Improving the texture and rheological qualities of a plant-based fishball analogue by using konjac glucomannan to enhance crosslinks with soy protein

Global fisheries pressure generates interest in sustainable seafood production and developing plant-based seafood. This study took fishball as an example of seafood products applying konjac glucomannan (KGM) in developing plant-based fishball (PFB) analogues mimicking the texture of fishball. Increasing KGM concentration (up to 8.0%) influenced texture and rheological properties of PFB progressively, where the hardness, chewiness, and gel strength of PFB were significantly enhanced. Decreased pH value (9.38 to 7.93) and increased α-helix, β-sheet, and helix/coil ratio (1.40 to 1.70%) validated a promotion of hydrogen bonds and ordered structures by KGM. The strengthened interaction strength and hydrogen bonds formed at -OH groups of KGM and amide linkage of soy protein could be responsible for textural improvement. A more compact and regular microstructure also validated a firmer texture in PFB with higher KGM levels. Besides, KGM (3.5–8.0%) significantly decreased instantaneous compliance J₀ (101.3 × 10⁻⁶ to 58.1 × 10⁻⁶ Pa⁻¹), indicating denser crosslinks and firmer structures. In conclusion, KGM improved the texture and viscoelasticity of PFB and had an excellent application value in developing plant-based seafood analogues.     

魔芋葡甘聚糖对面条品质及其淀粉体外消化的影响

本实验研究了魔芋葡甘聚糖对面条烹煮和质构品质及其淀粉体外消化的影响。采用质地剖面分析、扫描电 子显微镜和体外淀粉消化模型的方法研究质量分数0～5.00%添加量的魔芋葡甘聚糖对面条质构、烹煮及体外淀粉 消化性质的影响。结果表明：面条吸水率和膨胀率随魔芋葡甘聚糖添加量增加而升高,而烹煮损失率则先升高后降 低,在2.50%魔芋葡甘聚糖添加量时达到最低。面条质地剖面分析性质随着魔芋葡甘聚糖添加量的增加而改善,而 坚实度则下降。魔芋葡甘聚糖还可降低面条体外淀粉消化时葡萄糖释放速率,添加5.00%魔芋葡甘聚糖时面条升糖 指数值降低12.22%。实验结果表明,魔芋葡甘聚糖不但可改善面条品质,还可改善面条的营养性质,并且添加量在 2.50%时品质最佳。     

冷冻魔芋复合凝胶保水性和质构特性的调控

本研究将瓜尔豆胶、大豆油、乳化剂依次加入到魔芋凝胶中,以探究其对冷冻魔芋凝胶保水性和质构特性的影响。首先添加瓜尔豆胶到魔芋凝胶中,相比于控制组(纯魔芋凝胶),冷冻后的魔芋/瓜尔豆胶复合凝胶的保水性能提升,其冷冻析水率最多减小了3.63%,持水率最大升高了4.68%,硬度最多增大了930.74 g。为了进一步提高冷冻复合凝胶的保水性,将大豆油和乳化剂添加入魔芋/瓜尔豆胶复合凝胶中。添加大豆油可以增大魔芋/瓜尔豆胶凝胶的保水性,但复合凝胶硬度有所降低。在魔芋/瓜尔豆胶/大豆油复合凝胶中添加5种不同的乳化剂进行对比,发现单甘油脂肪酸酯对提高冷冻凝胶的保水性的效果最好。当瓜尔豆胶、大豆油和单甘油脂肪酸酯在复合凝胶中的比例分别为0.10%、5%和0.10%时,对比控制组,冷冻复合凝胶的析水率由25.37%降低到10.19%,持水率由62.55%升高至82.83%,但凝胶硬度降低。瓜尔豆胶、大豆油和单甘油脂肪酸酯的复合添加可以有效改善魔芋凝胶在冷冻后的保水能力,并改变了凝胶的质构特性。本研究为调控冷冻魔芋复合凝胶的性能提供了数据支撑,也为冷冻魔芋复合凝胶产品的生产提供了理论参考。     

