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1.
Raman spectroscopy, texture, proximate composition, and water binding analysis were carried out to evaluate the effect of thermal treatment and/or salt addition to meat batter. For this purpose, different meat batters were elaborated: control meat batter (no salt) and meat batters with low (1.0%) and high (2.5%) NaCl content with and without thermal treatment (70 degrees C/30 min). Increase (P < 0.05) in penetration force and hardness upon heating was observed. Results also showed hardness increasing (P < 0.05) as a function of salt addition in heated meat batter. Raman spectroscopy analysis revealed a significant (P < 0.05) decrease in alpha-helix content accompanied by an increase (P < 0.05) in beta-sheets resulting from heating. Significant (P < 0.05) correlations were found between these secondary structural changes in meat proteins and water binding and textural properties of meat batter. In this way, a significant correlation was found between beta-sheets, salt content, hardness, and chewiness in heated samples.  相似文献   

2.
油脂预乳化提高大豆拉丝蛋白素食香肠品质   总被引：2，自引：2，他引：0  
为了提高大豆拉丝蛋白(Textured Fibril Soy Protein,TFSP)素食香肠的品质,该研究将油脂预乳化工艺应用于TFSP素食香肠的加工,利用响应面试验设计优化了预乳化工艺条件,采用质构分析仪测定分析了产品的质构特性,并进行了感官评价。结果表明优化后的最佳预乳化工艺条件为菜籽油含量445g/L、大豆分离蛋白浓度105g/L、乳化机剪切速率9.0×103r/min。与对照组相比,此条件下制作的预乳化-TFSP素食香肠的凝胶强度、硬度和咀嚼性分别提高了约1倍、10%和26%,且产品口感鲜嫩、富有汁液感,感官评价得分显著提高。采用激光共聚焦显微镜观察分析了不同工艺制作的TFSP素食香肠在煮制前后微观结构的变化,结果发现油脂预乳化工艺可大大提高乳化油脂的稳定性和在香肠凝胶基质中的均匀分布,从而使乳化油脂的‘填充作用’得以发挥,不仅增强了TFSP素食香肠的保水保油能力,降低了蒸煮损失率,而且对香肠的质构和感官特性产生了重要影响。因此油脂预乳化工艺是一种辅助提高素食香肠整体品质行之有效的方法。  相似文献   

3.
Eleven rice genotypes with diverse Rapid Visco Analyzer (RVA) pasting characteristics were evaluated for their physicochemical and gel textural characteristics relative to their suitability for making rice noodles. Apparent amylose content (AC) was highly correlated with swelling power (r = -0.65, P < 0.05), flour swelling volume (FSV) (r = -0.67, P < 0.05), noodle hardness (r = 0.74, P < 0.01), gumminess (r = 0.82, P < 0.01), chewiness (r = 0.74, P < 0.01), and tensile strength (r = 0.72, P < 0.05). Solubility showed an inverse relationship with the pasting parameters and noodle rehydration, and a positive relationship with cooking loss, noodle hardness, and gumminess. FSV and most of the pasting parameters were negatively correlated with noodle hardness. RVA parameters and textural parameters of gels formed in the RVA canister were well correlated with actual noodle texture and may, therefore, be used for predicting rice noodle quality during early screening of genotypes in breeding programs.  相似文献   

4.
Certain physicochemical properties, including chemical composition, pasting, thermal parameters, and the gel texture of flour prepared from six cultivars of Thai rice with similar high‐amylose content were determined. These properties were correlated with the quality of vermicelli prepared from these flours for cooking and textural properties. Flour prepared from a Thai rice cultivar currently used for commercial production of vermicelli served as reference for these comparisons. Many similarities, but some significant differences, in the physicochemical properties were observed between the test rice flours and to the reference cultivar. Vermicelli prepared from all of the test rice flours were within an acceptable range for cooking quality but showed greater variation in textural quality. Among the physicochemical properties, gel hardness was well correlated with cooking and textural quality of vermicelli, and was useful for predicting overall vermicelli quality.  相似文献   

