Effects of water-soluble soybean polysaccharide on rheological properties,stability and lipid digestibility of oil-in-water emulsion during in vitro gastrointestinal digestion

Water-soluble soybean polysaccharide (SSPS) is a naturally occurring emulsifier. SSPS was used as the sole emulsifier to stabilize an oil-in-water (O/W) emulsion. The effects were investigated of different SSPS concentrations (3–20% (w/w)) on the lipid digestibility, rheological properties and stability of O/W emulsions during in vitro digestion model. The droplet size of the emulsions tended to increase during the oral phase because the emulsions were unstable and droplets coalesced, except with a SSPS concentration of 20% (w/w). The presence of SSPS markedly reduced the free fatty acid (FFA) content after its stabilized O/W emulsion passed through in vitro gastrointestinal digestion. The amount of FFA significantly decreased as the concentration of SSPS increased due to SSPS stabilization film on oil droplet surface and high viscous system. SSPS may be an attractive alternative ingredient to control the lipid digestibility of emulsions for various food products.     

添加黄原胶的纯胶乳液稳定性及流变特性研究

通过对添加黄原胶(XG)的纯胶乳液粒径、稳定动力学参数、静态和动态流变特性的考察,探讨不同含量XG导致纯胶乳液失稳及致稳的机理,并制备出具有长期贮藏稳定性的纯胶乳液。研究发现,含0.1%、0.2%XG的纯胶乳液较易发生排斥絮凝,稳定性分析结果显示未添加XG的纯胶乳液30 d内的稳定性系数(SI)较低,90 d后底部背散射光强度(BS)降低,而含0.5%XG的纯胶乳液90 d内稳定性较好;流变特性检测结果表明随着XG含量的增加,纯胶乳液的表观黏度增加,流动性指数(n)由0.939降为0.414,触变环变大,体系的假塑性增强,含0.5%XG的纯胶乳液贮能模量(G')大于耗能模量(G″)且δ值小于45°,形成弱凝胶结构,具有长期贮藏稳定性。     

脂质体在体外消化过程中的氧化稳定性

分别建立成人和婴儿体外胃、肠单独消化模型以及胃肠连续消化模型,通过检测脂质过氧化物值(POV)和硫代巴比妥酸(TBARS)反应物浓度,研究脂质体在模拟消化过程中的氧化稳定性。结果表明,脂质体在模拟人体单独胃消化过程中结构保持稳定,而在模拟小肠环境易受胰酶和胆盐的作用发生氧化,并且在模拟胃中和模拟肠中婴儿的POV和TBARS值均显著低于成人(p<0.05);在连续消化过程中,模拟婴儿胃部消化时间对其继续在小肠消化的氧化程度影响较小(p>0.05),而模拟成人胃肠连续消化产生的过氧化物量相对较多,脂质体氧化程度比较高,结构破坏较严重。      

Nanoencapsulation of black seed oil by coaxial electrospraying: characterisation,oxidative stability and in vitro gastrointestinal digestion

In this study, black seed oil-loaded zein nanoparticles were produced via coaxial electrospraying. Nanoparticles obtained under optimised conditions had a uniform morphology with a mean diameter of 136 nm and a core–shell structure verified by confocal laser scanning microscope. The encapsulation efficiency of the oil in nanoparticles ranged from 65.3 to 97.2%. The peroxide value of oil in nanoparticles with high encapsulation efficiency was approximately three times lower than unencapsulated oil when stored at 60 °C for 55 days. The totox value of the encapsulated oil in nanoparticles stored at 25 °C was lower than the critical totox value of 30. The amount of thymoquinone released from encapsulated oil was low at the end of the gastric digestion, but the bioaccessibility of thymoquinone from encapsulated oil increased during intestinal digestion compared with free oil. These results demonstrated the successful nanoencapsulation of black seed oil with the improved oxidative stability due to the coaxial structures formed. Black seed oil-loaded zein particles may have the potential to expand the use of black seed oil as a functional ingredient for food systems.     

Influence of xanthan gum and gluten on in vitro digestibility and textural properties of rice bread

Starch digestibility of gluten-free bread has been expected to be suppressed for the purpose of decreasing glycemic response. The objective of this study was to investigate the effects of adding xanthan gum and gluten on starch and protein digestibility of rice bread prepared using the developed recipe involving pickering stabilization of foams and emulsions. The extent of starch digestion of gluten-free bread was suppressed by adding 2% xanthan gum from 79.8% to 57.3%. This suppressive effect was diminished by using gluten and that of rice bread containing 2% xanthan gum and 20% gluten was 75.5%. The extent of starch digestion of gluten-free bread was similar or less than that of bread containing gluten. The gluten-free bread with 2% xanthan gum had significantly lower loaf volume, porosity, and sticker structure of breadcrumb than the control. The suppressive effects of xanthan gum on starch and protein digestion were mainly dependent on reducing accessibility of the enzyme into the inner structure.     

