Comparison of polysaccharide degradations by dynamic high-pressure homogenization

The mechanical degradation of polysaccharides was investigated using dynamic high and ultra-high-pressure homogenization (HPH). The objectives were to reduce the molar mass of polymer chains, and simultaneously, the apparent and intrinsic viscosity of polysaccharides in solution. The influence of homogenization pressure (up to 200 MPa) and cycles was compared on polysaccharides with different physical and structure properties: namely, guar gum, hydroxyethylcellulose (HEC), sodium carboxymethylcellulose (Na-CMC), sodium alginate (Na-alginate) and gum arabic. HPH was applied on semi-dilute solutions. The apparent changes in molar mass, gyration radius and intrinsic viscosity were deduced from size exclusion chromatography coupled on-line with multi-angle laser light scattering, differential viscometer detector and differential refractive index detector (SEC/MALS/DV/DRI), while the evolution of the critical overlap concentration (C^∗) was obtained by viscosimetry. A method based on a succession of homogenization cycles and polymer pre-concentration steps was developed to determine the minimum molar mass achieved at constant pressure. Molar mass, and intrinsic viscosity were shown to fall simultaneously while logically C^∗ increased during HPH for all polysaccharides, except gum arabic, probably because of its globular and branched structure. This highlights that the differences of polysaccharide structures and conformation (linear, branched…) exhibit a stronger impact on HPH treatments than polymer charge or molar mass. Finally, via an empirical approach linking the decrease of both molar masses and viscosities, we have evidenced a specific scaling exponent that should characterize the flexibility of the treated polymer (i.e. its ability to be degraded by HPH).     

高压均质协同高酰基结冷胶对青椒蛋蔬液流变特性及稳定性的影响

研究高压均质（high pressure homogenization,HPH）协同高酰基结冷胶（high acyl gellan gum,HA）处理对青椒蛋蔬液（liquid egg with green pepper juice,LEGP）稳定系数、持水力、流变特性、粒径及电位的影响,进而探讨HPH协同HA对LEGP流变特性及稳定性的影响。结果表明：HPH处理可以明显提高LEGP的稳定系数、持水力、屈服应力、表观黏度和ζ-电位绝对值,并减小体系粒径,说明HPH处理可以有效提高LEGP体系稳定性。与HPH相比,HPH协同HA处理可以进一步提高LEGP的稳定系数、持水力、屈服应力、表观黏度和ζ-电位绝对值,使体系粒径进一步减小且分布更均匀,表明HPH协同HA处理可以更好地提高LEGP体系稳定性;其中,均质压力为150 MPa时,LEGP的稳定系数和持水力达到最大。流变实验结果表明HPH处理或HPH协同HA处理样品的流变模型均符合Herschel-Buckley模型,且其流体为带屈服值的假塑性流体,其中,HPH协同HA处理均质压力为150 MPa时,LEGP的屈服应力、表观黏度和弹性模量最高,流体的假塑性最强,体系粒径最小,ζ-电位绝对值最大,LEGP表现出最高的稳定性。     

高酰基结冷胶凝胶特性的研究

研究了高酰基结冷胶溶液的凝胶特性并对其凝胶机理进行了分析,通过对高酰基结冷胶在不同浓度、温度、pH值和Ca2+盐条件下流变特性和凝胶强度的实验研究,结果表明:胶体浓度、温度、游离的二价阳离子含量以及pH值的差异都会对高酰基结冷胶的粘度和凝胶强度产生影响。对高酰基结冷胶作用力的初步考察结果表明:疏水作用、氢键作用、静电作用在形成凝胶的过程中均起关键作用,疏水作用影响最大。     

Study of emulsions stabilized with Phaseolus vulgaris or Phaseolus coccineus with the addition of Arabic gum, locust bean gum and xanthan gum

