体外消化和贮藏条件对粗壮脉纹孢菌孢子中类胡萝卜素稳定性的影响

采用国标测定粗壮脉纹孢菌(Neurospora crassa)孢子壁的基本组成成分,扫描电子显微镜观察孢子形态及颗粒大小,1,1-二苯基-2-三硝基苯肼和螯合金属离子法测定孢子中类胡萝卜素的抗氧化能力,分光光度法测定总类胡萝卜素的含量,分别研究不同体外消化体系和贮藏条件对孢子中类胡萝卜素稳定性的影响。结果发现,粗壮脉纹孢菌孢子壁中水分、粗纤维、粗脂肪、蛋白质、几丁质质量分数分别为(17.70±0.63)%、(29.90±0.03)%、(0.32±0.11)%、(28.32±0.89)%、(0.66±0.13)%,孢子中总类胡萝卜素含量为(776.42±2.05)μg/g孢子。经过口腔、胃和小肠消化后粗壮脉纹孢菌孢子壁局部均出现密集的小孔,孢子较未处理相比有一定程度的皱缩。消化过程中孢子中类胡萝卜素的释放率显著提高,口腔(9.35%)胃(18.78%)小肠(32.58%),消化液中抗氧化活性显著升高,口腔胃小肠;贮藏9 d后类胡萝卜素的减少率分别为:4℃避光组2.24%,25℃避光组3.19%,25℃光照组5.79%。研究表明粗壮脉纹孢菌孢子壁是一种适合包埋不稳定物质的壁材,且利于消化吸收。

Stability of Carotenoids in Neurospora crassa Spores during in Vitro Simulated Gastrointestinal Digestion and Storage

This work studied the chemical components of Neurospora crassa spores by national standard methods, and it also observed the morphology and size by scanning electron microscopy. Meanwhile, 1,1-diphenyl-2-picrylhydrazyl radical scavenging and metal chelating assays were used to evaluate the antioxidant capacity of carotenoids in Neurospora crassa spores, and total carotenoid content was determined spectrophotometrically. The effects of in vitro digestion and different storage conditions on the stability of carotenoids were studied as well. The results showed that the contents of water, crude fiber, crude fat, protein and chitin in the spore wall of Neurospora crassa were (17.70 ± 0.63)%, (29.90 ± 0.03)%, (0.32 ± 0.11)%, (28.32 ± 0.89)% and (0.66 ± 0.13)%, respectively. Total carotenoid content in the spores was (776.42 ± 2.05) μg/g. After oral, gastric and intestinal digestion, the spores became more collapsed and had closely spaced small holes in cell walls when compared to the control group. In addition, the release rate of carotenoids significantly increased during the entire digestion process: oral (9.35%) < gastric (18.78%) < small intestinal digestion (32.58%), so did the antioxidant capacity of digests. After 9-day storage at 4 ℃ in darkness, at 25 ℃ in darkness and at 25 ℃ in light, the amount of carotenoids decreased by 2.24%, 3.19% and 5.79%, respectively. All these data indicated that cell wall of Neurospora crassa spores could be a suitable wall material for encapsulation of unstable substances and be beneficial to digestion and absorption.