Study On The Preparation And Performance Evaluation Of Composite Edible Paper With Fiber From Red-flesh Apple And Konjac Gum

With the increasing improvement of people's living standard,people pay more attention to the health and food,and put forward higher requirements for packaging that is closely related to food.And since the 21st century,environmental and food safety issues brought by food packaging have received more people's attention.Today,food packaging is developing in a direction that emphasizes safety and more functionality at the same time.As a new type of natural degradable packaging material,edible packaging has advantages in environmental protection and other characteristics that are different from traditional packaging in the past.Edible packaging has appeared in many related directions of experimental research and production practice in countries around the world.Red-flesh apple in Xinjiang has a long history of cultivation and is a rare species of apple trees in China.There were red pigments in its leaves,branches,petals,stamens,fruits and wood,and many natural antioxidants also in fruits of red-flesh apple,which can delay aging and increase the body's immunity.Red-flesh apple have poor eating characteristics due to their sour taste,basically used for juice extraction in the food industry.But the red-flesh apple pomace which contains a lot of active ingredients such as polyphenols and dietary fiber cannot be fully utilized.Secondly,there are abundant resources of amorphophallus konjac in the south of Shaanxi province,but they have not been fully utilized.In this paper,the waste residues obtained from juiced red-flesh apple in Xinjiang were used as raw materials,the composite edible paper contains apple dietary fiber and konjac gum was prepared through adding plasticizers,enhancers,and other ingredients.The optimal formula of the composite edible paper was obtained through experiments,and the mechanical properties and packaging characteristics of edible paper were evaluated.At the same time,the antibacterial test was used to further explore the inhibitory effect of edible paper contains apple dietary fiber on the common foodborne pathogens(E.coli,Salmonella,and Staphylococcus aureus).The purpose of this research is to provide a theoretical basis for the application of edible paper product in edible packaging of food industry.The main findings of this paper were as follows:1.Using the integrity of edible paper and the ease of peeling as indicators,through pre-tests and single-factor tests to ascertain the glycerin,konjac gum and chitosan were used as plasticizer and enhancers respectively,the process parameters of the composite edible paper preparation were determined,they were cellulase added amount of 3%,enzyme hydrolysis time of 1.5 h,homogenization pressure of 400 bar,homogenization time of 25 min,drying temperature of 45?,drying time of 2.0 h.2.Using tensile strength and elongation at break as evaluation indicators,the optimal formula of the composite edible paper contains red-flesh apple fiber and konjac gum was determined by single factor and orthogonal experiments,they were apple dietary fiber of 5%,chitosan content of 3.75%,konjac gum added amount of 10.25%,glycerol added amount of 3.5%.The factors that affect the tensile strength of edible paper was in the order of glycerol added amount>chitosan added amount>konjac gum added amount.The factors that affect the elongation at break of edible paper was in the order of chitosan added amount>konjac guml added amount>glycerol added amount.3.The composite edible paper contains red-flesh apple fiber and konjac gum prepared with optimal ratio has good sensory characteristics with a smooth surface,uniform texture,and basically no bubbles in edible paper.This package material of edible paper prepared in experiment has good mechanical properties according to the analysis of mechanical properties,its tensile strength was 8.35 MPa and the elongation at break was 35.82%.The edible paper also has soluble and degradable properties through basic properties analysis.4.The properties of composite edible paper were characterized by those methods of scanning electron microscopy,infrared spectrum analysis,X-ray diffraction analysis,and thermogravimetric analysis.It was found that there was a strong interaction between the ingredients of edible paper contains red-flesh apple dietary fiber,also has good the compatibility of the entire blend system for edible paper.The research on packaging characteristics proved that this package material of edible paper has good heat-sealing performance,and the heat-sealing strength reaches 24.09 N/m.The edible paper also can dissolve quickly in hot water and could be used as a seasoning inner bag.5.The antibacterial properties of package materials of composite edible paper were explored by the filter paper method.Tests showed that samples of composite edible paper with a small amount of apple polyphenols had better antibacterial effects on Salmonella,Escherichia coli and Staphylococcus aureus,and the inhibition rate on the three test strains(Staphylococcus aureus,E.coli,Salmonella)of concentration 10-7 respectively reached 78.63%,80.67%,94.92%.At the same time,the composite edible paper also has good degradation properties at room temperature and would widely used in food packaging.