| Coconut is one of the popular tropical fruits and is widely used to make different types of foods.The natural emulsion extracted from the endosperm of mature coconuts by mechanical force is called coconut milk.It is rich in protein,vitamins,sugar,minerals and 18 kinds of amino acids needed by the human body.It is an excellent vegetable protein drink with good nourishing effect.However,at present,the varieties and tastes of coconut milk in our country are relatively simple,and new products are urgently needed to expand the market.In recent years,coarse grains and drinks have developed rapidly and the potential market demand is huge.In this study,coconut milk was used as a raw material to study the effects of corn granules,corn starch and waxy corn starch on the stability of coconut milk system,and through single factor and orthogonality.The test determined its compound stabilizer formulation,which aims to provide a theoretical basis for the stability testing of coconut milk and coarse grain coconut milk beverages,and provides certain support for improving the stability of the corresponding products during production,storage and transportation.The main research results of the paper are as follows:(1)The single factor effect of monoglyceride,sucrose fatty acid ester,diacetyl tartaric acid mono-diglyceride,sodium caseinate,and carrageenan on the stability of coconut milk was investigated using the index of clarity as an indicator.The effect of glycolic and carrageenan on the stability of coconut milk was the most significant.The optimal amount of emulsifier for coconut milk with different additives was optimized by orthogonal experiment.The optimal amount of emulsifier for coconut milk was:1%monoglyceride 0.1%of sucrose fatty acid ester,0.07%of diacetyl tartaric acid mono-diglyceride,0.08%of sodium caseinate,and 0.05%of carrageenan;optimal amount of emulsifier added to coconut starch coconut milk:1%monoglyceride,sucrose fat Acid ester 0.11%,diacetyl tartaric acid mono-diglyceride 0.07%,sodium caseinate 0.12%,carrageenan 0.03%;waxy maize starch coconut milk optimal emulsifier added amount:monoglyceride 1%,sucrose fatty acid The ester was 0.17%,diacetyl tartaric acid mono-diglyceride 0.05%,sodium caseinate 0.16%,and carrageenan 0.03%.(2)Explore the static and dynamic rheological properties of coconut milk with different additives.The results showed that all four types of coconut milk had shear thinning properties and were pseudoplastic non-Newtonian fluids,and their rheological properties obeyed the Herschel-Bulkley model.However,coconut milk with pure coconut milk,corn starch with coconut milk,and coconut starch with waxy corn starch were more easily sheared and thinned than coconut milk with strong pseudoplasticity.The dynamic rheological results showed that:4 coconut milk showed a certain degree of liquid viscosity.The nature of the gel does not exhibit gel properties,whereas corn kernels,corn starch,and these two additives increase the elasticity of the coconut milk system.(3)To study the effects of different corn additives on the particle size,color difference,Zeta potential,DSC,surface tension and sensory evaluation of coconut milk.The results showed that the average particle size of the coconut milk system after adding corn kernels,normal corn starch and waxy maize was increased,and the particle size distribution range of the system was enlarged,thereby reducing the stability of the coconut milk system;Adding corn kernels,regular cornstarch,and waxy cornstarch will affect the color of the coconut milk system and make the whole system more yellowish.Among them,the addition of corn kernels has the most significant effect on the color of coconut milk;Zeta potential results:compared with the pure Zeta potential of pure coconut milk,the addition of corn,normal cornstarch,and waxy cornstarch all result in a reduction in the Zeta potential of the coconut milk system,which affects the stability of the coconut milk system;DSC results:When the above three additives were added to coconut milk,the initial gelatinization temperature T0,the final gelatinization temperature Te,the peak gelatinization temperature Tp,and the hot enthalpy △H of the system all increased,and the additive was corn kernels.The sample is the most significant;sensory evaluation results:three additives will cause the coconut milk color dark yellow,a little stratification,but the corn starch and waxy jade flavor The addition of rice starch did not change the flavor of coconut milk itself,while the addition of corn kernels showed a superposition of corn and coconut milk flavors,which was not yet accepted by all assessors;surface tension measurement results:additives(corn kernels,corn Starch,waxy corn starch)will significantly increase the surface tension of the coconut milk system,thereby significantly reducing system stability.(4)Explore the stability,rheological properties,starch content,particle size and distribution,Zeta potential,total number of microbial colonies and coliform bacteria of four kinds of coconut milk after storage at different temperatures for 50 days.The results are as follows:Compared with before storage,the clear index of the 4 samples was slightly increased but not obvious after 50 days storage at room temperature;after 4℃ storage,the clarification indexes of the four samples were reduced,including the clarification index of coconut milk in corn kernels.Larger extent,high temperature storage has a greater impact on the stability of coconut milk containing corn kernels,low temperature environment can improve its storage stability;corn kernels containing coconut milk stored in high temperature environment,will precipitate more starch to make coconut milk beverage The viscosity of the liquid increases and the flowability decreases;the particle size distribution after storage measures the results:the addition of corn kernels in pure coconut milk,or both ordinary and waxy maize starches,incorporates insoluble particles in the coconut milk system and is stored at high temperatures.During the process,the particles will continue to aggregate,resulting in large particle size particles,which will affect the storage stability of the coconut milk system;the Zeta potential after storage results:high temperature storage will lead to coconut milk The absolute value of the Zeta potential decreased;the change in the number of microbial colonies and coliform bacteria:Four kinds of coconut milk stored at 4℃ and 40℃ for 50 days had no increase in the number of coliform bacteria and the total number of colonies.It was always 0.Good microbiological safety,in line with national standards. |
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