Extension of Shelf Life of Semi-dry Longan Pulp with Gaseous Chlorine Dioxide Generating Film

Authors: LIN, XIAN - Guangdong Academy Of Agricultural Sciences; CHEN, GAOHUI - Guangdong Academy Of Agricultural Sciences; Jin, Zhonglin; WEN, MING - Guangdong Academy Of Agricultural Sciences; WU, JIJUN - Guangdong Academy Of Agricultural Sciences; WEN, JING - Guangdong Academy Of Agricultural Sciences; XU, YUJUAN - Guangdong Academy Of Agricultural Sciences; AN, KEJING - Guangdong Academy Of Agricultural Sciences; YU, YUANSHAN - Guangdong Academy Of Agricultural Sciences

Submitted to: International Journal of Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2020
Publication Date: 1/16/2021
Citation: Lin, Xian, Chen, Gaohui, Jin, Z.T., Wen, Ming, Wu, Jijun, Wen, Jing, Xu, Yujuan, An, Kejing, Yu, Yuanshan 2021. Extension of shelf life of semi-dry longan pulp with gaseous chlorine dioxide generating film. International Journal of Food Microbiology. 337:108938. https://doi.org/10.1016/j.ijfoodmicro.2020.108938
DOI: https://doi.org/10.1016/j.ijfoodmicro.2020.108938

Interpretive Summary: Semi-dry fruit has better texture quality than fully dried one but its higher moisture content increases the risk for microbial growth during a long-term storage. A packaging system using gaseous chlorine dioxide generating film in a sealed container was developed to extend the shelf life of semi-dry longan. The antimicrobial film was activated by the moisture vapor from semi-dry longan pulp in the sealed container and released gaseous chlorine dioxide ClO2 into the headspace of the container. The antimicrobial tests showed that the antimicrobial film significantly inactivated artificially inoculated molds (>99.9%) and aerobic bacterial populations (> 99.9999%) in semi-dry longan pulp. The antimicrobial packaging did not significantly affect the food color throughout the 180-day storage period at room temperature. This study demonstrated an effective approach to develop a new antimicrobial packaging system for semi-dry longan pulp or other semi-dry fruits.

Technical Abstract: A packaging system using gaseous chlorine dioxide generating film (CDGF) in a sealed container was developed to extend the shelf life of semi-dry longan pulp (moisture content 38.8 wt.%; aw0.8). The antimicrobial properties, formation of chloroxyanion residues and effects of CDGF on the quality of semi-dry longan pulp were investigated. CDGF was triggered by the moisture vapor from semi-dry longan pulp in the sealed container and released gaseous ClO2 into the headspace of the container. The antifungal test showed that CDGF significantly inactivated artificially inoculated molds in semi-dry longan pulp and achieved reductions of over 3 log CFU/g after 28 days storage at room temperature (25°C). CDGF reduced total aerobic bacterial populations by over 6.4 log CFU/g and maintained these population levels at around 2.0 log CFU/g throughout the 180-day storage period at room temperature. The residual concentrations of chloride, chlorate and perchlorate in longan pulp increased and then decreased during the 180-day storage. Residual chloride levels were maintained at 1.5 mg/g after Day 120 and residual chlorate and perchlorate levels were not detected after Day 120 and Day 180, respectively, in CDGF-treated samples. CDGF treatments reduced total polyphenol content but didn’t have any significant impact on the levels of polysaccharides in samples. There were no significant differences between CDGF-treated and control samples in color changes during storage. The content of 5-hydroymethylfurfural (5-HMF) in both samples increased during storage, suggesting that the Maillard reaction occurred. This study demonstrated an effective approach to develop a new antimicrobial packaging system for semi-dry longan pulp.