Rheological properties,ginsenosides contents,sensory evaluations of Korean red ginseng extracts

Red ginseng extracts have gained popularity due to their positive impact on health. The objective of this study was to identify the rheological properties, ginsenosides contents and sensory characteristics of six different commercial red ginseng extracts in Korea. Ginseng extracts demonstrated different shear‐thinning flow behaviour (n = 0.59–0.78) with a consistency index (K = 46.77–105.78 Pa sⁿ), which meant they had different viscosity. The amount of ginsenosides and total solid contents were highly correlated (r = 0.954). Six significant attributes (ginseng, angelica, bitterness, ginger flavour and astringency) were identified and can be used as sensory parameters for the determination of the product quality. Hedonic levels of the product were assessed by a group of ninety‐five consumers in their 20 s (n = 32) and over 30 (n = 63). Cluster analysis revealed that consumer acceptance was divided into two major clusters for those that preferred strong (n = 43) and weak (n = 42) ginseng characteristics in the extract.     

Application of aged egg in enabling increased substitution of sucrose by litesse (polydextrose) in high-ratio cakes

Previous reports show that replacing sucrose by polydextrose in cakes leads to an elevation of the starch gelatinisation temperature such that it no longer coincides with the egg protein denaturation transition. It is known that as eggs age, the ovalbumin transforms to S-ovalbumin with a higher denaturation temperature. Linking these observations led to the hypothesis that baking reduced-sugar cakes with aged eggs might bring the starch gelatinisation into proximity of the protein denaturation thereby improving the final texture. Baking trials and instrumental texture evaluations of the resulting high-ratio cakes were carried out with fresh egg and egg that had been aged at 37°C for 3, 7 and 14 days. Texture changes that do exist are principally related to differences in the cake crumb density and crumb springiness.     

A nutritional, chemical and sensory evaluation of lupin (L. angustifolius) tempe

Tempe, a traditional Indonesian food, is usually made by the fermentation of soybeans. the substitution of soybeans with lupin seed kernels at levels of 50, 75 and 100% was investigated. Organoleptic evaluation using Australian (n = 17–22) and Indonesian panellists (n = 5–8) showed no significant difference ( P > 0.05) for taste, texture and overall acceptability between the samples. the process of soaking, boiling and fermenting the soybeans reduced the content of phytate (17%), protease inhibitors (98%) and oligosaccharides (77%). For lupin seed kernels the reductions were 60%, negligible and 86%, respectively, and for alkaloids 71%. the protease inhibitor content of lupin tempe was only one-fifth that of soy tempe.
Negligible changes in the protein quality of soybeans and lupins were observed. the Protein Efficiency Ratio (PER) was 2.30 for the boiled soybeans and 2.19 for soybean tempe. Cooked (boiled) lupins had a lower protein quality (PER = 0.84) which was not significantly altered by processing into tempe (PER = 0.91). the apparent digestibility of the cooked lupin (88.1%) and lupin tempe (88.4%) were similar to that of cooked soy (87.3%) and soy tempe (88.5%).
These results suggest good prospects for substituting lupin seed for soybeans in tempe production in cases where protein is not limiting and where the lower levels of antinutrients would be of nutritional benefit.     

Rheological,texture and sensory properties of kefir with high performance and native inulin

Rheological, textural, and sensory properties of kefirs with inulin were analysed. Besides, the effect of skim milk powder (SMP) and milk fat substitution was examined by high performance (HP) and native inulin. One-third of SMP was substituted by native (IQ) or HP (TEX!, HPX) inulin. Hardness of kefir with IQ inulin was lower than that with HP inulins or pure SMP. Analysis of cohesiveness and adhesiveness showed that kefir with inulin had higher firmness. Rheological analysis revealed that all manufactured kefirs had higher storage than loss modulus, and exhibited thixotropic and shear thinning behaviour. There were no significant differences in odour and consistency between kefirs with and without inulin. Only in case of whole milk powder (WMP) kefir, panellists noticed the difference in flavour, although kefirs based on SMP had the same scores. Substitution of SMP by inulin allowed for reducing 15% and 37% of caloric value in comparison with SMP and WMP kefir, respectively.     

