Pasting Properties of Non‐waxy Rice Starch‐Hydrocolloid Mixtures

The swelling and pasting properties of non‐waxy rice starch‐hydrocolloid mixtures were investigated using commercial and laboratory‐generated hydrocolloids. The swelling power of the rice starch‐hydrocolloid mixtures was generally depressed at low concentration of hydrocolloids (0–0.05%), but increased directly with increasing hydrocolloid concentrations (0.05–0.1%). In gellan gum dispersion, the swelling power at 100°C was higher than that of control. The rice starch‐hydrocolloids mixtures showed shear‐thinning flow behavior (n = 0.26–0.49). Hydrocolloids except the exopolysaccharide from S. chungbukensis (EPS‐CB) increased apparent viscosity and consistency index (K) of rice starch dispersions, but decreased the n value. Hydrocolloids enhanced the trough and final viscosity of rice starch dispersions but EPS‐CB reduced the viscosity of rice starch pastes. Hydrocolloids lowered peak viscosity but addition of guar gum resulted in high peak viscosity, apparent viscosity, and consistency index of rice starch dispersions. Total setback viscosity appeared to be not affected by hydrocolloids at low concentration (0.05%). The hot and cold paste of the starch‐gellan gum mixture exhibited the highest viscosity values in the Brookfield viscometer.     

Stability and Rheological Properties of Egg Yolk Granule Stabilized Emulsions with Pectin and Guar Gum

The effects of pectin and guar gum on rheology, microstructure and creaming stability of 1% (w/v) egg yolk granule stabilized emulsions were investigated. While the addition of low amount of pectin (0.1% (w/v)) had no effect on the emulsion viscosity, the addition of 0.5% (w/v) pectin greatly increased the viscosity. Granule-stabilized emulsion without hydrocolloids reflects the pseudoplastic behavior (shear-thinning behavior with flow behavior index, n < 1.0). Hydrocolloids, especially at high concentrations, affected the viscoelastic behavior of the emulsions and both storage (G′) and loss modulus (G′′) were regarded as frequency dependent. Emulsions behaved like a liquid with G′′ > G′ at lower frequencies, and like an elastic solid with G′ > G′′ at higher frequencies. Emulsion microstructure indicated that the presence of hydrocolloids induced flocculation. Creaming stability of emulsions was enhanced by the presence of hydrocolloids and increasing hydrocolloid concentration decreased the creaming by restricting the movement of oil droplets.     

Effect of enzymatic hydrolysis on the yield of cloudy carrot juice and the effects of hydrocolloids on color and cloud stability during ambient storage

The color and cloud stability of cloudy carrot juice were improved by enzymatic hydrolysis and addition of hydrocolloids. Cellulytic and pectolytic enzyme preparations were used to prepare the carrot juice and their optimum dosages were 1.6 g kg^?1 and 0.035 g kg^?1, respectively. Hydrocolloids including guar gum, pectin and flaxseed gum were each added to the carrot juice and assessed for their ability to stabilize the carrot juice. Pectin had no effect on the cloud stability of carrot juice. Guar gum and flaxseed gum stabilized the cloudy carrot juice owing to macromolecular steric repulsion, while flaxseed gum reduced the creaming of cloudy carrot juice owing to its emulsification. The color and β‐carotene content of carrot juice did not change during 6 months of storage. Copyright © 2004 Society of Chemical Industry     

Moisture Diffusivity During Drying of Pineapple and Mango Leather as Affected by Sucrose,Pectin, and Maltodextrin