不同木薯淀粉对冻融魔芋葡甘聚糖凝胶特性的比较分析

为探究不同木薯淀粉对冻融魔芋葡甘聚糖凝胶的影响,采用木薯淀粉（cassava starch,CS）、木薯醋酸酯淀粉（starch acetate,SA）、木薯乙酰化二淀粉己二酸酯淀粉（acetylated di-starch adipate,ADA）、木薯乙酰化二淀粉磷酸酯淀粉（acetylated di-starch phosphate starch,ADP）四种市售淀粉代替37.5%魔芋葡甘聚糖（konjac glucomannan,KGM）,制备冻融脱乙酰KGM/淀粉复合凝胶。通过质构仪、傅里叶红外光谱仪、热重分析仪、冷场扫描电镜分析其凝胶特性的变化。结果表明,4种木薯淀粉可以改善冻融KGM凝胶的凝胶特性,但不同木薯淀粉间存在差异,KGM/ADP凝胶表现出最优的保水性和热稳定性,与KGM凝胶相比,其析水率从29.75%下降至8.71%,持水率从73.68%提高至87.42%,硬度从274.36 g下降至176.33 g,弹性、内聚性及回复性无显著差异;不同木薯淀粉均未影响葡甘聚糖的脱乙酰行为和结晶形态,但ADP可以改变冻融KGM凝胶微观形貌,提高其抗脱水收缩能力。综合分析,ADP代替部分魔芋葡甘聚糖改善冻融KGM凝胶特性效果最佳,为其在魔芋凝胶食品的应用提供指导。     

脱乙酰魔芋葡甘聚糖性质及其脂类结合能力研究

采用红外及X-衍射等分析手段表征魔芋葡甘聚糖(KGM)与脱乙酰魔芋葡甘聚糖(Da-KGM)结构并比较其持水性和粘度,以纤维素为对照,采用体外模拟人体胃及肠道的pH环境,对比分析KGM及Da-KGM对脂肪及胆固醇的吸附能力。结果显示KGM脱乙酰基后1733 cm~(-1)处的乙酰基的特征吸收峰消失,结晶度增加,持水性下降83.7%,高粘度特性丧失;相比纤维素,KGM具有良好的脂肪及胆固醇吸附能力,其吸附总量随样品质量、吸附时间和胆固醇浓度的增加而增大,与天然KGM相比,Da-KGM的脂肪及胆固醇吸附能力降低,可能是因为KGM脱除乙酰基后KGM分子链间氢键作用加强致使与脂类结合位点减少,以及高粘度特性消失致使对脂类的直接包裹能力下降,提示KGM经脱乙酰加工成魔芋食品后在肠道与脂类的结合能力下降,其减肥降脂的生理功效可能受到影响。     

魔芋葡甘聚糖及其衍生物对禽肉重组火腿物性的影响

研究魔芋葡甘聚糖(KGM)及其衍生物(KSAP)对禽肉重组火腿感官、微观结构和力学特性的影响。感官评价结果表明：与未添加改良剂的空白组和添加复合磷酸盐的对照组相比,KGM和KSAP 均能有效改善鸭肉和鹅肉重组火腿的感官指标,减少表面油脂和水分析出。通过扫描电镜观察发现：添加KGM 和KSAP 后,火腿具有均匀致密的网络结构,原料肉组织表面覆盖连续包膜层。质构分析结果表明：与空白组和对照组相比,添加KGM和KSAP 的禽肉重组火腿组织致密性增强,凝胶弹性增大;火腿硬度值、胶着性和咀嚼度降低,弹性改善。     