Rheological, texture and sensory properties of low-fat mayonnaise with different fat mimetics

Application of whey protein isolate and low-methoxy pectin-based fat mimetics in mayonnaise was studied. Fat was partially substituted by different fat mimetics at levels of 50%, respectively, which the fat mimetics were referred to as PFM1 (microparticulate pectin gel), PFM2 (pectin weak-gel), and PFM3 (microparticulated combination of WPI and pectin). The full fat (Ff) (100% oil) mayonnaise without fat mimetic was used as a control experiment. Physicochemical, rheological, texture analysis, and sensory evaluation of the Ff and low fat (Lf) mayonnaises were performed. The results indicated that all Lf mayonnaises had significantly lower energy content, but higher water content than their Ff counterpart. In terms of texture, the formulation with pectin weak-gel as fat mimetic showed similar texture values as those of the Ff sample. Both Ff and Lf mayonnaises exhibited thixothopic shear thinning behaviour under steady shear tests and were rheologically classified as weak gels under small amplitude oscillatory shear tests. Sensory evaluation demonstrated that mayonnaises substituted with low-methoxy pectin were acceptable. This study shows good potential for pectin weak-gel and microparticulated pectin gel to be used as a fat mimetic in mayonnaise.     

Effect of whey and pea protein blends on the rheological and sensory properties of protein-based systems flavoured with cocoa

Whey and pea protein combined in different proportions (100W:0P, 75W:25P, 50W:50P, 25W:75P, 0W:100P) were used to prepare protein-based systems flavoured with cocoa and containing κ-carrageenan or κ-carrageenan/xanthan gum as thickeners. Steady and dynamic shear rheological properties of samples were measured at 10 °C and sensory differences were evaluated. Protein-based systems exhibited a shear-thinning flow behaviour that was fitted to the simplified Carreau model. Samples showed different viscoelastic properties, ranging from fluid-like to weak gel behaviour. For both types of system (with and without xanthan gum) viscosity, pseudoplasticity and elasticity rose on increasing the pea protein proportion in the blend. The sample with only whey protein obeyed the Cox-Merz rule, while in the rest of the samples complex viscosity was higher than apparent viscosity. Regarding sensory properties, the protein blend ratio mainly affected sample thickness, which rose as pea protein proportion increased. However, at the same time, the chocolate flavour and sweetness decreased and the off-flavour increased.     

Developing a prebiotic yogurt: Rheological,physico-chemical and microbiological aspects and adequacy of survival analysis methodology

The addition of prebiotics such as oligofructose to yogurt can result in a product with consumer benefits, since they stimulate growth of benefic bacteria present in the intestine and also provide a low calorie product, since one can add less sugar to the formulation due to their sweetening power. This work aimed to evaluate the effect of increasing concentrations of oligofructose addition on physicochemical, rheological and microbiological characteristics of non-flavored yogurt. Furthermore, it was investigated the reaction of consumers with the use of the survival analysis methodology. The addition of oligofructose showed no influence on the pH, proteolysis or the viability of Streptococcus thermophilus or Lactobacillus bulgaricus during 28 days of refrigerated storage (p > 0.05). According to rheological measurements the yogurt supplemented with oligofructose was characterized as a weak gel, showing thixotropic and pseudoplastic behavior. Survival analysis was used to investigate consumer responses with respect to different levels of supplementation of plain yogurt with oligofructose (0%, 2%, 4%, 6% and 8% wt. v⁻¹). Using the survival analysis and considering a rejection by 25% of the consumers, the level of oligofructose that can be added to the yogurt was shown to be 2.58% wt. v⁻¹.     

