| With the improvement of living standards and the accelerated pace of life,people’s demand for healthy and convenient foods is growing.Sweet potato and yam are the famous natural crop foods of our country.They are also treated as traditional Chinese medicines,which contain a variety of nutrients and functional active substances needed for human health.However,as root crops,the consumption of sweet potatoes and yam is limited by cooking,which is time-consuming and laborious,so it is urgent to develop ready-to-eat foods or health care products with them as main raw materials.Due to the problem of stability and color protection of the beverage,there is currently no commercial beverage with sweet potato or yam as main ingredient.In this paper,a new type of compound fruit and vegetable beverage was developed by using iron stick yam and Chuanshu 228,a newly cultivated sweet potato by Sichuan Academy of Agricultural Sciences,using single factor design and response surface optimization.In addition,dehydroepiandrosterone(DHEA)in sweet potato is one of the most important steroid hormones in the human body.It has many health functions,but no mature technology has been reported due to its difficult chemical extraction.In this paper,based on the Box-Benhnken response surface design,the DHEA extraction process in Chuanshu 228 red pulp and skin was optimized on the basis of single factor experiment.The research results can provide support for the comprehensive processing of Chuanshu 228.The main conclusions were as followed:Using the response surface model and fuzzy mathematics evaluation,the sensory analysis was carried out with the taste,flavor,aroma and color as the weight coefficient.The best formula of the fruit and vegetable beverage with Chuanshu 228 and iron stick yam as the main raw materials was: sweet potato juice: yam juice = 0.69,the amount of sucrose was 4.42% and the amount of mixed acid was 0.29%.The stability affected the clarity and storage stability of the beverage.The optimal stabilizer ratio of this beverage was: 0.08% of xanthan gum,0.16% of sodium alginate and 0.12% of Propylene glycol alginate(PGA).The color-keeping agent formula and process determine the color and permeability of the beverage.The best color-keeping agent ratio of the beverage was: ascorbic acid 0.362%,citric acid 0.553%,sodium chloride 0.200%,and the best color protection time and temperature were 40 min and 40 °C,respectively.Based on the ultrasound-assisted extraction,the HPLC analysis and the response surface method design,we optimized the DHEA chemical extraction from sweet potato pulp and skin.The results of single factor test showed that the amount of DHEA extraction from sweet potato skin was much higher than that of red pulp.The pH value,pre-fermentation time,acid extraction temperature and ultrasonic power had significant effects on DHEA extraction,but the extracted acid species had no significant effect.The results of response surface test showed that the optimal extraction process of DHEA from sweet potato skin was: pH=2.40,fermentation time 35.5 h,acid extraction temperature 80 °C,ultrasonic power 300 W.The extraction amount of DHEA from sweet potato skin was 0.390 mg/100 g.The optimum extraction process of DHEA from sweet potato pulp was: pH=2.47,fermentation time 35.0 h,acid extraction temperature 84 °C,ultrasonic power 270 W,DHEA extraction amount 0.165 mg/100 g.This extraction process is stable and effective,and is expected to be industrialized. |
PDF Full Text Request