亚麻籽木脂素研究进展

广泛存在于植物界的木脂素类化合物,能通过动物机体内微生物转化成动物木脂素,具有雌激素样和抗雌激素样生物活性.大量研究表明,动物木脂素及其在植物中的前体物质具有抗癌、抗氧化、抗心血管系统疾病等临床应用价值,且能通过与性激素受体结合等途径发挥其他生理作用,因而在动物生产领域有着重要的应用价值.很多学者就木脂素的检测方法、代谢转化、保健和生理学功能进行了研究.在各种植物籽实中,亚麻籽中的木脂素含量最高,而亚麻是我国北方广泛种植的经济作物,开发和利用亚麻籽木脂素将带来良好的经济和社会效益.     

亚麻籽中木脂素提取工艺的研究

传统的亚麻籽木脂素提取工艺步骤繁琐,提取物中有益成分散失。研究了溶剂法提取亚麻籽中木脂素的工艺,确定了最佳溶剂系统:质量分数为70%的乙醇,提取温度为室温,时间为24h。建立了中空纤维超滤膜超滤木脂素提取液的平均渗透通量数学模型,并用亚麻籽中木脂素提取液进行了实验验证。结果表明,该工艺步骤简单、易行,超滤模型的计算结果与实验结果基本吻合,所建立的模型可用于超滤过程渗透通量的预测。     

Flavonoid content of flaxseed. Influence of cultivar and environment

Summary Two studies, one with four cultivars grown at four locations during 1989 to 1993, and the second with a transgenic and its non-transformed parent cultivar grown at three locations for three years, were undertaken to explore the variation in total flavonoid content of flaxseed (Linum usitatissimum). Results of the analyses of variance for the first study showed significant cultivar as well as environmental effect on flavonoid content. Cultivar NorLin displayed the highest flavonoid content across the sites with a mean of 71 mg/100 g, and Omega, a yellow-seeded flaxseed cultivar, the lowest with a mean of 35 mg/100 g. There was no significant difference between a transgenic flaxseed and its non-transformed parent for total flavonoid content except for one location in 1991. Flavonoid content was inversely related to the protein content and there was a weak positive correlation between flavonoid and oil levels.     

Digestibility of energy,lipids and fatty acids of vegetable oils and poultry fat by pacu Piaractus mesopotamicus (Holmberg 1887)

Evaluation of vegetable oils and poultry fat digestibility is the first step to elicit their use in aquafeeds. This work aimed at determining apparent digestibility coefficients (ADCs) of energy, lipids and fatty acids of oil sources for pacu, a widely farmed neotropical Characin. A semipurified, omnivorous fish diet (344.2 g kg^?1 crude protein; 18.16 MJ kg^?1 gross energy) was used as reference diet. Test diets were obtained by adding 2 g kg^?1 chromium III oxide and replacing 15 g kg^?1 reference diet with fish, soybean, colza, corn and flaxseed oils and poultry fat. Juvenile pacu (64 ± 10.8 g; 14.6 ± 1.1 cm) were fed to apparent satiety, four times a day, and then transferred to cylindrical–conical aquaria for collection of faeces by sedimentation (n = 3). Apparent digestibility coefficients of energy and lipids were high for all tested oils (P > 0.05); ADCs of saturated fatty acid (SFA) were lower than monounsaturated fatty acids (MUFA) and polyunsaturated fatty acid (PUFA). Essential fatty acids (18:2n‐6 and 18:3n‐3) had high ADC (>93%), colza oil and poultry fat yielding the lowest ADC for 18:2n‐6 (P = 0.01) and 18:3n‐3 (P < 0.01), respectively. Corn oil, soybean oil and flaxseed oil were interesting sources of 18:2n‐6 and 18:3n‐3 dietary fatty acids for pacu.     

