南瓜皮多糖锌的制备及生物利用率研究

本研究以南瓜皮多糖和锌为原料制备南瓜皮多糖锌,通过单因素和响应面法优化得到最佳制备工艺,并采用体外模拟胃肠道消化法测定南瓜皮多糖锌中锌离子的生物利用率。结果表明:南瓜皮多糖锌的最佳制备工艺为:南瓜皮多糖与锌质量比18:1,反应时间104 min,反应pH9,此时螯合率达到最大值为99.37%±0.12%。通过电感耦合等离子体质谱仪测定锌含量约为23.17±0.05 mg/g。体外模拟胃肠道消化试验表明:多糖锌受胃中的酸性环境影响小,在肠道中多糖锌中锌离子的溶解率和透析率均高于无机锌。综上,南瓜皮多糖锌生物利用率高、稳定性好,为开发新型的多糖补锌剂以及提高南瓜资源的综合利用提供了依据。     

生姜皮多糖锌的制备及体外模拟消化研究

本研究将生姜皮多糖与硫酸锌结合,以螯合率为指标,采用单因素和响应面试验对其制备工艺进行优化,通过体外模拟胃肠道消化对生姜皮多糖锌和硫酸锌的消化与吸收情况进行分析。结果表明,制备生姜皮多糖锌的最佳工艺条件为:反应温度60 ℃,反应时间125 min,反应pH8,多糖与锌质量比24:1。在此条件下螯合率可达98.53%±0.31%,通过电感耦合等离子体质谱仪测定锌含量为21.17±0.25 mg/g。体外模拟胃肠道消化研究表明:生姜皮多糖锌在胃肠液中溶解率相对稳定,胃液对生姜皮多糖锌的溶解率影响较小,肠液中生姜皮多糖锌的溶解率和透析率均高于硫酸锌。综上,生姜皮多糖锌具有较高的稳定性和生物接受率,可作为一种新型锌补充剂。     

绿豆多肽锌螯合物的制备及其结构与体外消化的分析

为生产易被人体消化吸收的锌补充剂,提高绿豆的附加值,本实验将绿豆多肽与锌进行螯合,以螯合能力为指标,采用单因素与响应面结合的方法,对螯合工艺进行优化;运用傅里叶红外光谱、紫外光谱、扫描电镜、X-射线衍射等方法比较螯合前后结构的变化;并利用体外模拟胃肠道消化测定肽锌螯合物中锌离子的生物利用率。结果表明:制备肽锌螯合物的最佳条件为肽锌质量比6.20∶1、反应温度50℃、反应时间83 min、反应pH 6.3,在此条件下螯合率达到52.19 mg/g;光谱分析表明,多肽的氨基、羧基与酰胺基参与了反应;扫描电镜、X-射线衍射显示多肽与螯合物在表面微观结构和结晶程度上均有较大改变;体外模拟胃肠道消化研究表明肽锌螯合物中锌离子的溶解率和透析率均显著高于无机锌盐。实验综合表明生成了一种新型螯合物,且螯合物锌离子的生物利用率较高,具有潜在的应用意义。     

金针菇多糖螯合钙的制备工艺研究

金针菇多糖具有重要生物活性,为了提高其综合利用价值,研究以金针菇干粉提取的金针菇多糖为原料,探讨金针菇多糖与氯化钙溶液的最佳螯合工艺,制备出具营养强化功能的金针菇多糖螯合钙产品。通过单因素试验和正交试验,以多糖和钙离子的螯合率为考察指标,研究了螯合时间、氯化钙溶液初始质量浓度、金针菇多糖与氯化钙溶液的质量比、溶液pH和螯合温度等因素对金针菇多糖螯合效果的影响,确定最佳螯合工艺,并分析了多糖螯合钙前后的结构及抗氧化活性变化。结果表明:金针菇多糖螯合钙最佳工艺条件为氯化钙初始质量浓度5.0mg/m L,金针菇多糖与氯化钙的质量比8:1,p H5,螯合时间5 h,所得螯合率达最高78.30%;红外光谱分析表明金针菇多糖中-OH与Ca离子发生配位作用生成稳定螯合物;且金针菇多糖与钙离子螯合物抗氧化性优于未螯合的金针菇多糖。     

