Study On Quality Analysis And Storage Characteristics And Stability Of Not From Concentrate Apple Juice

Apple juice is one of the most popular juice drinks with better appearance,sense and nutritional value in the world.Presently,the largest sale apple juice is made from concentrate in the market,but in recent years a drink called 'Not from concentrate'(NFC)has emerged as a world leader.The NFC juice is not concentrated and reduced by adding water.Instead,the juice is freshly squeezed and sold in a package after sterilization,which abolishes the process of juice concentration,reduces the loss of nutrients caused by repeated heating and shortens the conversion time from raw materials to finished products.High quality raw materials are required for producing high quality products in the processing of NFC juice.Therefore,it is very important to carry out the research on the tracking of NFC juice quality.At present,the research mainly focuses on the influence of variety,origin,maturity and other factors of fruit on the quality of juice.However,there are few studies focused on the influence of the fruit maturity period on the quality of juice.The difference in the maturity period would greatly cause the difference in fruit quality,thus affecting the quality of juice.In this experiment,22 apple varieties including medium maturity,mid-late maturity and late maturity were used as materials to study the influence of fruit maturity period on the juice quality,which could provide theoretical guidance for industrial production.Short storage period is one of the main factors restricting the development of NFC juice industry.At present,the cold(40C)and frozen(-180C)storage are the main temperatures for the storage of juice,but there are still a lot of problems in the industrial production.Although the juice stored at 4? reduces the energy consumption,there are lots of problems such as severe nutritional loss,shorter shelf life and difficulty for long-term storage and transport.Storage at-18? can effectively inhibit the growth of microorganisms,reducing the loss of nutrients,but some disadvantages still existed,for example,it requires high energy consumption,and it is difficult to thaw and the microbial would pollute secondary in the process of thawing.Freezing point temperature has been used in the storage of biology and living cells in recent years.And the juice is in a semi-frozen state when storage at its freezing point temperature.The effects of storage at different temperature on the juice quality were studied and it could provide theoretical basis for storage and transportation of NFC juice industry.Although NFC juice retains the appearance,texture and taste of pulp,it is prone to stratification and sedimentation during storage,which affects marketing and promotion of NFC juice.In this experiment,homogenization and addition of carboxymethyl cellulose(CMC)were used to improve the storage stability.Additionally,the mechanisms are researched to provide theoretical basis for the industrial production of NFC juice.The paper studied the quality of NFC juice,the influence of storage temperature on the quality of juice and the storage stability of NFC juice.The main conclusions are as follows:(1)By comparing the physicochemical characteristics of NFC fruit juice of medium,mid-late and late maturation,it can be seen that the content of soluble solids increased with the delay of the maturation period.In addition,the results of cluster analysis showed that the content of chlorogenic acid in the juice of medium maturation was lower than that of mid-late and late maturation.The results of e-nose showed that the difference of juice aroma was mainly determined by the variety and had nothing to do with the maturity stage.Considering the nutrition and physicochemical characteristics,the fruit of late maturation varieties was more suitable for juice making and processing.(2)The effects of storage temperature including room temperature(25?),cold(4?),freezing point(-1.5?)and frozen temperature(-18?)on the quality of NFC juice were studied.The results showed that the higher the storage temperature,the more loss of polyphenols and physicochemical properties.Additionally,the aroma components of fruit juice were significantly reduced during the storage,however,the highest aroma components were retained by storage at freezing point temperature after 150 days.Meanwhile,the results of multivariate statistical analysis based on the e-tongue showed that the freezing point temperature could maintain the closest sensory characteristics to the control group.Therefore,freezing point temperature showed the great potential in the industrial production of NFC juice.(3)The storage stability of juice can be effectively improved by homo gen ization,adding CMC and adding CMC after homogenization.The mechanism of improving the stability by homogenization were reducing the particle size of suspended solids and increasing the negative charge of juice.Additionally,adding CMC can improve the stability of juice by increasing the negative charge and viscosity of juice.The sample juice treated with adding CMC after homogenization maintained a stable system after 90 storage 90 days,which solved the problem of stratification and sedimentation of NFC juice in industry.In conclusion,the paper further discusses the research on the quality tracking and storage stability of juice based on the existing research on juice processing.Meanwhile,the study establishes the theoretical basis for the industrial production,storage and transportation of NFC juice in China.