限氧热泵干燥与油脂对β-胡萝卜素生物接近度的影响

Impact of Oxygen Limited Heat Pump Drying and Oil on Bioaccessibility of β-carotene in Carrots

胡萝卜富含维生素A原类胡萝卜素,但含水率较高,不宜储存。将其干燥制成脱水蔬菜可以有效地延长货架期、保留营养价值。利用体外消化模型评估了胡萝卜经CO2源限氧热泵干燥后的β-胡萝卜素生物接近度及油脂对其的影响。以低速离心得到的上清液中的β-胡萝卜素释放率和超微过滤得到的胶束相中的β-胡萝卜素胶束率为指标评估β-胡萝卜素生物接近度。尽管干燥对胡萝卜中β-胡萝卜素的保留率有消极影响,但对其生物接近度却有积极作用。尤其是以CO2作为干燥介质可以极大地提高β-胡萝卜素的保留率和生物接近度。油脂的添加使得新鲜胡萝卜和干制品中的β-胡萝卜素释放率和胶束率都显著升高。

Carrots contains high level of provitamin A carotenoids,especially β-carotene,which plays the function of antioxidation and scavenging free radicals in vivo. But they also have high level moisture content. This character negatively impacts the length of time that carrots can be stored. Dehydration of carrots can effectively increase storage time and retain nutrition. But in the drying process of carrots,theβ-carotene degradation reaction rate would be significantly increased by destruction of tissue integrity,temperature rise,and contacting with light and oxygen,which could change the nutritional value of carrots. Carrots were dried by oxygen limited heat pump firstly,and then in vitro digestion model was used to evaluate the effect of different drying medium and oil on bioaccessibility of β-carotene in carrots during drying process. The bioaccessibility of β-carotene was measured by β-carotene release rate in supernatant by using low-speed centrifugation and β-carotene micellar rate in micelle phase by ultrafiltration. Although there was negative impact on β-carotene retention rate by drying process,there was positive impact on the bioaccessibility. Especially when CO2 was used as a drying medium,it increased the retention rate and bioaccessibility of β-carotene significantly. In addition,there was significant increase in the release rate and micellar rate of β-carotene in fresh and dried carrots when oil was added. Anyhow,there was significant increase of bioaccessibility of carrots by heat pump drying and adding oil. This may enhance the bioavailability of human beings.