Concentrated O/W emulsions formulated by binary and ternary mixtures of sodium caseinate,xanthan and guar gums: rheological properties,microstructure, and stability

Food Science and Biotechnology - The effects of xanthan gum (XG) (0, 0.3, 0.6 wt%), guar gum (GG) (0, 0.3, 0.6 wt%) and XG:GG mixtures (0.3–0.3, 0.3–0.6, 0.6–0.3 and 0.6–0.6...     

乳清分离蛋白-黄原胶复合乳化剂制备南瓜籽油O/W型乳液及其稳定性北大核心CSCD

为提高南瓜籽油(PSO)的稳定性,以及提高由单一乳清分离蛋白(WPI)作为乳化剂制备的水包油(O/W)型乳液的稳定性,制备了黄原胶(XG)与乳清分离蛋白协同稳定的南瓜籽油O/W型乳液,探究了黄原胶添加量及添加顺序对乳液性质及其稳定性的影响。结果表明:黄原胶质量浓度为2.0 mg/mL时,乳液平均粒径最小,为(10.53±0.06)μm,而ζ-电位绝对值最大,为(37.92±0.61)mV,乳液稳定性最好;黄原胶添加顺序不同,乳液稳定性有所差别,其中乳液WPI-PSO-XG(乳清分离蛋白与南瓜籽油乳化得粗乳液,再加黄原胶二次分散得到的乳液)的物理和化学稳定性最好;加速氧化实验显示,乳液的过氧化值(POV)及硫代巴比妥酸反应物(TBARS)值均低于南瓜籽油,其中乳液WPI-PSO-XG的POV和TBARS值最低,与南瓜籽油相比,分别降低了16.13 mmol/kg和17.63μmol/L,表现出良好的氧化稳定性。说明南瓜籽油与乳清分离蛋白制备成初乳液,再加入黄原胶,可使乳液稳定性提高。     

菊糖对马铃薯淀粉糊流变特性及体外消化的影响

为了研究菊糖对马铃薯淀粉糊流变特性及体外消化的影响,以马铃薯淀粉为原料,通过流变仪测试和体外酶解等方法测定菊糖-马铃薯淀粉共混体系的特性变化。流变仪测试结果表明:在试验的菊糖添加量范围内,菊糖-马铃薯淀粉共混糊的流变学特性均符合幂率模型,为假塑性流体;菊糖的添加在一定程度上降低了淀粉糊黏度,且随着添加量的增加,这一趋势加大。体外酶解结果表明:菊糖可以在一定程度上抑制马铃薯淀粉的水解速度及程度,且随着菊糖添加量的增加其抑制程度也相应增加;水解指数HI及预测血糖值e GI均随着菊糖添加量的增加而逐渐降低;在菊糖最大添加量时(菊糖与淀粉配比为1∶5),菊糖-淀粉共混体系的水解率、HI和e GI值分别由原淀粉的70%、57.87和71.48降至50%、42.74和63.17。研究结果提示适量的菊糖不仅可以改善马铃薯淀粉糊的流变性能,还可以降低其血糖指数。     

Effect of Alyssum homolocarpum seed gum,Tween 80 and NaCl on droplets characteristics,flow properties and physical stability of ultrasonically prepared corn oil-in-water emulsions

Response surface methodology was used to investigate the influence of Alyssum homolocarpum seed gum (0.25–1%), Tween 80 (0.1–1%) and NaCl (0–1%) on characteristics of ultrasonically prepared corn oil-in-water emulsion. For each response, a second-order polynomial model was developed using multiple linear regression analysis. It was shown that increasing the gum concentration and Tween 80 content decreased the mean diameter of droplets, span and creaming index. Although the increase of gum concentration had a positive effect on viscosity, Tween 80 revealed to have no significant effect on these responses. Optimum formulation for a stable emulsion was found to be 1% A. homolocarpum seed gum, 0.96% Tween 80 and no NaCl. However, using salt at higher gum concentration did not have negative effect on the emulsion properties.     

Technological properties,in vitro starch digestibility and in vivo glycaemic index of bread containing crude malva nut gum

The effects of crude malva nut gum (CMG) on the texture, digestion and the glycaemic index (GI) of white bread were investigated. Different CMG levels (0%, 2.5%, 5%, 7.5% and 10% w/w based on weight of flour) were added into a bread formula. The lightness (L*) and loaf‐specific volumes of the bread decreased with increased CMG levels. Firmness of the bread increased with increased CMG content. The in vitro starch digestion kinetics showed that bread containing CMG had generally lower predicted GI (74–81 vs. the control). In vivo human testing showed that increasing the CMG reduced the GI of the bread. The GI values of bread containing CMG ranged from 73 to 98 of the control. Overall liking scores of consumers ranged between ‘like slightly’ and ‘like moderately’ (6.1–7.1) compared to 7.1 for the control. Thus, the addition of CMG in carbohydrate‐based foods may lower the GI.     