5.
研究比较了旱地苹果专用肥与化肥、农家肥对果园土壤理化性质、果实产量及品质的影响,在10年生红富士果园设置不覆膜+化肥(CK)、不覆膜+农家肥(T1)、不覆膜+苹果专用肥(T2)、覆膜+化肥(FCK)、覆膜+农家肥(FT1)、覆膜+苹果专用肥(FT2)6个处理。结果表明:在未覆膜条件下,与CK相比,T1和T2处理均降低了土壤容重,增加了土壤贮水量,但两者间差异不显著;T1和T2处理显著提高了土壤有机质含量,在0~20 cm土层较CK处理分别提高36.77%和33.73%;T2处理提高了土壤中速效养分含量,其0~60 cm土层碱解氮、有效磷、速效钾平均含量分别较CK提高7.34%、9.05%、5.90%;各施肥处理苹果年均产量顺序为T2CK≥T1,T2处理的果实硬度(7.19 kg·cm-2)和糖酸比(33.23)均最高。与未覆膜相比,覆膜条件下,各处理(FCK、FT1、FT2)土壤容重均有所降低,土壤贮水量、有机质、速效养分、果实产量和品质均得到提高,以FT2处理整体效果最好。综合分析表明,施用苹果专用肥提高了果实产量和品质,改善了土壤肥力,是果园简便高效的施肥技术。  相似文献   

6.
为了探究稳定剂对蛋白液鸡蛋干质构特性的影响,以蛋白液为主要原料制作鸡蛋干,分析不同加水量、NaCl添加量以及不同种类稳定剂及添加量对鸡蛋干感官评分、硬度、胶着性、咀嚼性、弹性、粘聚性、回复性等参数的影响。结果表明,鸡蛋干的感官评分和质构参数随着水、NaCl的添加量变化而发生明显改变,在加水量12%、加盐量1.5%的条件下,鸡蛋干的品质相对较好。与不添加稳定剂的对照组(CK)相比,单独添加复合磷酸盐、谷氨酰胺转氨酶(TG酶)、瓜尔豆胶、结冷胶的试验组的鸡蛋干感官评分均提高,质构同样得到不同程度的改善。上述稳定剂的各自最佳添加量分别为:复合磷酸盐0.20%、TG酶0.25%、瓜尔豆胶0.25%、结冷胶0.10%。本研究结果为改进蛋白液鸡蛋干的加工配方,有效提升蛋白液鸡蛋干的感官品质和质构特性提供了一定的技术指导。  相似文献   

7.
Origin of multiexponential T(2) relaxation in muscle myowater.   总被引：5，自引：0，他引：5  
To obtain a further understanding of the nature of the multiexponential T(2) relaxation seen in muscle tissue water (myowater), relaxation measurements were carried out on whole, minced, and homogenized pork of three different qualities with regard to water-holding capacity (normal, red soft exudative, and dark firm dry). Whole, minced, and homogenized pork all resulted in multiexponential T(2) relaxation (three components) independently of the quality, even though microscopic studies on homogenized meat revealed considerable disruption of the macroscopic structure. This states that the relaxation behavior in meat cannot be explained by intra-/extracellular compartmentalization of the water as suggested in earlier studies. Subsequent studies of T(2) relaxation in either whole meat, where the structure integrity was changed by the introduction of dimethyl sulfoxide (membrane disruption) or urea (protein denaturation), or minced meat with added NaCl (inter-/intraprotein interactions) lead to the suggestion that in whole meat (i) the fastest relaxation component reflects water tightly associated with macromolecules, (ii) the intermediate relaxation component reflects water located within highly organized protein structures, for example, water in tertiary and/or quaternary protein structures and spatials with high myofibrillar protein densities including actin and myosin filament structures, and (iii) the slowest relaxation component reflects the extra-myofibrillar water containing the sarcoplasmatic protein fraction. Finally, relaxation patterns in heat-set gels of superprecipitated actomyosin and bovine serum albumin similar to that identified in whole meat support the proposed nature of T(2) relaxation in muscle myowater.  相似文献   

