| Chrysanthemum morifolium Chuju(Chuju)is one of the four famous chrysanthemum,which conta:ins chlorogenic acid and other active substances.It received a national geographical indication product.At present,the development of the industry is limited because of narrow market,which sell dried flowers mostly.Therefore,the effect of ultra-fine grinding on the physical and chemical properties of Chuju powder was investigated by taking the submicron powder of Chuju powder as the object.Then the yoghurt was developed with Chuju powder as raw material,and the formula of Chuju submicron powder yoghurt was optimized.In addition,whether the submicron powder of Chuju could inhibit the growth of lactic acid bacteria was explored.Finally,the storage characteristics of Chuju submicron powder yoghurt were studied.The main research contents and results are as follows:(1)The physical and chemical properties of two kinds of submicron powder and common powder of Chuju were studied,including angle of repose and slide,bulk density,wettability,water solubility and dispersion,scanning electron microscope(SEM)image and dissolution ability of main active components,etc.The results showed that the submicron powder of Chuju had higher bulk density,better fluidity and better wettability than the common powder of Chuju.The water solubility and dispersion of Chuju submicron powder were improved.Submicron powder had long cracks on its plant cell.The superfine grinding technology has no significant effect on the species and content of active substances which could promote the dissolution of rutin and chlorogenic acid.(2)Chuju submicron powder was added into skim milk to develop Chuju submicron powder yoghurt.The formula were optimized by exploring the effect of the particle size of Chuju submicron powder,the amount of submicron powder and sugar on the yoghurt quality.On the basis of the single factor experiments with the amount of Gellan gum,pectin,xanthan gum,the combination of three stabilizers of yogurt was optimized by response surface analysis.The results showed that the optimum formula of yogurt was detrmined as follows:0.2%submicron powder of Chuju,5%sugar,0.3‰ Gellan gum and 0.28‰ xanthan gum.Under this conditions,the yoghurt was yellowish,and its color was even and bright.The proportion of sour taste and sweet taste was appropriate,the tissue was fine and smooth and no precipitation.The flavor substances of Chuju submicron powder yoghurt were determined by gas chromatography-mass spectrometry(GC-MS).It was found that Chuju not only had 5 kinds of flavor components with the original yoghurt,but also contained 6 kinds of unique flavor components of Chuju.(3)The effect of Chuju powder on lactic acid bacteria in yoghurt was analyzed by particle size,addition and germicidal method.The results showed that Chuju had no significant effect on Lactobacillus and Streptococcus thermophilus in yoghurt.Therefore,in the formula range of Chuju submicron powder yoghurt,the addition of Chuju had no significant effect on the fermentation of lactic acid bacteria.(4)The changes of the various indexes of Chuju submicron powder yoghurt during storage period were studied by accelerated destruction test and temperature fluctuation experiment.The shelf life of Chuju submicron powder yoghurt was predicted by Arrhenius model.The results showed that during the storage period,the acidity of Chuju submicron powder yoghurt increased gradually with storage time,and the increasing rate of its value increased with the temperature in the accelerated destruction experiment.The pH and sensory score decreased with the storage time,and the rate of its value increased with the temperature.In the temperature fluctuation test,the acidity,pH and sensory score of yoghurt were greatly affected by temperature fluctuation.The kinetic prediction model of Chuju submicron powder yoghurt shows that the shelf life was predicted to be 22 days. |
PDF Full Text Request