Investigation Of Homogenization Treatments On Stability Of Carrot-Apple-Peach Mixed Juices And Bioaccessibility Of Bioactive Components

This research investigated the effect of high pressure homogenization?HPH?and juice ratio of individual juices on stability,flow behavior properties and bioaccessibility of bioactive components?polyphenols and carotenoids?in cloudy mixed juice,consisting of carrot,apple and peach.Major results are as followings.The effect of HPH on spoilage microorganisms,cloud stability and flow behavior properties was investigated.HPH treatments included pressure of 25 MPa,100 MPa,140 MPa and 180 MPa,pass of 1and 2 and inlet temperature of 25 ^oC and 40 ^oC,respectively.With carrot,apple and peach in volume ratios of 30:50:20,which was selected by a sensory evaluation showed that increasing pressure and pass improved cloud stability,while increasing temperature showed negative effect.Herschel Bulkey model could be well fitted to viscosity related data.Compared with control?non-homogenized,NH?sample,HPH at 140 MPa and 25 ^oC for 1 pass resulted in three times higher flow behavior index?n?.Increased IT also enhanced n.Besides,total soluble solids?TSS?content was not affected by HPH processing,even though pH and color showed slight changes.Compared with NH sample,HPH at 140 MPa resulted in 4 log₁₀ and 3 log₁₀ reductions in total plate count and Y&M count,respectively.Thus,HPH at 140 MPa could effectively be used for enhancing cloud stability,improving flow behavior and reducing microorganisms in cloudy mixed juice.The effect of HPH processing combined with juice ratio on overall quality attributes the mixed juices were investigated.Five mixed juices were prepared with carrot puree,clear apple juice and peach juice at ratios of 50:30:20,40:40:20,30:50:20,40:30:30 and 30:40:30.Relationships of functional properties with physicochemical and particle characteristics were analyzed,while relevance of bioactive compounds and antioxidant activity?AOA?with water-soluble pectin?WSP?characteristics were also investigated.As the results indicated,juice ratio of individual juices affected physicochemical attributes and composition of WSP and bioactive compounds.HPH processing decreased particle size and altered WSP characteristics.Moreover,HPH influenced functional properties of mixed juices including cloud stability and rheological behavior,which were correlated with physicochemical and particle characteristics.Polyphenols contributed more for AOA.HPH processing enhanced polyphenol content,which showed significant positive correlations with content and degree of methylesterification?DM?of WSP.Thus,AOA was relevance to both polyphenol and WSP contents,implying that interactions between polyphenol and pectin could enhance AOA.The effect of juice related WSP characteristics,total carotenoid bioaccessibility?TCB?and total polyphenol bioaccessibility?TPB?in oil and emulsion incorporated high pressure homogenized mixed juices was investigated.The five mixed juices were subjected to homogenization at 140 MPa and 25 ^oC for 1 pass.Galacturonic acid?GalA?content,DM,neutral sugars and molecular weight?M_w?were analyzed.Bioaccessibility of carotenoids and polyphenols was evaluated by using either corn oil or corn oil emulsion.As the results indicated,distinct particle and WSP characteristics were observed among different juice ratios of homogenized mixed juices.Small intestinal digesta showed varied particle and rheological properties.Besides,TCB was significantly higher when added with oil or emulsion than no oil added.Nevertheless,the ratio at 30:40:30 of carrot,apple and peach exhibited the highest TCB,WSP content and DM value,while the ratio at 30:50:20 showed the highest TPB.Results highlighted the potential of manipulating juice ratio to enhance TCB and TPB.Moreover,bioaccessibility of bioactive compounds exhibited significant correlations with particle properties and WSP characteristics,respectively.TCB showed upward polynomial correlations with volume-mean and area-mean diameters of digesta,respectively,while exhibited downward polynomial correlations with WSP content and DM,respectively.Meanwhile,TPB showed upward polynomial correlations with WSP content and DM,respectively.The effect of homogenization treatments on mixed juice?carrot,apple and peach at 30:40:30 ratio?properties were investigated,including characteristics of WSP and bioaccessibility of carotenoids.Treatments included simple blending,which was followed by colloid milling and HPH pressure of 25MPa,50 MPa,75 MPa,100 MPa and 140 MPa,pass of 1,2 and 3,and IT of 25 ^oC,50 ^oC and 70 ^oC,respectively.Bioaccessibility of carotenoids was evaluated by using either corn oil or Tween20-formulated corn oil emulsion.As the results indicated,increased pressure decreased M_w,GalA content and branching,and enhanced DM and chain linearity,suggesting degradation of RG-I fragments.Pass 2 at 140 MPa enhanced GalA content,nevertheless reduced DM,suggesting rearrangement of depolymerized fractions.Moreover,the M_w,GalA content and DM were increased at elevated IT combined with HPH pressure,signifying thermosolubilization of certain HG-rich pectin.Besides,small intestinal digesta of different treated samples showed varied particle properties for micellar and undigested fractions as implied by particle size distribution?PSD?,particle charge and microstructure.TCB was enhanced by high pressure,elevated IT,and addition of oil and emulsion.Results highlighted the potential of manipulating HPH parameters to enhance TCB of mixed juice.Meanwhile,the TCB exhibited significant negative correlations with GalA content and M_w of WSP,and positive correlations with DM and chain linearity.This highlighted TCB was directly related with WSP structural characteristics.In summary,HPH improved fuctional properties of cloudy mixed juice,which showed significant correlations with physicochemical,particle and WSP characteristics.Polyphenols contributed more for antioxidant activity,which had significant correlations with HPH-modified WSP characteristics.Juice ratios could be manipulated to enhance carotenoid and polyphenol bioaccessibility,which showed significant correlations with particle properties and WSP characteristics.The carotenoid bioaccessibility could be enhanced at high HPH pressure?140 MPa?combined with elevated IT?70 ^oC?,and was positively related to DM and chain linearity of pectin polymers.