8.
Nuclear magnetic resonance (NMR) measurements were carried out on pork longissimus muscle, which pre rigor had been manipulated to various muscle lengths, to investigate the relationship between the microstructure of meat and the NMR T(2) relaxation. Distributed exponential analysis of the NMR T(2) relaxation data revealed the existence of three distinct water populations: T(2b), T(21), and T(22). A high, significant correlation was found between the T(21) time constant and the sarcomere length (r = 0.84) and calculated ration of myofilament lattice volume in the I-band and A-band regions, respectively (r = 0.84), considering sigmoid relationships. The result implies that the T(21) time constant mainly is determined by the structure of the myofilament lattice and so strongly supports a previously proposed theory that the T(21) population corresponds to water located within a highly organized myofibrillar protein matrix including actin and myosin filament structures. A high correlation was also found between the T(22) population and the water-holding capacity (WHC) (r = 0.76), which suggests that the WHC is mainly determined by the amount of loosely bound extramyofibrillar water. However, the correlation between NMR T(2) parameters and WHC was further increased (r = 0.84) by including the T(21) time constant in the correlation analysis. This implies that the formation of drip loss is an ongoing process involving the transfer of water from myofibrils to the extracellular space and is affected by structural features at several levels of organization within the muscle tissue. This study demonstrates the advantages of NMR T(2) relaxation as an effective technique for obtaining further understanding of the relationship between the microstructure of meat, its WHC, water mobility, and water distribution.  相似文献   

9.
Fourier transform infrared (FT-IR) microspectroscopy and low-field (LF) proton NMR transverse relaxation measurements were used to study the changes in protein secondary structure and water distribution as a consequence of aging (1 day and 14 days) followed by salting (3%, 6%, and 9% NaCl) and cooking (65 degrees C). An enhanced water uptake and increased proton NMR relaxation times after salting were observed in aged meat (14 days) compared with nonaged meat (1 day). FT-IR bands revealed that salting induced an increase in native beta-sheet structure while aging triggered an increase in native alpha-helical structure before cooking, which could explain the effects of aging and salting on water distribution and water uptake. Moreover, the decrease in T2 relaxation times and loss of water upon cooking were attributed to an increase in aggregated beta-sheet structures and a simultaneous decrease in native protein structures. Finally, aging increased the cooking loss and subsequently decreased the final yield, which corresponded to a further decrease in T2 relaxation times in aged meat upon cooking. However, salting weakened the effect of aging on the final yield, which is consistent with the increased T2 relaxation times upon salting for aged meat after cooking and the weaker effect of aging on protein secondary structural changes for samples treated with high salt concentration. The present study reveals that changes in water distribution during aging, salting, and cooking are not only due to the accepted causal connection, i.e., proteolytic degradation of myofibrillar structures, change in electrostatic repulsion, and dissolution and denaturation of proteins, but also dynamic changes in specific protein secondary structures.  相似文献   

10.
胡萝卜复合火腿和香肠的质构特性及显微结构(简报)   总被引：3，自引：0，他引：3  
为探索蔬菜复合肉制品品质特性的评价方法,分别用物性分析仪和扫描电镜研究了胡萝卜复合火腿和香肠的质构特性和显微结构。质构测定结果表明:与对照组相比,HLB-1复合火腿(鲜胡萝卜25%)和HLB-2复合火腿(胡萝卜粉2.5%)的硬度分别降低了70.94%和57.23%,咀嚼度分别降低了64.81%和34.86%;与对照组比较,胡萝卜复合香肠(鲜胡萝卜25%)的硬度和咀嚼度分别降低了30.84%和51.30%。感官评定结果表明:与对照组比较,胡萝卜复合火腿和香肠的口感更柔和细腻、嫩度更好。通过扫描电镜对产品结构的观察表明:在添加了鲜胡萝卜的火腿和香肠中均发现了圆形光滑的小颗粒状物质,复合肉制品内部的细微结构均匀、结构比较膨松,这在一定程度上解释了胡萝卜复合火腿和香肠的感官和质构特征。  相似文献   

