improve the total phenolic contents by −1.8% to 16.4%, total flavonoid content by 7.7%–18.7%, DPPH radical scavenging by 9.5%–12.2%, and ABTS+ antioxidant activity by 17.8%–27.4%, although they prolonged the later stages drying of ginger. Besides, the PVOD‐ and USOD‐pretreated dried samples had less brownings than the untreated‐dried samples which could be attributed to the inactivation of polyphenol oxidase (PPO) and peroxidase (POD). The PPO activity was significantly reduced in the PVOD and USOD ginger, whereas POD activity was decreased in USOD ginger but increased in PVOD ginger. Moreover, PVOD pretreatment also led to a better preservation of volatile profiles and cell structure than USOD treatment. Therefore, both PVOD and USOD are effective pretreatments for drying of ginger.

Modeling of vacuum‐ and ultrasound‐assisted osmodehydration of carrot cubes followed by combined infrared and spouted bed drying using artificial neural network and regression models

“…The vacuum applied to the osmotic process also reduced the drying time but more time was needed to dry than the sonicated samples. The reason may be attributed to adsorption of more osmotic solution for VOD‐treated samples than UOD‐treated samples that reduced the rate of water release from the tissue (An et al, 2019). Regarding the using vacuum at the beginning of the OD process, a hydrodynamic mechanism occurred which causes the formation of pressure gradient.…”

“…The schematic illustration of developed network inputs/outputs for dehydration process for VOD-treated samples than UOD-treated samples that reduced the rate of water release from the tissue (An et al, 2019). Regarding the using vacuum at the beginning of the OD process, a hydrodynamic mechanism occurred which causes the formation of pressure gradient.…”

The effect of filtrated osmotic solutions based on chokeberry juice enriched with mint extract on volatile compounds in dried apples

“…Also, incorporation of mint extract during OD could force the volatile organic compounds (VOCs) into the sample and as a result reduce VOCs losses during drying. There are several studies concerning the influence of OD on the volatile profile of different fruits and vegetables, for example, strawberries (Blanda et al, 2009; Rizzolo, Gerli, Prinzivalli, Buratti, & Torreggiani, 2007), Wumei fruit (Luo et al, 2019), cherry tomato (Heredia, Peinado, Rosa, Andrés, & Escriche, 2012), mango (Torres, Talens, Carot, Chiralt, & Escriche, 2007), Chinese ginger (An et al, 2019), and guava fruits (Pino, Panadés, Fito, Chiralt, & Ortega, 2008). However, there is lack of research that recognize the phenomena occurring during OD carried out in filtrated concentrated fruit juices that facilitates the transport of particles from the OS into the sample and results in higher retention of volatile compounds in the biological porous material.…”

Effects of High-Pressure, Hydrothermal, and Enzyme-Assisted Treatment on the Taste and Flavor Profile of Water-Soluble Ginger (Zingiber officinale) Extract

“…Regardless of hydrothermal and high-pressure, the enzyme-assisted samples had a significant increase in flavor compounds ( Figure 3 B,C), and there was no effect of high-pressure treatment ( Figure 3 D). In a study of Australian ginger treated with supercritical carbon dioxide, heat drying reduced alcohol compounds (geraniol and citronellol) while significantly increasing the concentrations of monoterpene and sesquiterpene hydrocarbon compounds [ 61 , 62 ]. The enzyme-assisted treatment effectively enhanced flavor compounds.…”