Lightness and gloss of peach gels: effect of fruit and sugar content

 Lightness and gloss were studied in peach gels prepared with different quantities of sugar and peach pulp, using a mixture of xanthan and locust bean gum as gelling agents. Colour was described in terms of the colour coordinates established by the Commission Internationale de l'Eclairage and gloss was determined as a percentage. The values of lightness determined optically (L^*), when ranked, corresponded well with those determined by eye, but there was less similarity between the ranked values of gloss determined optically and by eye. There was a clear relationship between the sensory evaluation of lightness and gloss and the fruit and sugar content of these gels. Mathematical equations were developed to relate both L^* and gloss values determined optically with fruit and sugar concentrations. It was found that fruit had a greater effect than sugar on the L^* values and that gloss depended only on the sugar content. Finally, the gloss of gels prepared with different gelling agents were compared and it was found that lightness can affect the sensory evaluation of gloss. Received: 15 July 1997 / Revised version: 3 February 1998     

Lightness and gloss of peach gels: effect of fruit and sugar content

 Lightness and gloss were studied in peach gels prepared with different quantities of sugar and peach pulp, using a mixture of xanthan and locust bean gum as gelling agents. Colour was described in terms of the colour coordinates established by the Commission Internationale de l'Eclairage and gloss was determined as a percentage. The values of lightness determined optically (L^*), when ranked, corresponded well with those determined by eye, but there was less similarity between the ranked values of gloss determined optically and by eye. There was a clear relationship between the sensory evaluation of lightness and gloss and the fruit and sugar content of these gels. Mathematical equations were developed to relate both L^* and gloss values determined optically with fruit and sugar concentrations. It was found that fruit had a greater effect than sugar on the L^* values and that gloss depended only on the sugar content. Finally, the gloss of gels prepared with different gelling agents were compared and it was found that lightness can affect the sensory evaluation of gloss. Received: 15 July 1997 / Revised version: 3 February 1998     

Stress Relaxation of Fruit Gels. Evaluation of Models and Effects of Composition

Stress relaxation behavior of kappa carrageenan (1%) gels (C) and kappa carrageenan (0.5%) plus locust bean gum (0.5%) gels (G) was studied. Effects of addition of sugar (18.3, 36.6 and 55° Brix) and fruit pulp (15%) on relaxation response were analyzed. Curves were fitted to Maxwell (M), Peleg (P) and simplified Maxwell (SM) equations. All three equations were valid to quantify relaxation behavior of fruit gels and to evaluate the effects of changes in composition, with P and SM equations being simpler. Locust bean gum increased initial stress decay rate and decreased proportion of unrelaxed force. Sucrose produced the opposite effect. Fruit pulp effects were weak and dependent on gelling system.     

EFFECT OF OTHER HYDROCOLLOIDS ON THE TEXTURE OF KAPPA CARRAGEENAN GELS1

The effect of different hydrocolloids on the breaking strength, cohesiveness and rigidity of kappa carrageenan gels was studied using comression tests with the Instron. Instrumental measurements were supplemented with benchtop sensory evaluation of texture by mouth, gel clarity and syneresis. The evaluated hydrocolloids included locust bean gum, iota carrageenan, amidated low methoxyl pectin, xanthan gum, and their selected combinations. Best gels were obtained by using 0.15% kappa carrageenan and 0.85% iota carrageenan, or 0.2% kappa carrageenan, 0.2% locust bean gum and 0.6% amidated LM pectin. Although none duplicated the textural quality of gelatine gels, they represented a wide range of interesting and potentially useful textures.     

Carrageenan,pectin and xanthan/locust bean gum gels. Trends in their food use

There are unlikely to be any completely new gelling agents, due to the high cost of proving them acceptable; exploitation of such agents as carrageenan and pectin is likely to be intensified.Both of these gelling materials, together with xanthan/locust bean gum gels are discussed in detail. Their values in food formulations are considered, with some estimate of their future development.food formulations are considered, with     

卡拉胶/刺槐豆胶对猪肉糜品质的影响研究

亲水性胶体是用于改善肉制品品质的常用添加剂之一。本文通过在猪肉糜中添加卡拉胶和刺槐豆胶,研究两种胶体及其复配对猪肉糜色差、质构、水分活度的影响。研究结果表明,适宜比例的卡拉胶与刺槐豆胶的复配胶对猪肉糜品质的改善起到了一定的作用。卡拉胶/刺槐豆胶添加量为0.16%/0.24%时,猪肉糜品质较佳,硬度达到521.20±15.40,咀嚼性达到27.00±10.40,失水率降低至0.040±0.002。     