11.
为了探究酶制剂对非发酵面团在冻融循环后的品质的影响,该文比较了2种酶制剂转谷氨酰胺酶(TGase)与木聚糖酶(xylanase)对非发酵面团冻融品质的改良效果。结果表明,与对照组相比,添加转谷氨酰胺酶和木聚糖酶均能改变冻融后面团蛋白各组分的含量。添加转谷氨酰胺酶使醇溶蛋白以及谷蛋白含量显著下降(P0.05)、谷蛋白大聚合体含量有所上升。添加木聚糖酶则使醇溶蛋白含量上升,使谷蛋白含量显著降低(P0.05)。转谷氨酰胺酶对面团中戊聚糖含量影响不显著(P0.05),而添加木聚糖酶使面团中可溶性戊聚糖含量显著上升(P0.05)。转谷氨酰胺酶的添加加速了冻融循环后非发酵面团的失水,木聚糖酶则显著降低了其失水率(P0.05)。除在10 g/kg转谷氨酰胺酶显著降至1.32 ms外,弛豫时间T2(1)基本维持在1.75 ms,而弛豫时间T2(2)均有所减小;添加转谷氨酰胺酶后,深层结合水相对含量呈逐渐上升趋势;而木聚糖酶则反之。木聚糖酶使冻融面团强韧性与对照组相比显著增强(P0.05),剪切力小幅下降,硬度显著下降(P0.05);与转谷氨酰胺酶相比,木聚糖酶更能缓解冻融面团的质构劣变;转谷氨酰胺酶改善冻融熟面坯的黏性、弹性与内聚性,木聚糖酶则改善"硬度上升,弹性下降"的劣变现象。在改善冻融面团流变特性方面,转谷氨酰胺酶效果更为显著(P0.05)。因此,添加转谷氨酰胺酶与木聚糖酶均能在一定程度上改善冷冻非发酵面团在冻融条件下的品质劣变,但它们的作用方面有所差异。研究结果为两者能够在冷冻非发酵面制品中被广泛地应用提供理论基础。  相似文献   

12.
The effect of arabic gum (AG) and xanthan gum (XG) on the physicochemical properties of 2% pesticide avermyctin in water emulsions was systematically investigated by measuring creaming stability, droplet size, zeta potential, and rheology. Addition of AG and XG had significant influence on the physicochemical properties of emulsions. Emulsions showed high stability throughout the storage time in the AG concentration range of 0-0.14%. In contrast, addition of XG induced the apparent creaming of emulsion as the XG concentration increased from 0.011 to 0.15%, which might be well explained by the depletion flocculation of droplets. The droplet diameter increased progressively with increasing AG concentration; however, it sharply grew initially with XG concentration and reached a maximum, followed by a gradual decrease. Zeta potential increased gradually as AG concentration was lower than 0.081%, followed by a slight decrease, whereas it reduced dramatically as XG concentration increased from 0.011 to 0.040% and then remained almost unchanged. In the AG concentration range of 0-0.14%, the emulsion exhibited typical Newtonian flow behavior and the viscosity decreased a little. The XG emulsion exhibited Newtonian flow behavior at low XG concentrations (≤0.019%), whereas, non-Newtonian flow behavior was displayed at relatively high XG concentrations (>0.019%), wherein viscosity value and yield value increased gradually as XG concentration increased. In addition, the curves of shear stress versus shear rate for XG emulsion and solution were well fitted by a power law model and the Herschel-Bulkley model; the Herschel-Bulkley model fitted much better. The present study would provide useful information for the reasonable application of AG and XG in making stable pesticide emulsion.  相似文献   

13.
Furundu, a meat substitute, is traditionally prepared by cooking the karkade (Hibiscus sabdariffa L.) seed and then fermenting it for 9 days. Physicochemical and functional properties of raw and cooked seed and of furundu ferments were analyzed. Furundu preparation resulted in significant changes in karkade seed major nutrients. Total polyphenols and phytic acid were also reduced. The increase in total acidity and fat acidity coupled with a decrease in pH indicates microbial hydrolysis of the major nutrients; proteins, carbohydrates, and fats. In vitro digestibility of the seed proteins reached the maximum value (82.7%) at the sixth day of fermentation, but thereafter it significantly decreased. The effect of furundu preparation on N solubility profiles and functional properties, such as emulsification and foaming properties and other related parameters, is investigated in water and in 1 M NaCl extracts from defatted flour samples. The results show that cooking followed by fermentation affects proteins solubility in water and 1 M NaCl. The foaming capacity (FC) from the flour of raw seed decreased as a result of cooking. Fermentation for 9 days significantly increased the FC of the cooked seed, restoring the inherent value. Foam from fermented samples collapsed more rapidly during a period of 120 min as compared to the foam from raw and cooked karkade seeds; stability in 1 M NaCl was lower as compared to those in water. In water, the emulsion stability (ES) from the fermented samples was significantly higher than that of the raw seed flour. Addition of 1 M NaCl significantly decreased the ES of the fermented samples.  相似文献   

