Instrumental Textural and Rheological Properties of Raw,Dried, and Cooked Noodles with Transglutaminase

Textural and rheological properties of raw, dried, and cooked noodles with microbial transglutaminase were evaluated by an instrumental texture analyser. Generally, the strength of the noodles significantly increased with microbial transglutaminase concentration from 0 to 1.0%. The cutting force of raw noodle is a good indicator to predict the strength of dried and cooked noodle products. Mechanical stress relaxation data of cooked noodles were fitted well by both Maxwell and Peleg-Normand models. The fitted parameters, λ₁ and k₂, were more sensitive to the changes in viscoelastic properties than k₁ and %SR. Significant correlations were found between textural characteristics and stress relaxation parameters. Results of this study suggest that dried or cooked noodle with good quality can be produced by incubating with 0.5–1.0% microbial transglutaminase for 30 min at 30?°C.     

Instrumental Textural Perception of Food and Comparative Biomaterials

Exposing an extruded corn snack, an extruded biodegradable packing material, carrots, and wood chip cork to relative humidity conditions ranging from 29.5 to 97.5% changed their moisture content and affected the respective internal structures. The extruded corn snack and extruded biodegradable packing material specimens evaluated after 24 h, absorbed moisture and lost crispness. Carrot and cork specimens were evaluated after 48 h; carrots lost moisture, became softer, and decreased in hardness from 55.02 ± 7.59 to 23.6 ± 8.6 N, while cork specimens were unchanged. For all products, loss of moisture increased surface roughness. Increasing moisture amplified turgidity and strength in extruded biodegradable packing material, decreased crispness in extruded corn snack, and stiffness in carrot, but produced no changes in the wood chip cork.     

Varietal Comparison of The Chemical,Physical, and Mechanical Properties of Five Colored Table Grapes

The visual attributes of table grapes, their chemical constituents, and mechanical properties are involved in consumer acceptability because they are correlated to sensory perception. Usually, instrumental measurements are preferred to the sensory evaluations because they reduce variations in subjective judgments and can be carried out more easily. In this work, chemical-physical attributes and texture properties of five black table grapes (Alphonse Lavallée, Black magic, Cardinal, Perlon, Regina nera) were studied in order to identify significant varietal differences. Spectrophotometric and HPLC methods and texture analysis test were used to evaluate color index, sugars and acid composition, phenolic characteristics, and mechanical properties of the skin and the pulp of berries. Many differences were found among varieties in technological maturity indexes, hydroxycinnamic acid, anthocyanin content and profile, and relative CIE L*, a*, b* parameters, but the more relevant differences were found in mechanical properties. Principal component analysis showed that the texture profile analysis parameters (hardness, cohesiveness, gumminess, and resilience) and berry skin characteristics (break skin energy, skin modulus of elasticy) were the best indices able to fulfill the aim of this work. Almost all of the parameters showed differences among cultivars, confirming their importance in the characterization of the variety as well as in the assessment of potential consumer acceptability. In particular, the cultivars demonstrated different reactions to the compression test; thus, the texture analysis parameters can be appropriate to explain varietal differences and to allow their differentiation.     

Rheological and Textural Properties of Pacific Whiting Surimi Gels As Influenced by Chicken Plasma

Rheological properties of Pacific whiting surimi, in the absence and presence of chicken plasma (CP) at different levels (0.3–3.0%, w/w), were studied by dynamic rheological (small strain) and torsion fracture measurements, respectively. The surimi paste exhibited two major distinctive rheological transitions during heating (1°C/min) from 20 to 90°C with peaks observed at 33 and 56°C. The abrupt loss of G′ upon heating from 47 to 57°C, and the occurrence of small peak of phase angle at the same temperature range were prevented by the addition of CP. Nevertheless, the final G′ of the surimi paste added with CP was lower than that of the control. But shear fracture stress of both kamaboko and modori gels increased as the CP levels increased and shear strain increased with the addition of CP up to 2% (P < 0.05). CP inhibited the degradation of myosin heavy chains (MHC) caused by endogenous proteinases as indicated by more retained MHC and lowered TCA-soluble peptide content. Whiteness of gels decreased somewhat with increasing CP levels. CP, thus, could be a helpful additive for improving gelling properties of Pacific whiting surimi     

