黄刺玫籽油的超临界CO_2萃取及营养成分分析

采用超临界CO_2萃取技术萃取黄刺玫籽油。采用单因素试验考察了黄刺玫籽粉碎粒度、水分含量、萃取压力、萃取温度、萃取时间、CO_2流量、分离压力及分离温度对黄刺玫籽油萃取率的影响,并通过正交试验确定了最佳工艺条件。得到超临界CO_2萃取黄刺玫籽油的最佳工艺条件为:粉碎粒度40目,水分含量5.0%,萃取压力25 MPa,萃取温度40℃,CO_2流量15 L/h,萃取时间2 h,分离压力8.5 MPa,分离温度45℃。在最佳工艺条件下,黄刺玫籽油萃取率可达94.38%。对黄刺玫籽油的理化性质、脂肪酸组成、VE、VA及微量元素进行了分析检测。结果表明:黄刺玫籽油酸值(KOH)为0.73 mg/g、过氧化值为0.026 g/100 g;脂肪酸组成主要为棕榈酸(3.57%)、硬脂酸(1.45%)、油酸(16.95%)、亚油酸(53.88%)及亚麻酸(24.06%),其中不饱和脂肪酸含量为94.89%;黄刺玫籽油中含有VE193.5μg/g、VA36.8μg/g及多种微量元素。     

油菜蜂花粉油亚临界萃取及其HPLC分析

采用亚临界萃取油菜蜂花粉油,探讨了萃取温度、萃取压力和萃取时间对提取率的影响,并通过正交实验确定了最佳工艺条件。结果表明：在萃取压力0.9MPa,萃取温度30℃,萃取时间3h下,效果最佳,测得提取率为73.667%。经HPLC分析,共鉴定出16种脂肪酸和2种维生素,测定其相对含量：不饱和脂肪酸占63.83%,亚麻酸等n-3系列不饱和脂肪酸为24%,亚油酸、花生四烯酸等n-6系列不饱和脂肪酸的含量为20.87%,维生素A53mg/100g,维生素E780mg/100g。     

猕猴桃籽油的超临界二氧化碳萃取研究

本文根据超临界流体萃取技术的基本原理,以猕猴桃籽为原料,采用单因素试验的方法,考察了原料粉碎度、投料量、萃取压力、萃取温度、CO2流量、时间、分离温度等对超临界CO2萃取的影响。气相色谱分析了猕猴桃籽油的组成,α-亚麻酸含量高达60.71%,根据国家标准方法分析了猕猴桃籽油的品质,证明优于溶剂法提取得到的猕猴桃籽油。     

亚临界萃取文冠果籽油工艺的响应面优化

探讨了亚临界萃取文冠果籽油的工艺条件,通过单因素实验研究原料粒度、萃取温度和萃取时间对提油率的影响,在此基础上,采用Box-Behnken设计响应面实验,优化确定最佳工艺条件。结果表明,在四氟乙烷(R134a)为溶剂、萃取压力1.0 MPa、萃取次数3次下,亚临界萃取文冠果籽油的最佳条件为:原料粒度66目、萃取温度41℃、萃取时间56 min,在此条件下提油率为97.18%。文冠果籽油理化性质测定结果表明,其酸值(KOH)为0.8 mg/g,过氧化值为0.20 g/100 g,总砷含量小于0.01 mg/kg,铅含量小于0.005 mg/kg,溶剂残留未检出,相对密度为0.929 3,折光指数为1.471。利用气相色谱分析文冠果籽油的脂肪酸组成,共鉴定出13种脂肪酸,主要是棕榈酸(6.10%)、油酸(28.77%)、亚油酸(45.62%)、二十碳烯酸(6.78%)、硬脂酸(1.79%),其中不饱和脂肪酸占总组分的81.91%。     

莴苣籽油的超临界CO_2萃取工艺及其脂肪酸组成分析

以莴苣籽为原料,利用超临界CO2对其进行萃取。通过单因素实验考察了萃取压力、萃取温度、萃取时间、CO2流量、一次性投料量、粉碎粒度对莴苣籽油得率的影响。在单因素实验的基础上,采用正交实验优化了超临界CO2萃取莴苣籽油的最佳工艺,并采用气相色谱-质谱(GC-MS)联用技术分析其脂肪酸组成。结果表明,超临界CO2萃取莴苣籽油的最佳工艺条件为:一次性投料量50 g,粉碎粒度24目,萃取压力30 MPa,萃取温度45℃,CO2流量6 L/min和萃取时间4 h。在最佳工艺条件下,莴苣籽油得率为17.92%。莴苣籽油脂肪酸组成主要为亚油酸(56.420%)、油酸(22.562%)、棕榈酸(7.795%),其中不饱和脂肪酸含量为86.682%。     

