Effect Of Processing Technology On Quality Characteristics Of Lily Cloudy Juice

Lily bulb is one kind of important edible and medical plant species with a long history in China,due to their high nutritional value and health promoting properties to moisten the lung,relieve cough and calm the nerves.Therefore,the development of food around the functional characteristics of lily has always received much attention.In this paper,a series of changes of quality characteristics in the processing of lily beverage were studied,and the effects of hot water blanching enzyme treatment and high pressure homogenization treatment on the quality characteristics of lily beverages were investigated.Besides,the key technologies and raw material formulations of the lily beverages were optimized.The main results are as follows:1.The thermal effect on polyphenol oxidase(PPO)and peroxidase(POD)inactivation kinetics as well as functional properties of lily bulbs were investigated.The inactivation kinetics of PPO and POD were followed the first-order model.Estimated activation energies and Z_Tvalues of PPO and POD inactivation process were 108.30,122.84 k J mol^-1and 19.65,23.36?,respectively.L^*of the whiteness of the samples blanched at 95 and 100? was significantly higher than that of ones treated at 80 to 90?.RVA viscoamylogram results showed that blanching caused significant increases in peak viscosity,trough viscosity,final viscosity,and setback values of lily samples while led to decreases in enthalpy values.Lily samples with or without blanching exhibited pseudoplastic behavior with yield stress,and the flow behavior could be well described by the Herschel-Bulkley rheological model.Blanching also caused an increase of storage modulus and loss modulus of lily samples.2.The effects of high-pressure homogenization(HPH)on the structural,physical,and rheological properties of lily pulp were investigated.Different pressures ranging from 0 MPa to 100 MPa were used.The focus was on evaluating the changes in the particle size distribution(PSD),structure,pulp sedimentation behavior,serum cloudiness(SC),total soluble solids(TSS),color,and rheological behavior of the pulps.PSD analysis showed that the diameter of suspended lily particles significantly decreased with an increasing homogenization pressure.The suspended particles observed through optical microscopy became small after homogenization,highlighting the effect of HPH on disrupting the suspended particles.Compared with the untreated pulp,the SC and sedimentation velocity of the homogenized pulps decreased due to the disruption of the suspended particles.The effects of HPH on the sedimentation index and SC exhibited an asymptotic behavior similar to that of the changes in the particle size of lily pulp.Moreover,HPH processing reduced the viscosity of lily pulp and increased the TSS and lightness of the homogenized pulps.HPH significantly modified the structural,physical,and rheological properties of lily pulp.The pulp homogenized above 60 MPa had good suspension stability.This finding indicates that HPH technology can be used to improve the stability of lily pulp.3.Through single factor test,orthogonal test and sensory evaluation,the best formula of lily beverage was determined as follows:the lily pulps 15%,sugar 6%and malt dextrin 20%.Furthermore,by comparing the stabilization effect of different stabilizers,which was determined to use the compound stabilizer of 0.05%AGAR,0.05%sodium alginate and 0.05%CMC could obtain a uniform and non-stratification,stable and good fluidity lily beverage.