Instrumental Textural Properties of Mango (cv Nam Doc Mai) at Commercial Harvesting Time

Mango fruit (Mangifera indica L., cv Nam Doc Mai number 4) of three different sizes, were evaluated for their instrumental texture properties, in accordance with the exporter requirements at commercial harvesting time. The size classification of mangoes was determined by the mass of the fruit. The large size weighed more than 351 g, the medium size 330–350 g, and the small size 260–329 g. The results of deformation at a force of 20 N, energy of absorption from a compression test and the average hardness from puncture tests varied for the different sizes. The large size showed firmer and more elastic in relation to the compression force, as well as the hardest and most rigid in response to the puncture force. The peel and flesh strengths of large, medium, and small sizes at the commercial harvesting date did not differ with bio-yield force, which indicated that the strength of the flesh under the peel was very close to the rupture force, which indicated the strength of peel. Examples of the applications of these properties for postharvest handling are described.     

Instrumental Textural Characteristics of Restructured Carrot Cubes

Studies were carried out on the instrumental textural evaluation of restructured carrot cubes. The experiment was conducted by incorporating different levels of alginate, glucono delta lactone (GDL), and calcium salt to the carrot pulp. Investigations showed that as pulp level increased from 0 to 90%, there was a corresponding decrease in failure stress, failure strain, and deformability modulus. Instrumental textural profile analysis (TPA) parameters viz. hardness, springiness, gumminess, cohesiveness, chewiness, and resilience also showed a similar trend. Effect of formulation variables, i.e., alginate, GDL, and calcium salt on hardness (response variable) were evaluated by the application of response surface methodology. All the three ingredients showed a significant (P < 0.05) influence on hardness of carrot gel. Heat treatment of restructured carrot samples resulted in an increased hardness, cohesiveness, gumminess, and chewiness while springiness, cohesiveness, and resilience decreased. The data indicated that the shrinkage during thermal treatment may be responsible for the change in textural attributes. The authors concluded that a thermally stable restructured product with appreciable textural integrity can be obtained from carrot pulp.     

Textural and Rheological Properties of Cooked Potatoes

Cooked potato samples of different cultivars and specific gravities were analyzed for textural and rheological properties by sensory evaluation, texture profile analysis (TPA) and stress relaxation tests. Mealiness was correlated with the product of cohesiveness and adhesiveness, but not with other TPA parameters. Stress relaxation tests of cooked potatoes yielded a Maxwell model consisting of two viscous and three elastic elements. One of the elastic moduli was correlated with mealiness. Hardness by sensory evaluation correlated well with hardness and fracturability by TPA, and with the three elastic moduli in the relaxation model.     

凝胶油基人造奶油质地和流变性能

凝胶油作为潜在的能够替代传统氢化奶油的新方法,具有低饱和脂肪酸和零反式脂肪酸的优势,所受关注 度越来越高。本实验以精炼大豆油为基料油,β-谷甾醇和卵磷脂等比例混合物作为复合凝胶剂,制备得到凝胶油基 人造奶油。主要研究了凝胶剂质量分数和水分体积分数对凝胶油基人造奶油质地、流变学性能、微观网络结构和结 晶度的影响。结果表明：当水分体积分数提高时,能够在更低的凝胶剂质量分数下形成均相人造奶油体系;随着凝 胶剂质量分数和水分体积分数的增加,人造奶油的硬度和弹性增大;样品网络结构和结晶度的分析结果表明,随着 凝胶剂质量分数和水分体积分数的增加,人造奶油的结晶度增加,微观三维网络结构更加完整,油-水两相接触面 积变大,最终使得人造奶油体系结构更加均匀和稳定,硬度和弹性也更大。     

