Composite coatings based on konjac glucomannan and sodium alginate modified with allicin and in situ SiOx for ginger rhizomes preservation

Abstract

AbstractGinger is a condiment vegetable and widely cultivated in many countries for its important role as spice and medicinal herb in international trade. However, the quality of fresh ginger will reduce after harvest and during storage. In the present study, edible coatings were developed based on konjac glucomannan (KGM) and sodium alginate (SA), incorporating with allicin and in situ SiOx. The coatings were characterized, and the effects of the coatings on the quality of ginger were evaluated. The results demonstrate that the addition of allicin improve the compatibility of KGM and SA in film, and the addition of allicin and in situ SiOx promote more hydrogen bond formation in the film. The physicochemical properties of KGM/SA film are improved due to modification, and allicin coating is optimal for mechanical properties, while allicin‐SiOx film is optimal both for mechanical properties and gas barrier. The KGM/SA coatings especially KGM/SA‐allicin‐SiOx significantly inhibited the total phenol, flavonoid, total soluble sugars content, enzyme activities such as peroxidase (POD), polyphenol oxidase (PPO), and cellulase of gingers during storage. In addition, KGM/SA coatings effectively preserved the ascorbic acid (AsA), and titratable acidity (TA). Over all, KGA/SA coatings, especially with allicin and in situ SiOx, exhibited more significant and positive effects on quality of gingers during storage. Therefore, the KGM/SA coatings are promising in gingers preservation.