Study On The Stability Of Non-concentrated Reduction(NFC) Freshly Squeezed Orange Juice And Establishment Of Quality Evaluation Model

Not from concentrate?NFC?orange juice is a kind of non-additive orange juice obtained by using sweet orange fruit as raw material and sterilizing it after mechanical pressing.Currently,there are two types of NFC juice on the market.One type called NFC juice is to directly fill fresh fruit juice after instant high temperature sterilization?higher than 100??,which only retains the nutritional content and flavor of fresh fruit to a certain extent,this product type can be stored at room temperature and the shelf life extending to 3 months,and the price of this product is relatively low due to lower costs.The other called NFC fresh squeezed fruit juice is sterilization by pasteurization?less than 100??or non-thermal sterilization during processing,which can preserve the nutritional content and flavor of fresh fruits to the greatest extent,but this type requires cold chain transportation and cold storage.The shelf life of this product is about 1 month,and the price is higher.At present,there are few studies on the quality stability of NFC fresh orange juice.In this paper,NFC fresh orange juice products with transparent packaging of polyethylene terephthalate?PET?at 85?for 30 s are used as test materials?combined with orange varieties such as Hamlin,Valencia and Pera?.NFC fresh orange juice?provided by Deqing Jiayu Beverage Co.,Ltd.?was used to study the effect of light on the quality stability of NFC fresh-squeezed orange juice under low temperature storage.Meanwhile,through the accelerated test,characteristic indicators to evaluate the stability of NFC fresh-squeezed orange juice was selected,and a quality evaluation model was established.These can provide technical parameters for companies to control the quality of NFC freshly squeezed fruit juice products.The main findings are as follows:?1?Light had little effect on sugar content,acid content,turbidity,pulp precipitation rate,and Browning Index?BI?in NFC freshly squeezed orange juice under low temperature storage,but reduced total flavonoids,Vc,and total antioxidant capacity.The content of iso-oxidation indicators promoted the production of limonin,and also changed the types and contents of aroma substances.It promoted the degradation of?-myrcene and?-terpineol.Therefore,under low temperature conditions,avoiding light is more conducive to the preservation of NFC freshly squeezed orange juice.It is recommended that companies should use light-proof packaging materials.?2?The effects of temperature and storage time on BI,turbidity,color difference,pulp precipitation rate,limonin,and Vc were significant.The higher the temperature is,the higher the BI,turbidity,pulp precipitation,and limonin content,the lower the Vc and citric acid content are.Under high temperature conditions,the fructose and glucose content increased significantly,and the sucrose content decreased.The type and content of sugar acid significantly affect the taste and flavor of fruit juice.Therefore,these characteristics should be considered during stability studies.?3?The quality indicators of NFC freshly squeezed orange juice at different temperatures was analyzed by using Multiple Linear Regression?MLR?and the results were as follows:Browning index=-0.037×Vc+0.274×pulp precipitation rate+0.167×SSC+0.027×5-HMF-0.029×limonin-0.288×fructose+0.263×glucose+0.01×sucrose+3.309.Based on the principal component analysis of the quality index of NFC freshly squeezed orange juice under different storage conditions,a sensory evaluation model is established.The expression of the sensory comprehensive evaluation function F was:F=?67.7×F₁?+?13.86×F₂?/?67.7+13.86?=-0.059 X₁+0.141 X₂-0.005 X₃+0.075 X₄+0.149 X₅+0.143 X₆-X₁₃represent:SSC,5-HMF,Limonin,Citric Acid,Fructose,Glucose,Sucrose,L*,a*,b*,Turbidity,browning index and Pulp Precipitation Rate.The key indicators affecting the sensory score of NFC freshly orange juice were fructose,glucose,sucrose and L value,a value and b value.In this paper,a systematic study of the quality stability of NFC freshly squeezed orange juice under low temperature storage is conducted.An objective and fast model for evaluating the quality of NFC freshly squeezed orange juice is established,providing theoretical basis and technical parameters for product quality control of enterprises.However,this article only studies the changes in the quality stability of NFC freshly squeezed orange juice after a single sterilization parameter?85?,30 s?under low temperature storage.In further research,the stability difference of different varieties of NFC freshly squeezed orange juice and the optimization of sterilization process should be studied forprolonging the shelf life of NFC freshly squeezed orange juice products,and establishing a mature system for NFC freshly squeezed orange juice quality evaluation.