Study On The Browning Of Passion Fruit Juice

Nonenzymatic browning is a common phenomemon during the passion fruit juicestorage, which badly lower the edible and commercial value. In order to solve thebrowning problems, we study on: nonenzymatic browning of passion fruit juice duringstorage, antioxidation performance of passion fruit Juice adding Vb-Na and the selectionand application of anti-brown additives of passion fruit juice. The purpose of this paperwas to provide guidance for practical production. The results of the study are as follow:1. Study on non-enzymatic browning of passion fruit juice during storageIt is easy to find non-enzymetic browning in passion fruit juice during storage. Thechanging regularity of material of non-enzymetic browning in juice and its relatedbrowning relationship during storage was studied in this paper. The results showed thatthe temperature was higher or the period was longer, the total sugar, reducing sugars,amino nitrogen and Vc were much less, on the contrary, browing degrees and5-HMFwere more，total phenol remained unchanged.therefore，the oxygenolysis of Vc andMaillard reaction mainly lead to the non-enzymetic browning of passion fruit juice duringstorage.2. Study on antioxidation performance of passion fruit Juice adding Vb-NaAdding Vb-Na to passion fruit juice, the effect of temperature, air and AlCl3onoxydative browning of passion fruit juice were examined. The experimental resultsshowed that: the absorbance of the juice with Vb-Na was34.90%lower than that oforiginal juice at100℃for5h; Air oxidated at90℃for5h, the absorbance of the juicewith Vb-Na was39.78%lower than that of original juice; Adding6mL0.1mol·L-1AlCl3,the absorbance of the juice with Vb-Na was25.13%lower than that of original juice atroom temperature for5h. The hydroxyl radical clearance of the juice with Vb-Na is50.66%, which was1.63times that of original juice.3. The selection and application of anti-brown additives of passion fruit juiceMaking Single factor and orthogonal test on tropical fruit passion fruit withanti-brown additives：Vb-Na, phytic acid, NaCl, CaCl₂, ascorbic acid, sodium erythorbate.The effect of the anti-brown in the single factor is: Vb-Na> phytic acid> ascorbic acid>sodium erythorbate, but NaCl and CaCl₂can’t play anti-brown role in the fruit juice. In theorthogonal test, the optimal browning inhibiting effect comes out while the concentrationof ascorbic acid, Vb-Na and phytic acid are0.029%,0.06%and0.02%, respectively, andthe absorbance value of the passion fruit juice with these anti-brown additives is0.165, which accounts for44.72%of commercial passion fruit juice in the same condition.