超临界CO2萃取条件对紫苏籽油脂肪酸组成的影响及工艺优化

利用超临界萃取技术提取紫苏籽油,研究萃取压力、萃取温度、萃取时间、CO_2流量对主要脂肪酸组分含量的影响,并以亚麻酸萃取率为评价指标采用正交试验进行工艺优化。结果表明,棕榈酸、硬脂酸含量与萃取压力和萃取时间负相关,因萃取温度与CO_2流量的变化趋势是先降后升;油酸、亚油酸含量因CO_2流量的变化趋势是先降后升;亚麻酸含量与萃取压力和萃取时间正相关,因萃取温度与CO_2流量的变化趋势是先升后降。超临界CO_2萃取紫苏籽油的最佳工艺条件为:萃取压力25 MPa、萃取温度40℃、萃取时间2.0 h、CO_2流量20 L/h。在该工艺条件下亚麻酸萃取率为88.09%。所得紫苏籽油符合食用植物油质量要求。     

亚临界丁烷萃取柚籽油的工艺研究及其营养评价

采用亚临界丁烷法萃取精制柚籽油。在单因素试验基础上,通过正交试验优化工艺,并对柚籽油的营养成分进行分析。结果表明:料液比1∶4.0(g/m L)、萃取时间50 min、萃取温度50℃、萃取次数2次为最佳萃取条件,在此条件下,提取率为34.36%;柚籽油中维生素E的含量为29.76 mg/kg,角鲨烯为30.50 mg/kg,β-谷甾醇为1 750.00 mg/kg;其相对密度为0.94,烟点为249.80℃,凝固点为3～4℃,酸值为0.27 mg/g,过氧化值为0.20 mmol/kg,皂化值为185.10 mg/g,碘价为124.20 g/100 g,不饱和脂肪酸占比68.12%。     

滇牡丹籽油的超临界CO_2萃取工艺优化及其脂肪酸成分分析

以滇牡丹籽为原料,以萃取率为指标,用正交实验法分析讨论超临界CO2萃取过程中萃取时间、萃取温度、萃取压力及CO2流量对滇牡丹籽油萃取率的影响。采用GC-MS技术对滇牡丹籽油脂肪酸成分进行分析,并与栽培品种凤丹牡丹籽油的脂肪酸成分进行比较。结果表明:超临界CO2萃取滇牡丹籽油的最佳工艺条件为萃取时间60 min、萃取温度40℃、萃取压力45 MPa、CO2流量20 kg/h,在此条件下滇牡丹籽油萃取率为27.34%。滇牡丹籽油中不饱和脂肪酸的含量为89.34%,其中亚麻酸72.26%,亚油酸14.25%。滇牡丹籽油中不饱和脂肪酸的含量与凤丹牡丹籽油的很接近,然而其亚麻酸、油酸的含量高于凤丹牡丹籽油的。     

苹果籽油中维生素E含量的测定及提取方法比较

采用荧光分光光度法对苹果籽油中的维生素E含量进行测定,试验发现:苹果籽油中的维生素含量达249.0 mg/100 g油,且采用超临界CO2萃取的苹果籽油中维生素E含量高于有机溶剂提取.     

超临界CO_2萃取黑加仑籽油研究

利用超临界CO2萃取技术,对影响黑加仑油萃取工艺条件进行研究,得出最佳工艺条件:投料量300g、萃取温度30℃、萃取压力25MPa,粉碎度50目、萃取时间3.5h;在此条件下黑加仑提油率为90.78%。超临界CO2法得到黑加仑籽油不饱和脂肪酸含量达90%以上,其中γ-亚麻酸含量为15.2%,品质优于溶剂萃取。     

Effects of dietary supplementation of vitamins D(3) and E on quality characteristics of pigs and longissimus muscle antioxidative capacity