降解魔芋胶调控面团的加工性能及馒头品质

为提升主食馒头中膳食纤维的添加量,但同时不影响加工性能和馒头品质,本文采用湿热降解程度不同的魔芋胶添加于面团并用于制作馒头,考察对面团特性及馒头品质的影响。结果表明,轻度降解魔芋胶（KGM-1,420 ku）相对未降解魔芋胶（654 ku）对面团关键粉质特性、拉伸特性、流变特性、微观结构等影响更小,对加工难度和效率影响不大;当添加KGM时,馒头比容最大,从2.32 mL/g（空白组）增大至2.55 mL/g。KGM-1对馒头的质构特性影响最大,弹性增加至0.97,硬度与咀嚼性分别降低为878.55 g和660.33,与空白组相比差异显著（p<0.05）,抑制馒头老化的效果也得以显著增强。综合对比,轻度降解的魔芋胶（KGM-1）,无论是相对原魔芋胶,还是相对降解程度更大的魔芋胶（190 ku、104 ku、56 ku）,均更加有利于馒头品质和长期贮藏。轻度湿热降解可提升馒头中魔芋胶添加量的同时,减少对加工特性影响并提升了馒头初始品质和长期贮藏品质,这一意外发现为馒头用专用魔芋胶的制备指明了目标。     

魔芋葡甘聚糖-可得然胶共混凝胶替代动物脂肪对乳化肠品质特性的影响

为探究魔芋葡甘聚糖（konjac glucomannan,KGM）和可得然胶（curdran gum,CUD）的添加对猪肉乳化肠品质特性的影响,采用KGM-CUD共混凝胶代替乳化肠中质量分数依次为0%（G1组,对照组）、33%（G2组）、66%（G3组）以及100%（G4组）的猪背膘,研究KGM-CUD共混凝胶对猪肉乳化肠蒸煮损失、色差、持水性、质构特性和脂质氧化的影响,并进行感官评价。结果表明：当KGM-CUD共混凝胶质量分数为0.3%,且KGM∶CUD=8∶2（m/m）时,KGM-CUD共混凝胶乳化效果最佳。与对照组G1组相比,G2组和G3组蒸煮损失显著降低（P＜0.05）,持水性无显著差异（P＞0.05）;G2组红度值显著上升（P＜0.05）;G3组红度值和硬度显著上升（P＜0.05）。随着替代比例的上升,乳化肠抗氧化能力逐渐增强,G2组和G3组微观结构与对照组相比无显著差异,但G4组存在明显空隙,且总体可接受度略有降低。结果表明,用0.3%的KGM-CUD共混凝胶（KGM∶CUD=8∶2）替代乳化肠66%的脂肪时,能提高乳化肠的营养价值和产品质量,显著延长保藏期。     

品质改良剂对浅发酵腊肠产品特性的影响及主成分分析

为改善浅发酵香肠组织易松散，肉质干硬等问题，分别添加0.2%复合磷酸盐（CP）、0.2%魔芋胶（KGM）、0.2%乙酰化双淀粉己二酸酯（ADA）及2.0%玉米淀粉（CST）作为品质改良剂，探究其对产品风干效率、质构、理化、蒸煮损失及微生物等特性的影响。结果表明，添加质改良剂的产品水分活度a_w值均较高；KGM和ADA对降低产品硬度，提升口感，改善产品色泽和组织紧实度具有显著作用（P<0.01）；CP和ADA能显著降低产品蒸煮损失（P<0.01）；CST在贮藏初期可提高香肠保水性，减少蒸煮损失，但经30 d的贮藏期后，保水作用大大降低。并且CST能促进微生物增值，而KGM则会抑制微生物生长。进一步的主成分分析（PCA）显示，乳酸菌含量、硬度和咀嚼性之间有显著的正相关关系，与a_w之间呈显著的负相关，色泽和pH之间具有正相关关系。通过综合评分确定各品质改良剂综合排序为:ADA>KGM>CST>CP>CK，乙酰化双淀粉己二酸酯和魔芋胶对改善香肠品质具有较好效果。本研究显示出品质改良剂对浅发酵香肠产品质构、色泽、保水性等有显著的改善作用，而使产品a_w提高可能对产品可贮性导致不利影响，对此有待进一步探究。     

Effects of konjac glucomannan on physicochemical properties of myofibrillar protein and surimi gels from grass carp (Ctenopharyngodon idella)