Elucidation of the structure,antioxidant, and interfacial properties of flaxseed proteins tailored by microwave treatment

The microwave treatment is commonly applied to flaxseed to release nutrients, inactivate enzymes, remove cyanogens, and intensify flavors. The current study aimed to explore the influences of microwave exposure on the antioxidant and interfacial properties of flaxseed protein isolates (FPI), focusing on the altering composition and molecular structure. The results showed that after microwave exposure (700 W, 1–5 min), more compact assembly of storage proteins and subsequent permeation by membrane fragments of oil bodies occurred for cold-pressing flaxseed flours. Moreover, the particle sizes of FPI was progressively reduced with the decrement ranged from 37.84 to 60.66% (P<0.05), whereas the zeta potential values initially decreased and then substantially recovered during 1–5 min of microwave exposure. The conformation unfolding, chain cross-linking, and depolymerization were sequentially induced for FPI based on the analysis of fluorescence emission spectra, secondary structure, and protein subunit profiles, thereby affecting the dispersion or aggregation properties between albumin and globulin fractions in FPI. Microwave exposure retained specific phenolic acids and superior in vitro antioxidant activities of FPI. The inferior gas–water interface absorption and the loose/porous assembly structure were observed for the foams prepared by FPI, concurrent with obviously shrinking foaming properties upon microwave exposure. Improving oil–water interface activities of FPI produced the emulsion droplets with descending sizes and dense interface coating, which were then mildly destabilized due to the lipid leakage and weakened rheological behavior with microwave exposure extended to 5 min. Our findings elucidated that microwave treatment could tailor the application functionality of protein fractions in flaxseed based on their in situ structural remodeling.     

主成分分析法结合响应面优化亚麻籽胶与壳聚糖复合膜成膜工艺

为优化亚麻籽胶与壳聚糖复合膜的成膜工艺,以亚麻籽胶和壳聚糖为主要材料制备复合膜,研究亚麻籽胶膜液∶壳聚糖膜液(V/V)、壳聚糖质量浓度和甘油添加量对复合膜性能的影响,并以复合膜性能综合评分为考察指标,结合主成分分析法和响应面试验法,优化复合膜制备工艺参数。结果表明,复合膜最优制备工艺为：亚麻籽胶膜液∶壳聚糖膜液(V/V)为20∶10,壳聚糖质量浓度1.0 g/100 mL,甘油质量分数21%;在此条件下制备的复合膜性能综合评分为0.724,膜的各项指标分别为：拉伸强度(18.16±0.17)MPa,断裂伸长率57.15%±0.14%,水蒸气透过率(1.30±0.02)(g·mm)/(h·m²·kPa),氧气透过率(7.30±0.08)cm³/(m²·d·Pa),透光率95.55%±0.09%。该研究结果可为复合膜在食品保鲜中的应用提供理论基础。     

日粮中添加亚麻籽对肉羊消化代谢的影响

16只体重相近,均值为(34.06±1.68)kg的杂交公羔羊按单因素随机设计原理被分成4组,每组4只,日粮中添加0%,5%,10%,15%亚麻籽进行消化代谢试验,研究不同水平的亚麻籽对绵羊消化代谢的影响。结果表明:随着亚麻籽添加水平的提高,干物质的采食量表现下降的趋势,但干物质的表观消化率各组间没有差异(P>0.05);亚麻籽的含量与可消化氮和沉积氮呈现负相关趋势,氮的表观消化率各组间差异显著(P<0.05),呈现逐渐递减的现象;有机物的表观消化率变化幅度不大,前3组差异不显著(P>0.05),添加15%亚麻籽的Ⅳ组与其他组比较差异显著;粗脂肪的表观消化率与亚麻籽的添加水平呈正相关,且各组间表现显著;纤维类物质中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)随着亚麻籽添加水平的增加而表现大幅度的下降,各组间差异显著(P<0.05)。     

亚麻籽粉对肉羊肌肉品质的改善作用

文章旨在评估日粮添加不同水平亚麻籽粉对羊肉理化特性及感官指标的影响.试验选择平均体重为(42.38±3.25)kg的肉羊100只,随机分为4组,每组5个重复,每个重复5头羊.各组分别饲喂基础日粮+0、1％、1.5％和2％的亚麻籽粉,试验持续6周.结果:日粮添加1.5％和2％亚麻籽粉较其他两组显著提高了羊肉粗脂肪含量(P...     

内蒙古丰镇市亚麻籽油的超临界CO2萃取和气质联用检测

试验选择3个等压（21、28、35MPa）提取条件,研究超临界CO2萃取亚麻籽油过程中压力对亚麻籽油得率的影响．并使用GC—MS（气相色谱-质谱联用）检测超临界CO2萃取亚麻籽油和传统压榨法提取亚麻籽油的脂质组成和各组分的含量。结果发现,在35MPa下萃取120min亚麻籽油的得率最高,为35．65％,可以达到实际应用的需求;超临界CO2萃取亚麻籽油与压榨油在脂肪酸构成上基本相同,前者α-亚麻酸的含量略高。