Effect of addition of sucrose and aspartame on the compression resistance of hydrocolloids gels

The effect of adding sucrose (5–25% w/w) and aspartame (0.04–0.16% w/w) on the compression resistance of three hydrocolloid gelled systems: κ‐carrageenan, gellan gum and κ‐carrageenan/locust bean gum at three different concentrations (0.3, 0.75 and 1.2% w/w) was studied. Sucrose addition increased true rupture stress in the three‐gelled systems, this effect being stronger in gellan gels. The deformability modulus increased with sucrose concentration in gellan gels, but not in the other systems. Rupture stress and deformability modulus increased with the addition of sucrose only in the harder gels (0.75 and 1.2% w/w). The effect of sucrose addition on the true rupture strain was significant but, in general, not important, mainly for lower gum concentrations. Aspartame addition did not affect the compression parameters.     

Effects of gelatinisation level, gum and transglutaminase on the quality characteristics of rice noodle

The aim of the present study was to investigate the effects of gelatinisation level, gum (locust bean gum, xanthan gum, 3%) and/or transglutaminase (TG, 0.5%) on quality characteristics of rice noodle. In order to improve the dough forming ability, rice flour was gelatinised at levels of 15%, 20%, 25% and 30%. Noodle samples were evaluated in terms of cooking loss, total organic matter (TOM), water absorption, swelling volume, maximum force, colour, sensory properties, pasting properties. Noodle sample with a gelatinisation level of 25% had better cooking and sensory properties. Gum and/or TG were added to this noodle formula. The noodle samples including xanthan gum had better cooking and sensory properties. TG caused a significant decrease in TOM. The samples including locust bean gum had significantly higher maximum force values. Xanthan gum caused decreases in some Rapid ViscoAnalyzer viscosity values of the noodle samples, while locust bean gum caused increases.     

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.     

Textural properties of legume protein isolate and polysaccharide gels

The influence of legume proteins from lupin, pea and fababean on the formation of gels prepared by heat treatment in the absence or presence of xanthan gum, locust bean gum and NaCl was investigated. The resulting fracture and texture properties of gels not only are associated with the heating process used to form the gel but also depend on the conformational aspects of xanthan–locust bean gum in admixture with legume proteins, which after 10 days of aging reinforce the system. The fracture and textural properties are explained in terms of the effect of the protein–polysaccharide molecular structure and physicochemical conditions applied in the gel system during the gel preparation and measurements. Copyright © 2006 Society of Chemical Industry     

Konjac/gellan gum mixed gels improve the quality of reduced-fat frankfurters

Mixed gels of konjac (1%, 2%) and gellan gum (0.25%, 0.5%) were incorporated into reduced-fat (18%) frankfurters and compared with reduced-fat and high-fat (28%) controls for physicochemical, textural, sensory properties and storage stability. C28 (control at 28% fat) had the highest (P<0.05) lightness (L*) and yellowness (b*) values but the lowest redness (a*). C28 had the lowest textural hardness, shear force value and sensory firmness but highest juiciness scores. Treatments containing konjac/gellan gum mixed gels were not different from C28 in sensory overall acceptability, among them K1G5 (1% konjac/0.5% gellan gum) was numerically higher. C18 had the highest TPC (～7.8 log CFU/g) after 12 weeks of storage, followed by gum-containing treatments. In conclusion, it appears feasible to incorporate konjac/gellan gum mixed gel at current levels to reduced-fat frankfurter for acceptable sensory merits with reasonable shelf life.     

Sensory quality of low-sugar orange gels with gellan, xanthan and locust bean gums

