Study On The Influence Of Different Preparation Conditions On The Quality Characteristics Of Sunflower Butter

Preparation conditions are the key steps in the process of sunflower butter.The roasted temperature,time and moisture content have decisive effect on the flavor and quality of the sunflower butter product.At the same time,sunflower butter is a multi-phase unstable system,which is prone to oil separation and other phenomena that are not conducive to production and sales.In this project,the influence of the physical and chemical indexes,volatile flavor substances,non-volatile flavor components and rheological properties on sunflower butter were studied by controlling the roasted temperature,time and initial moisture content of the sunflower seeds,and determined the characteristic flavor components and important flavor substances of sunflower butter,and to explore the properties of the sunflower butter.The preparation process has an important significance for the establishment of the flavor evaluation system in sunflower butter and the research development of new products,in order to provide a certain reference for the industrial production of the sunflower butter.(1)The L ~* value of the sunflower seeds was decreased after roasting,and the a ~* value,b ~* value and ΔE all showed an increasing trend.The color changed trend of sunflower butter was consistent with the sunflower seeds.The fat oxidation degree of the samples prepared by low temperature-long time roasting was the deepest.The samples prepared under 170℃-35 min and high temperature-short time roasting conditions found little difference except for the acid value.Increasing the roasting temperature was beneficial to increase the oxidative stability of sunflower butter,while the increase of initial moisture content may cause oxidative rancidity of oil.(2)Different preparation conditions had a great influence on the components of volatile flavor of the sunflower butter,and the roasting process significantly increased the types and quantities of volatile flavor substances.After roasted,the relative content of volatile flavor substances,especially the pyrazines,pyridines,aldehydes and alcohols were significantly increased except for the hydrocarbons of the sunflower butter.The increased of initial moisture content would affect the formation of pyrazines and aldehydes,which had a negative impact on the flavor of sunflower butter.Pyrazines,aldehydes and alcohols were the key flavor components of roasted sunflower butter samples.The characteristic flavor substances in the control group were n-hexanol and acetic acid.Principal component analysis indicated that the N-hexanol and acetic acid were the characteristic flavor substances of sunflower butter prepared by unroasted seeds.Aldehydes such as n-hexanal,octanal and(E,E)-2,4-decadienal were the characteristic flavor substances of sunflower butter prepared with low temperature-long time,which had obvious taste of lipid oxidation.Pyrazines such as 2,3,5-trimethylpyrazine,3-ethyl-2,5-dimethylpyrazine,and 2,3-diethyl-5-methylpyrazine were the characteristic flavor substances of sunflower butter roasted at 170℃-35 min and high temperature-short time.(3)The total sugar content of sunflower butter was increased after roasted,while the content of reducing sugar significantly decreased.The types and contents of free amino acids in different samples were different.After roasted,the content of bitter amino acids in sunflower butter is higher,which indicates that the sunflower butter gradually reduce the sweet taste after roasted,and gradually tend to be bitter.The amino acid that has an important contribution to the taste of sunflower butter is arginine.The difference in chlorogenic acid content might cause the overall taste of different sunflower butters to be different.The results of sensory evaluation showed that the samples with initial moisture content of 5.40%,roasted at 170℃-35 min had the highest overall acceptance.The mutual balance,mutual influence and promotion of various flavors form the final flavor of sunflower butter.(4)The addition of soybean protein isolate and monoglyceride could significantly reduce the oil extraction rate of sunflower butter.The effect of compounding soybean protein isolate and monoglyceride is better than that of single addition.The addition of soy protein isolate could increase the median diameter,volume average diameter and area average diameter of sunflower butter.With the addition of monoglyceride,the particle size of sunflower butter was decreased.Sunflower butter was non-Newtonian fluids,which had the pseudoplasticity of shear thinning,and had certain thixotropy and weak gel properties.The stability of sunflower butter added with 2% soybean protein isolate was better than other samples.For the samples added with mixed stabilizers,the apparent viscosity of sunflower butter increased with the addition of monoglyceride,and temperature has a greater influence on its viscosity.The thixotropic loop area of the sample with 2% fixed soybean protein isolate and 0.5% monoglyceride is the smallest,and it is easier to restore to the original structure.With the addition of monoglyceride,the hardness,viscosity,cohesiveness and adhesiveness of sunflower butter shown an increasing trend.When the addition of monoglyceride is more than 0.5%,it may be difficult for consumers to accept.