The Preparation Of Sodium Alginate Geraniol Gel Beads And Its Application In The Storage Of Rice

Rice as the main grain in China,the annual circulation of hundreds of millions of tons,is an important material to ensure the basic life of the people.However,rice is prone to mildew in bad weather conditions,resulting in waste and food safety problems.How to keep the rice fresh in the process of storage and logistics is an important subject in China.The plant essential oil with high efficiency and low toxicity was used for mildew proof and fresh keeping of rice.Five kinds of food essential oils were studied and geraniol had obvious bacteriostatic effect on fungi.But the bacteriostatic agent of plant essential oil has some disadvantages such as poor stability and volatile.High concentration of bacteriostatic agent directly acting on rice is easy to produce adverse effects.Therefore,it is of practical significance to study the preparation of plant essential oil microcapsule and its effect on rice storage quality.Geraniol microcapsules were prepared by extruded exogenous gel method.The effect of concentration of sodium alginate,geranial,β-cyclodextrin and Ca Cl₂ on the preparation of gel beads was determined by single factor experiment.On this basis,three factor and three level response surface experiments were designed for concentration of sodium alginate,geranial,β-cyclodextrin,and two models were established.The embedding rate and drug loading rate of geraniol were analyzed and predicted by two models.The results showed that the embedding rate and drug loading rate were 39.85%and 25.75%,with little difference from the predicted value.In order to solve the problem of low embedding rate and fast release of sodium alginate gel beads,polysaccharide was added.The results showed that geraniol gel beads combined with chitosan had higher embedding rate and drug loading rate,respectively 42.37%and27.36%.Finally,chitosan was selected as the complex polysaccharide and it was characterized by SEM,FT-IR,TGA and release characteristic curves.The results showed that the addition of chitosan improved the surface structure of the gel beads.The results also showed that geraniol was simply embedded into the wall material of the microcapsule and did not react with it.The results showed that the release pattern of geraniol was from fast to slow.By simulating different storage environments,the effects of different temperature and humidity conditions on mildew proof and fresh keeping effect of geraniol gel beads were investigated.First of all,through the determination of the fatty acid value,the amylose content,the soluble protein content and the number of colonies indicators,we can find Changes of rice samples during storage when different amounts of geraniol gel beads were added.Compared with the control group,rice samples with more gel beads had less obvious mildew,after 25 days of storage.The dosage of geraniol gel beads was determined to be3g/kg.Different temperature and humidity storage experiment results show that geraniol gel beads have obvious effect of mildew proof and fresh keeping,when the ambient humidity is80%,the temperature is 35°C.Control group and experimental group rice samples were stored at 15℃and no obvious mildew occurred.At 35℃storage temperature,the higher the humidity,the more obvious of the mildew phenomenon of rice samples.it can be seen that temperature has more influence on the storage quality of rice than the environmental humidity.