Effects of reducing the sucrose content (from 55 to 30 ^°Brix in the final product) and of the use of gellan gum or a mixture of gellan, xanthan and locust bean gums (3:1:1) on the mechanical characteristics (maximum rupture force and deformation at rupture) of orange gels prepared with 15% w/w fruit pulp, sucrose and different amounts of hydrocolloids (0.25, 0.4, 0.55 and 0.7% w/w) were studied by uniaxial compression. The concentration of aspartame needed to compensate for sweetness loss was determined by a paired-comparison constant-stimulus method. Sensory characteristics (texture, appearance and flavour) of low-sugar orange gels (30 ^°Brix) with 0.5% w/w aspartame and different amounts (0.55 and 0.7% w/w) of gellan or the mixture of gums were analysed by the free choice profile method in comparison with the high-sucrose reference material (55 ^°Brix and 0.4% w/w gellan). Use of the mixture of gums permitted the obtention of low-sugar orange gels showing mechanical characteristics similar to those of the reference gel, though some differences in texture were perceived. The low-sugar gels were slightly lighter in colour and slightly more bitter and refreshing than the reference sample. Received: 29 November 1995/Revised version: 13 May 1996     

番石榴保健果冻的研制

以番石榴果汁为主要原料,长角豆胶、卡拉胶和琼脂为主要胶体,并配以木糖醇、柠檬酸等其他辅料,通过单因素实验、正交实验和感官评定法,对番石榴保健果冻的加工工艺进行了研究。研究结果表明,番石榴汁用量为25%、木糖醇添加量14%、柠檬酸添加量0.12%、刺槐豆胶0.6%、卡拉胶0.7%、琼脂0.3%、氯化钾0.1%的工艺参数可制得果味浓郁、口感滑爽、质地均匀、风味独特的营养保健果冻。     

Eating quality of low‐fat beef burgers containing fat‐replacing functional blends

Tapioca starch, carrageenan, oat fibre, pectin, whey protein and a commercial mixture of carrageenan and locust bean gum were assessed for their ability to mimic fat characteristics in cooked low‐fat (10%) beef burgers. Thirteen different blends of the ingredients were formulated in order to examine their effects on quality parameters of low‐fat beef burgers. The beef burgers were tested for cook yield, water‐holding capacity (WHC), retention of shape, sensory and mechanical texture analysis. Most blends significantly (P<0.05) increased both cook yield and WHC, in particular blends containing tapioca starch, oat fibre, whey protein and the carrageenan/locust bean gum mixture. These blends substantially reduced both Warner–Bratzler and Kramer shear values. Sensory analysis showed that beef burgers containing tapioca starch, oat fibre and whey protein were acceptable in terms of flavour and texture. The low‐fat control was found to be the toughest and driest of the beef burgers examined. This study shows that blends of these ingredients can be used to offset the poor quality associated with low‐fat beef burgers. © 1999 Society of Chemical Industry     

Effect of polysaccharides with different ionic charge on the rheological,microstructural and textural properties of acid milk gels

The effects of addition of polysaccharides with different ionic charge on rheology, microstructure, texture and water holding capacity (WHC) of acid milk gels were studied and compared to that of gelatin addition. Similar to gelatin, starch (neutral) and xanthan gum (anionic) did not prevent milk gelation in the first 30 min of the acidification stage, even at high concentrations, and the typical casein network in acid milk gels could still be seen from electron micrographs; gelling and melting of these hydrocolloids were observed during the cooling and heating stages at specific concentrations. On the other hand, two neutral polysaccharides, guar gum (≥ 0.05%) and locust bean gum [LBG] (≥ 0.1%) inhibited milk gelation from the beginning of the acidification stage; the microstructure of the gel was modified greatly and no gelling/melting was observed during the cooling or heating stages. Another anionic polysaccharide, carrageenan, induced earlier milk gelation at low concentration (≤ 0.05%), but inhibited gelation entirely at high concentration (0.2%); inflections at ~ 27 °C and 21 °C were also observed during the cooling and heating stages at 0.05% concentration. The gel microstructure was not changed greatly, but showed smaller particle size at a carrageenan concentration of 0.05% than control sample. None of the polysaccharides showed as much improvement in WHC of the milk gels as gelatin did. Hence, xanthan and starch were found to be closer to gelatin in their effect on acid milk gels compared to guar gum, LBG and carrageenan.     