The properties of o/w emulsions stabilized with 1%w/v common bean (Phaseolus vulgaris L.), V or scarlet runner bean (P. coccineus L.), Coc extracted by isoelectric precipitation or ultrafiltration, at pH 7.0 and 5.5, with the addition of Arabic gum, locust bean gum, xanthan gum and a mixture of xanthan gum–locust bean gum (0.1 %w/v and 0.25 %w/v) are studied. The stability of emulsions was evaluated on the basis of oil droplet size, creaming, viscosity and protein adsorption measurements. The addition of Arabic gum, caused an increase in D[4,3] values and a decrease in the amount of protein adsorbed at the interface. The addition of locust bean gum in some emulsions reduced the amount of protein adsorbed. The addition of xanthan and to a less extend of the polysaccharide mixture, promoted a decrease in D[4,3]. So, emulsion stability was affected by the polysaccharide nature. Differences were also observed with respect to the protein nature, the method of its preparation and emulsion's pH. All polysaccharides enhanced the emulsions viscosity with xanthan and xanthan–locust bean gum exhibiting the higher values. V isolates and isoelectricaly precipitated isolates of both V, Coc showed higher viscosity values. The stability was enhanced by the increase of the viscosity of the continuous phase and the creation of a network, which prevents the oil droplets from coalescence.     

The effect of exogenous enzymes and mechanical treatment on mango purée: Microscopic,mesoscopic, and macroscopic evaluation

This paper addresses to what extent mango purée macroscopic properties (consistency) is related to its particle physical properties such as mesoscopic (particle size) and microscopic (morphology) properties. To manipulate mango purée particle sizes, high pressure homogenization (HPH) was used. Commercial fungal and bacterial (cell wall) polysaccharide degrading enzymes without/with HPH (different sequences) were used to understand the contribution of specific (cell wall) polysaccharides and the relevant parameters to consistency changes. The results reflect that, unlike endo-cellulase, pectin methylesterase (PME) together with endo-polygalacturonase (PG), and α-amylase significantly contributed to consistency decrease. HPH only, although largely changing the particle size, did not change the purée consistency, but the combination of HPH with an enzymatic treatment decreased it substantially. Enzymes, while having minimal effect on particle sizes, induced a type-dependent modification of particles’ morphology, showing the accessibility of particle polymers (in addition to the expected serum polymers) to enzymes.Industrial relevanceHigh consistency of mango purée that limits its processing is industrially decreased by dilution with water, requiring further flavor reconstitution and sugar addition. The consistency is believed to be related to pectin and starch. As physical and enzymatic pectin modifications are allowed by regulatory authorities, our study aimed at better understanding and controlling the flow properties of mango purée by both physical (high pressure homogenization) and enzymatic polysaccharides manipulations. Our findings highlight that in situ polysaccharide functionalization could be an industrially relevant alternative to commonly used additives in food systems for controlling the sensorial (i.e. taste and texture) properties.     

Frozen Concentrated Orange Juice (FCOJ) Processed by the High Pressure Homogenization (HPH) Technology: Effect on the Ready-to-Drink Juice

The high pressure homogenization (HPH) process can be used to reduce the consistency of frozen concentrated orange juice (FCOJ), which is highly desirable in industrial processing due to the reduction in energy costs. The production of FCOJ is almost entirely destined to obtaining the reconstituted (ready-to-drink (RTD)) juice. Consequently, this study aimed to evaluate the effect of the HPH processing on the ready-to-drink juice. FCOJ (66°Brix) was processed by HPH up to 150 MPa and then diluted to 11°Brix for evaluation. The RTD juice was evaluated by pulp sedimentation, instrumental colour, turbidity (serum cloudiness), rheological properties and sensorial perception. The HPH process decreased the absorbance of the serum phase, which was related to the disruption of the suspended particles. Further, the process slightly reduced the RTD juice viscosity. However, the HPH showed no effect on the product colour, pulp sedimentation behaviour and sensorial perception (visual aspect, odour, flavour, viscosity, overall liking). Therefore, it was concluded that the HPH process can be used to promote desirable effects on FCOJ, without affecting the RTD juice properties.     

Tribological properties of neutral polysaccharide solutions under simulated oral conditions

ABSTRACT:  Predictability of the perception of foods thickened by polysaccharides is only poor. Therefore, the effect of saliva on the lubrication properties of 2 types of neutral polysaccharides, cross-linked starch and locust bean gum, was studied. Despite the similar bulk rheological behavior of the 2 polysaccharides, the starch solution exhibited a significantly lower friction coefficient. Although starch viscosity was strongly decreased upon 10 s incubation with human saliva, a low friction coefficient was retained. The presence of remaining granules is held partly responsible for this. Addition of starch granules to locust bean gum also resulted in a decrease in the friction coefficient, but the effect was smaller compared to starch solutions digested by saliva. Smaller contact angles were measured for (digested) starch compared to locust bean gum solutions. This points to other parameters that assist in lubrication, such as the interaction of starch solution constituents with the rubbing surfaces. In addition, the importance of bulk viscosity for spreadability on surfaces was demonstrated. This study illustrates that the type of starch will determine not only the viscosity change but also the presence of intact granules upon digestion by saliva in the oral cavity; the combination of these 2 properties is regarded to be responsible for the poor predictability of sensory responses of starch containing foods.     