Microbial, physical and sensory properties of yogurt supplemented with lentil flour

In this study, skim milk (9.5% w/v solid content) was supplemented with 1-3% (w/v) lentil flour or skim milk powder, inoculated with a yogurt culture, fermented and stored at 4 °C. Acid production during the fermentation, microbial growth, physical properties (pH, syneresis, and color), rheological properties (dynamic oscillation temperature sweep test at 4-50 °C), during 28 days of refrigerated storage and also sensory properties (flavor, mouth feel, overall acceptance and color) after production, were studied. Milk supplementation with 1-3% lentil flour enhanced acid production during fermentation, but the microbial population (CFU) of both S. thermophilus and L. delbrueckii subsp. bulgaricus were in the same range in all lentil flour and skim milk powder supplemented yogurts. The average pH of samples decreased from 4.5 to 4.1 after 28 days storage. Syneresis in 1-2% lentil flour supplemented yogurts was significantly higher than all other samples; however, greater lentil supplementation (3%) resulted in the lowest syneresis during the 28 days storage. With respect to color, “a” and “L” values did not significantly differ in all samples and remained constant after 28 days whereas “b” value increased as a result of lentil supplementation. Yogurt with 3% lentil flour showed higher storage (G') and loss (G?) moduli in comparison with samples supplemented with 1-3% skim milk powder and the non-supplemented control yogurt. Storage modulus (G') was higher than loss modulus (G?) in all samples and at all temperatures between 4 and 50 °C and they showed a hysteresis loop over this temperature range when the samples were heated and cooled. 1-2% lentil flour supplemented yogurt showed comparable sensory properties in comparison with 1-2% skim milk powder supplemented yogurt and the control sample.     

Rheological behavior and organoleptic effects of ovalbumin addition in yogurt mousse production

Yogurt mousse is a novel, high added-value dairy product that has been well received by the market. This paper presents a study of the effect of the addition of ovalbumin to the product on its rheological and organoleptic qualities. The ovalbumin was previously separated from egg white with a high grade of purity using an ion exchange resin synthesized by the authors. Diverse rheological tests at different temperatures and corresponding sensorial assessments were conducted to compare samples without and with added ovalbumin.The obtained results confirm that the product is viscoelastic and combines the properties of foams and emulsions; the elastic component is greater than the viscous component. Moreover, at temperatures ranging from 5 to 15°C, a usual interval of consumption, the product behaves rheologically in a similar way. Conversely, the addition of ovalbumin under the assayed conditions also makes the elastic character of the product increase at a given temperature. Finally, the sensorial assessment tests and determinations of stability and volume yield enabled us to verify that the addition of ovalbumin at an amount of 1.3% hardly alters the stability, resistance to shear stress, or the texture and improves the degree of foaming. Therefore, the product with additive is of good commercial quality.     

Heat Induced Gelation of Pea (Pisum sativum) Mixed Globulins, Vicilin and Legumin

Mixed globulins (MG) were extracted from ground dry peas (Pisum sativum, B-160) with 0.5M NaCl, 50 mM potassium phosphate, pH 7.2, and isolated by precipitation at pH 4.5. Crude vicilin and legumin were fractionated from the MG by dialysis against 0.2M NaCl, pH 4.8, and centrifugation, then further purified using DEAE-cellulose chromatography. Conditions for maximum gel hardness of heat induced MG gel, as determined with an Instron Universal Testing Machine, were heating for 20 min at pH 7.1 at 87°C. Purified vicilin, but not legumin, formed heat induced gels. The relationship was linear between protein (globulin) concentration and log gel hardness. At all protein concentrations studied, as proportion of legumin decreased, gel hardness increased.     

Flavour evaluation of three black mulberry (Morus nigra) cultivars using GC/MS,chemical and sensory data

The flavour characteristics of three black mulberry (Morus nigra) cultivars from the Aegean region of Turkey were investigated using GC/MS and sensory analysis techniques. A total of 18 flavour compounds were identified by GC/MS in the three cultivars. Total sugar content varied between 11.3 and 16.2%, pH between 3.60 and 3.80 and total acidity between 1.51 and 1.79%. The sensory assessment indicated that black mulberry has fruity, sweet, sour, musky and woody flavour notes and fruity, acid, musky, leafy and woody‐fresh aroma characteristics. The evaluation of GC/MS and sensory data revealed that ethyl linolenate was the most effective compound contributing to the unique flavour of black mulberry. © 2002 Society of Chemical Industry     

