Study On The Preparation And Application Of Lard-based Puff Pastry Margarine

Puff pastry margarine is one of the necessary materials for the preparation of croissant,butterfly cracker and other crisp snacks.However,the existing domestic puff-pastry margarine is poor in plasticity and contains trans-fatty acids(TFA).Therefore,it is meaningful to look for a new method for the preparation of zero trans puff pastry margarine with good plasticity.Lard is rich in resources and has easy digestive properties,while the problem of large crystals lead to its poor applicability.Consequently,the fat was modified by physical blending,chemical and enzymatic interesterification in the subject.Furtherly,the emulsifiers were added into the modified oil to observe the effect on its crystallization behavior.Finally,applied the modified oil into production practice and make good quality of puff pastry margarine for baking applications.Firstly,the blend of palm stearin(ST)and lard(LD)were used to prepare the zero transfatty acids base oil of puff pastry margarine.On the basis of SFC curve to be consistent with commercial oil,the ratio of palm stearin to lard was 20%,30%,40%,50%,60% and 70%.CH3 ONa and Lipozyme TL IM were selected for chemical interesterification and enzymatic interesterification respectively.Then the physical and chemical properties of the blends before and after interesterification were evaluated systematically,including solid fat content profiles,compatibility,the fatty acid and TAG composition,thermal properties,polymorphism microstructure,hardness and their crystal type.The results showed that the content of TFA(C18:1 t)was lower than the standard 0.3%,which met the requirements of zero trans-fatty acid oil.The TAG composition significantly changed after interesterification and the main TAG were PLO,POO,POSt and POP.After reaction,the S3 and U3 content were increased,while the SU2 and S2 U content were reduced.In the compatibility study,the samples obtained by the three treatments all have good compatibility.The thermal properties of the original blends before and after the interesterification were obviously different.Interesterification resulted in the right shift of high melting peak,which demonstrated the increase of S3 TAG levels.The obvious breadth increase of middle melting peak may be associated with a more homogenous S2U/SU2 type TAG composition.Similarly,the left shift of low melting peak suggested an increase in U3 TAGs.The primary crystals were changed from β to β′ type and crystal diameter became significantly smaller and more uniform.When the ratio of ST was between 30% and 40%,the hardness was about 300 g,which is in accord with the requirements of base oil of zero trans puff pastry margarine.Secondly,choosing distilled monoglycerides(DMGS),mono-and diglycerides(MONODIGS),propylene glycol monostearate(PGMS),lactic acid ester of monoglycerides(LACTEM),polyglycerol esters(PGE),and sucrose esters(P-170)as emulsifiers,studied the effect of emulsifiers on crystallization behavior in the blends before and after interesterification.It was shown that DMGS,PGE and P-170 corresponded smaller crystalline size and higher hardness at 20℃,while the other emulsifiers had little effect.The effect of the emulsifiers on the 4.6 ? peak value of physical mixture was more obvious.Afer the addition of PGE and P-170,partial crystalline of the physical mixed sample was changed from β’ to β.While the emulsifiers had little effect on the crystal transition of the samples after chemical and enzymatic interesterification and the peaks at 4.6 ? were weaker,even disappeared.The β’ crystal content of samples CIE30-4,CIE30-5,EIE40-4,EIE40-5 and EIE40-6,was close to 100%.Finally,the baking test of the four kinds puff pastry margarine was carried out and the baking properties were evaluated.The results showed that compared with the commercial puffpastry margarine,there was no significant difference in texture,hardness,graininess and viscosity of the oil prepared by chemical and enzymatic interesterification,while the specific volume,swelling rate and sensory evaluation showed better baking properties.