| Cookie is a favorite food for their taste and quality.With the development of social economy and the improvement of people’s health awareness,it has become a trend to demand more healthy Cookie products.Tea is rich in functional substances and it would be better to develop tea cookies accompany with the composition and flavor of tea.At present,the products of tea cookies in the market mainly made with ultramicro green tea powder,and the tea powder mainly derived from middle or small leaf tea species with special cultivation condition and special processing technology,the cost of the tea powder is so high that increased the cost of cookie made with green tea powder.On the other hand,the color of the cookies made with tea powder generally is dim.Large-leaf tea species contain more abundant contents and owned higher biological yields than middle-leaf tea species.In this study,the green tea original from large-leaf tea species was selected and manufactured into tea powder by simple grind processing,then the low cost self-made tea powder was used to develop tea cookies with better quality in taste and flavor.The main results are asfollows: 1、The quality characteristics comparison between commercial ultramicro tea powder and self-made green tea powderThe content of self-made green tea powder(>140 mesh)was better than that of commercially ultramicro tea powder.The former contained 23.38%,27.75%,and 3.43% of total polyphenols,total protein,and free amino acid,respectively,compared to 12.89%,22.14%,and 1.65% terms in latter sample respectively.In terms of particle size of tea powder,the average particle size and distribution of ultramicro tea powder was better than those of self-made green tea powder,the former being 28.6 μm and range from 5.01μm to 93.5 μm,and the latter being 71 μm and range from 8.6 μm to 277 μm.2、The optimized processing of ultramicro tea powder cookie(1)The single factor experiment of processing results showed,with the increase ofbaking temperature and baking time,the quality of tea cookie exhibits typical changed: the degree of greenness is gradually weakened accompany with the degree of yellow is deepened,including brightness L* gradually decreased,the a* value increased significantly,and the b* value decreased significantly.In terms of texture,the brittleness and hardness both increased significantly,but the crushing distance decreased significantly.As to the antioxidant activity of cookie there exhibited a significant decrease.(2)Orthogonal test results of ultramicro tea powder cookies showed the influence on taste quality was surface temperature(A)> baking time(C)> base temperature(B),the order on the color of ultramicro tea powder cookie was the base temperature(B)> surface temperature(A)> baking time(C).The order on texture is that surface(A)> base temperature(B)>baking time(C).The optimized processing parameters of ultramicro tea powder cookie as: surface temperature 180℃,base temperature 95℃,baking for 18 min,and the formed cookies owned the highest sensory score and good color.3、The development of green tea cookies made with self-made green tea powder(1)The single factor experiment showed,the surface brightness L* values of green tea cookies decreased gradually along with the increased ratio of green tea powder,so does the a* and b* values significantly decreased,but the surface color of cookie exhibit deeper green and blue color.The brittleness and hardness of cookies increased significantly,but the breaking distance decreased significantly.The optimized ratio of tea powder(particle size >140 mesh)is 5% according to the sensory evaluaion.With the increasment of baking temperature and baking time,the brightness L* of green tea cookies decreased gradually,and the a*value increased significantly but the b* value decreased significantly,the greenness of cookies surface decreased gradually but the degree of yellow increased.The brittleness and hardness of the biscuits both increased significantly,the breaking distance and the antioxidant activity of the cookies all decreased significantly.(2)The orthogonal experiments of self-made tea powder processed green tea cookies showed that the order of influence on the sensory quality of green tea cookies was that surface temperature(A)> baking time(C)> bottom flame temperature(B);The sequence of the influence of the color of the cookie is that surface temperature(A)> baking time(C)> base temperature(B);the order of influence on the texture characteristics of green teacookie is that surface temperature(A)> base temperature(B)>baking time(C).The optimized baking process parameters: surface temperature 180℃,base temperature 95℃,baking for 18 minutes.4、Comparison of quality factors in different cookiesThe quality analysis showed that the protein content of green tea cookies(8.11%)was significantly higher than that of ultramicro tea powder cookies(7.53%)and common cookies(6.61%),and the total polyphenol content(0.53%)was also significantly greater than that of ultramicro tea powder cookies(0.29%)and regular cookies(0.01%),the nutritional quality of green tea cookies is better.In terms of antioxidant activity,green tea cookies> ultramicro tea powder cookies> common cookies.Electronic nose and GC-MS determination of volatile flavor results showed that the green tea cookie flavor was better than that of the ultramicro tea powder cookies and general cookies.5、Correlation between sensory evaluation and instrument determination indexThe analysis showed that there was a certain correlation between the chroma value,texture index and sensory evaluation measured by the cookie device.The regression equations were: Y=8.7440+0.1595X1-0.4615X2(Y is the color of cookies.Sensory scores,X1 is its brightness L*,X2 is its red-green degree a*),Y=9.32826752+11.743682819X2(Y is the cookie color sensory score,X2 is the breaking distance mm). |
PDF Full Text Request