The Extraction,Product Modification And Oxidative Stability Of Sauce Residue Oil

Soy sauce residue,the main byproduct during the fermentation of soy sauce,is yeilded a lot but currently underutilized,which leads to serious waste of resources.This paper tried to optimize the extraction program through extracting crude fat in the method of ultrasonic strengthening,on the base of wet sauce residue as raw material containing 35.01%crude fat?dry basis?and acetone as the solvent.After pretreatment of the resulting fat,it carried on conjugate isomers for a certain time with iodine catalyst and N₂ under 180?.Then the oxidative stability of conjugated oil was explored.The specific studies of this paper were as follows:In the first part,crude fat from soy sauce residue was extracted.Through acetone soxhlet extraction of the fat from wet sauce residue under 75?water bathing for 15hours,the residual crude fat content in the pulp was 0.57%according to the first of soxhlet extraction method on GB/T5009.6-2003,which illustrated that acetone worked as solvent during the extraction of wet sauce residue was feasible.Based on that,the experiment carried on ultrasonic extraction with residual crude fat content in the sauce residue as indicator,the wet sauce residue as raw material and acetone as solvent extraction,which concluded that the optimal conditions of crude fat extraction from wet sauce residue was 8 times'extraction with each time 15 minutes,the ultrasonic power 360 w and material liquid ratio10 g:30 ml.Under that optimal condition,the residual fat of wet sauce residue was 1.86%.Then a comparison was made under non-ultrasonic with the same other conditions,which showed the residual content of crude fat was 10.2%.As a result,it is concluded that ultrasonic can accelerate the acetone extraction of wet sauce residue crude fat content.Furthermore,n-hexane is regarded as solvent in the industry.To make a contrast,the experiment was also carried out with n-hexane as solvent under the optimal ultrasonic condition,which showed the residual fat of wet sauce residue was 26.7%.To sum up,acetone was better than n-hexane working as solvent under high moisture condition.The paper also showed that the fat residual was 30.14%if acetone extracting sauce residue containing 63%moisture one time.While with the same method,it was 17.40%if sauce residue containing 5.72%moisture.It showed that acetone extracting the lower moisture raw took more advantageous although it can extract higher ones.In the second part,conjugate heterogeneous of the sauce residue crude fat was studied.Experiments showed that acid value had a great impact on fat conjugate heterogeneous reaction,the higher the acid value,the slower the reaction.While the acids value of the sauce residue crude fat was high,in order to make full use of it,this paper reduced its acid value through the method of methyl esterification.The best way to reduce acid value can be concluded as follows after a series of experiments,alcohol oil quality ratio 0.8,the percentage of concentrated sulfuric acid content being 4%of crude fat quality,the temperature 70?and the reaction time for 20 minutes.Under these optimal conditions,the acid value of raw material can drop rapidly to 1.8 mgKOH/g from 103 mgKOH/g.When acid value was under 0.5 mgKOH/g,the conjugate efficiency can raise up to the highest29.85%.As sauce residue crude fat mainly comes from soy sauce residue of soybean paste,this paper selected a series of soybean fat in different peroxide value as raw materials to study the influence of peroxide value on conjugated isomerization reaction.The results showed that conjugate conversion rate decreased along with the increase of peroxide value.Besides,due to the color of fat seemed deeper,this paper has further studied about the influence of fat pigment on conjugated isomerization.Through adding different content wood activated carbon respectively to decolonize the sauce residue ester oil and sauce residue crude fat and their conjugate heterogeneous reaction,it displayed that the color of methyl sauce residue fat was more lighter after decolorizing than non-decolorizing,And the lighter Methyl color after bleaching,the better the conjugated isomerization,but the sauce residue oil without Methylesterification did not comply with that law.In the third part,the oxidation stability of conjugate methyl ester oil was studied.In convenience of comparison,all samples were made into methyl ester form in this paper.Through analysis of samples'structure in methods of UV,IR and ¹H NMR,the results can be concluded that the three main products of alkali isomerization were mainly based on cis trans-CLA and the trans cis-CLA conjugated kinds,while the main products of methyl iodine conjugate oil were mostly the cis trans-CLA and the reflect-CLA kinds.Then the Oxidation stability of alkali isomerization with different methyl ester oil as raw materials was studied,which indicated that the higher the conjugate conversion rate was,the better the Oxidation stability was.In addition,it can be concluded that the oxidation stability of alkali isomerization oil was better than iodine isomerization oil by comparing the same raw oil oxidation stability in different making methods.Finally,this paper explored the product antioxidants selection.Through measurement of their peroxide value according to GB/T5538-2005,it showed that with the same quantity of BHT,BHA and TBHQ,the TBHQ has the best antioxidant effect on the alkali isomerization product,BHT has the best antioxidant effect on soybean iodine isomerization product and fat soy sauce residue iodine isomerization product,but the BHA has the best antioxidant effect on corn oil iodine isomerization product.