The cryoprotective effect of konjac glucomannan (KGM) on myofibrillar protein from grass carp (Ctenopharyngodon idella) during frozen storage at −18 °C and the influence of five levels of KGM (0%, 0.5%, 1%, 1.5%, and 2%) on texture properties, water-holding capacity, and whiteness of grass carp surimi gels were investigated. KGM as a novel cryoprotectant could significantly mitigate the decrease in salt extractable protein (SEP), Ca²⁺-ATPase activity, and total sulphydryl and active sulphydryl contents of myofibrillar protein during frozen storage. KGM at the level of 1% showed the same good cryoprotective effect as a conventional cryoprotectant (10% sucrose–sorbitol, 1:1, w/w). As the levels of KGM increased, breaking force and deformation of grass carp surimi gels increased significantly. Water-holding properties of the surimi gels are improved with the increasing addition of KGM, but the whiteness decreased and the colour became darker. The optimum addition level of KGM was suggested to be 1%.     

直链/支链淀粉对鱼丸质构特性及感官品质的影响

为探究直链/支链淀粉对不同来源（海水鱼/淡水鱼）鱼丸的质构特性以及感官品质的影响,采用质构剖面分析法（texture profile analysis,TPA）测定鱼丸的质构特性,结合感官品质评定方法对鱼丸质构进行综合评定,并辅以持水性分析和微观结构观察,研究鱼丸凝胶性质。结果表明：相对于直链淀粉,支链淀粉在鱼丸加工工艺中能更有效地提高其硬度和咀嚼性。以鲅鱼肉作为鱼丸原料相较于巴沙鱼肉具有更高的蛋白质及更低的脂肪含量,更为优越的质构特性、感官品质以及持水性。     

Effects of Water-Glycerol and Water-Sorbitol Interactions on the Physical Properties of Konjac Glucomannan Films

Konjac glucomannan (KGM)‐edible films were prepared with different amounts of glycerol or sorbitol as a plasticizer. Films were characterized by moisture sorption isotherm, and following conditioning at different relative humidities, by differential scanning calorimetry and tensile tests. Moisture and polyols (sorbitol and glycerol) were found to plasticize KGM‐based films with respect to their tensile properties. However, thermal properties and water sorption capacity (WSC) of polyolplasticized KGM films were found to vary with water activity (a_w), namely at low a_w (< 0.6), WSC and melting enthalpy were decreased with increasing in polyol content and the opposite was true at higher a_w (>0.6). This was attributed to extensive interactions between plasticizer and KGM that reduced the available active site (‐OH groups) for water adsorption. The presence of polyols at low a_w appeared to suppress crystalline structures due probably to restricted molecular mobility. These effects were diminished when the moisture content was >20%.     

Effect of ripening with Penicillium roqueforti on texture,microstructure, water distribution and volatiles of chicken breast meat

In this study, the influence of ripening with Penicillium roqueforti on texture, microstructure, protein structure, water mobility and volatile flavour compounds of chicken breast meat was investigated. Scanning electron microscopy (SEM) and transmission electron microscope (TEM) images showed that the granule formed and chicken myofibril fractured after ripening. Reduction in α-helix and increases in β-sheet structure content accompanied by decrease in hardness and springiness and increase in gumminess were found in ripened chicken breast meat. Low field nuclear magnetic resonance (LF-NMR) revealed that increasing intra-myofibrillar water and decreasing extra-myofibrillar water resulted in the higher water-holding capacity after ripening with P. roqueforti. In addition, chicken breast meat ripened with P. roqueforti contained more volatile flavour compounds, in particular aldehydes.     

