Physicochemical Properties Of Pomegranate Peel And Its Polyphenols On The Quality Of Jujube Lactic Beverage

The physicochemical properties and antioxidant activity of different particle sizes pomegranate peel were determined.The pomegranate peel was used as raw material and was crushed and sieved with a universal grinder.In addition,the polyphenols in pomegranate peel within the specific particle size range were extracted by ultrasonic wave and the polyphenols content and antioxidant capacity of the extract were determined.The lactic acid fermentation supplemented by pomegranate peel extract to develop a new type of jujube lactic acid bacteria fermentation beverage,and its physical and chemical indicators,sensory characteristics and antioxidant properties in-depth study.Get the following conclusion:(1)The particle size of pomegranate peel had no significant effect on its basic physical and chemical indexes.Lightness value of pomegranate peel increased from 36.89±0.49 to44.18±0.10.The whiteness value decreases with the decrease of particle size,while the yellowness value changes in the opposite direction.Pomegranate peel particle size reduction can also lead to loose,tap density were significantly reduced,poor mobility.In addition,the particle size also affects the water holding and oil holding capacity of pomegranate peel powder.The water holding capacity of pomegranate peel powder decreases with the decrease of particle size,from 4.89±0.13 g/g to 2.28±0.07 g/g,Oil holding capacity increases with decreasing particle size.(2)The total phenolic content increased from 99.08±3.28 mg/g to 120.93±6.39 mg/g with the decrease of particle size of pomegranate dulcified powder,and the total flavonoid content increased from 142.6±2.56 mg/g to 190.17±9.27 mg/g.The total reducing power and scavenging ability of free radical(DPPH,ABTS)of pomegranate peel powder increased with the decrease of particle size.The DPPH radical scavenging ability increased from 130.44±1.9mgVc/g to 157.65±0.38 mgVc/g,and the ABTS free radicals scavenging capacity increased from 63.77±1.3 mgVc/g to 75.83±1.53 mgVc/g,and the total reduction capacity increased from 259.0±13.79 mgVc/g to 330.14±4.98 mgVc/g.(3)The DSC results showed that the thermal resistance of pomegranate peel particles,the lower the melting temperature and the lower the melting temperature.Therefore,as the particle size of pomegranate peel decreased,the melting temperature increased.SEM results show that crushing can affect the microstructure and surface characteristics of pomegranatepowder,and also support the changes of fluidity,oil holding capacity and antioxidant capacity with decreasing particle size.(4)The content and the content of soluble polyphenols in the water extract of pomegranate peel powder were determined by HPLC.The results showed that the highest content of pomegranate peel was punicalagin(160.53±4.21 mg/g),followed by gallic acid(9.83±0.22 mg/g)followed by ellagic acid(2.48±0.15 mg/g).The antioxidant activity of water extract of Pomegranate peel was tested by measuring the scavenging ability of two free radicals(DPPH,ABTS)and total reducing ability.The results showed that the extract of pomegranate peel had excellent free radical scavenging ability and transition metal chelation ability.(5)Pomegranate peel extract can significantly improve the acidity of jujube lactic acid drinks and change its color.The L * value of jujube lactic acid beverage decreased from62.42±0.05 to 56.89±0.43,the a * value increased from 0.53±0.11 to 2.00±0.15,and the b *value increased from 23.36±0.17 to 26.64±0.50 with the increase of water extract of pomegranate peel,while producing significant color difference,can be observed directly with the human eye.(6)Pomegranate peel extract can significantly increase the total phenolic and total flavonoid content of jujube lactic acid beverage and enhance its free radical scavenging ability and reducing ability.With the increase of pomegranate peel extract,the total phenolic content of jujube lactic acid beverage increased from 863.5 mg/L to 1597.3 mg/L,and the total flavonoid content increased from 263.3 mg/L to 952.7 mg/L.The free radical scavenging capacity of jujube lactic acid beverage increased with the addition of pomegranate peel extract.The ABTS free radical scavenging capacity increased from 207.7 mgVc/L to 1232.0 mgVc/L,DPPH radical scavenging ability increased from 1146.0 mgVc/L to 1433.4 mg Vc/L,total reducing power increased from 520.9 mgVc/L to 3725.4 mgVc/L.(7)Sensory evaluation found no significant effect on the sensory quality of jujube lactic acid beverage by addition of pomegranate extract.In addition,GC-MS was used to verify the effect of pomegranate peel extract on the volatile odor of beverage.The results showed that pomegranate peel extract not only does it not adversely affect it,but it also significantly enhances its antioxidant activity,making it the best natural anti-oxidant additive for beverages or juices.