| Gold pomfret is an important economic fish for marine aquaculture in China.A large number of by-products will be produced during production and processing,such as fish heads,fish bones and fish offal,etc.Direct discard will cause waste of resources and environmental pollution.In this paper,with the goal of high-value utilization of the internal organs of golden pomfret,using internal organs as raw materials,the optimal preparation conditions of crude fish oil extraction-refining-microencapsulation were studied,and the physical and chemical properties of fish oil and fish oil microcapsules were analyzed with a view to The effective use of the internal organs of the gold pomfret provides data basis and theoretical basis.The specific research content and results are as follows:1.Analysis of the nutrient composition of the guts of gold pomfretThe nutrient composition analysis of the guts of the golden pomfret by drying method,Kjeldahl method and Soxhlet extraction method showed that the main component of the guts of the pomfret is crude fat,with a content of up to 55.07%,followed by the moisture content of 32.97%,The lower protein and ash contents are 4.65% and 1.12%,respectively.The results of the study indicate that the giblets of gold pomfret are a good raw material for extracting fish oil.2.Optimization of crude fish oil extraction conditionsThe crude fish oil in the internal organs of golden pomfret was extracted by dilute alkaline hydrolysis method.Using the extraction rate and physical and chemical properties of fish oil as indicators,the extraction conditions were optimized using single factor and orthogonal tests.The optimal conditions are: hydrolysis p H 9.0,hydrolysis temperature The salting-out temperature is 55 ° C,the salting-out temperature is 45 ° C,and the salting-out time is 10 min.Under this condition,the extraction rate of fish oil reaches81.56%.Crude fish oil iodine value 121.24 g / 100 g,acid value 5.22 mg / g,peroxide value9.45 meq / kg,unsaponifiable matter 0.58%,insoluble impurities 0.29%,moisture and volatile matter 0.19%,anisidine value is 9.0,physical and chemical indicators All meet the first-class standard of national standard SC / T3502-2016 crude fish oil.3.Refining crude fish oilBy refining phosphoric acid,dehydrating sodium hydroxide and decolorizing activated clay,the best process conditions were determined as follows: 1.5% degumming agent dosage,degumming temperature 70 ?,degumming time 15 min;deacidification temperature 70 ?,The amount of deacidification agent is 2%;the amount of decolorization agent is 15%,and the decolorization temperature is 60 ?.After refining,the golden pomfret viscera fish oil is clear and bluish yellow,with a slight fishy smell;the fish oil physical and chemical indicators are: acid value 0.42 mg KOH / g,iodine value127.81 g / 100 g,peroxide value 0.47 meq / kg,without saponification Substance 0.34%,insoluble impurities 0.08%,moisture and volatiles 0.17%,anisidine value 2.3%,no significant change in fatty acid composition and content before and after crude fish oil refining.Enrichment of DHA and EPA in refined fish oil by lipase hydrolysis method.After 20 hours of enrichment reaction,the acid value of fish oil is 0.67 mg / g,iodine value is184.42 g / 100 g,peroxide value is 2.09 meq / kg,and unsaponifiable matter is 0.32.%,Insoluble impurities 0.06%,water and volatile matter 0.07%,anisidine value 3.16,physical and chemical indicators meet the national standard SC / T3502-2016 first-class standard of refined fish oil,DHA and EPA total content of 31.75%,in line with SC / T 3503-Requirements for the total amount of EPA and DHA in the 2000 polyene fish oil product standard.4.Preparation and physical and chemical properties of fish oil microcapsulesUsing gelatin(GE)and gum arabic(GA)as the capsule wall material,and gold pomfret visceral fish oil as the core material,the fish oil microcapsules were prepared by the complex coagulation method and the spray drying method.The response surface method discussed the preparation process conditions.The best conditions were: p H 4.0,gelatin to acacia ratio 1.4,core wall ratio 0.7,wall material mass fraction 1.5%,and the embedding rate reached 70% under this condition.The physical and chemical properties of the fish oil microcapsules were determined.The results showed that the fish oil microcapsules were white fine powder;light fishy smell;particle size 2.59 um;moisture content 3.66%;ash content 0.83%,crude protein content 23.56%;density and viscosity Small size,good fluidity and solubility;microcapsule formation was observed through optical microscope and scanning electron microscope,no cracks and holes on the surface,but there were dents.Fourier transform infrared spectroscopy analysis confirmed the formation of microcapsules,thermogravimetric And the results of differential scanning calorimetry analysis show that microcapsules can be kept stable at room temperature and have high thermal stability.It is proved by accelerated storage experiments that microencapsulated fish oil shows lower compared with non-microencapsulated fish oil The peroxide value significantly prolongs the storage period of fish oil. |
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