Effect of polymorphisms in the leptin, leptin receptor, and acyl-coenzyme A:diacylglycerol acyltransferase 1 (DGAT1) genes and genetic polymorphism of milk proteins on cheese characteristics

Cheese production has increased worldwide during the last decade and is expected to increase within the coming decade as well. Despite this, the relations between cow genetics and cheese characteristics are not fully known. The aim of this study was to determine if polymorphisms in the leptin (LEP), leptin receptor (LEPR), and acyl-coenzyme A:diacylglycerol acyltransferase 1 (DGAT1) genes as well as genetic variants of β-casein (β-CN), κ-CN, and β-lactoglobulin (β-LG) affect technological properties important for cheese production and, hence, could act as genetic makers for cheese quality. Individual milk samples from the Swedish Red and the Swedish Holstein breeds were analyzed for sizes of CN micelles and fat globules as well as rennet-induced gel strength, gelation time, and yield stress. Model cheeses were produced to study yield, hardness, and pH of the cheeses. The A1457G, A252T, A59V, and C963T single nucleotide polymorphisms (SNP) were analyzed on the LEP gene, the T945M SNP on the LEPR gene, and the Nt984+8(A-G) SNP on the DGAT1 gene. In addition, genetic variants of β-CN, κ-CN, and β-LG were determined. The results indicate that technological properties were influenced by the LEPR_T945M polymorphism, which had an association with gel strength, yield stress, and cheese hardness (T > C). However, also LEP_A252T was shown to affect gel strength (T > A), whereas the LEP_A59V had an effect on fat globule size (T > C). For the milk protein genes, favorable effects were found for the A and B variants of β-LG and κ-CN, respectively, on gel strength, gelation time, and yield stress. In addition, the B variant of κ-CN was shown to be associated with smaller CN micelles than the A variant. Thus, the results demonstrate potential genetic markers for cheese characteristics. However, milk composition traits also affected the obtained results, thus making it necessary to thoroughly assess the different aspects regarding the influence of gene effects on cheese characteristics before directly selecting for certain alleles or genetic variants to improve the processing and quality of cheese.     

Interrelations among physical characteristics,sensory perception and oral processing of protein-based soft-solid structures

Oral processing is essential in breaking down the physicochemical structure of the food and thus important to the sensory perception of food in the mouth. To have an understanding of protein-based, soft-solid texture perception, a multidisciplinary approach was applied that combined studies of food microstructure with mechanical properties, sensory evaluation, and oral physiology. Model foods were developed by combining ion-induced micro-phase separation and protein-polysaccharide phase separation and inversion. Activities of masseter, anterior temporalis and anterior digastric muscles during oral processing were recorded by electromyography (EMG), while jaw movement amplitudes, durations, and velocities were simultaneously collected by a three-dimensional jaw tracking system (JT-3D). Changes in the microstructure of mixed gels significantly altered the characteristics of the chewing sequence, including the muscle activities, number of chews, chewing duration and chewing frequency. Mechanical attributes related to structural breakdown and sensory perception of firmness were highly correlated with the amount of muscle activity required to transform the initial structure into a bolus ready for swallowing. Chewing frequency was linked to mechanical properties such as recoverable energy, fracture strain and water holding capacity of the gels. Increased adhesiveness and moisture release also resulted in slower chewing frequency. Evaluation of oral processing parameters at various stages (i.e., first cycle, first 5 cycles, and last 3 cycles) was found to be a useful method to investigate the dynamic nature of sensory perception at first bite, during chewing and after swallowing. The study showed that muscle activity and jaw movement can be used to understand the links between physical properties of foods and sensory texture.     

The effect of binary cosolvent systems (glycerol–sucrose mixtures) on the heat-induced gelation mechanism of bovine serum albumin

The influence of cosolvent composition on the thermal denaturation and gelation of bovine serum albumin (BSA) has been studied. Cosolvent composition was varied by changing the ratio of glycerol to sucrose in 40 wt% cosolvent solutions containing BSA. Differential scanning calorimetry measurements on 0.5 wt% BSA solutions showed that the thermal denaturation temperature of the protein increased with increasing sucrose content. Temperature scanning dynamic shear rheology and turbidity measurements on 4 wt% BSA solutions showed that the gelation temperature and final gel strength increased with increasing sucrose concentration. These observations were attributed to the fact that sucrose was more effective than glycerol at increasing the thermal stability and attraction between globular BSA molecules through a steric exclusion effect. The molecular origin of these effects is the tendency for the system to minimize the contact area of the protein molecules with the surrounding cosolvent solution.     