14.
The effects of addition of alpha-casein (alpha-CN) to dried egg white (DEW) were investigated by measuring transparency, hardness, and water-holding capacity (WHC) of the heat-induced gels. A DEW concentration of 8% (w/w) was required for formation of a self-supporting gel following heating at 80 degrees C for 20 min at pH 7. Solutions of alpha-CN, even up to a protein concentration of 12% (w/w), did not gel under the same conditions. The addition of alpha-CN (0.5-4%) to 8% DEW caused the increase in gel hardness gels, as compared with DEW gels alone at a total amount of protein concentrations, and the mixed gels became transparent with the increase of added alpha-CN concentrations. The 10% mixed protein solutions of alpha-CN (3-6%) and DEW (4-7%) formed transparent gels, although each protein did not gel individually at their protein concentrations. Mixture with 2:8 mixing ratio of alpha-CN to DEW at a total protein concentration of 10% showed synergistic effects in improving DEW gel properties above pH 7 and below 25 mM NaCl. The improvements (hardness, transparency, and WHC) of DEW gel by alpha-CN seem to be caused mainly by the inhibition of alpha-CN against heat coagulation of DEW protein.  相似文献   

15.
This study introduces the use of combined 23Na magnetic resonance imaging (MRI) and 23Na NMR relaxometry for the study of meat curing. The diffusion of sodium ions into the meat was measured using 23Na MRI on a 1 kg meat sample brined in 10% w/w NaCl for 3-100 h. Calculations revealed a diffusion coefficient of 1 x 10(-5) cm2/s after 3 h of curing and subsequently decreasing to 8 x 10(-6) cm2/s at longer curing times, suggesting that changes occur in the microscopic structure of the meat during curing. The microscopic mobility and distribution of sodium was measured using 23Na relaxometry. Two sodium populations were observed, and with increasing length of curing time the relaxation times of these changed, reflecting a salt-induced swelling and increase in myofibrillar pore sizes. Accordingly, the present study demonstrated that pore size and thereby salt-induced swelling in meat can be assessed using 23Na relaxometry.  相似文献   

16.
The effects of Trichoderma reesei tyrosinase-catalyzed cross-linking of isolated chicken breast myofibril proteins as a simplified model system were studied with special emphasis on the thermal stability and gel formation of myofibrillar proteins. In addition, tyrosinase-catalyzed cross-linking was utilized to modify the firmness, water-holding capacity (WHC), and microstructure of cooked chicken breast meat homogenate gels. According to SDS-PAGE, the myosin heavy chain (MHC) and troponin T were the most sensitive proteins to the action of tyrosinase, whereas actin was not affected to the same extent. Calorimetric enthalpy (DeltaH) of the major thermal transition associated with myosin denaturation was reduced and with actin denaturation increased in the presence of tyrosinase. Low-amplitude viscoelastic measurements at constant temperatures of 25 degrees C and 40 degrees C showed that tyrosinase substantially increased the storage modulus (G') of the 4% myofibrillar protein suspension in the 0.35 M NaCl concentration. The effect was the most pronounced with high-enzyme dosages and at 40 degrees C. Without tyrosinase, the G' increase was low. Tyrosinase increased the firmness of the cooked phosphate-free and low-meat chicken breast meat homogenate gels compared to the corresponding controls. Tyrosinase maintained gel firmness at the control level of the low-salt homogenate gel and weakened it when both salt and phosphate levels were low. Tyrosinase improved the WHC of the low-meat and low-salt homogenate gels and maintained it at the level of the corresponding controls of phosphate-free and low-salt/low-phosphate homogenate gels. Microstructural characterization showed that a collagen network was formed in the presence of tyrosinase. Keywords: Chicken myofibrillar proteins; protein modification; cross-linking; tyrosinase; gelation; thermal stability; texture; water-holding capacity; microstructure.  相似文献   

