Study On Corn And Green Tea Used In Process Of Cookies

Cookies are bakery products with a sweet flavor. It is well popular with both youngand old. Cookies are exquisitely designed, taste fragrant, sweet and crushable,.but theycontain high fat and sugar. With the improvement of consumers’health concepts and livingconditions, people are pursuing higher qualities of life and daily foodstuff was to meet therequirements of nutrition and health. This thesis studied the manufacturing techniques ofcorn flour and tea powder applied in cookies to find the best recipe and baking technique.It also studied the effects exerted by corn flour and tea powder on the quality and storageperformance of cookies, which will not only enrich the assortments of bakery products butalso improve the added value of corn and tea, thus improving the efficiency of resourcesand providing certain theoretical foundation for the study of corn, tea and bakery products.This thesis studied the processing techniques of corn cookies and green corn cookies,as well as the influence of corn and green tea on the sensorial, textural andphysicochemical indexes of cookies. The storage performance of the product was alsoresearched.The recipes and processing techniques of corn cookies and green corn cookies werestudied to find out the recipes and technological processes of the two cookies. It was foundthat the best recipe for corn cookies was: sugar40share, butter60share, corn flour25share, flour75share, eggs15share; the best recipe of the green corn cookies was: sugar50share, butter60share, flour77share, corn flour20share, tea powder3share and eggs15share. Best quality could be achieved if both of the cookies were baked for12minunder150℃primer and180℃surface fire.The influence of corn flour and green tea powder on the cookies’ textural andphysicochemical indexes was researched. Corn flour can reduce the hardness andchewiness of cookies and decrease the absolute value of stickiness, which are virtuouseffects on the textual indexes of cookies; tea powder also reduces the absolute value ofstickiness, but only on the cookies’ hardness and chewiness. It was found, through thecombination with sensorial assessments, that cookies could not be accepted by consumerswhen the hardness exceeded30N and the softness and crushable degree performed bestwhen the hardness was between14N and18N; when the absolute value of stickinessexceeded0.2N.S, the cookies would easily stick on the teeth and oral walls; when thechewiness value was under2N, the cookies would taste better. Corn flour graduallyincreased the water content in cookies while tea powder was just on the contrary; both of them can reduce the content of free fat in cookies and better the greasy taste.Changes in textural indexes during the storage were also explored by textureexamination and comparisons between the products and the control group. During thestorage, the hardness of corn cookies decreased3.98N, absolute value of adhesivenessrose0.045N.S, the chewiness decreased0.38N; the hardness of corn-tea cookies decreased4.43N, absolute value of adhesiveness rose0.026N.S, the chewiness decreased0.08N; thehardness of the control group decreased1.8N, absolute value of adhesiveness rose0.05N.S, the chewiness decreased0.27N; These changes in textural indexes have directly led tothe reduction in sensorial quality, making the cookies soft and sticky.Meanwhile, physicochemical indexes during the storage were also researched. Testsand measurements of the water content, peroxide value and acid value were conducted andcomparisons were made between the products and the control group. During storage, thewater content of corn cookies, green corn cookies and common cookies rosed:4.01-4.49%,3.47-3.96%3.72-4.10%. Because of rising of water content, corn cookies turned soft andthe sensorial quality also reduced. In the second week, the peroxide value of the controlgroup reached the national standard of0.25g/100g, which is the national cookies hygienestandard; the peroxide value of corn cookies reached0.26g/100g in the third week and thegreen corn cookies reached0.28g/100g in the fourth week. In the third week, the acidvalue of corn cookies and common cookies reached5.02and5.15respectively, bothexceeding the national standards. The acid value of green corn cookies rose to5.3in thefourth week, exceeding the regulated number in the national standards. The results alsoshow that the addition of tea is of certain significance to prolonging cookies’ qualityguarantee period.