辣木籽多糖的超高压辅助提取工艺及其抗氧化活性分析

超高压辅助提取技术是一种天然产物新型绿色高效提取技术,在保证提取效率的同时能最大限度保持天然产物的生物活性。为探究超高压辅助提取技术对辣木籽多糖的提取效果及其抗氧化活性的影响,本研究以辣木籽为原料,通过超高压辅助提取技术提取辣木籽中的水溶性多糖,以多糖得率为考察指标,以提取压力、提取时间、料液比、粉碎度作为单因素,在单因素试验基础上,采用正交试验设计方法优化辣木籽多糖的超高压辅助提取工艺,并通过测定总抗氧化能力、清除DPPH自由基（DPPH•）和羟自由基（•OH）的能力来分析辣木籽水溶性多糖的抗氧化活性。结果表明,辣木籽多糖最佳的超高压辅助提取工艺条件为：提取压力100 MPa、保压时间6 min、料液比（g/mL）1:15、粉碎度100目筛,在最佳提取工艺条件下辣木籽多糖最大提取得率为0.346%;在测试范围内辣木籽多糖清除DPPH自由基能力随多糖浓度的增加而增加,并有较好的线性关系,清除率达到50%时对应的浓度（IC₅₀）为0.0439 g/L,但是其抗氧化能力低于相同浓度的Vc,在测试范围内清除羟自由基能力也随辣木籽多糖浓度的增加而增加,也有较好的线性关系,IC₅₀为0.1666 g/L,其抗氧化能力与同浓度的Vc较接近,辣木籽多糖的总抗氧化能力为0.0482 mmol/L（以硫酸亚铁的当量浓度表示）。与热水提取方法相比,超高压辅助提取方法能够缩短提取时间,提取温度大大降低,提取效率显著提高;而且提取的辣木籽水溶性多糖具有较好的抗氧化能力,可以作为天然抗氧化剂进行开发利用。本研究结果可为天然抗氧化剂的开发、辣木资源的综合开发及高值化利用提供技术支持和参考。

Ultra-high Pressure Assisted Extraction and Antioxidant Activity of Polysaccharide from Moringa oleifera Seeds

Ultra-high pressure assisted extraction (UHP) is a new green and high efficient extraction technology for natural products, and the biological activity of the natural products can be kept as much as possible. With Moringa oleifera seeds powder as the experimental material, the water-soluble polysaccharide was extracted by a new ultra-high pressure assisted extraction technology. The antioxidant activities of the water-soluble polysaccharide from M. oleifera seed were evaluated by the total antioxidant capacity and DPPH and hydroxyl radicals scavenging ability. Taking the yield of polysaccharide as an evaluation index, the effects of pulverization degree, pressure, pressure holding time and ratio of material to liquid on the yield of water-soluble polysaccharide from M. oleifera seed were investigated by the single factor experiment method. The orthogonal experiment design method was used to get the optimum ultra-high pressure assisted extraction conditions of polysaccharide from M. oleifera seed. The experiment results showed that the optimum technological conditions of the polysaccharide from M. oleifera seed were determined as follows: holding pressure of 6 min, solid-liquid ratio of 1:15 (g/mL), extraction pressure of 100 MPa and degree of pulverization of 100 mesh. The yield of the polysaccharide from M. oleifera seed under this optimum condition was 0.346%. The experiment results also showed that the scavenging abilities for DPPH and hydroxyl radicals increased with the increase of concentration of the polysaccharide from M. oleifera seed and there was a good linear relationship between concentration of the polysaccharide from M. oleifera seed and the radical scavenging ability. The IC₅₀ (the concentration when the radical scavenging rate is 50%) of the polysaccharide from M. oleifera seed for DPPH and hydroxyl radicals was 0.0439 g/L and 0.1666 g/L respectively, and the antioxidant ability was lower than that of Vc at the same concentration, which indicated that the water-soluble polysaccharide from M. oleifera seed had certain antioxidant capacity within a certain concentration range. The total antioxidant capacity of the water-soluble polysaccharide from M. oleifera seed was 0.0482 mmol/L (Expressed as the equivalent concentration of FeSO₄). The water-soluble polysaccharide from M. oleifera seed can be extracted effectively in lower temperature and shorter time by ultra-high pressure assisted extraction technology compared with hot-water extraction method and the water-soluble polysaccharide from M. oleifera seed has good antioxidant activities and can be exploited and used as a natural antioxidant. The results of this study could provide technical support and reference for the exploration of natural antioxidant and the development and high value comprehensive utilization of M. Oleifera.