亚临界水提取南瓜皮多糖工艺优化及其抗氧化能力

为建立南瓜皮多糖提取方法,利用环境友好型的亚临界水技术提取南瓜皮多糖。通过响应面试验优化亚临界水提取南瓜皮多糖的最佳工艺条件,并对其抗氧化能力和α-淀粉酶与α-葡萄糖苷酶抑制能力进行评价。结果表明,亚临界水提取南瓜皮多糖的最佳工艺条件为提取温度137.39 ℃、提取时间8.08 min、提取压力5.35 MPa。在该条件下,南瓜皮多糖得率为29.846 3%,结果表明：亚临界水法提取南瓜皮多糖是一种高效的提取技术。该试验提取的南瓜皮多糖中总糖含量为58.00%,糖醛酸含量为17.41%,蛋白含量为2.01%,总酚含量为0.63%,主要由阿拉伯糖、半乳糖、葡萄糖和葡萄糖醛酸组成,分子量为29.975 kDa,具有良好的抗氧化能力和对α-淀粉酶与α-葡萄糖苷酶的抑制能力。     

正交试验优化花生肽螯合锌的制备工艺

研究了花生蛋白水解物和锌离子制备肽锌螯合物的工艺条件,以螯合率为评价指标,考察肽与锌的质量比、反应pH、反应温度和反应时间对螯合反应的影响。在单因素试验基础上,采用4因素3水平正交法确定花生肽-锌螯合物的制备工艺。最佳工艺条件:花生肽-锌质量比4∶1、反应体系pH 6.0、反应温度50℃、反应时间40 min。在此条件下,锌的螯合率为57.04%。     

负载柚皮苷的环糊精-多糖基凝胶球的制备、特性及缓释性的研究

为了使柚皮苷具有更好的水溶性和缓释性能,利用羟丙基-β-环糊精对柚皮苷较强的包合能力,先形成水溶性包合物,再以果胶与海藻酸钠复合多糖为载体,利用离子凝胶法诱导形成水凝胶外层,制备柚皮苷-复合多糖水凝胶球。研究了复合多糖浓度、果胶与海藻酸钠质量比、CaCl₂质量浓度和柚皮苷添加量对多糖凝胶球机械性能、粒径及载药能力的影响,并以包封率为指标进行优化实验。结果表明,复合多糖浓度为3%,果胶与海藻酸钠质量比为3:1,氯化钙质量浓度为5%,柚皮苷添加量为5.5 mg/mL,制备的凝胶球包封率为68.34%±0.49%。扫描电镜显示,复合多糖凝胶球表面皱缩但结构致密,内部结构疏松多孔;红外光谱结果表明,柚皮苷与羟丙基-β-环糊精形成的包合物被成功包埋在凝胶球中;溶胀和体外模拟消化实验表明复合多糖凝胶球具有一定的pH敏感性和较好的缓释性。本研究制备的复合多糖凝胶球载体,可有效增加柚皮苷的溶解性和提高其生物利用度,并为柑橘黄酮在食品中的应用提供参考。     

静态超高压制备黑茶多糖铁及其体外消化特性

目的：针对传统加热法制备多糖铁费时、铁结合率较低等不足,研究和优化静态超高压制备黑茶多糖铁工艺,并明确其体外模拟消化特性。方法：以黑茶中提取的茶多糖为原料,采用静态超高压法制备黑茶多糖铁,优化其制备工艺条件,并考察其体外模拟消化过程中的稳定性和生物可利用性。结果：压力、糖铁比和处理时间对制备的黑茶多糖铁中铁含量的影响呈非线性关系,且具有二次作用和交互作用;各因素对铁含量影响的大小顺序为糖铁比>处理时间>压力。黑茶多糖铁的最佳制备工艺为糖铁比（m_黑茶多糖∶m_三氯化铁）1.7∶1.0,压力425 MPa,处理时间22 min,制得的黑茶多糖铁中铁质量分数为16.78%。体外胃、肠模拟消化表明黑茶多糖铁较FeSO₄稳定性更好,至消化结束可溶性铁含量高达86.82%。结论：静态超高压制备黑茶多糖铁效率高,且制备的黑茶多糖铁具有较高的潜在生物利用度。     

鳕鱼骨明胶多肽螯合钙制备工艺及其在体外模拟消化液中的稳定性

为探究鳕鱼骨明胶多肽螯合钙的较佳制备工艺及其消化吸收稳定性,以螯合率为指标对鳕鱼骨明胶多肽与CaCl2的螯合工艺进行了优化,并利用体外胃肠模拟消化系统考察了产物在胃肠道环境中螯合率的变化情况。通过Box-Behnken试验设计与响应面分析,优化后螯合工艺确定为酶解时间1.5 h、肽钙质量比8∶1、pH 5.5、螯合温度50 ℃、螯合时间1 h,最终螯合率可达93.47%。扫描电子显微镜结果显示,鳕鱼骨明胶多肽与Ca2＋螯合后由粗糙的纤维状结构变为光滑的球状颗粒;傅里叶变换红外光谱显示Ca2＋和鱼骨明胶肽的氨基端与羧基端相结合。体外模拟消化实验证明,钙肽螯合物在模拟胃液中结构易受破坏,螯合率从60.74%降低到3.64%;在模拟肠液中螯合率随着时间的延长,由10.74%上升至53.38%（120 min）。研究结果为水产加工副产物的高值化利用及鱼骨明胶多肽螯合钙这一新型补钙制剂的开发提供了理论支持与技术参考。     