The effect of the addition of sucrose (0, 5, 10%), pectin (0, 1, 2%), and maltodextrin (0, 2.5, 5%) on the moisture diffusion from pineapple and mango pulp during the making of fruit leather was studied in a cabinet drier. The drying rate of both pineapple and mango leather was reduced by the addition of sucrose, pectin, and maltodextrin. Drying rate constant of both pineapple and mango leather was most significantly affected by sucrose followed by maltodextrin and pectin. The drying rate constant (k) of 0.214 and 0.116 1/h was lowest in the pineapple and mango pulp containing 10, 2, and 5% of sucrose, pectin, and maltodextrin, respectively. The experimental moisture effective diffusivity varied from 6.64–12.93?×?10^?7 m²/sec and 1.65–4.03?×?10^?7 m²/sec for pineapple and mango leather, respectively, and the coefficient of determination (R²) of regression coefficients for effective moisture diffusivity was 0.82 and 0.96, respectively. The effect of addition of pectin was most significant on moisture diffusivity both in pineapple and mango leather.     

亲水性胶体对广式腊肠水分迁移及质构的影响

本文研究了卡拉胶、魔芋胶、瓜尔豆胶及其复配对广式腊肠烘烤过程中水分迁移、产品质构、感官等质量品质的影响。结果表明,广式腊肠添加亲水性胶体后,可略有提高产品的水分含量,尤其是瓜尔豆胶组(19.94%),比对照提高4.02%;在烘烤中期,亲水性胶体可降低广式腊肠的干燥速率,整体而言,亲水性胶体对烘烤过程中水分散失影响较小。胶体添加组感官得分除D3组,均高于对照组,其中添加复配卡拉胶与魔芋胶的感官综合得分最高,达到87.5;除瓜尔豆胶外,单独胶体和复配胶均能一定程度上改善广式腊肠的质构特性,尤其是复配胶体组。广式腊肠添加亲水性胶体后,复水率显著提高(p0.05),尤其是瓜尔豆胶及其复配组,达到3.79%。复配胶的加入可改善广式腊肠的感官品质、质构特性及复水性,不同亲水性胶体有不同的作用特点。     

Effect of hydrocolloids on the rheological, microscopic, mass transfer characteristics during frying and quality characteristics of puri

Effect of hydrocolloids such as guar gum (GG), arabic gum (AG), carrageenan (CG), locust bean gum (LBG), xanthan gum (XN), hydroxypropyl methylcellulose (HPMC) and carboxymethylcellulose (CMC) at 0.5% w/w level on rheological and quality parameters of puri from whole wheat flour was studied. Hydrocolloids like CMC, XN and HPMC increased the water absorption of puri dough, while it decreased in all other samples. The dough development time and mixing tolerance index values increased, while dough stability did not get affected. On addition of hydrocolloid, there was a reduction in the pasting temperature, while the peak viscosity, hot paste viscosity and cold paste viscosity values increased. Hardness, cohesiveness and adhesiveness properties of the puri dough increased with the addition of hydrocolloids. All the hydrocolloids used in general helped in retention of moisture in the puri and hence remained softer and pliable, while there was a significant reduction in the oil content of puri samples containing hydrocolloids. Among the different hydrocolloids used, addition of guar gum at 0.5% w/w level led to puris having improved quality characteristics to a greater extent with respect to moisture retention, lowering of oil content upon frying with softer and pliable texture and better keeping quality. The mass transfer studies confirmed that the mass transfer co-efficient values for moisture loss and oil uptake were lower in puris with guar gum than control.     

Quality Characteristics and Glass Transition Temperature of Hydrocolloid Pre-Treated Frozen Pre-Cut Carrot

