| As one major style of moon cake in China, Cantonese-style moon cake is popular for its delicate taste and unique flavor. But it has become a kind of high-calorie food because lots of sugar and fat are used in it. Being low-energy, nutritious and healthy, low-calorie moon cake stuffing has been becoming a new trend recently.In the present work, TPA evaluation methodology of moon cake was established according to sensory test and instrument analysis. The high-calorie and low-calorie white gourd stuffing formulas were optimized by Mixture D-Optimal design.At the same time, the correlation between the content of several moon cake ingredients and TPA parameters during the process of moon cake’s softening was discussed. The volatile flavor compounds in high-calorie and low-calorie white gourd stuffing were also investigated.The main methods, results and conclusions in the study were as follows:1. Formula optimization of traditional Cantonese-style moon cake’s white gourd stuffing.With different addition of sugar, the sensory score of moon cake is very significant negatively correlated with hardness, cohensiveness and resilisence (p<0.01). The related coefficients are-0.941,-0.855and-0.834respectively. Hardness, cohensiveness and resilience can evaluate the quality of moon cake objectively, the smaller TPA parameters are, and the better quality of moon cake is. The optimal formula of high-calorie white gourd stuffing optimazed by Mixture D-Optimal design was:white gourd puree:75.5%, sugar:19.0%, peanut oil:4.5%, corn starch:1.0%. 2. The correlation between the content of water and fat in different parts of moon cake and TPA parameters during the process of moon cake’s softening.The hardness is very significant correlated (p≤0.01) with the content of water and fat in moon cake skin, the content of water in outer filling and the content of fat in inner filling. The cohensiveness is very significant positively correlated (p≤0.01) with resilience, and the resilience is very significant negatively correlated (p≤0.01) with the content of fat in inner filling. According to the correlation analysis results between the content of water and fat in different parts of moon cake and TPA parameters, regression analysis was conducted by choosing some main instrument analysis indexes as the dependent variable, while some indexes as the independent variables. The predictive equations for hardness and resilience could be set up respectively from regression analysis to describe the relationship between the content of water and fat in different parts of moon cake and TPA parameters.3. Formula optimization of low-calorie Cantonese-style moon cake’s white gourd stuffing.Used as fat substitutes in white gourd stuffing, Maltodextrin, inulin and simplesse100affected the hardness of moon cake significantly (p≤0.01), and were not appropriate for low-calorie stuffing. While maltitol, xylitol and isomaltooligosaccharide are appropriate as sugar substitutes to keep the tastes of white gourd stuffing. Two optimized formulas formed by simplex centroid experiment were as follows:melon slurry:75.5%, maltitol:19.0%, peanut oil:4.5%, corn starch:1.0%; melon slurry:75.5%, sucrose:3.3%, xylitol:15.7%, peanut oil:4.5%, corn starch:1.0%.4. The volatile flavor compounds in high-calorie and low-calorie White gourd stuffingHead space solid phase microextraction (SPME) technique combined with GC-MS was employed to analyze volatile compounds in white gourd stuffing processing. It was found that alcohols and aldehydes were the major volatile flavor compounds in its processing and their relative amount decreased after frying and baking. Moreover, hexanal was detected in the whole processing. The major volatile flavor compounds in the two different low-calories white gourd stuffing were basically same. A large number of octanes appeared while2-tert-Butyl-1,4-benzoquinones decomposed during flying and baking. Hexanal, cis-octene, trans-2-hexenal, p-xylene, cis-2-heptenal, octanal, nonanal, trans-2-decanoic acid, cis-2,4-decadienal were probably produced during frying, and remained in the baking process. Trans-2-Hexen-l-ol and hexanol were detected only in the mixturing process. Overall, the volatile flavor compounds in the low-calorie white gourd stuffing were richer than that of low-calorie white gourd stuffing. |
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