枸杞南瓜粉的制备、体外消化特性和抗氧化活性的研究

以枸杞、南瓜为原料，利用植物乳杆菌（Lactobacillu plantarum）和鼠李糖乳杆菌（Lactobacillus rhamnosus）混菌（5∶1）发酵枸杞南瓜汁，以喷雾干燥法制备枸杞南瓜粉，采用单因素试验及正交试验优化喷雾干燥工艺，并通过体外模拟胃肠消化试验及自由基清除试验研究枸杞南瓜粉的消化特性及氧化活性。结果表明，最佳喷雾干燥工艺为进口热风温度160 ℃，进料流量7.5 mL/min，脱脂乳粉添加量2.5%。在此优化条件下，枸杞南瓜粉呈淡红色，集粉率40.3%、感官评分89.3分。体外消化特性及抗氧化活性试验结果表明，消化结束后测得发酵组消化液中总多酚、总黄酮含量分别上升了2.21%、6.35%，2,2-联氮-二（3-乙基-苯并噻唑-6-磺酸）二铵盐（ABTS+）自由基、1,1-二苯基-2-三硝基苯肼（DPPH）自由基、羟基自由基清除率分别为58.26%、86.43%、70.98%，显著高于对照组（P＜0.05），且肠消化阶段的抗氧化能力显著高于胃消化阶段（P＜0.05）。

Preparation,digestion property and antioxidant activity in vitro of Lycium barbarum pumpkin powder

Using Lycium barbarum and pumpkin as the raw materials, L. barbarum pumpkin juice was fermented by mixed-strains of Lactobacillu plantarum and Lactobacillus rhamnosus (5∶1), and then the L. barbarum pumpkin powder was prepared by spray drying method. The spray drying process was optimized by single-factor and orthogonal tests, and the digestion property and antioxidant activity of L. barbarum pumpkin powder were evaluated by simulated gastrointestinal digestion tests in vitro and free radical scavenging tests. The results showed that the optimal spray drying process was as follows: inlet hot air temperature 160 ℃, feed flow rate 7.5 ml/min, skim milk powder addition 2.5%. Under the optimal conditions, the L. barbarum pumpkin powder was light red, the powder collection rate was 40.3%, and the sensory score was 89.3. The digestion property in vitro and the results of antioxidant activity tests showed that the content of total polyphenols and total flavonoids in the fermented group after digestion increased by 2.21% and 6.35%, respectively. The free radicals scavenging rates of (2,2'-azinobis(3-ethylbenzthiazoline-6-sulphonate) diammonium salt (ABTS+), 1,1-diphenyl-2-picrylhydrazyl (DPPH), and hydroxyl were 58.26%, 86.43% and 70.98%, respectively, which was significantly higher than the control (P＜0.05), and the antioxidant capacity in intestinal digestion phase was significantly higher than that in the gastric digestion phase (P＜0.05).