Drying characteristics and quality of red ginseng using far-infrared rays

Abstract

BackgroundThe current typical drying methods for red ginseng are sun drying and hot-air drying. The purpose of this study was to investigate drying characteristics of red ginseng by using far-infrared drying.MethodsThe far-infrared drying tests on red ginseng were conducted at two drying stages: (1) high temperature for 24 h drying and (2) low temperature drying until the final moisture content was 13 ± 0.5% (wet basis). The high temperature drying stage included three drying chamber temperature conditions of 60°C, 65°C, and 70°C. The low temperature drying stage was conducted at temperatures of 45°C and 50°C. Drying characteristics were analyzed based on factors such as drying rate, color changes, energy consumption, and saponin content. The results were compared with those of the hot-air and sun drying methods.ResultsThe results revealed that increases in drying temperature caused a decrease in drying time and energy consumption for far-infrared drying. The saponin content decreased under all drying conditions after drying, the highest value (11.34 mg/g) was observed at drying conditions of 60∼50°C. The sun drying condition showed the lowest color difference value when compared with far-infrared and hot-air drying.ConclusionThe far-infrared drying showed a faster drying rate, higher saponin content, lower color difference value, and a decrease in energy consumption than seen in hot-air drying.

The effects of drying conditions on bioactive compounds and antioxidant activity of the Australian maroon bush, Scaevola spinescens

“…These findings (Table ) are in agreement with previous studies, which found that increasing the hot air oven drying temperature caused an increase in the extractable antioxidant activity in dried ginseng (Ning et al, ; Yang et al, ) and shiitake mushrooms (Li et al, ). In addition to the inactivation of PPO (Krapfenbauer et al, ), the reduction in oxygen‐exposure time (Wojdyło et al, ), and the increased liberation of compounds present in bound form in the plant matrix (Hayat et al, ) previously discussed, Yang et al () have suggested that the increased antioxidant activity in plant samples dried at high temperatures may also be attributable to the Maillard reaction.…”

“…These findings (Table 2) are in agreement with previous studies, which found that increasing the hot air oven drying temperature caused an increase in the extractable antioxidant activity in dried ginseng (Ning et al, 2015;Yang et al, 2006) and shiitake mushrooms (Li et al, 2007).…”

“…Drying of plant material precedes extraction and is a critical step in the preservation of bioactive compounds in plant matrices (Dang et al, ; Khoddami, Wilkes, & Roberts, ; Papoutsis et al, ; Vu, Scarlett, & Vuong, ). The drying process can lead to the degradation of bioactive compounds, especially if the compounds are heat‐sensitive (Nguyen et al, ; Nguyen, Van Vuong, Bowyer, Van Altena, & Scarlett, ; Ning, Lee, & Han, ; Vu et al, ). However, the drying process, often involving increased temperatures, can also release bound compounds resulting in higher recoveries upon extraction (Nindo, Sun, Wang, Tang, & Powers, ; Papoutsis et al, ; Sharma et al, ; Wojdyło, Figiel, & Oszmiański, ).…”

“…Drying of plant material precedes extraction and is a critical step in the preservation of bioactive compounds in plant matrices (Dang et al, 2017;Khoddami, Wilkes, & Roberts, 2013;Papoutsis et al, 2017;Vu, Scarlett, & Vuong, 2017). The drying process can lead to the degradation of bioactive compounds, especially if the compounds are heat-sensitive (Nguyen et al, 2016;Nguyen, Van Vuong, Bowyer, Van Altena, & Scarlett, 2015;Ning, Lee, & Han, 2015;Vu et al, 2017).…”

The influence of vegetable puree containing carotenoids on the nutrient composition and structure of milk yoghurt

“…Determination of dry matter and moisture content To determine dry matter and the initial moisture content of the pumpkins, 20 g of pumpkin and experimental yoghurt samples was dried in an oven (WFO-600ND, TokyoRiKakai, Japan) at 105°C for 24 h. The moisture content was determined from weights before and after drying (Ning et al 2015).…”