Study On The Effect Of Phospholipase A₁ Degumming On The Quality Of Camillia Oil And Emulsifying Properties Of By-products

Enzymatic degumming is developed fastly in recent years, which makes use of phospholipase to convert phospholipids into hydratable form.Compared with the traditional degumming process, enzymatic degumming has many advantages. Apart from the high degumming rate, an enhancement in product yields and a reduction in operating costs have also be observed.Camellia oil contains a variety of functional components such as tocopherols, carotene and polyphenols and it is reputed to reduce blood pressure and cholesterol level, to prevent cancer and to anti-cancer. Therefore, the application of enzymatic degumming in camellia oil also offers a safe biological route and ecofriendly solution for industrial application.Firstly,enzymatic degumming can guarantee the achievement of low phosphorus contents（P<10 mg/kg） required for physical refining.After degumming, the camellia oil is subsequently bleached and deodorized,so enzymatic degumming can guarantee the reduction in the amount of acid, alkali, and wastewater used during the process, an enhancement in oil yield and a reduction in environmental pollution.Thirly, enzymatic degumming process allows recovering a gum with a high concentration of lysophospholipids,which enhance the added value.Therefore, the aim of this work was to study the qualities of degummed camellia oil after different kinds of treatments.And the test results were compared so as to make a comparison of the PLA₁ degumming process and acid degumming process to provide some theoretical references for the camellia oil refining industries. The main findings are as follows:First, the effect of the acid degumming and enzymatic degumming process on quality of camellia oil were investigated. The optimization experiments of acid and PLA₁ degumming were conducted by single factor tests. The optimal condition for acid degumming were determined as follows: citric acid（ concentration 45 %） dosage 0.2 %（ based on the mass of crude oil）, water dosage 2.5 %（ based on the mass of crude oil）,acid reaction temperature 60 ℃ and reaction time 30 min,under these conditions, the degumming rate was 60.70 %.The optimal conditions for PLA₁ degumming were determined as follows: reaction time 3 h, PLA₁ addition 40 mg/kg, reaction temperature 45 ℃, water addition 2 %, p H5.0,and the degumming rate was 94.19 %,33.49 % higher than acid degumming. Otherwise, oil yield was 96.87 % under PLA₁ degumming while oil yield was 95.37 % under acid degumming.Moreover, the quality index of the two kinds of degumming oil such as acid value, peroxide value, color（except acid value） and tocopherols,polyphenols,sterol,β-carotene content was no significant difference.Meanwhile, oxidation induction of camellia oil was obviously increased to 17.14 h from 9.43 h after the enzymatic treatment. Therefore, PLA₁ degumming reach higher degumming rate and oil yield than that of acid degumming, and oxidative stability of camellia oil was obviously increased after the enzymatic treatment.Second, the composition of by-products obtained from oil residue by defferent degumming process were detected by fourier transform infrared spectroscopy（FT-IR） and electrospray mass spectrometry（ESI- MS） techniques.And the results showed the phosphorus contents was 2.94 % in PLA₁ oil residue,1.54 % higher than that of acid oil residue.And there were phosphatidylethanolamine（PE）,phosphatidylinositol（PI）,phosphatidic acid（PA） and lysophosphatidic acid（Lyso-PA）,lyso-phosphatidylserine（ Lyso-PS） in the oil residue by acid degumming. Meanwhile, there were lysophospholipids and glycerol-phospholipids（GPL）in the oil residue by enzymatic degumming.Third, the effects of addition,p H,ionic concentrations and heat treatment on emulsifying properties of by-product obtained from oil residue by acid degumming and PLA₁ degumming. And the results showed that the emulsibility and emulsion stability of Lyso-PL was superior to PL with the same addition,serve as O/W emulsion. The emulsibility and emulsifying stability of Lyso-PL was also better than PL under the different p H and ionic strengths.Especially,at high Na Cl concentration（400 m M）, PL emulsion had bad emulsification and oil water dissociation,while Lyso-PL emulsion remained relatively stable.And after modifications,emulsifying ability of PL at 5 m M Ca Cl2 were much improved.Otherwise, Lyso-PL had better emulsifying stability than PL when they were subjected to a heating treatment（80 ℃,30 min）.