Trans Fatty Acid Contents in Selected Dietary Fats in the Estonian Market

In response to public concern, this study assessed the fatty acid (FA) composition of blended spreads, margarines and shortenings in the Estonian retail market in 2011. Special attention was paid to the trans fatty acids (TFA) composition. The changes in these characteristics of selected dietary fats in the market over recent years are also presented. Twenty-six edible fat brands, available in the Estonian retail market in 2011, were purchased and FA compositions were analyzed by chromatography. Saturated fatty acids (SFA) were the dominant group of FAs for all blended spreads (49.6 to 65.8%), and for the majority of shortenings (from 21.1 to 54.6%). Cis monounsaturated fatty acids (MUFA) were the dominant group of FAs for the majority of margarines, ranging from 25.3% to 50.5%. The total TFA for blended spreads varied from 1.18% to 9.08%, for margarines from 0.04% to 34.96% and for shortenings from 0.14% to 39.50%. Octadecenoic (C18:1) isomers were the main TFA found. Compared to 2008/2009, the industrially produced TFA (IP-TFA) content in several of the dietary fat brands was much reduced in 2011. This voluntary reformulation was probably a response to consumer demand associated with a public health campaign directed against IP-TFA in Estonian foods, and were mainly achieved by replacing TFA with SFA C12:0-C16:0. Practical Application: Present paper is directed toward public health related institutions and food industries producing foods with potentially high contents of trans fatty acids (TFA). According to the public concern TFA content in domestic blended spreads has declined significantly over the past 3 y in Estonia. The reduction in the TFA content was achieved by replacing TFA with saturated fatty acids (SFA) (C12:0-C16:0). To shift food composition toward healthier product formulations, mandatory labeling of the sum of IP-TFA and SFA (C12:0-C16:0) was recommended.     

Rheological, textural and spectral characteristics of sorbitol substituted mango jam

Full replacement of sucrose with sorbitol is feasible in mango jam manufacturing. Dynamic rheological tests characterized mango jam manufactured with sucrose/sorbitol as a weak gel. Mango jam did not follow Cox-Merz or modified Cox-Merz rule. The storage- and loss- moduli increased with sucrose concentration up to 60%, but decreased at higher sucrose concentrations. Gel strength decreased with increasing sorbitol concentration because of weaker junction zones in pectin gel network. FTIR spectra revealed that C-O and C-C stretching vibrations are indicators of the gel strength because pectin polymeric chain network formation in fruit jam is due to hydrogen bonding and hydrophobic interactions.     

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.     

大豆分离蛋白流变学特性的研究

大豆分离蛋白是以低变性脱脂大豆粉或浓缩大豆蛋白为原料，经碱、酸等一系列处理后得到的组分较均一、机能特性较强的蛋白质。大豆分离蛋白的等电点在ｐＨ４．２～５．６范围内。在该范围内大豆分离蛋白的溶解性、粘度、起泡性及泡沫稳定性、乳化性及持水性最弱；在该范围的两侧，随酸度或碱度增加，这些特性逐渐增强。大豆分离蛋白的粘度随浓度增加而增大，数学模型为ｙ＝１．１０３ｅ~（０．６０２８ｘ）＋１．０６，表现为非牛顿假塑性流体。     

The Effect of Cooking Water Composition on Textural and Cooking Properties of Spaghetti

The effect of cooking water on both textural and cooking properties of spaghetti was investigated for spaghetti samples, which differ in protein content. The samples were analysed after cooking in deionised, laboratory tap water, deionised water with 2.5% salt and deionised water with 5.0% salt. Brands A, B, and C were usual durum wheat spaghetti and brand D was spaghetti enriched with bran. Regardless of the cooking water used, brand D had higher hardness and lower adhesiveness than other spaghetti samples and required longer cooking time to achieve optimum cooking. It was found that samples cooked deionised water had lower hardness and adhesiveness values as compared to samples cooked in salty water. It can be concluded that a certain amount of salt in the cooking water improves textural characteristics of cooked pasta.     