The effect of hydrocolloid pre-treatment, i.e., pectin, carboxy methyl cellulose, xanthan gum and sodium alginate on textural properties, drip losses and sensory quality as well as on glass transition temperature (T_g′′′) of the frozen-thawed pre-cut carrots was studied. Untreated frozen samples showed detrimental effects in texture and also excessive drip losses while the carrot tissue integrity was well retained in the hydrocolloid pre-treated samples. As the concentration of the hydrocolloid increased, hardness and fracturability were also found to increase. However, adhesiveness was observed to follow a reverse trend. Xanthan gum (0.4%) resulted in higher texture retention than other hydrocolloids used as well as than the control samples. Hydrocolloids imparted lightness and higher red and yellowness to the carrot samples due to reduced solute mobility and moisture conditioning effects. Overall acceptability of the hydrocolloid pre-treated samples was found to be more than the experimental control samples. All the hydrocolloids were found to be effective in increasing the T_g′′′ to an extent, ?2.73 to ?0.28°C compared with T_g′′′ (?5.4°C) of untreated carrot samples. T_g′′′ increased to almost 74% in CMC (0.4%) pre-treated samples. The maximum enhancement was found in carboxy methyl cellulose followed by pectin, sodium alginate, and xanthan gum. The threshold concentrations in terms of sensory attributes were determined for optimal conditioning of the product prior to freezing.     

Long-term storage stability of selected potato starch – Non-starchy hydrocolloid binary gels

All 3, 4 and 5% potato starch gels containing either κ-carrageenan, guar gum or xanthan gum were prepared and their stability in terms of rheological and textural properties was checked on 30 day storage. It was shown that rheology of these binary potato starch – non-starchy hydrocolloid mixtures could be controlled by anionic character of the admixed hydrocolloid. Depending on the hydrocolloid added, gels made of the tuber starch can either retain their pattern typical for tuber starches or turn into that typical for gels of cereal starches. Hydrocolloids added plasticity to the binary gels but it was lost to a significant extent within the first day of storage. Resulting gels with dominating elastic character are rheologically and texturally fairly stable for subsequent 30 days of storage. Generally, hydrocolloids stabilized potato starch gel on long-time storage to the extent dependent on the gel concentration.     

常见亲水胶体对烘焙食品品质影响的研究进展（网络首发、推荐阅读）

亲水胶体具有良好的功能特性,如改善食品的乳化、胶凝、溶解性和质构等特性。在烘焙食品中,亲水胶体用于改善面团、面包和蛋糕特性,提高感官质量以及延长食品货架期。已经有研究报道了亲水胶体在面包、饼干、蛋糕和面食制备中的潜在用途。综述常见的亲水胶体（黄原胶、瓜尔胶、阿拉伯胶、K-卡拉胶、刺梧桐胶、海藻酸盐、甲基纤维素、羧甲基纤维素和羟丙基甲基纤维素）对焙烤食品的流变学、理化、质构以及其它品质特性的影响,亲水胶体的加入使得产品的颜色、外观、风味和整体可接受性显著改善。     

Determination of the fruit content of cherry fruit preparations by gravimetric quantification of hemicellulose

A method recently developed for the determination of the fruit content of strawberry fruit preparations by gravimetric quantification of hemicellulose was extended to cherry fruit preparations. Isolation of the alcohol-insoluble residue (AIR) and sequential fractionation of the cell wall compounds from cherries (Prunus cerasus L. cv. ‘Oblacinska’) was performed yielding the amount of fresh cherries per gram hemicellulose. Cherry fruit preparations with varying fruit contents (30–40%) were produced using different hydrocolloid systems (pectin, starch, guar gum, xanthan gum, carrageenan, and combinations thereof). After separation of the hydrocolloids by enzymatical digestion and successive extraction, the fruit preparations were subjected to AIR isolation. The AIR was fractionated to yield the hemicellulose fraction, which was quantified gravimetrically for the calculation of the fruit content. Compared to strawberries, modifications including additional extraction steps for the sequential fractionation were required to separate the pectin of the cherries exhaustively. Calculated and initial fruit contents were in good agreement for the single hydrocolloid components pectin and starch as well as for the combinations pectin/xanthan gum and pectin/carrageenan (26.8% vs. 30%, 38.6% vs. 40%, 42.5% vs. 40%, 37.6% vs. 40%, and 41.2% vs. 40%), whereas the preparations produced with more complex hydrocolloid systems (pectin/xanthan gum/guar gum and starch/xanthan/guar gum) showed larger deviations in their contents (46.2% vs. 40%, 49.6% vs. 40%). It is concluded that the novel method is generally suitable for the determination of the fruit content of fruit preparations, but steps of sample preparation need to be individually adapted to the different fruit matrices.     