结冷胶凝胶特性及在食品工业中的应用

目的:介绍新型微生物多糖--结冷胶的凝胶特性及其在食品工业中的应用现状和前景.方法:查阅今年来国内外的相关文献报道,并进行分析、整理和归纳.结果:结冷胶组织相容性和复配性能良好,具有良好的透明性,凝胶性能卓越,具有独特的胶凝和融化温度,可形成多种凝胶质构,在极低的用量下形成的预(弱)凝胶可以发挥良好的悬浮、稳定作用.结论:结冷胶作为一种新型凝胶剂,其优异的性能将在食品工业中得到广泛应用.     

罗望子的研究——Ⅱ.罗望子种子多糖的提取及其流变性质的研究

本文研究罗望子种子多糖的提取及其流变性质,结果表明,其产率51.20％,含蛋白质1.76％,脂肪0.42％,粘度944cps,凝胶强度400g/cm~2;可得无味无臭,灰白至白色粉末,具有良好的稳定性(耐热,耐盐,耐酸,耐冷冻解冻性),增粘性(与糖类或黄原胶的协同效应),胶凝性(与蔗糖形成弹性强有咬劲的凝胶),是一种多功能的食品添加剂。 本文用热水提胶,等电点沉降蛋白质,异丙醇沉淀提取罗望子种子多糖的方法,能获得高纯度,稳定性和胶凝性好的产品。此外,还获得一种优质蛋白质——罗望子蛋白;对开发我国新的食品添加剂和新的蛋白质营养源具有重要意义。     

Effects of hydrocolloids and high-pressure-heating processing on minced fish gels

Multivariate statistical methods were applied to data sets of measured gelling properties of blue whiting mince with several hydrocolloids added (locust bean gum, guar gum, xanthan gum, carboxymethylcellulose, 1-carrageenan, 3-carrageenan or alginate) induced under different pressure-time-temperature gelling conditions. The main differences between gels were attributed to the process; all the gels were classified in three clusters on the basis of gelling treatment: (1) high-pressure at moderate heating, (2) high-pressure at cold temperature and (3) heating at atmospheric pressure. Cluster 1 was characterized by very elastic, light gels with high water holding capacity. In cluster 2, gels presented high puncture test properties (breaking deformation, breaking force, work of penetration) and high cohesiveness and water holding capacity. Cluster 3 gels presented low penetration test properties and cohesiveness; high adhesiveness and hardness; high lightness and yellowness. Each cluster was subdivided to describe the gel properties between the hydrocolloid groups, attributing the differences mainly to yellowness (b*), breaking deformation, breaking force and work of penetration.     

Impact of Guar and Wheat Bran on the Physical and Nutritional Quality of Extruded Breakfast Cereals

Two non‐starch polysaccharides, guar gum and wheat bran, were used at 15% replacement level in a cereal base to produce an extruded breakfast cereal product from both wholemeal and high‐ratio wheat flour mixes. The inclusion of the non‐starch polysaccharides into the flour bases had no significant effect on the expansion ratio of the products. However, the product density and bulk density of the extruded products increased with guar gum and wheat bran addition. The pasting properties of the raw flour and polysaccharide base as well as the extruded products were altered with the incorporation of polysaccharides, with guar gum‐enriched products showing elevated peak and final viscosity readings. This appeared to be related to moisture manipulation and hence the regulation of gelatinisation. In vitro starch hydrolysis of the raw bases and the extruded samples illustrated that the extrusion process significantly increased the availability of carbohydrates for digestion. Additionally, the inclusion of non‐starch polysaccharides in the raw bases significantly reduced the rate and extent of carbohydrate hydrolysis. This potentially glycaemic reducing action was also evident in the extruded products where the incorporation of guar gum at 15% yielded a reduction of starch hydrolysis of 36% in the wholemeal base and 32% in the high‐ratio white wheat flour base.     