罗非鱼鳞胶原蛋白肽锌螯合物制备工艺优化

为了获得罗非鱼鳞胶原蛋白肽锌螯合物的最佳制备工艺,采用响应面法进行优化其制备工艺,建立了肽锌螯合率与pH、肽锌质量比、时间和温度的数学模型。得到最佳制备工艺参数为:pH 5.0、肽锌质量比2.5∶1、时间35 min和温度54℃,肽锌螯合率的预测值为92.79%,验证试验值为91.96%,与预测值无显著性差异。     

南瓜多糖复合酶法提取及纯化的研究

南瓜中的有效成分南瓜多糖对糖尿病症状有显著的治疗效果,为了开发和利用这一功能成分,本实验采用酶解的方法提取南瓜多糖。首先利用正交试验确定复合酶添加量为纤维素酶1%,果胶酶1.5%,木瓜蛋白酶1%;利用正交试验确定复合酶的最佳反应条件为温度40℃,pH值为5.5,反应时间为30min。在最佳条件下,多糖的提取率为28.8%。将复合酶法制得的南瓜粗多糖经脱色、透析后,上DEAE-纤维素柱层析,得到三种级分。主要级分PPIII经SepharoseCL-4B凝胶柱层析、紫外扫描和冻融分析鉴定为均一组分。     

Speciation of zinc in pumpkin seeds (Cucurbita pepo) and degradation of its species in the human digestive tract

Pumpkin seeds are one of the foodstuffs recommended in diets which do not contain other Zn-rich sources. The main objectives of this work were to get information on Zn and its species in pumpkin seeds, and their possible degradation in the human gastrointestinal tract, indicative of Zn bioaccessibility. A sequential analytical approach was applied, focusing on total Zn, spatial Zn distribution, extractability, speciation and bioaccessibility of Zn and its species. It was shown that water extracts of pumpkin seeds exhibit a specific Zn species fingerprint with ca. 30% of a low-MW fraction (0.5–2 kDa) and ca. 60% of an intermediate/high-MW fraction (10–20 kDa). Digestion of Zn species under simulated stomach conditions proved that Zn species identified in plant extracts were completely decomposed to Zn²⁺. The subsequent digestion under intestinal conditions showed that Zn becomes less accessible, indicating that antinutrients like naturally present phytate may be responsible for complex formation in the small intestines, thus reducing the potential for Zn bioavailability.     

Determination of bioaccessibility of beta-carotene in vegetables by in vitro methods

The in vitro method in use for the determination of beta-carotene bioaccessibility involves simulated gastrointestinal digestion followed by ultracentrifugation to separate the micellar fraction containing bioaccessible beta-carotene and its quantitation. In this study, the suitability of two alternatives viz., membrane filtration and equilibrium dialysis were examined to separate the micellar fraction. Values of beta-carotene bioaccessibility obtained with the membrane filtration method were similar to those obtained by the ultracentrifugation method. Equilibrium dialysis was found not suitable for this purpose. Among the vegetables analyzed, fenugreek leaves had the highest content of beta-carotene (9.15 mg/100 g), followed by amaranth (8.17 mg/100 g), carrot (8.14 mg/100 g) and pumpkin (1.90 mg/100 g). Percent bioaccessibility of beta-carotene ranged from 6.7 in fenugreek leaves to 20.3 in carrot. Heat treatment of these vegetables by pressure cooking and stir-frying had a beneficial influence on the bioaccessibility of beta-carotene from these vegetables. The increase in the percent bioaccessibility of beta-carotene as a result of pressure-cooking was 100, 48 and 19% for fenugreek leaves, amaranth and carrot, respectively. Stir-frying in presence of a small quantity of oil led to an enormous increase in the bioaccessibility of beta-carotene from these vegetables, the increase being 263% (fenugreek leaves), 192% (amaranth leaves), 63% (carrot) and 53% (pumpkin).     