Linear Rate of Water Crystallization as Influenced by Viscosity of Hydrocolloid Suspensions

The linear rate of water crystallization at −3°C was measured in various hydrocolloid suspensions, each at several different viscosities. For any given hydrocolloid suspension, the linear rate of water crystallization decreased as viscosity was increased, but it differed among hydrocolloid suspensions adjusted to the same viscosity. Thus, viscosity, over the range studied, is not a good predictor of a hydrocolloid's ability to inhibit crystallization. When studied at −3°C and a viscosity of 3.0 Pa·s, locust bean and guar gum were the most effective crystallization retardants among the five hydrocolloids studied; however, all hydrocolloids on a molar basis were far less effective than sucrose. The beneficial effects of hydrocolloids on the texture of frozen desserts may arise from some attribute other than control of crystal size.     

The rheological behaviors and morphological characteristics of different food hydrocolloids ground to sub-micro particles: in terms of temperature and particle size

Temperature sweep tests and steady shear properties of five different food hydrocolloids (guar gum, xanthan gum, carboxymethylcellulose, pectin and carrageenan) in two different particle sizes groups have been determined at 25, 40, 60 and 80 °C in 1% aqueous solution. Also, the Scanning Electron Microscopy (SEM) images of gums were taken to investigate the morphological properties of the samples. The particle size and processing temperature significantly affected all rheological parameters of the hydrocolloid solutions. The flow behavior of the samples was fitted to Ostwald de Waele model (R²?=?0.959). The highest n value was recorded at 60 °C for all samples. The most drastic changes in consistency coefficient (K) values of the samples were observed in carrageenan solution and it was ranged from 0.013 to 1.774 Pa.sⁿ before the size reduction and from 0.007 to 0.337 Pa.sⁿ after the size reduction process. As the consistency coefficient (K) and apparent viscosity (η₅₀) decreased with the temperature, the flow behavior index increased in both group of samples. As a result, it was concluded that the increase in processing temperature and size reduction process caused a decrease in resistance of hydrocolloid solutions subjected to the deformation, which is a very important factor affecting the quality and good mouth-feel of products.     

Linear Rate of Water Crystallization as Influenced by Temperature of Hydrocolloid Suspensions

The object of this study was to assess the abilities of various hydrocolloids to inhibit water crystallization at temperatures ranging from −3 to −5°C. In all instances, decreases in the initial super-cooling temperature or the hydrocolloid concentration caused increases in the linear rate of crystallization. The linear rate of crystallization vs. temperature plots indicated that suspensions of guar gum alone or with microcrystalline cellulose, locust bean gum, and carrageenan exhibited the greatest temperature dependence, whereas suspensions of guar gum-sucrose, carboxymethylcellulose-sucrose, and sodium alginate alone or with microcrystalline cellulose exhibited the least temperature dependence. At a 1% (wt/vol) level of use, guar gum and locust bean gum exhibited the smallest linear rate of crystallization at −5°C and carrageenan and sodium alginate (1.5% wt/vol) exhibited the largest. The results obtained from this study indicate that hydrocolloids retard the rate of water crystallization and that some are more effective than others. However, all hydrocolloids tested are far less effective than sucrose in retarding rate of water crystallization.     