利用稳定剂复配改善模拟干酪质地特性的研究

为解决模拟干酪的质地比天然干酪差的问题,研究了在模拟干酪配方中添加稳定剂的单因素试验,研究发现使用单一稳定剂的模拟干酪出现弹性较弱、黏聚性较差、添加量过多时产品过硬等缺陷,所以本试验通过对稳定剂进行复配,来改善产品质地,在单因素基础上,采用{3,2}单纯格子设计法对卡拉胶、刺槐豆胶和瓜尔豆胶3种稳定剂进行复配试验,通过检测硬度、弹性、黏聚性和感官评分,获得最优稳定剂的配比,结果为复配稳定剂添加总量为0.40%,卡拉胶、刺槐豆胶和瓜尔豆胶的质量比为1∶0.91∶1.02时,模拟干酪感官评价最好。这是由于稳定剂间的协效性,使模拟干酪质地方面更接近天然干酪。     

Strain-hardening properties of physical weak gels of biopolymers

Weak gels of biopolymers are frequently used in food applications. Dynamic rheological measurements, performed at low strain in the linear domain are useful to characterize the network properties, e.g. gelation, ageing and mechanical recovery after shearing. However, the rupture properties of these gels are also of great interest to complete their characterization.Several weak gels containing carrageenan, xanthan–locust bean gum, pectin or alginate–pectin were investigated. The behaviour of these gels under large strain was studied either in dynamic mode or under constant low shear rate conditions. In many cases, a strain-hardening behaviour was observed: above the upper limit of the linear domain, the stress increased more than proportionally to the strain. A good agreement in stress–strain variations was observed between the results from dynamic and constant shear rate modes.This hardening effect, generally associated with a large deformability, gave to these gels a large resistance to rupture, with regards to their modulus. This can be related to the functionality of the biopolymer systems in terms of texture or suspension properties. As an example, in fluid gels, it allows the suspension of particles with a very weak network (typically a modulus of 1 Pa).     

酶法制备甘露低聚糖

利用枯草芽孢杆菌产生的碱性甘露聚糖酶,以魔芋、槐豆胶、瓜尔胶与田菁胶为原料,制备甘露低聚糖。比较了酶对底物水解反应动力学,对低聚糖制备过程中的水解液进行了还原糖测定,并通过质谱对最终酶解液组分进行分析。结果表明:魔芋与槐豆胶为甘露聚糖酶的最适水解底物,水解8h后,还原糖得率稳定,可作为甘露低聚糖生产的指导依据。酶解24h后,魔芋、槐豆胶、瓜尔豆胶及田菁胶的主要产物分别为二糖至九糖、五糖至十糖、二糖至十糖和二糖至十糖。利用酶法生产甘露低聚糖的方法具有水解过程简单、产物聚合度低、纯度高的优点。     

PHYSICAL,CHEMICAL AND SENSORY PROPERTIES OF SUGAR‐FREE JELLY*

The increase in diabetes and obesity has increased the demand for sugar‐free/low‐calorie products. Three jelly formulations were prepared using sucralose, low‐methoxyl pectin and maltodextrin with either xanthan gum or locust bean gum (LBG) used singly or in combination and stored at 4C or 43C for shelf life evaluation. Jelly treatments were evaluated for chemical, physical and sensory properties. The combination of xanthan gum and LBG significantly reduced syneresis compared with either gum used singly. The combination of xanthan gum and LBG resulted in significantly higher firmness and springiness values than using xanthan gum or LBG alone. The overall acceptability, aroma, taste, texture, spreadability and sensory attributes for no sugar‐added grape jelly averaged 5.8–6.4 in a 9‐point hedonic scale consumer acceptance study.     

Effect of gums on the multi-scale characteristics and 3D printing performance of potato starch gel

This research investigated the multi-scale characteristics of potato starch gel (PSG) with different addition ratios of xanthan gum (XG) and locust bean gum (LBG). These characteristics are closely related and had significant impacts on 3D printing performance. Both xanthan gum and locust bean gum were able to increase the apparent viscosity, storage modulus (G′) and loss modulus (G″) of the blended gel system to varying degrees. Large amplitude oscillation shear (LAOS) was used to detect slight rheological differences led by microstructure changes. The critical strain values of the blended gel system rose as the addition ratio of locust bean gum increased. At the same time, the elastic and viscous Lissajous curves could characterize the viscoelastic changes under large strains. Fourier transforms infrared spectroscopy (FT-IR) illustrated that locust bean gum could strengthen the hydrogen bonds so that the gel had stronger mechanical properties compared with the addition of xanthan gum. Scanning electron microscopy (SEM) could observe the changes in the microstructure of the blended gel systems with addition of different addition ratios of gums. From the perspectives of 3D printing results and data analysis, the appropriate amount of xanthan gum improved the fineness and fluidity of the gels by virtue of its lubricating and coating characteristics, while the locust bean gum enabled them to have stronger shape retention abilities and better performances of resisting compressed deformation.