The effects of addition of vitamin D₃ and vitamin E to pig diets on blood plasma calcium concentration, meat quality (longissimus muscle) and antioxidative capacity were investigated. Two treatments consisted of supplementation with vitamin D₃ (500,000 IU/d) for 5 days separately (group D) and a combination of vitamin E (500 mg α-tocopheryl acetate/kg diet) for 30 days and vitamin D₃ (500,000 IU/d) for 5 days (group D + E) to growing-finishing pigs before slaughter. Pigs fed with vitamin D₃ had higher (P < 0.01) plasma calcium concentration compared with control pigs. Dietary supplementation of vitamin E significantly (P < 0.05) increased the concentration of α-tocopherol in meat (longissimus muscle). Vitamin D₃ supplementation resulted in higher (P = 0.07) a^∗ values of loin chops at 5 days of storage. Vitamin D₃ and vitamin E supplementation did not affect other meat quality characteristics or tenderness (quantified by Warner–Bratzler shear force). Antioxidative capacity (measured as MDA production after incubation of longissimus muscle homogenates with Fe²⁺/ascorbate) was improved by vitamin E and partly by vitamin D₃ supplementation.     

How proficiency testing can improve the quality of analytical data using vitamin analysis as an example

Analysis for vitamins is difficult and many factors affect data quality. Factors include the matrix, whether the vitamin is naturally present within the matrix or is added, the molecular form of the vitamin, vitamin stability and solubility. Uniformity of the vitamin within the sample is also known to affect results in addition to the methodology used.     

Vitamin D2 stability in milk during processing,packaging and storage

Stability of vitamin D2 in milk was determined in vitamin D2 fortified milk. Reverse phase high pressure liquid chromatography was used to determine the vitamin D₂ loss during processing, packaging and under light. The percentage losses during pasteurization, boiling and sterilization were demonstrated to be statistically insignificant. Milk was stored for seven days in both glass and plastic bottles under refrigerated temperature, non significant loss of vitamin D₂ was observed, whereas, when stored in polyethylene pouches significant loss was observed as vitamin D₂ decreased from 596.66 to 548.04 IU. This clearly indicated that vitamin D₂ was sorbed up by polyethylene material during storage resulting in its loss. Milk samples were stored for 32 h under three different light intensities (14,852,970 and 4455 lux). Non significant loss of vitamin D₂ was observed in glass packaging, whereas significant loss was observed in polyethylene pouches. In milk fortified with both calcium and vitamin D₂, non significant effect of calcium was observed on the loss of vitamin D₂.     

高效液相色谱法测定维生素K胶囊中维生素K2含量不确定度评估

目的评估高效液相色谱法测定维生素K胶囊中的维生素K_2含量的不确定度。方法采用高效液相色谱法测定维生素K胶囊中的维生素K_2含量,建立数学模型,对测定过程的主要不确定度分量进行计算,得出合成不确定度和扩展不确定度。结果维生素K胶囊中维生素K_2的含量为181.2μg/g时,在置信区间95%下,其扩展不确定度为7.5μg/g(k=2)。结论不确定度的主要来源为标准曲线配制的过程,该评估模型为维生素K胶囊中维生素K_2的含量测定的准确性提供了参考依据。     

天然燕麦中维生素B12的测定中2种微生物法前处理方式的比较

目的研究使用微生物法对燕麦中维生素B_(12)测定的可行性。方法以国标法为基础,采用标准前处理方式和添加淀粉酶的前处理方式分别对6份燕麦中的维生素B_(12)进行测定,比较2种不同前处理方式对检测结果的影响。结果国标法测定的标准曲线在维生素B_(12)的浓度为0.01~0.1 ng范围内具有良好的线性关系(r2=0.995)。前处理过程中加入20 m L浓度为1%的α-淀粉酶溶液可充分提取出燕麦样品中的维生素B_(12)。标准处理法的最大相对标准偏差(relative standard deviation,RSD)为10.2%,酶解处理法最大RSD为8.83%。结论对于燕麦中维生素B_(12)的测定,酶解处理法有更好的适用性,检测结果更为可靠。     

A novel nanosensor based on Pt:Co nanoalloy ionic liquid carbon paste electrode for voltammetric determination of vitamin B9 in food samples

In this work we describe a novel nanoalloy (Pt:Co) room temperature ionic liquid (RTIL) modified carbon paste electrode as a high sensitive sensor for voltammetric determination of vitamin B₉ in food samples. The sensor exhibits an enhanced effectiveness for the electro-oxidation of vitamin B₉ in aqueous solution. The oxidation peak potential for this matter at a surface of the ionic liquid (n-hexyl-3-methylimidazolium hexafluoro phosphate) Pt:Co carbon paste electrode (Pt:Co/IL/CPE) appeared at 685 mV that was about 110 mV lower than the oxidation peak potential at the surface of the traditional carbon paste electrode (CPE) under similar condition. The mechanism of the electro-oxidation process on the surface of the modified electrode was analyzed. Square wave voltammetry (SWV) was applied as a very sensitive electrochemical method for the determination of sub-micro-molar amounts of vitamin B₉. The linear response range and detection limit were found to be 1.0 × 10⁻⁷ to 5.0 × 10⁻⁴ M and 4.0 × 10⁻⁸ M, respectively. The prepared modified electrode shows several advantages such as simple preparation method, high stability, high sensitivity, and excellent catalytic activity, long-term stability and remarkable voltammetric reproducibility for eletrooxidation of vitamin B₉. The proposed sensor was successfully applied for the determination of vitamin B₉ in food samples.     