17.
Monoacylglycerol‐stabilized oil in water emulsion (MAG gel) is an alternate shortening that is free of trans fatty acids, and low in saturated fatty acids. However, the behavior of MAG gels in comparison to other lipids has not been studied. This study investigated effects of structured MAG gel, a mixture of MAG gel unstructured components (Mixture), canola oil (Oil), or interesterified soy shortening (IE Soy) at different levels (6–24%) on hard or soft wheat dough properties. Doughs were prepared with different lipid types at equivalent lipid contents. Dough mixing and water absorption parameters were evaluated using a farinograph; gluten behavior was measured using a gluten peak tester (GPT); and pasting characteristics were measured using a micro‐viscoamylograph (MVAG). Water absorption values decreased with increasing lipid content. Dough development times were similar between the MAG gel and IE Soy, but farinogram curve characteristics during mixing were similar between MAG gel, Mixture, and Oil. The trend for peak max time in GPT was similar between MAG gel and IE Soy exhibiting delayed gluten aggregation; whereas Mixture and Oil exhibited earlier gluten aggregation. In MVAG, starch interaction with monoglyceride component of MAG gel and Mixture appeared to be the dominating factor resulting in increased pasting temperature and a second viscosity peak during cooling at higher levels of lipid addition.  相似文献   

18.
Low-field (LF) (1)H NMR T 2 relaxation measurements were used to study changes in water distribution in lean (Atlantic cod) and fatty (Atlantic salmon) fish during salting in 15% NaCl and 25% NaCl brines. The NMR data were treated by PCA, continuous distribution analysis, and biexponential fitting and compared with physicochemical data. Two main water pools were observed in unsalted fish, T 21, with relaxation times in the range 20-100 ms, and T 22, with relaxation times in the range 100-300 ms. Pronounced changes in T 2 relaxation data were observed during salting, revealing changes in the water properties. Salting in 15% brine lead to a shift toward longer relaxation times, reflecting increased water mobility, whereas, salting in saturated brines had the opposite effect. Water mobility changes were observed earlier in the salting process for cod compared to salmon. Good linear correlations ( F 相似文献   

19.
Hydrocolloid interaction with water, protein, and starch in wheat dough   总被引：1，自引：0，他引：1  
Interaction of hydrocolloids (xanthan gum, locust bean gum, guar gum, and high-methoxyl pectin) with macrocomponents of dough (water, starch, and protein) was evaluated by different techniques. (1)H spin-spin NMR relaxation assays were applied to study the mobility of the gluten-hydrocolloid-water matrix, and the amount of freezable water was determined by differential scanning calorimetry (DSC). Starch gelatinization parameters (T, enthalpy) were also analyzed by DSC. The influence of additives on the protein matrix was studied by Fourier transform (FT) Raman assays; analysis of the extracted gliadins and glutenins was performed by electrophoresis (SDS-PAGE). A significantly higher molecular mobility was found in matrices containing xanthan gum, whereas pectin led to the lowest molecular mobility. Freezable water showed a trend of increasing in the presence of hydrocolloids, particularly under conditions of water restriction. Starch gelatinization final temperature was decreased when hydrocolloids were added in the presence of enough water. In general, FT-Raman and SDS-PAGE indicated that hydrocolloid addition promoted a more disordered and labile network, particularly in the case of pectin addition. On the other hand, results obtained for dough with guar gum would indicate a good compatibility between this hydrocolloid and the gluten network.  相似文献   

20.
Low-field NMR T(2) and Fourier transform infrared (FT-IR) measurements were performed on meat samples of two qualities (normal and high ultimate pH) during cooking from 28 degrees C to 81 degrees C. Pronounced changes in both T(2) relaxation data and FT-IR spectroscopic data were observed during cooking, revealing severe changes in the water properties and structural organization of proteins. The FT-IR data revealed major changes in bands in the amide I region (1700-1600 cm(-)(1)), and a tentative assignment of these is discussed. Distributed NMR T(2) relaxation data and FT-IR spectra were compared by partial least-squares regression. This revealed a correlation between the FT-IR peaks reflecting beta-sheet and alpha-helix structures and the NMR relaxation populations reflecting hydration water (T(2B) approximately 0-10 ms), myofibrillar water (T(21) approximately 35-50 ms), and also expelled "bulk" water (T(2) relaxation times >1000 ms). Accordingly, the present study demonstrates that definite structural changes in proteins during cooking of meat are associated with simultaneous alterations in the chemical-physical properties of the water within the meat.  相似文献   

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