Evaluation of Lepidium sativum seed and guar gum to improve dough rheology and quality parameters in composite rice–wheat bread

The effects of hydrocolloids in rice–wheat flour were studied. Hydrocolloids at 0%, 0.3%, 0.6% and 1% w/w (flour basis) and guar (G), Lepidium sativum seed (L) and guar-L. sativum seed (GL) gum were tested as additives to the rice/flour in various combinations. The quality parameters for the experiment were assessed with farinography, extensography, amylography and texture profile analysis. The evaluation of dough rheology showed that water absorption, dough development time, dough stability and viscosity all increased with the addition of hydrocolloids alone or in a combination. It was demonstrated that G₁L₁ promoted the highest effect. The mixing tolerance index and gelatinization temperature decreased with an increased hydrocolloid concentration. Extensibility value for the dough that incorporated guar and L. sativum seed gum increased with increasing hydrocolloid concentration from 0.3% to 0.6% and then decreased at 1%. The water activity of all bread didn't have significant differences with increasing hydrocolloids concentration but this parameter 24 decreased during storage. Firmness decreased with increasing hydrocolloid concentration and increased with increasing storage time. The sensory evaluation by a consumer panel gave the higher score for overall acceptability to G_0.3L_0.3 and G_0.3L_0.6 samples. The results also showed that G₁L₁, G₁L_0.6 and G_0.6L₁ samples had high specific volume and porosity.     

黄原胶和瓜尔豆胶对小麦淀粉冻融稳定性的影响

将小麦淀粉分别与黄原胶和瓜尔豆胶以一定的比例复配,利用析水率实验、DSC方法和SEM微观结构观察等方法,研究亲水胶体黄原胶和瓜尔豆胶在5次冻融循环过程中对小麦淀粉稳定性的影响。研究结果表明:小麦淀粉的析水率随着循环次数的增加而增加,黄原胶和瓜尔豆胶能够明显降低冻融过程中小麦淀粉的析水率,从而抑制小麦淀粉冻融过程中的老化,且随着亲水胶体浓度的增加,对冻融稳定性的改善作用越强;小麦淀粉经过5次冻融循环后,淀粉胶基形成了大量的孔洞,并产生不连续丝状的,类似纤维的结构,且基质较薄,添加亲水胶体后显著改变了小麦淀粉的表观形态,孔洞明显减少,且淀粉基质增厚,形成了类似片状的网络结构。因此,黄原胶和瓜尔豆胶均能在一定程度上改善小麦淀粉的冻融稳定性,且与添加浓度有关。     

Rheological properties of whey protein isolate stabilized emulsions with pectin and guar gum

Dynamic oscillatory and steady-shear rheological tests were carried out to evaluate the rheological properties of whey protein isolate (WPI) stabilized emulsions with and without hydrocolloids (pectin and guar gum) at pH 7.0. Viscosity and also consistency index of emulsions increased with hydrocolloid concentration. At γ = 20 s⁻¹, the value of viscosity of the emulsion with 0.5% (w/v) pectin was about fivefold higher than that of the emulsion without pectin. Flow curves were analyzed using power law model through a fitting procedure. Flow behaviour index of all emulsions except for containing 0.5% (w/v) guar gum was approximately in the range of 0.9–1.0, which corresponds to near-Newtonian behaviour. The shear thinning behaviour of emulsions containing 0.5% (w/w) guar gum was confirmed by flow behaviour index, n, of 0.396. Both storage (G′) and loss modulus (G″) increased with an increase in frequency. Emulsions behaved like a liquid with G″ > G′ at lower frequencies; and like an elastic solid with G′ > G″ at higher frequencies. Effect of guar gum was more pronounced on dynamic properties. Phase angle values decreased from 89 to <10° with increasing frequency and indicated the viscoelasticity of WPI-stabilized emulsions with and without pectin/guar gum.     

十二种常见亲水胶体对馒头品质影响的研究

本文研究了12种亲水胶体不同添加量(0.2%、0.6%、1.0%)对馒头质构、比容、水分含量及持水力的影响。结果表明:适宜浓度的瓜尔豆胶,高甲氧基柑橘果胶在降低馒头硬度及咀嚼性的同时提高了馒头弹性(p<0.05),总体上有效地改善了馒头的质构特性。0.2%的瓜尔豆胶及魔芋胶,0.2%~1.0%的高甲氧基柑橘果胶、阿拉伯胶及乳清水解蛋白,0.6%~1.0%的低甲氧基柑橘果胶及酪蛋白钠使馒头比容显著增加(p<0.05)。在室温及-4 ℃条件下,与空白比较,除阿拉伯胶对馒头持水力无显著影响外,其他亲水胶体均能不同程度的提高显著馒头的持水力。由此可知,添加适宜浓度的瓜尔豆胶、高甲氧基柑橘果胶对馒头综合品质具有较好的改良效果。     