南瓜多糖提取方法研究

通过正交试验确定南瓜多糖热水浸提法最佳提取工艺,然后以提取液中多糖含量为指标,对热水浸提法、超声波法和复合酶法提取南瓜多糖进行了比较研究。结果表明,三种方法中复合酶法不仅提取率最高,工艺最简易,而且制得的粗多糖中蛋白质含量低,不需要进行脱蛋白工艺,是较佳的南瓜多糖提取方法。     

响应面法优化超声波提取南瓜皮叶黄素的工艺研究

本实验以南瓜皮为原料,采用超声波辅助溶剂法提取其中的叶黄素,考察提取溶剂类型及比例、超声功率、液固比和超声提取时间对南瓜皮中反式叶黄素及其顺式异构体提取量的影响。在单因素实验基础上,通过响应面法优化工艺条件。结果表明:南瓜皮叶黄素提取的最佳溶剂为乙醇-石油醚(2:1,V/V),南瓜皮叶黄素提取物中共鉴定出1种反式叶黄素和4种叶黄素顺式异构体(9-顺式叶黄素,9'-顺式叶黄素,13/13'-顺式叶黄素,15-顺式-叶黄素)。此外,超声波提取南瓜皮反式叶黄素最佳的工艺条件为:乙醇/石油醚体积比2:1、液固比40:1 (mL/g)、超声功率210 W、提取时间30 min。验证优化工艺得到反式叶黄素的实际提取量为(229.7±9.1) μg/g dw,叶黄素顺式异构体实际提取量为(9.4±0.2) μg/g dw,与预测值相近。研究结果为叶黄素的高效提取及南瓜皮的综合利用提供了参考。     

灵芝多糖的复合酶法提取工艺优化

以灵芝子实体为原料,采用复合酶法(纤维素酶、半纤维素酶、木瓜蛋白酶)提取灵芝多糖,并分析工艺条件对多糖提取率的影响。在正交试验确定复合酶比例的基础上,采用响应面法对复合酶法提取灵芝多糖的提取条件进行了优化,得到最优工艺条件。研究结果表明,复合酶比例为:纤维素酶3.5%、半纤维素酶4.0%、木瓜蛋白酶3.0%;最佳酶解提取条件为:酶解处理pH值、温度和时间分别为5.70、50℃和81 min,在此条件下灵芝多糖的提取率为3.73%。     

河蚬多肽螯合亚铁的制备工艺研究

以河蚬肉为原料制备河蚬多肽,探讨河蚬多肽与亚铁离子螯合的最佳工艺条件。在单因素实验的基础上,采用响应面分析法对河蚬多肽螯合亚铁离子的工艺条件进行优化,确定最佳的螯合工艺条件为pH6.0,多肽与亚铁离子质量比1.5:1,螯合时间41 min,螯合温度31℃,螯合率预测值为82.40%,实测值为81.63%。红外光谱分析表明,多肽中的氨基和羧基均参与了螯合反应。本研究拓宽了河蚬的加工利用途径,并为多肽螯合亚铁的开发应用提供理论基础。     

Polyethylenimine-modified fungal biomass as a high-capacity biosorbent for Cr(VI) anions: sorption capacity and uptake mechanisms

Heavy metal pollution in the aqueous environment is a problem of global concern. Biosorption has been considered as a promising technology for the removal of low levels of toxic metals from industrial effluents and natural waters. A modified fungal biomass of Penicillium chrysogenum with positive surface charges was prepared by grafting polyethylenimine (PEI) onto the biomass surface in a two-step reaction. The presence of PEI on the biomass surface was verified by FTIR and X-ray photoelectron spectroscopy (XPS) analyses. Due to the high density of amine groups in the long chains of PEI molecules on the surface, the modified biomass was found to possess positive zeta potential at pH below 10.4 as well as high sorption capacity for anionic Cr(VI). Using the Langmuir adsorption isotherm, the maximum sorption capacity for Cr(VI) at a pH range of 4.3-5.5 was 5.37 mmol/g of biomass dry weight, the highest sorption capacity for Cr(VI) compared to other sorbents reported in the literature. Scanning electronic microscopy (SEM) provided evidence of chromium aggregates formed on the biomass surface. XPS results verified the presence of Cr(III) on the biomass surface in the pH range 2.5-10.5, suggesting that some Cr(VI) anions were reduced to Cr(III) during the sorption. The sorption kinetics indicated that redox reaction occurred on the biomass surface, and whether the converted Cr(III) ions were released to solution or adsorbed on the biomass depended on the solution pH. Sorption mechanisms including electrostatic interaction, chelation, and precipitation were found to be involved in the complex sorption of chromium on the PEI-modified biomass.