Rheological,textural, micro-structural and sensory properties of mango jam

Mango jam behaved as pseudoplastic fluid exhibiting yield stress. The Herschel–Bulkley (HB) model described adequately the steady-state rheological behavior of jam. Temperature dependence of the consistency index followed Arrhenius relationship. Time dependent structural breakdown characteristics of mango jam followed Hahn model. Hardness of mango jam increased with pectin concentration and acidity. Hardness increased up to 60% sugar concentration but decreased with further increase in sugar concentration at all pH and pectin levels. Stickiness, work of shear, and adhesion did not show any systematic trend with pH, pectin, and sugar concentration. The overall acceptability was rated highest for mango jam prepared with 65% sugar, 1% pectin at pH 3.4. Principal component analysis (PCA) revealed that hardness and work of shear are the most relevant among all the characteristics (physicochemical, sensory, textural, rheological, and compositional) studied for mango jam. Microstructure of mango jam was found to be composed of network regions with large pores as well as dense, compact regions with small pores.     

Rheological, textural and melting properties of commercial samples of some of the different types of pasteurized processed cheese

The detailed rheological and textural properties of commercially available samples of the three major categories of pasteurized processed cheese in the USA, that is, pasteurized process American cheese (PPA), pasteurized process cheese product (PPP) and pasteurized process cheese food (PPF), were analysed. All samples had similar pH values, ranging from 5.65 to 5.87, but most were ∼5.7. Even within each of the categories considerable differences were observed in textural and melting behaviour. The samples with the lowest melt and the lowest loss tangent parameter from the rheological tests were two PPF and one PPA samples. These two PPF samples also had the highest hardness and adhesiveness force. Significant correlations were observed between several textural, rheological and melting properties.     

Rheological and textural properties of sorghum-based formulations modified with variable amounts of native or pregelatinised cassava starch

Sorghum bread was made from native or pregelatinised cassava starch and sorghum flour in the ratio 10:90, 20:80, 30:70, 40:60 and 50:50. The other ingredients, measured on flour-weight-basis, were water (100%), sugar (6.7%), egg white (6%), fat (2%), salt (1.7%) and yeast (1.5%). The dynamic oscillatory behaviours of the batters were affected by the amount and type of starch. In the amplitude sweep measurements, increasing concentration of native starch decreased storage modulus, whereas increasing concentration of pregelatinised starch increased the linear viscoelastic range of the batters. In the frequency sweep measurements, the loss factor of batters treated with native starch declined with increasing frequency. Batters treated with 10 or 20% pregelatinised starch showed declining loss factors, whereas batters treated with 40 or 50% pregelatinised starch showed increasing loss factors with increasing frequency. Sorghum-based batters containing native starch gave bread with better crumb properties than batters containing pregelatinised starch. Crumb firmness and chewiness declined with increasing native or pregelatinised starch concentration. Crumb adhesiveness of breads containing pregelatinised starch increased with increasing starch content but was not affected by native starch. Cohesiveness, springiness and resilience increased with increasing native starch content, but were minimally affected by increasing pregelatinised starch content.     

Rheological Properties of Cabbage Pulp

The rheological behavior of cabbage pulp was determined using a computer controlled rotational rheometer at a temperature range of 20, 30, 40, and 50°C. The flow behavior of pulp was pseudoplastic and fitted well to the Casson model. In all the cases, the effect of soluble solids on apparent viscosity was more pronounced than the effect of temperature. The combined effect of temperature and soluble solid content on viscosity was also given. The activation energy value of 3–6°Brix cabbage puree varied from 7 to 12.6 kJ/mol when shear rate increased from 1 to 10 s^?1. The exponential model developed had an excellent fit (r² > 0.87) and would be useful for the engineering applications.     

Instrumental Textural Properties of Mesir Paste Kept at Different Temperatures

Traditional mesir paste bar samples were kept at different temperatures (4 ± 1°C, 20 ± 1°C, or 30 ± 1°C) and their textural properties were determined by conducting instrumental texture profile analysis. Total sugar content of mesir was 85 g/100 g sample, whereas the inverted sugar amount was 79 g/100 g. Saccharose content of mesir was 10 g/100 g. It was determined that temperature significantly affected the textural attributes of mesir paste samples (P < 0.05). Hardness of mesir paste kept in a refrigerator was 2241 N, whereas it was 273 N and 8.24 N for the samples kept at ambient temperature and 30 ± 1°C, respectively.