The effects of pre-treatment with vitamin B6 on memory retrieval in rats

The effects of pre-treatment with vitamin B₆ on memory retrieval in adult male Wistar rats were evaluated using a step-through passive avoidance task. The rats were divided into three groups of 10 each. All animals were fed standard rodent chow. Vitamin B₆ (50 or 100 mg/kg) was administered intraperitoneally (i.p.) every other day for 1 month before training was initiated. Three retention tests were performed to assess the memory of the rats. Vitamin B₆ (100 mg/kg) significantly increased the step-through latency of the passive avoidance response compared with the control in the first retention test of the passive avoidance paradigm (p < 0.05). In addition, vitamin B₆ at 100 mg/kg significantly increased memory retrieval in the second and third retention tests conducted 2 days and 1 week after training, respectively, compared with the control (p < 0.05). These results indicate that pre-treatment with vitamin B₆ potentially enhances memory retrieval.     

Effect of dietary beta-agonist treatment, vitamin D3 supplementation and electrical stimulation of carcasses on colour and drip loss of steaks from feedlot steers

In this study, 20 young steers received no beta-agonist (C) and 100 animals all received zilpaterol hydrochloride (Z), with 1 group receiving Z while the other 4 groups receiving Z and vitamin D₃ at the following levels (IU/animal/day) and durations before slaughter: 7 million for 3 days (3D7M) or 6 days (6D7M), 7 million for 6 days with 7 days no supplementation (6D7M7N) and 1 million for 9 days (9D1M). Left carcass sides were electrically stimulated (ES) and right sides not (NES). Samples were analysed fresh or vacuum-aged for 14 days post mortem. Parameters included drip loss and instrumental colour measurements. In general, zilpaterol showed increased drip loss, lighter meat, and reduced redness. Vitamin D₃ supplementation could not consistently overcome these negative effects. All vitamin D₃ treatments reduced drip loss of stimulated aged steaks.     

The effects of a beta-agonist treatment, vitamin D3 supplementation and electrical stimulation on meat quality of feedlot steers

In this study, 20 young steers received no beta-agonist (C), 100 animals all received zilpaterol hydrochloride (Z), with 1 group only receiving Z while the other 4 groups received zilpaterol and vitamin D3 at the following levels (IU/animal/day) and durations before slaughter: 7 million for 3 days (3D7M); 7 million for 6 days (6D7M); 7 million for 6 days with 7 days no supplementation (6D7M7N) and 1 million for 9 days (9D1M). Left carcass sides were electrically stimulated (ES) and the right side not stimulated (NES). Samples were aged for 3 or 14 days post mortem. Parameters included Warner-Bratzler shear force (WBSF), myofibril filament length, sarcomere length and calpastatin and calpain enzyme activity. Both ES and prolonged aging reduced WBSF (P<0.001). 6D7M, 6D7M7N and Z remained significantly tougher than C (P<0.001), while 3D7M and 9D1M improved WBSF under NES conditions. ES is more effective to alleviate beta-agonist induced toughness than high vitamin D3 supplements.     

国内外维生素D2蘑菇粉食品安全相关规定研究

目前欧盟、澳大利亚、新西兰等国家和地区允许在普通食品中添加维生素D₂蘑菇粉;美国拟将维生素D₂蘑菇粉列入作为特定食品类别中的营养添加剂;中国、CAC等国家和国际组织尚未制订或公布在普通食品中添加维生素D₂蘑菇粉的法律法规与标准。本文对维生素D₂蘑菇粉生产技术与产品特点进行概述;对国内外有关维生素D₂蘑菇粉食品安全相关法律法规与标准进行梳理,为有关产品研发、食品安全监管、消费指导等提供参考。维生素D₂蘑菇粉作为一种新兴的食品原料,食品业界和食品安全监管部门应对其发展情况应予以关注;在实施产品研发、食品安全监管和制定消费指导意见时,可参考有关国家和国际组织的相关规定和标准。