Study On The Choice Of Processing Citrus And Optimization Of Technological Parameters Of Citrus Juice With Compound Pectinase

People are fond of citrus fruits, which are aromatic, delicious, and have high nutritional value. Apart from the rich juice, sweet and sour, Citrus also have rich sugars, organic acids, minerals, cellulose, amino acids and vitamins, especially higher vitamin C content than other fruits. Furthermore, good maturity, strong fragrance, rich juice and good color are required to processing citrus. The issue take the world's largest processing citrus type--the most tangerine one as the main research object, and the same to lemon --a unique type of citrus, then selected special type which is most suited for juice processing. Comprehensive physical and chemical sensory evaluation were given under the use of fuzzy math, then citrus fruits' POD Properties and how Compound pectinase raises citrus juice yield were studied deeply. The main results are as the following.1. All various citrus cultivated in Sichuan are analyzed comprehensively under fuzzy mathematical comprehensive assessment. The results showed that the rank of sweet orange's integrated quality is: Jiang'an # (Sichuan Jiangan)≈Beibei 447# (Sichuan Luzhou) "dead citrus (Sichuan Jiangan)" Prince 4 # (Sichuan Luzhou) "Florida orange (4 Province)" Peng'an 100 # (Luzhou, Sichuan Province); the rank of Lemon's integrated quality is: You Lectra lemon (4 Province)≧ Tahiti lemon (Sichuan Great Britain).2. Jiang'an35# and Beibei447# as a sweet orange selected the best sweet orange varieties just mature in different seasons, the former mature in early summer, the latter in the winter, which can extend processing time. Meanwhile other varieties of citrus can be used as alternate resources to produce hybrid citrus juice, which can reduce production costs and extend the time.3. In indexes of color, aroma and soluble solids, Yolik lemon is superior to Tahiti lemon; But Tahiti juicy lemon have the superior processing capabilities with thin peel and rich juice. The two can be combined with each other to make up deficiencies, which can be produced lemon juice with excellent characteristics and convenient processing expectably.4. Under the optimum conditions, the comparative results of the POD activities in several citrus albedo are as follows: Tahiti lemon is highest, which is far higher than other citrus, Yolik lemon is second, and again is Peng'an100#, then Beibei447#, Wangzi4# and Florida orange.5. The optimum pH of several citrus albedo was 5. 0, the optimum temperature range of 40^C to 60℃respectively; The POD activities increase along with the increasing of substrate (H₂0₂) concentration, and reach saturation point at 0.07% H₂0₂.6. Both of 0.1% Vc and 0.5% Na₂SO₃ are the strong inhibitors for POD activity in Tahiti albedo.7. Considering the changes of soluble solids, relative viscosity and color saturation, we make use of pectinase to raise juice yield through L₉(3⁴) orthogonal experiment. The conclusion is: the best combination of orange (Beibei447# as the representative) is A₁B₃C₂, hydrolysis time 30min, hydrolysis temperature 55℃, the enzyme dosage 40mg/100ml, juice yield more than 50%; Lemon (Yolik lemon as representative) is A₂B₁C₃, hydrolysis time 110min, hydrolysis temperature 35℃, the enzyme dosage 45mg/100ml, juice rate more than 40%...