| Eggplant,rich in dietary fiber and phytonutrients,has a high nutritional value and a strong hydrophilic/oil-absorption attribute.The eggplant pulp homogenates/powder has a potential to serve as a new safety and healthy emulsion stabilizer.However,varieties,pretreatment methods and freezing/thawing cycles may affect the eggplant pulp homogenate/powder-stabilized emulsions.What's more,there has been no researches on the application of eggplant pulp homogenates in the meat batter.The purpose of this paper was to study the effects of eggplant varieties and different pretreatments and freezing/thawing treatment on the stability and rheological properties of eggplant pulp homogenate/powder-stabilized emulsions and its preliminary application in meat batter.Effects of Varieties on Emulsifying and Rheological Properties of Eggplant Pulp.Three common eggplants(Fast Round Eggplant,Big Dragon Eggplant and Hang Eggplant)were used to determine the main components eggplant pulp and emulsifying properties and rheological properties of eggplant pulp-stabilized emulsions.The results showed that Hang Eggplant had the highest dry matter content(7.30%±0.10%)(fresh basis),crude protein content(13.40%±0.06%)(dry basis),crude fiber content(12.60%±1.53%)(dry basis)and hemicellulose content(10.11%±0.08%)(dry basis).The emulsions Cl decreased and the stability were improved with the increase of dry matter addition.Hang Eggplant pulp emulsion had the best emulsion stability with the lowest Cl(46.63%±1.43%),the smallest mean particle size and the narrowest particle size distribution when prepared with the same dry matter addition.All emulsions were non-Ne-wtonian fluids with decreasing viscosity when increasing shear rate.And the apparent viscosity and G' value showed a significant trend of Hang Eggplant>Fast Round Eggplant>Big Dragon Eggplant(p<0.05).Therefore,the Hang Eggplant was the most proper variety for developing the eggplant-origin emulsifier in this study.Effects of Pretreatments and Freezing/Thawing on Eggplant Pulp Homogenates/Powder Emulsion.The Hang Eggplant from Chapter Two was used for four different pretreatments of the eggplant pulp(Pretreatment A:powdered after dried at 105?;Pretreatment B:powdered after dried at 50?C;Pretreatment C:powdered after lyophilization;Pretreatment D:fresh eggplant pulp homogenates).The appearances,emulsion stability,particle size and distribution and rheological properties of eggplant emulsions were explored after four pretreatments.The results showed that different pretreatments of samples gave emulsions different emulsifying properties.All emulsions from four pretreatments were non-Newtonian fluids with shear thinning behavior with typical elastic gel-like properties.Freezing/thawing treatment deteriorated emulsion systems and decreased their stabilities in different degrees.Emulsions stabilized by samples of Pretreatment D and B showed better emulsifying properties with lower CI and smaller mean droplet size and narrower distribution than those of Pretreatment C and A,while the difference between Pretreatment D and B was insignificant(p>0.05).Thus,Pretreatment D and B were more suitable for exploring the extent of potential eggplant-origin emulsifier.And considering the convenience of industrial application and storage and transportation,Pretreatment B had a better promising potential for eggplant pulp to be used as an emulsion stabilizer for large-scale industrialization.Effects of Pretreated Eggplant Pulp Addition and Freezing/thawing Cycles on the Quality of Meat Batter,Effect of pretreated eggplant pulp addition and freezing/thawing cycles on the quality of meat batter were studied and the results showed that the thawing loss,cooking loss and L value decreased and a value and b value increased with the increasing addition of pretreated eggplant pulp(0-6 g/100 g pork).The texture scores showed an upward trend and then a slight drop followed by another increase.And tests showed the addition of 1.5 g/100 g pork had the best quality.Compared with the smooth surface and compact and elastic texture of F Samples(meat products with pretreated eggplant pulp),the W Samples(meat products without pretreated eggplant pulp)had a shrinking volume,unsmooth surface covered with jagged gap and a loose internal structure,and it was even difficult to form a intact gel-like appearance.After freezing/thawing,the W Samples showed a higher average and standard deviation of thawing loss than the F Samples and all texture scores were lower than that of the F Samples except for the cohesion and elasticity at the eighth freezing/thawing treatment. |
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