魔芋葡甘聚糖与阿拉伯胶复合水溶胶流变特性及结构表征

为了研究魔芋葡甘聚糖（Konjac glucomannan,KGM）与阿拉伯胶（Gum arabic,GA）复合水溶胶的性质,提升其在食品工业中的应用性能,本文以不同比例的KGM/GA复合水溶胶为研究载体,采用流变仪、FT-IR、XRD和SEM对其流变特性与结构表征进行研究,探讨添加比例对KGM/GA复合水溶胶性能的影响。结果表明,KGM和GA具有良好的相容性,在恰当的复配比例下,二者可以起到协同增效的作用,GA可以改善KGM的流变性和透明度,KGM可以改善GA的粘弹性和稳定性;KGM和GA通过氢键的增加和乙酰基的减少,促进相互的交联,加强复合水溶胶体系的分子间作用力,形成均匀规则的稳定结构。当KGM:GA为5:5（w/w）时,得到综合性能优异的KGM/GA复合水溶胶,与KGM单一体系相比,透明度提高了65.82%,结晶度增强了14.57%,此时样品的黏度适中、稳定性高、粘弹性较好,有望为食品级粘合剂和膳食纤维类饮品等的开发提供一定的理论参考。     

热烫方式对桃微观结构、酶促褐变及相关品质的影响

本实验采用热水与蒸汽两种热烫方式对桃进行预处理,研究其对微观结构、酶促褐变及相关品质的影响,确定桃脯前处理的最佳热烫条件。结果表明:随热烫时间（0~80 s）的增加,两种处理方式对桃品质的影响基本一致,表面微观结构塌陷、多酚氧化酶（PPO）和过氧化物酶（POD）钝化失活、质构下降、褐变度减弱、V_C含量降低、总酚含量及抗氧化能力上升。相关性分析和聚类分析结果表明:PPO、POD、硬度、褐变度、V_C间呈极显著相关（P<0.01）;总酚、DPPH·清除能力、亚铁离子还原能力间呈极显著相关（P<0.01）。热水与蒸汽热烫前40 s内各理化品质变化接近,具有较高的相关性,而热水与蒸汽热烫60 s和80 s的品质变化相关程度较高。总之,相比于热水处理,蒸汽处理能较好地维持桃的品质。当蒸汽处理80 s时,在有效钝化PPO和POD的基础上,仍能维持相对饱满的组织结构和较好的色泽品质,且V_C含量也保持在较高水平,是适宜桃脯前处理的最佳热烫条件。     

Utilization of two plant polysaccharides to improve fresh goat milk cheese: Texture,rheological properties,and microstructure characterization

This study aimed to evaluate the effects of added jujube polysaccharide (JP) and Lycium barbarum polysaccharide (LBP) on the texture, rheological properties, and microstructure of goat milk cheese. Seven groups of fresh goat milk cheese were produced with 4 levels (0, 0.2, 0.6, and 1%, wt/wt) of JP and LBP. The goat milk cheese containing 1% JP showed the highest water-holding capacity, hardness, and the strongest rheological properties by creating a denser and more stable casein network structure. In addition, the yield of goat milk cheese was substantially improved as a result of JP incorporation. Cheeses containing LBP expressed lower fat content, higher moisture, and softer texture compared with the control cheese. Fourier-transform infrared spectroscopy and low-field nuclear magnetic resonance analysis demonstrated that the addition of JP improved the stability of the secondary protein structure in cheese and significantly enhanced the binding capacity of the casein matrix to water molecules due to strengthened intermolecular interactions. The current research demonstrated the potential feasibility of modifying the texture of goat milk cheese by JP or LBP, available for developing tunable goat milk cheese to satisfy consumer preferences and production needs.     

酶解魔芋葡甘聚糖对冷冻面团拉伸特性的影响

将魔芋葡甘聚糖(KGM)及其酶解产物(KGM Ⅰ、KGM Ⅱ、KGM Ⅲ)加入冷冻面团中,通过高效液相色谱法、电子扫描显微镜、核磁共振技术以及质构分析仪等研究魔芋葡甘聚糖及其酶解产物对冷冻面团拉伸特性的影响。结果表明:随着冻融循环时间由0 d延长至60 d,未添加KGM及其酶解产物的面团中游离巯基含量由7.81 μmol/L上升至9.65 μmol/L,面筋蛋白分子量由1.98×105 Da下降至1.39×105 Da,β-折叠含量降低,自由水所占比例增加了3.96%,且面团内部孔洞增多,面筋网络破坏严重,拉伸能力明显降低。冻融循环时间达60 d的面团加入2.0%的KGM Ⅱ后,面筋蛋白中游离巯基含量则由9.65 μmol/L下降至5.38 μmol/L,面筋蛋白分子量由1.39×105 Da增大至2.11×105 Da,自由水所占比例下降,面筋蛋白包裹淀粉颗粒的能力逐渐上升,面团拉伸能力回升,而KGM、KGM Ⅰ和KGM Ⅲ的加入对冷冻面团性质的影响较KGM Ⅱ小,表明添加2.0%的KGM Ⅱ能够明显抑制二硫键的断裂和二级结构的变化,防止面团的水分散失,维持面团的拉伸能力。     

