快干型聚乙烯醇／淀粉胶粘剂的研究

以聚乙烯醇(PVA)和玉米淀粉为原料制取水性高分子胶粘剂,填充高岭土改善快干性,通过考察原料配比、氧化剂、快干剂用量等因素的影响,给出了胶粘剂的最佳配方。测试产品的快干性、粘接强度和耐水性等主要指标,性能超过市售的103和825胶,并且其生产工艺简单、成本低于前者。     

超高效液相色谱-四级杆/静电场轨道阱高分辨质谱快速同时测定玉米中多种真菌毒素和农药残留

采用直接提取稀释快速前处理技术,利用超高效液相色谱-四级杆/静电场轨道阱高分辨质谱,建立了玉米中常见的16种真菌毒素和11种农药残留的快速同时分析方法。样品采用乙腈：水：乙酸溶液(70:29:1, v/v/v)提取,提取液稀释后即可进行仪器测定。以C₁₈色谱柱进行色谱分离,通过全扫描模式进行定量检测。结果表明,16种真菌毒素和11种农药残留在本实验的线性范围内都具有良好的线性关系,相关系数(R₂)大于0.999,高中低三浓度添加水平回收率(n=6)为79.6%~116.9%,相对标准偏差为0.5%~12.2%。方法简单、快速和准确,可满足玉米真菌毒素和农药残留的日常检测和监测工作的需要。     

玉米黄色素提取工艺优化及其抗癌活性研究

探究超声辅助酶法制备玉米黄色素的最佳工艺,以及玉米黄色素对人胃腺癌细胞(BGC-823)生长的抑制作用。通过单因素和响应面试验,探讨超声辅助酶法制备玉米黄色素的最佳条件;用制备的玉米黄色素处理BGC-823细胞,并进行形态学观察和MTT法细胞存活率检测,初步考察其抗癌活性。超声辅助酶法提取玉米黄色素的最佳条件为:酶活力10 000U/g,超声功率400 W,酶解温度35℃,该条件下提取率达最大,为(72.64±0.42)μg/g;细胞形态学观察及MTT细胞活力检测显示玉米黄色素对BGC-823细胞具有一定的生长抑制作用。超声辅助酶法提取玉米黄色素是一种有效的提取方法,制备的玉米黄色素对BGC-823细胞生长有较强的抑制作用。     

葵花籽油微乳提取玉米黄粉中天然色素的研究

研究食品级的葵花籽油微乳提取玉米黄粉中天然色素的应用。以葵花籽油微乳为提取剂,在单因素试验基础上,以固液比、温度和时间为评价指标,利用三因素三水平的响应面分析法优化出葵花籽油微乳提取玉米黄色素的最佳工艺条件,建立了回归模型,并对提取后的葵花籽油微乳进行性能的表征。结果表明,影响色素提取效果的因素主次顺序是固液比温度时间;根据响应面和SAS软件优化出的结果,最佳提取条件取为:固液比1:42、温度71℃、时间1.5 h,在此条件下的实际提取得率为0.34 mg/g,与预测的理论值相近,表明该模型能够真实的反应筛选条件对色素提取得率的影响。提取后葵花籽油微乳的性状良好,粒径变化不大,稳定性较好。     

高效液相色谱-串联质谱法测定玉米中虫酰肼 残留量

目的建立高效液相色谱-串联质谱法检测玉米中虫酰肼的残留量。方法样品经含1%乙酸的乙腈溶液提取,再经N-丙基乙二胺(PSA)、石墨化炭黑和十八烷基硅烷(octadecylsilane,ODS)净化,用ACQUITY UPLC BEH C_(18)(100 mm×2.1 mm,1.7μm)柱分离,以0.1%乙酸水溶液和乙腈作为流动相进行梯度洗脱,然后经质谱法检测,以外标法定量。结果虫酰肼在4~100 ng/m L浓度范围内时,线性关系良好,相关系数为0.9933。在0.001、0.05和25.0 mg/kg 3个水平加标的平均加标回收率为85.5%~105.0%之间,相对标准偏差均小于10.1%,检出限为0.001 mg/kg。结论本方法灵敏准确、操作简便,可适用于玉米中虫酰肼残留量的测定。     

玉米油中主要营养因子在精炼与储存过程中的变化

分析了国内主要市售品牌玉米油中主要营养因子的含量,探讨了精炼工艺和储藏时间对玉米油中主要营养因子的影响。结果显示:不同品牌市售玉米油中脂肪酸含量差别较小,而生育酚和植物甾醇含量差别较大,其中生育酚含量范围为56.2~98.3 mg/100 g,植物甾醇含量范围为105.8~216.4 mg/100 g;精炼工艺脱臭对玉米油中亚油酸、α-亚麻酸、生育酚和植物甾醇含量有显著降低的效果(P0.05),脱皂能显著降低植物甾醇含量(P0.05),其他工艺均无显著影响(P0.05);精炼后常温储藏6个月后的玉米油中除油酸含量显著降低外,其他脂肪酸含量无显著变化(P0.05),生育酚和植物甾醇含量均显著减少(P0.05);复配添加维生素E和迷迭香提取物对玉米油的氧化稳定性具有显著的提升作用(P0.05)。     

In vitro digestibility of processed and fermented soya bean,cowpea and maize

Tropical legumes, ie soya bean and cowpea, were pre‐treated and subsequently fermented using pure cultures of Rhizopus spp. Impact of soaking, cooking and fermentation of the legumes on their digestibility was determined using an in vitro digestion method. Processing of white maize included, amongst others, natural lactic acid fermentation, cooking and saccharification using barley malt. An in vitro method was standardised to carry out comparative determinations of the dry matter digestibility of cereal and legume food samples as a function of processing conditions, without attempting to exactly mimic gastrointestinal digestion. Using this method based on upper digestive tract digestion, it was observed that digestibility of the legumes increased during cooking and fermentation. Cooking improved the total digestibility of both soya bean and cowpea from 36.5 to 44.8% and from 15.4 to 40.9% respectively. Subsequent fungal fermentation increased total digestibility only by about 3% for both soya bean and cowpea. Digestibility was also influenced by fungal strain and fermentation time. Cooking and subsequent saccharification using malt almost tripled total digestibility of white maize from 25.5 to 63.6%, whereas lactic fermentation of maize had no effect on in vitro dry matter digestibility. Although total digestibility of cooked legumes was only slightly improved by mould fermentation (3% for both soya bean and cowpea), the level of water‐soluble dry matter of food samples increased during fermentation with Rhizopus oryzae from 7.0 up to 27.3% for soya bean and from 4.3 up to 24.1% for cowpea. These fermented products could therefore play a role as sources of easily available nutrients for individuals suffering from digestive disorders. © 2000 Society of Chemical Industry