EFFECTS OF HYDROCOLLOIDS AND ASPARTAME ON SENSORY VISCOSITY AND SWEETNESS OF LOW CALORIE PEACH NECTARS

Effects were studied of interactions between each of three hydrocolloids-xanthan gum, guar gum and methylcellulose- and aspartame on sweetness intensity and sensory viscosity of low-calorie peach nectars (60% fruit purée with no sucrose added). The flows of the nectars were characterized as near Newtonian without hydrocolloids, as Bingham plastic at lower hydrocolloids concentrations and as pseudoplastic at higher concentrations (Ostwald flow for guar and methylcellulose, and Herschel-Bulkley for xanthan). Hydrocolloids concentrations were selected to cover viscosity range of commercial whole nectars: 0.10 and 0.20% xanthan or guar, and 0.15 and 0.30% methylcellulose. Aspartame concentrations tested were derived from the calculation of equisweet concentration as referred to a control nectar sample with sucrose (14°Brix) and of the upper and lower limen value: 0.216, 0.360 (equisweet), 0.502, and 0.644 g/L. Addition of either guar or methylcellulose did not alter the perceived sweetness in aspartame-sweetened peach nectars. Xanthan addition, even at 0.10%, significantly lowered sweetness of samples sweetened with the highest aspartame concentration (0.644 g/L). Addition of aspartame did not modify the perceived viscosity in samples thickened with either xanthan or guar gums. At all methylcellulose concentrations tested, samples with the lowest aspartame concentration (0.216 g/L) were perceived as less viscous.     

Evaluation of the time-dependent stability of starch-hydrocolloid binary gels involving NMR relaxation time measurements

A novel, non-destructive method of evaluation of the time-dependent stability of starch gels and binary starch-non-starchy hydrocolloid gels is presented. The low-field NMR technique applied provided the following results. On storage at room temperature, binary potato starch gels with xanthan gum are more stable in time than gels with guar gum and κ-carrageenan. Xanthan and guar gums as well as κ-carrageenan are dispensable as stabilizers of stored potato starch gel and building the cassava gel structure lasted over 96 h. In the binary system with cassava starch, guar gum performed best regardless storage temperature. At room temperature, admixture of hydrocolloids to plain cornstarch gels resulted in remove of water molecules from the gel network. Stabilization of cornstarch gels with hydrocolloids was, practically, dispensable and even non-beneficial regardless storage temperature. None among tested hydrocolloids stabilized the oat starch gel. On cold storage, κ-carrageenan performed best.     

Contribution of hydrocolloids to gelling properties of blue whiting muscle

 Several hydrocolloids (locust bean gum, guar gum, xanthan gum, iota-carrageenan, kappa-carrageenan, carboxymethylcellulose and alginate) were added in different concentrations (0.5, 1.0, 2.0, 3.0, and 4.0%) to determine their behaviour as additives in washed blue whiting muscle mince. Higher percentages significantly reduced rheological properties, which in some cases fell to values below that of the control gel, with no added hydrocolloids. Water holding capacity, on the other hand, was lowest at low concentrations. Gel colour was virtually unaffected by the presence of different hydrocolloid concentrations in the formulation. Discriminant analysis differentiated the various hydrocolloids used, chiefly on the basis of hardness; however, the most influential factor affected by the concentration of hydrocolloid was breaking force. In this manner, it was defined what properties can be achieved by addition of these ingredients obtaining a variety of characteristics. Received: 7 June 1999 / Revised version: 19 July 1999