Study On The Key Processing Techniques Of Puerariae Powder And The Compound Beverage And Its Functional Evaluation

Radix Puerariae, root of Pueraria lobata(Willd.) Ohwi or Pueraria thomsonii Benth, which is a kind of medical and edible plants,has demonstrated to be rich in starch, dietary fiber, various amino acids and vitamins. Many researches have also reported that Radix Puerariae contain isoflavones, Pueraside, triterpenoidal saponins and alkaloids that have strong ability to scavenge free radicals, regulate blood lipid metabolism, improve insulin and anti-cancer function. Therefore it is widely used for food, medicine industry and health supplement. This paper investigated the nutritional components of Radix Puerariae from different habitats and the PPO characters to propose an optimum spray drying processing of puerariae powder production. Then the byproducts juice of pueraria starch combined with aqueous extract of Ampelopsis grossedentata, Kudingcha, honeysuckle and sweet tea were used to develop a new puerariae compound beverage. With three kinds of commercially available puerariae beverage as contrast, electronic tongue was applied to optimize the formula, and the product function was evaluated by radicals scavenging in vitro and animal models of blood glucose and lipid reducing. The results showed as follows:1. The analysis of puerariae nutritional components demonstrated that the dietary fiber, crude fat, total isoflavone, calcium, magnesium, iron and zinc content in Pueraria thomsonii Benth were all less than that in Pueraria lobata(Willd.) Ohwi,while the starch content was opposite. The starch and protein content of puerariae of different habitats showed significant difference(P<0.05), while there is no significant difference of the contents of crude fat, dietary fiber and total isoflavones between these puerariaes. All puerariaes contain seventeen amino acids including seven essential amino acids. Compared with pueraria starch, whole pueraria powder reserved nutritional and functional components more effectively.2. The study on properties of PPO demonstrated that the optimum p H of PPO in puerariae is 4.4, the optimum temperature is 50℃. Heat treatment under 90~100℃for 90~150s would deactivate PPO. According to the orthogonal test which aimed at analyze the inhibition effects of different inhibitors on PPO, the best conditions of the color-protection of puerariae were addition of 0.25% citric acid, 0.35% ascorbic acid and 0.4% calcium chloride with soaking for 40 min.3. The maximum formulation of stabilizer and emulsifier during spray drying with 0.4% compound emulsifier(sucrose ester: monoglyceride=7:3), 0.1% sodium alginate, 0.2% xanthan gum combined with 25% maltodextrin and 2% lecithin, would allow puerariae powder dissolved easily and homogenized. The optimum processing of spray drying of the puerariae powder is inlet air temperature 170 ℃, outlet air temperature 80℃, solid content 16%, peristaltic pump 6R/s. Under these conditions,the powder yield would reach to 24.21%, water content 4.4%, starch content 51.51%,total isoflavones 6.35mg/g, and the dissolving evaluation score is 7.8.4. The optimum formulation for compound juice consists of 35% puerariae juice,2.5% Ampelopsis grossedentata juice, 7.5% Kudingcha juice, 10% honeysuckle juice and 10% sweet tea juice. And the final product of compound beverage is made with100% compound juice in the addition of β-CD 0.3g/100 ml, 0.04g/100 m L ascorbic aicd, honey 5g/m L. The clarity of this product can reach to 90% after cryoprecipitate and centrifugation at low temperature with 4000r/min for 10 min. Electronic tongue detection and principal component analysis(PCA) showed that cumulative contributing rate of two major components could reach to 85.44%. Electronic tongue could effectively differentiate the gustation of different puerariae beverages. The analysis of bitter and astringent taste of compound juice and puerariae beverages showed that β-CD and honey could encapsulate bitterness and astringency in the beverage remarkably, thus improving the flavor quality.5. The free radicles scavenging experiments in vitro showed that the puerariae compound beverage have stronger ability than three kinds of commercially available puerariae beverages(N, D, G) to scavange the·OH, DPPH·and O2- free radicals, andIC50 of puerariae compound beverage was 0.289mg/m L, 0.111 mg/m L and 0.107mg/m L, respectively.6. The animal studies indicated that after 30 d of gavage with the pueraria compound beverage and three kinds of commercially available products(N, D, G),the blood glucose decreased rates of the high dose groups of these beverages were42.28%, 32.34%, 25.40%, 21.94%, respectively, and showed significant differencescompared with the high blood glucose control group(P<0.05). Except the low dose group of G pueraria beverage, each group could significantly reduce the TC and TG contents by 9.74%~41.32% and 10.36%~36.79% in the serum of mice respectively,and except the low dose groups of four kinds of beverage, each group could increase the HDL-C content by 4.22%~39.76% in the serum of mice compared with the high blood lipid control group.