Extraction methods and some physical properties of mesquite (Prosopis chilensis (Mol) Stuntz) seed gum

To evaluate the potential use of mesquite (Prosopis chilensis (Mol) Stuntz) seed gum, the behaviour of the gum was studied using two extraction methods (alkaline and acid), different pH values, two concentrations (0.2 and 0.4% w/v) and different temperatures. The capacity of the gum to stabilise food foams was also evaluated. The alkaline extraction yield (24.9%) was higher than the acid extraction yield (17.7%). Owing molecular to hydrolysis caused by the acid, acid extraction resulted in a lower protein content. Gum from acid extraction had a higher viscosity than that from alkaline extraction at all temperatures investigated (10, 20, 30, 40, 50 and 60 °C). There were no significant differences between the viscosities of mucilage dispersions at the different values of pH studied (3.0, 4.0 and 5.0). The addition of extracted mesquite gum (obtained by either method and at either concentration studied) to egg white foam provided a higher stability and decreased the liquid drainage and collapse of the foam. Copyright © 2004 Society of Chemical Industry     

亚麻籽胶对米糠油体稳定性及消化的影响

米糠油体作为天然水包油乳状液,在食品工业中具有良好的应用前景。为了进一步提高米糠油体的稳定性,本研究制备了亚麻籽胶稳定的米糠油体,探究亚麻籽胶质量分数对米糠油体稳定性及消化的影响。结果表明：亚麻籽胶质量分数为0.5%时,米糠油体平均粒径最小,zeta-电位绝对值最大,表观黏度增加,稳定性最好。体外模拟消化实验表明,米糠油体脂肪酸释放率为95%,亚麻籽胶的添加减缓了米糠油体脂肪酸的释放(89%),可以起到缓释脂肪酸的效果。本研究对于提高油体稳定性及拓宽米糠油体作为功能因子递送载体在食品加工中的应用有重要意义。     

The effect of pH and calcium ion on rheological behaviour of β‐lactoglobulin‐basil seed gum mixed gels

Effect of pH (4.5–7.5) and Ca²⁺ (0.01–0.5 m ) on gelation of single and mixed systems of 10% β‐lactoglobulin (BLG) and 1% basil seed gum (BSG) was investigated. The gelling point of BLG and BSG gels was strongly pH‐dependent, and stiffer gels formed at higher pH. The BLG gels were formed upon heating to 90 °C and reinforced on cooling to 20 °C; however, the gelation of BSG occurred at temperatures below 70 °C. By increasing Ca²⁺ concentration, storage modulus of BLG and BSG gels were increased, although pH had a greater effect than Ca²⁺. In contrast, mixed systems showed two distinct types of behaviour: BLG gel formation and BSG network, suggesting that phase‐separated gels were formed. In addition, higher strength was obtained for BLG‐BSG mixture at higher Ca²⁺ concentration.     

胃肠道消化过程中脂质氧化的影响因素、健康危害及控制研究进展

研究证实,油脂和富含脂质的食品极易在胃肠道消化过程中发生氧化反应,产生的丙二醛、4-羟基-2-己烯醛（4-HHE）等氧化产物能够对机体造成健康危害。本文对胃肠道消化过程中脂质氧化反应的影响因素、健康危害及植物多酚、类黑精等食品组分干预作用等方面的研究进展进行综述,以期为通过改善膳食结构等途径减少胃肠道消化过程中脂质氧化反应造成的健康危害提供参考。      

瓜尔胶对木薯淀粉消化性、糊化特性、水分运动性的影响

研究瓜尔胶对木薯淀粉消化性的影响,采用Englyst法测定淀粉的消化性,比较与分析了瓜尔胶/木薯淀粉体系的糊化特性、水分运动性、微观结构的差异,从而探究瓜尔胶对木薯淀粉消化性的影响机理。结果表明:瓜尔胶添加量较低时,糊化后冷却至37℃的体系结构疏松、具有较高的水分运动性,瓜尔胶促进淀粉的酶解,抗消化淀粉含量较低;继续提高瓜尔胶添加量时,糊化后冷却至37℃的体系结构越加紧密、水分运动性降低,瓜尔胶形成空间位阻,降低酶与底物的可及性,瓜尔胶反而抑制淀粉的酶解,抗消化淀粉含量较高。      

Oil-in-water emulsions stabilized by sodium caseinate: Influence of pH,high-pressure homogenization and locust bean gum addition

The effect of pH, addition of a thickening agent (locust bean gum) or high-pressure homogenization on the stability of oil-in-water emulsions added by sodium caseinate (Na-CN) was evaluated. For this purpose, emulsions were characterized by visual analysis, microstructure and rheological measurements. Most of the systems were not stable, showing phase separation a few minutes after emulsion preparation. However, creaming behavior was largely affected by the pH, homogenization pressure or locust bean gum (LBG) concentration. The most stable systems were obtained for emulsions homogenized at high pressure, containing an increased amount of LBG or with pH values close to the isoelectric point (pI) of sodium caseinate, which was attributed to the size reduction of the droplets, the higher viscosity of continuous phase and the emulsion gelation (elastic network formation), respectively. All the studied mechanisms were efficient to decrease the molecular mobility, which slowed down the phase separation of the emulsions. In addition, the use of sodium caseinate was also essential to stabilize the emulsions, since it promoted the electrostatic repulsive interactions between droplets.