高压均质处理次数对肌原纤维蛋白水溶液结构及理化特性的影响

以鸡肉中的肌原纤维蛋白（myofibrillar proteins,MP）为对象,研究在103 MPa压力条件下不同高压均质（high pressure homogenization,HPH）处理次数（1～6 次）对MP水溶液结构以及理化特性的影响。结果表明：HPH可以显著提高MP在水中的溶解性（P＜0.05）。随着HPH处理次数的增加,MP在水溶液中的粒径先减小后变大;表观黏度减小,流动能力增强;表面疏水性和活性巯基含量先增加后减少;圆二色光谱结果显示不同HPH处理次数对MP水溶液的二级结构构象的影响不同;过多的HPH处理次数会导致MP水溶液中蛋白质聚集,从而影响其溶解性和稳定性;经过4 次HPH处理的MP水溶液具有较好的溶解性和稳定性。说明通过选择适当次数的HPH处理可以实现对MP在水中溶解性的调控,为其在食品加工中的应用提供新思路。     

Influence of non-starch polysaccharides on the in vitro digestibility and viscosity of starch suspensions

The effects of adding non-starch polysaccharides (xanthan gum, guar gum, konjac glucomannan, and pectin) on the starch digestibility and viscosity of raw starch suspensions in a mixed system were determined. Each type of polysaccharide was added to high-amylose corn starch suspensions at defined concentrations. High-amylose rice starch suspensions mixed with xanthan and guar gum were prepared for comparison. The extent of starch digestibility was determined by an in vitro method, and the glucose diffusibility from the dialysis tube in the presence of polysaccharides was measured. The added polysaccharides were observed to decrease the starch digestibility in a mixed system. When compared at the same concentration, xanthan gum showed the most pronounced suppressive effect on starch digestibility and glucose diffusibility from the dialysis tube. The addition of polysaccharides increased the viscosity of the starch suspension. Significant relations were found between the extent of starch digestibility and the apparent viscosity at low shear rate.     

Effect of high pressure homogenization (HPH) on the rheological properties of tomato juice: Time-dependent and steady-state shear

High pressure homogenization (HPH) is a non-thermal technology that has been widely studied as a partial or total substitute for the thermal processing of food. Although microbial inactivation has been widely studied, there are only a few works in the literature reporting the physicochemical changes caused in fruit products due to HPH, especially those regarding the rheological properties. The present work evaluated the effect of HPH (up to 150 MPa) on the time-dependent and steady-state shear rheological properties of tomato juice. HPH reduced the mean particle diameter and particle size distribution (PSD), and increased its consistency and thixotropy. The rheological results were in accordance with the PSD observed. The rheological properties of the juice were evaluated by the Herschel–Bulkley and Falguera–Ibarz models (steady-state shear) and Figoni–Shoemaker and Weltman models (time-dependent). The parameters of these equations were modelled as a function of the homogenization pressure. The models obtained described the experimental values well, and contributed to future studies on product and process development.     

Normal force-controlled tribological measurement of soft drinks and lubrication additives

This paper describes the use of a normal force-controlled tribology device for assessing mouthfeel-related lubrication properties of soft drinks samples and lubrication additives. Samples were sheared between a tribology pair comprised of steel and thermoplastic elastomer surfaces with the 3-contact ball-on-inclined plane tribometer. The boundary lubrication of lemon lime soft drinks was significantly lower than cola soft drinks. The resolution of the instrument was further investigated by measuring the lubrication of confined very dilute non gelling neutral and strongly charged β-1,4 polysaccharides. Poor lubrication was seen with the galactomannans locust bean gum and guar gum. Overall, these experiments demonstrate that tribology yields reproducible results that relate to functional properties of iso-viscous fluids in a dilute regime.     