Study on Stabilizing Mechanism of Konjac Glucomannan in Tea Infusions

ABSTRACT:  The stabilizing mechanism of konjac glucomannan (KGM) in tea infusions was studied using a conventional transmission electron microscope (TEM), scanning electron microscope (SEM), ethanol sedimentation, and other methods. As a result, many water-soluble complexes among the KGM molecules and tea components such as thearubigins (TRs), theaflavins (TFs), total catechins (TC), and tea polyphenols (TPP) were obviously formed in tea infusions with addition of KGM. The aggregations of tea components, which caused tea cream down, were decreased because of KGM addition and the stability of suspended particles in tea-KGM infusions was enhanced. These findings suggested that the strong adsorption happened among KGM and tea components and particles through strong hydrogen bonding functions. Molecular weight of KGM in tea infusions was smaller than that in water solution. In water solution, it was 4.83 × 10⁵, but in black tea infusions 3.41 × 10⁵, and in oolong tea infusions 3.51 × 10⁵. The experiments also revealed that the tea-KGM infusions had stronger antielectrolyte coagulation capacity and the static electrification action exists among the molecules of tea infusions. These findings indicated that KGM could be a useful stabilizer for stability of the tea infusions.     

豌豆蛋白的添加对猪肉盐溶蛋白凝胶特性的影响

将豌豆蛋白加入到猪肉盐溶蛋白溶液中制备凝胶,研究豌豆蛋白对其共混热诱导凝胶色泽、蒸煮得率、保水性、质构、动态流变性、微观结构及水分迁移等特性的影响。结果表明,随豌豆蛋白添加量的增加,凝胶的L*值、a*值均呈下降趋势,b*值上升;保水性和蒸煮得率均持续增加,4%时保水性为86.84%,与10%相比差异不显著(p>0.05),蒸煮得率为88.31%,与6%、8%相比,差异不显著(p>0.05),但与10%相比,差异显著(p<0.05);硬度、咀嚼性持续上升,弹性与回复性先上升后下降,添加量为4%时最大,分别为0.961、0.405;储能模量G'值随豌豆蛋白添加量的增加而升高,且初始值与终值均高于对照(p<0.05);豌豆蛋白可以提高共混凝胶不易流动水的比例,降低自由水的比例;豌豆蛋白添加量为4%时,凝胶网络结构高度有序、均匀致密。因此,豌豆蛋白可以提高猪肉盐溶蛋白形成凝胶的能力;添加量为4%时,形成的共混凝胶品质最好。     

Effects of konjac glucomannan on heat-induced changes of physicochemical and structural properties of surimi gels

This work demonstrated the protective effects of konjac glucomannan (KGM) on the physicochemical and structural properties of surimi gels subjected to 120 °C. The T₂ relaxation of LF-NMR which was used to detect water mobility, changed more obviously with the addition of deacetylated KGM than with the native, which indirectly implied that deacetylated KGM more pronouncedly influenced the protein structure. Hydrophobic interaction, ionic, hydrogen, and disulfide bonds, were sheltered by deacetylated KGM to greater extent than by native KGM. Raman spectra showed that the reduction of the main random-coil secondary protein structure at 120 °C was more significantly mitigated by deacetylated KGM. The interactions between protein and native or deacetylated KGM were investigated by X-ray diffraction, finding that protein and polysaccharide complexes might be formed. The microstructure of the mixed gels, determined by confocal laser scanning microscopy, demonstrated native and deacetylated KGM helped protein aggregation recover to uniform distribution.