Quality Characteristics of dried Kimchi by Cyclic Low Pressure Drying

Abstract

This study aimed to economically produce high quality of dried kimchi through a cyclic low pressure drying device in order to overcome the disadvantages of the conventional drying process. The moisture content of dried kimchi obtained from the cyclic low pressure drying process was found to be uniformly reduced according to drying time. Also, cyclic low pressure drying showed the shortest change and a stable reduction in drying rate. Further, cyclic low pressure drying did not markedly change pH, titratable acidity, or salt content. In addition cyclic low pressure drying compared with fresh kimchi showed the similar color values and maintained the flavor of the kimchi. In conclusion, cyclic low pressure drying resulted in superior rehydration and sensory scores.

Effects of different drying methods on physicochemical properties, volatile profile, and sensory characteristics of kimchi powder

“…In this study, we attempted to identify a method suitable for kimchi powder production by investigating the physicochemical properties and sensory characteristics of kimchi dried using five drying methods. Kimchi maturity can be categorized into three stages based on the acidity: pre-, optimum-, and over-mature at titratable acidity levels of \ 0.3%, 0.3-0.8%, and 0.8-1.0%, respectively (Cho and Lee, 1979;Ku et al, 2005;Seo et al, 2013). The samples were dried until they reached optimum maturity, and 10% moisture content was considered acceptable for the dried kimchi as this is the moisture content of commercial kimchi powder.…”

“…To extend shelf life and to use as a food ingredient, kimchi is dehydrated by various methods such as freeze drying, hot air drying, and vacuum drying (Park et al, 2016;Seo et al, 2013). Hot air drying involves a continuously flowing hot stream of air to remove the surface moisture of kimchi while freeze drying reduces the surrounding pressure to allow the frozen water in the material to directly sublimate from the solid to gas phase after freezing the product at low temperature (Park et al, 2016).…”

Effect of balanced low pressure drying of curcuma longa leaf on skin immune activation activities

“…The balanced low pressure drying and ultrasonication extraction (UE) method showed the highest yield of 13.20%, followed by 12.90% of a freeze drying by 70% ethanol extraction (FE), 12.11% of balanced drying by only ethanol extraction without UE and 11.78% of hot air drying (HE) as shown in table 1. It was interesting that the extraction yield from BE was not much different from that from FE that was relatively expensive and time consuming process, possibly because of less shrinkage of the leaf structures during balanced low temperature drying under low pressure condition [10,13]. Related to hard structured materials such as stems and roots, the leaves become desiccated and crumbled when they went through hot air pretreatment before going through the main process, the hot water extraction.…”

“…Therefore, a balanced low pressure drying method was introduced to reduce the loss of active ingredients even though in general a freeze drying would be useful; however, a freeze drying process is considered to be very expensive and may not be feasible for large industrial scale productions. To overcome this limitation in drying relatively soft plant materials, the balanced low pressure pretreatment process could be employed since it has as high yield as freeze drying process even though it requires relatively large plant equipment and systems such as large size air blowing system and holding device for maintaining regular pressure inside the chamber [10,13]. Through this drying process, the alteration of the material and the damage are minimized since the leaves are dried under balanced drying conditions with constantly reducing the humidity at low pressure and low temperature.…”

“…This process is a relatively new method to dry thin and soft plant materials even though this drying process could save time and cost, and also avoid the desiccation of thin parts of the leaves and the alteration of active ingredients by high temperature. Thus, in this work, balanced low pressure drying was selected as a treatment process that can yield the same high drying efficiency as freeze drying method with relatively low price [13].…”