The Preparation And Properties Of The Peach Gum Edible Packaging Film

As a kind of natural polysaccharide,peach gum polysaccharide can be used to prepare functional edible film.In this study,effects of peach gum concentration,hydrolysis pH and temperature on viscosity and reducing sugar content of hydrolyzed solution were investigated.With commercial peach gum as raw material and glycerol as emulsifier,edible commercial peach gum film was produced by casting method.The film-forming ratio was optimized through single factor and orthogonal experiments.Internal structure,surface morphology and thermodynamic properties of the base film were characterized.Edible antibacterial composite films were prepared by compounding paraben and cinnamaldehyde with commercial peach gum respectively.The optimal volume fractions of two antibacterial agents were determined by measuring relevant properties of antibacterial composite films.The biocompatible between antibacterial agents and commercial peach gum was investigated.Edible commercial peach gum films were applied to packaging of real foods at the same time.The specific research content is as follows:(1)Acid hydrolysis of raw peach gum was carried out to examine the effects of peach gum concentration,hydrolysis pH and hydrolysis temperature on viscosity and reducing sugar of peach gum hydrolysate.Viscosity and reducing sugar content of hydrolyzed solution all increased with peach gum concentration.When hydrolysis pH decreased,viscosity decreased while content of reducing sugar increased.Viscosity and reducing sugar content were negatively correlated with temperature.The raw peach gum polysaccharides contained monosaccharides with a pyran ring structure and molecular chains were linked by ?-glycosidic bonds.(2)The single factor experiments were conducted to examine the influences of peach gum concentration,volume fraction of acetic acid and glycerin on the tensile strength and elongation at break of edible commercial peach gum film.A three-factor and three-level orthogonal experiment was designed to obtain the optimum film-forming ratio of edible peach gum film: concentration of commercial peach gumwas 2.5%,volume fraction of glycerin was 0.25%.The increase of glycerin volume fraction decreased the surface roughness and thermal stability of edible commercial peach gum film.(3)The biocompatibility between antibacterial agents and commercial peach gum were investigated.The addition of antibacterial agents increased the mechanical properties of composite film but decreased the brightness.As volume fraction of antibacterial agents increased,the tensile strength and elongation at break of composite film increased first and decreased then.When volume fraction of paraben and cinnamaldehyde were 0.60% and 0.50% respectively,the tensile strength and elongation at break of composite film reached maximum.The mechanical properties of films decreased rapidly in the first 150 days,and then became stable after 360 days.The mechanical properties were reduced about 30% during whole storage time.IR spectra showed that no new chemical bonds were formed between peach gum polysaccharide and antibacterial agents.The addition of antibacterial agents increased surface roughness and thermal stability of the composite film.Effects of the paraben were greater compared to cinnamaldehyde.The biocompatibility of the antimicrobial agent and the commercial peach gum was good.(4)Application of edible commercial peach gum film on cold fresh pork preservation was studied.The commercial peach gum base film did not show obvious antibacterial effect,but composite film could extend the shelf life of cold fresh pork by 2-3 days.Since commercial peach gum had good adhesiveness,it can be used as a substitute for sugar to prepare functional foods.The commercial peach gum film was used to package snack food due to wrap and twist properties.