多糖的增稠、胶凝及乳化特性研究进展

多糖是可再生的天然大分子物质,具有显著的增稠、胶凝、乳化等特性,在食品工业中常作为添加剂应用。然而,多糖种类繁杂、结构差异大、流变特性多样,长期以来国内有关多糖流变学特性的报道相对有限。本文从多糖水溶性高分子的本质特征出发,综述了食品多糖增稠、胶凝、乳化特性及其凝胶化影响因素的基本原理,同时介绍了非凝胶多糖和表面活性多糖分子聚集的原理,旨在为多糖在食品工业中的进一步应用提供理论指导。     

Surface tension of Phaseolus vulgaris and coccineus proteins and effect of polysaccharides on their foaming properties

The surface tension of protein isolates from common bean (Phaseolus vulgaris L.) and scarlet runner bean (Phaseolus coccineus L.), prepared by isoelectric precipitation and ultrafiltration was evaluated, with respect to protein concentration (0.001–0.1% w/v) and pH (pH 4.5, 5.5, 7.0 and 8.0). Surface tension was most reduced, and with a higher rate of reduction at higher protein concentration and at pH 8.0. Foams (1, 2% w/v protein), at the same pH values, with and without the addition of polysaccharides, were studied. The proteins’ foaming behaviour was related to their adsorption behaviour. Arabic gum, locust bean gum (0.1% and 0.25% w/v), xanthan gum and a xanthan/locust bean gum mixture (0.1% w/v) had a positive effect on foam creation. All polysaccharides increased foam stability, probably due to the viscosity increase and to the creation of a network, which prevents the air droplets from coalescence. Isolates from P. coccineus and isolates obtained by ultrafiltration seemed to exhibit better foaming properties.     

Effect of high pressure processing on gastrointestinal fate of carotenoids in mango juice: Insights obtained from macroscopic to microscopic scales

High hydrostatic pressure (HHP) and high-pressure homogenization (HPH) were applied to mango juice to explore their effects on gastric retention rate (G-CRR), bioaccessibility (BAC) of total and individual carotenoids, and the corresponding mechanisms from macroscopic to microscopic scales. Compared to the control, both HHP and HPH at 50 MPa had no significant effect on BAC and G-CRR, whereas HPH at 100 MPa significantly increased BAC by 44.33% and G-CRR by 11.84%. Further HHP treatments (particularly at 400 MPa) on the 100 MPa-HPH-pretreated samples significantly increased BAC by 71.37% and G-CRR by 24.24%. Violaxanthins/esters were less stable than carotenes in the stomach, resulting in lower bioaccessibility of violaxanthins/esters. G-CRR and BAC were negatively correlated with the viscosity and particle size of juice, whereas they were positively correlated with the solubility/dispersibility of carotenoids. In addition, pectin-carotenoid interactions may also be an important factor affecting the digestive fate of carotenoids in juice.Industrial relevanceHigh pressure processing (High hydrostatic pressure, HHP, and high pressure homogenization, HPH) is a non-thermal technique and its effect on the bioaccessibility of carotenoids in fruits and vegetables have attracted attention from researchers. Our research found that HPH and HHP combined treatment could decrease the particle size of mango juice, and increase the viscosity and turbidity as well as the bioaccessibility of carotenoids therein. This technology can be used to preserve the physical stability of mango juice and improve the nutritional value.     

Effect of finger millet (Eleusine coracana, Indaf-15) malt esterases on the functional characteristics of non-starch polysaccharides

Acetic acid esterase (AAE) (E.C 3.1.1.6) and ferulic acid esterase (FAE) (E.C 3.1.1.73) cleaves the acetyl groups substituted at O-2/O-3 of the xylan backbone and feruloyl groups substituted at 5′–OH group of arabinosyl residues, respectively of arabinoxylans. These enzymes modulate the functional properties of cereal arabinoxylans such as viscosity, foam stabilization and gelling. In the present study, water-soluble non-starch polysaccharides (WSPs) from ragi, wheat flours were isolated, and their functional characteristics were studied in the presence of purified esterases. Relative viscosities of the enzyme treated WSPs were marginally less than the untreated ones. Untreated WSPs from wheat and ragi were found to stabilize the thermal disruption of protein foams compared to the esterase treated ones. AAE treated WSPs of wheat and ragi showed increased gelation while FAE treated ones showed slight decrease in comparison with their respective controls. Xanthan gum (XG), which was deacetylated by purified AAE, showed improved gelation (ratio of relative viscosities for 0, 1 and 2 h of control and enzyme treated blend is 1:1.16, 1:1.35 and 1:1.20, respectively) when blended with locust bean gum (LBG).