Influence of calcium fortification on sensory, physical and rheological characteristics of fruit yogurt

There has been great demand of calcium fortified dairy products as they can serve as an ideal vehicle for carrying extra calcium to fulfill the nutritional needs but there is need to generate information on the effect of fortification of calcium on the physical properties of these products. In the present study, the calcium enriched mango yogurt was prepared after fortification of pasteurized yogurt mix with 50 mg Ca/100 ml of calcium lactate, this level selected from a preliminary study of sensory evaluation. Fortification of yogurt with calcium lactate at this level significantly (P<0.005) increased the water holding capacity (WHC) by 2.99% on 1st day of storage. WHC of calcium fortified fruit yogurt was higher than control fruit yogurt on 7th and 14th day of storage. Measurements performed on slowly stirred samples (flow curves and final apparent viscosity) showed that calcium-enriched fruit yogurt had stronger structures. Calcium fortified fruit yogurt showed less shear thinning behavior as compared to control. Also, apparent viscosity measurements at constant shear rate showed a significantly (P<0.05) less decrease in initial apparent viscosity in calcium fortified fruit yogurt. However, no statistically significant (P>0.05) difference was observed in tan δ values of control and calcium fortified fruit yogurt indicating similar nature of bonds involved in the gel structure formation of both the yogurt samples. The more firm structure of the calcium fortified fruit yogurt is thus attributed to the higher extent of colloidal calcium phosphate cross-linking between casein micelles due to increased calcium content by fortification. Also flavor, color, and body and texture scores of control and calcium fortified fruit yogurt did not show any significant difference (P>0.05).     

The sensory attributes of cakes containing large numbers of low sugar raisins, as evaluated by consumers and a trained sensory panel

The sensory attributes of cakes, containing a greater number of low sugar raisins (LSR) than that normally used, were evaluated by two different groups of trained and untrained panellists. The purpose of this sensory evaluation was to find out whether such bakery products were more attractive to consumers than normal cakes and could be further promoted in the market. Cakes containing LSR and additional lemon peel scored more poorly than cakes containing only raisins, both in terms of taste and overall preference. Cakes containing only LSR had good sensory characteristics and could be considered as competitive products when compared with similar products already on the market. Young people found cakes with raisins tasty, but they did not consume them readily. The special advantages of these cakes are their natural ingredients, raisins with lower amount of sugars, good taste and high quality, all of which should be emphasized to make them attractive in the market.     

Formulation,process conditions,and biological evaluation of dairy mixed gels containing fava bean and milk proteins: Effect on protein retention in growing young rats

Food formulation and process conditions can indirectly influence AA digestibility and bioavailability. Here we investigated the effects of formulation and process conditions used in the manufacture of novel blended dairy gels (called “mixed gels” here) containing fava bean (Vicia faba) globular proteins on both protein composition and metabolism when given to young rats. Three mixed dairy gels containing casein micelles and fava bean proteins were produced either by chemical acidification (A) with glucono-δ-lactone (GDL) or by lactic acid fermentation. Fermented gels containing casein and fava bean proteins were produced without (F) or with (FW) whey proteins. The AA composition of mixed gels was evaluated. The electrophoretic patterns of mixed protein gels analyzed by densitometry evidenced heat denaturation and aggregation via disulfide bonds of fava bean 11S legumin that could aggregate upon heating of the mixtures before gelation. Moreover, fermented gels showed no particular protein proteolysis compared with gel obtained by GDL-induced acidification. Kinetics of acidification were also evaluated. The pH decreased rapidly during gelation of GDL-induced acid gel compared with fermented gel. Freeze-dried F, A, and FW mixed gels were then fed to 30 young (1 mo old) male Wistar rats for 21 d (n = 10/diet). Fermented mixed gels significantly increased protein efficiency ratio (+58%) and lean mass (+26%), particularly muscle mass (+9%), and muscle protein content (+15%) compared with GDL-induced acid gel. Furthermore, F and FW formulas led to significantly higher apparent digestibility and true digestibility (+7%) than A formula. Blending fava bean, casein, and whey proteins in the fermented gel FW resulted in 10% higher leucine content and significantly higher protein retention in young rats (+7% and +28%) than the F and A mixed gels, respectively. Based on protein gain in young rats, the fermented fava bean, casein, and whey mixed proteins gel was the most promising candidate for further development of mixed protein gels with enhanced nutritional benefits.     

