Effects of CO2 pretreatment on the volatile compounds of dried Chinese jujube (Zizyphus jujuba Miller)

Abstract

The aim of this study was to investigate whether anaerobic metabolites could induce volatile compounds and improve aroma of dried jujube (Ziziphus jujuba Miller). Jujube fruits were incubated in a polyvinyl chloride bag containing 5% CO 2 and 95% N 2 for up to 168 h at 25 °C and 3 samples were randomly removed every 6 h and oven dried to a moisture content of ≅ 20%. The volatile compounds of control and 5% CO 2 -pretreated Chinese jujube fruits were extracted by simultaneous distillation extraction and identified by gas chromatography-mass spectrometry(GC-MS). The acetaldehyde and ethanol contents were determined by gas chromatography (GC). The results indicated that a large accumulation of acetaldehyde and ethanol caused changes in aroma composition of dried jujube products and 5% CO 2 pretreatment led to an increase in the levels of some compounds, particularly esters, acetaldehydes, and ethanol, whereas the amount of acids were decreased significantly. Principal component analysis showed that integrative scores of 5% CO 2 pretreatment at 120 h were the highest, and aroma quality was better than that of the control. Relatively low concentrations of anaerobic respiration metabolites are good for jujube fruit aroma composition.

Characterization of Volatile Component Changes in Jujube Fruits during Cold Storage by Using Headspace-Gas Chromatography-Ion Mobility Spectrometry

“…Chen et al reported that acids were the major group among all the volatile chemicals in dried jujube fruits. Moreover, pre-treatment of jujube fruits with 5% CO 2 can induce a decrease in acid content during drying, which is mainly caused by a decrease in lauric acid and nutmeg acid content [18]. 2-Methoxy-4-cresol was a newly detected component in the VOCs of jujube fruits, which appeared with high content in fresh DZ but not found in fresh JS and showed a pleasant clove-like flavor [50].…”

“…Aroma profiles are important characteristics to evaluate the quality of fruits. Several studies have reported that the volatile compounds of jujube fruits are affected by many factors, such as growth period [14], extraction methods [15], the load [16], and processing methods [17,18,19,20]. However, few reports have been associated with changes in volatile compounds of jujube fruits during cold storage, which should be considered.…”

Comparison of volatile compositions of 15 different varieties of Chinese jujube (Ziziphus jujuba Mill.)

“…However, its content in other cultivars was lower than that of n-decanoic acid. Besides, it is worthy of mention that the acids was reported to be the major group among all the volatile chemicals in dried jujube (Chen et al 2017).…”

Comparison of physical and chemical composition of three chinese jujube (Ziziphus jujuba Mill.) cultivars cultivated in four districts of Xinjiang region in China

“…Xinjiang is an important jujube production region in China and its annual yield has significantly increased since 2010 (Jin et al, 2015). Ot has been reported that the Xinjiang region has a total 483,628 hectares jujube planting area, which can result in a more than 2.5 million tons annual production on the fresh jujube fruits (Chen et al, 2017). Geographically, Xinjiang is in the northwest of China, and it possesses a high day-to-night temperature difference.…”