Effect of novel atmospheric‐pressure jet pretreatment on the drying kinetics and quality of white grapes

Abstract

BACKGROUND Raisin is a popular snack and a common constituent of many foods owing to its good flavor and nutritional value. Conventional drying of grapes can be a slow and energy‐consuming process as their waxy surface hinders efficient moisture migration. A drying pretreatment that disrupts the waxy cuticle is usually applied to increase the drying rate. RESULTS The application of an atmospheric‐pressure air plasma jet to the grape surface could effectively enhance the drying kinetics and decrease the drying time by more than 20%. Through etching of the waxy cuticle, the air plasma jet optimally improves the quality of the final product. Although the surface hydrophilicity was increased by 40%, the physical appearance, color, and texture of plasma‐treated raisins were similar to the product from untreated control and chemical‐treated groups. A more than twofold increase in the total phenolic content and antioxidant capacity was observed when compared to other experimental groups. CONCLUSIONS The results indicate that atmospheric plasma could be a better option than using chemicals to pretreat grapes before drying since it leaves no toxic residue, while successfully preserving the product quality. This work shows the great potential for the application of atmospheric air plasma in the drying of food materials. © 2019 Society of Chemical Industry

Helium Atmospheric Pressure Plasma Jet Source Treatment of White Grapes Juice for Winemaking

“…Our plasma source mean electrical power, around 8 W, was close to the values reported by Guo, Lukic, Nishime, Pankaj and Sarangapani (2-20 W) [26,36,[92][93][94], but lower than 20-50 W as reported by Starek, Mujahid, Wang [38,95,96], or less than 50-200 W as reported by Bao, Pan, Zhao, Xiang, Laurita, Sainz-Garcia [29,40,41,43,97,98], and even far less than 300-750 W as reported by Ashtiani, Huang, Fan, Jambrak, Zhou [30,42,44,99,100]. The higher the dissipated plasma power got, the higher the possibility of thermal treatment of the sample was.…”

“…Most of them pointed out the need to assess the barrel aging on the wine product, slowing down the fermentation process and even stopping it and green technologies for wine treatment for long term storage. Among these, plasma technologies based on gas discharges, at atmospheric pressure, are on the way to replacing old and expensive methods for fruit juice, wine and yeast treatment, the goal being the long-term storage, aging and even decontamination of such products, and seems to meet most of the criteria required by the winemakers [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]. Depending on the utilization, the plasma source needs be tuned as to comply with the application requirements (power, electric field, reactive species).…”

Producing high quality mung bean sprout using atmospheric cold plasma treatment: better physical appearance and higher γ‐aminobutyric acid (GABA) content

“…The effect of plasma treatment was clearly indicated by the microscopic observations, in agreement with the previously reported investigations. 41,42 According to previous literature, a disturbed waxy cuticle would allow higher trans-epidermal moisture migration 32 and, thus, it is rational to expect an enhanced moisture and gas permeability for the plasma-treated seeds. When subjected to the plasma treatment, the seed surface is attacked by a high concentration of low-energy ions, UV light, gas splash and reactive nitrogen species (RNS) or reactive oxygen species (ROS) erosion that causes severe coat etching and internal damage.…”

“…To evaluate the effect of plasma treatment on the surface property of mung beans, the contact angle between a water droplet and the bean epidermis was measured using a contact angle meter (FTA125, First Ten Angstroms, Newark, CA, USA) at room temperature using a method modified from a previously published paper. 32 For comparison, the measurements of contact were taken both before and after the plasma treatment. In brief, the samples were placed on a stationary support, and then a fixed volume of water (0.4 mL) was carefully dropped onto the beans surface using a syringe.…”

Traditional and recent development of pretreatment and drying process of grapes during raisin production: A review of novel pretreatment and drying methods of grapes

“…The wastewater produced from chemical pretreatment contains larger quantities of corrosive chemicals, high saline and organic solids, which is a severe problem for the environment (Adiletta et al., 2016; Bai, Sun, Xiao, Mujumdar, & Gao, 2013; Wang et al., 2017). In this sense, physical pretreatments producing no residue would be preferable (Huang, Wu, Wu, & Ting, 2019). The abrasion method, type of physical pretreatment, showed a significant increase in the drying rate of grapes due to the formation of microcracks on the grape peel surface (Selvi, Baskar, & Aruna, 2014).…”