Simultaneous determination of aspartame,cyclamate, saccharin and acesulfame-K in soft drinks and tabletop sweetener formulations by capillary electrophoresis with capacitively coupled contactless conductivity detection

Capillary electrophoresis (CE) with capacitively coupled contactless conductivity detection (C⁴D) was used for simple, rapid, and simultaneous determination of aspartame, cyclamate, saccharin and acesulfame-K in commercial samples of soft drinks and tabletop sweetener formulations. A buffer solution containing 100 mmol L⁻¹ tris(hydroxymethyl)aminomethane (TRIS) and 10 mmol L⁻¹ histidine (His) was used as background electrolyte (BGE). A complete separation of the analytes could be attained in less than 6 min. The limits of detection (LOD) and quantification (LOQ) were considered better than those usually obtained by CE with photometric detection. Recoveries ranging from 94% to 108% were obtained for samples spiked with standard solutions of the sweeteners. The relative standard deviation (RSD) for the analysis of the samples with the CE-C⁴D method varied in the range of 1.5%–6.5%.     

An enzyme‐based method for the rapid determination of sucrose,glucose and fructose in sugar beet roots and the effects of impact damage and postharvest storage in clamps

A high‐throughput enzyme‐coupled assay is described for the determination of sucrose, glucose and fructose in sugar beet roots. This method is sensitive, rapid and inexpensive and has been used to highlight the increases in sucrose loss following root stresses such as freezing or aggressive harvesting. Sugar beet roots lose 12.5% of their sucrose following an episode of impact damage greater than 2 J, rising to 19.7% loss after 8 J, with concurrent increases in glucose and fructose. Increases in glucose and fructose are particularly pronounced following a period of clamp storage (up to 2.3 and 3.3 µg mg^?1 fresh weight, respectively). © 2001 Society of Chemical Industry     

Effect of Dioscorea opposita Thunb. (yam) supplementation on physicochemical and sensory characteristics of yogurt

A study was conducted to examine the physicochemical, microbial, and sensory properties of yogurt made by supplementing powdered yam Dioscorea opposita Thunb. (YPT) at different concentrations (0.2, 0.4, 0.6, and 0.8%, wt/vol) into milk, which was pasteurized and then fermented at 43°C for 6 h and stored for 16 d. The pH values of all samples decreased, whereas viscosity values and mean microbial counts increased during storage. The L* and a* color values (indicators of lightness and redness, respectively) of yogurt samples were not remarkably influenced by adding YPT, whereas the b* values (indicating yellowness) significantly increased with the addition of YPT at all concentrations at 0 d of storage, probably due to the original yellow color of yam powder. In functional component analyses, when the concentration of YPT increased, the amount of allantoin and diosgenin proportionally increased. The content of allantoin was 3.22 and diosgenin 4.69 μg/mL when 0.2% (wt/vol) YPT was supplemented and did not change quantitatively during the storage period (16 d). The sensory test revealed that the overall acceptability scores of YPT-supplemented yogurt samples (0.2 to 0.6%, wt/vol) were quite similar to those of the control throughout the storage period of 16 d. Based on the data obtained from the present study, it was concluded that the concentrations (0.2 to 0.6%, wt/vol) of YPT could be used to produce YPT-supplemented yogurt without significant adverse effects on physicochemical, microbial, and sensory properties, and enhance functional components from the supplementation.