Research On The Processing Technology And Stability Of Whole Citrus Juice

Citrus is the world's largest fruit and has a high nutritional value.China is a big producer of citrus,but 70% of citrus juice still needs to be imported.The proportion of citrus juice extracts is not high,the yield of juice is low,and the nutritional function is insufficient.These factors seriously restrict the development of China's citrus juice industry.The residual fruit residue after citrus juice accounts for 40% to 50% of the fruit quality.The whole fruit juice can effectively achieve 100% full utilization of citrus,retains the full citrus nutrition to the maximum degree,and has no waste residue,and has very broad application prospects..This study was conducted through variety screening,efficient enzymatic hydrolysis,and stability studies to provide a theoretical basis for the development of whole fruit juice products.The main research methods and results of the paper are as follows:(1)Eighteen quality indicators of 30 citrus varieties were measured and analyzed,and the principal component analysis method was used to select the most suitable whole fruit juice varieties.The results showed that the number of seeds among different cultivars,such as naringin,naringenin,tangerine,limonin,and nomilin,were significantly different.However,the differences in juice yield,L value and b value between different cultivars were smaller.According to different processing needs can choose from the bitterness factor,processing factor,color factor,nutrition factor,acidity factor,sweetness factor in terms of the needs of the appropriate species.(2)Through single-factor and orthogonal test,with the juice yield and suspension stability as indicators,a compound enzyme consisting of pectinase and protease was used to optimize the process.The results showed that the best technology was as follows : the amount of pectinase added was0.01%,the amount of protease added was 0.2%,the enzymolysis time was40 min,and the enzymolysis temperature was 40?.The fruit juice with30% pulp content had a juice yield of 83.27% and the OD at 660 nm was0.431.And the whole fruit juice with 20% and 30% pulp content under this process has better sensory quality.(3)The changes in pectin content,amino acid content,and rheological properties before and behind the enzymatic hydrolysis of cloudy juice were studied.The changes of the centrifugal sedimentation rate,pH value,soluble solids,chromaticity,particle size and distribution in the storage period of 7 days,14 days,21 days,and 28 days at 4°C were studied.The results showed that the content of pectin in the enzymatic hydrolyzed juice was decreased,amino acid content was increased,and it was closer to Newtonian fluid;during the storage period,the centrifugal sedimentation rate increased,the pH value decreased,and the median particle size and volume average particle size of the cloudy juice were both increased.The soluble solids content of cloudy juice did not change significantly,L value and b value decreased,and a value increased.