【作者】 张曼；

【导师】 梅林； 李新林；

【作者基本信息】 安徽农业大学 ， 农业硕士（专业学位）， 2024， 硕士

【摘要】 肉制品中的饱和脂肪酸摄入过量会引起诸多健康危害,脂肪替代物可以有效降低饱和脂肪酸含量。然而,脂肪替代可能造成肉制品质地和风味变差、保质期缩短、不便加工等问题。复合凝胶被证明是理想的动物脂肪替代品之一。本文主要利用一株乳酸片球菌S1代谢的具有抗氧化性胞外多糖(EPS)与鸡蛋清蛋白(EWP)制备凝胶性能良好的EPS-EWP复合凝胶,并首次评估该复合凝胶在猪肉香肠中作为动物脂肪替代品的潜力。这对于开发脂肪替代品和创新低脂营养肉制品有指导性意义,对于满足社会日益高涨的健康需求有重要性价值。具体研究结果如下:(1)EPS-EWP复合凝胶特性主要研究EPS添加量对EPS-EWP复合凝胶理化性质(水分分布、质构特性、流变特性和微观结构)、蛋白质结构和化学作用力的影响。结果显示:0.6%EPS的EPS-EWP复合凝胶具有更加致密、光滑的凝胶微观结构,最佳硬度(223.46 g)和弹性(0.83 g)。此时,复合凝胶的自由水含量较低,持水能力、表观黏度、储能模量和耗损模量均较强。0.6%EPS的EPS-EWP复合凝胶分子间作用力增强,结构更稳定,其二级结构中无规则卷曲向有序的β-折叠转变,形成致密均匀的网络结构。分子对接从分子水平阐明了疏水相互作用和氢键是EWP与EPS相互作用的主要驱动力。(2)EPS-EWP复合凝胶替代脂肪对香肠品质的影响利用复合凝胶替代香肠中猪背脂肪制备低脂香肠。相比对照组,复合凝胶替代比为93.75%的香肠蒸煮损失减少了42.86%,硬度和咀嚼度均得到显著改善,色泽无明显变化,横截面积空洞较少且细小,微观结构均匀光滑。复合凝胶的加入使肉糜表观黏度增大,增强了其储能模量。特别是,随着替代比增加至93.75%,香肠的水分流动性和自由水比例逐渐减少,香肠的二级结构改变,β-折叠含量增加。另外,在短期贮藏期间,所有香肠的p H值均呈上升趋势,替代比越高的香肠p H值越高。在第8 d时,低脂香肠(替代比93.75%)的脂肪氧化抑制效果比对照组香肠提升了32.87%。替代比小于93.75%的香肠与对照香肠的整体气味相似,感官特性良好,总体可接受度最高。更多还原

【Abstract】 Excessive intake of saturated fatty acids in meat products can cause many health hazards,and fat substitutes can be effective in reducing saturated fatty acid content.However,fat substitution may cause problems such as deterioration of texture and flavour,shortened shelf life and inconvenient processing of meat products.Composite gels have been shown to be one of the ideal animal fat substitutes.This thesis focuses on the use of extracellular polysaccharides(EPS)with antioxidant properties metabolised by a strain of Pediococcus lactis S1 and egg white protein(EWP)to prepare EPS-EWP composite gels with good gel properties and to evaluate for the first time the potential of this composite gel as an animal fat substitute in pork sausages.This is instructive for the development of fat substitutes and innovative low-fat nutritious meat products,which are of importance value in meeting the rising health needs of the society.The specific findings of the study are as follows:(1)Characterization of the EPS-EWP composite gelThe effects of EPS added amounts on the physicochemical properties(moisture distribution,texture characteristics,rheological properties and microstructure),protein structure and chemical forces of EPS-EWP composite gels were studied.The results showed that the EPS-EWP composite gel with 0.6% EPS had a denser and smoother microstructure,the best hardness(223.46 g)and water holding capacity(94.67%).At this time,the free water content of the composite gel was low,and the water-holding capacity,apparent viscosity,storage modulus and the consumption modulus were strong.The intermolecular forces of the EPS-EWP composite gel with 0.6% EPS were enhanced,the structure was more stable,and the irregular curls in its secondary structure were transformed to ordered β-folding,forming a dense and uniform network structure.Molecular docking clarified from the molecular level that hydrophobic interactions and hydrogen bonding are the main driving forces for the interaction between EWP and EPS.(2)Effect of fat replacement by EPS-EWP composite gel on sausage qualityLow-fat sausages were prepared by replacing pig back fat in sausages with composite gel.Compared with the control group,the sausage with 93.75% composite gel substitution ratio showed a 42.86% reduction in cooking loss,a significant improvement in hardness and chewiness,no significant change in colour,fewer and finer voids in the cross-sectional area,and a uniform and smooth microstructure.The addition of composite gel increased the apparent viscosity of minced meat and enhanced its energy storage modulus.In particular,as the substitution ratio increased to 93.75%,the water mobility and free water percentage of the sausage gradually decreased,and the secondary structure of the sausage was altered with an increase in β-folding content.In addition,the p H of all sausages showed an increasing trend during short-term storage,and the higher the substitution ratio,the higher the p H of the sausages.At 8 d,the fat oxidation inhibition effect of low-fat sausages(93.75% substitution ratio)was 32.87%higher than that of control sausages.Sausages with substitution ratios less than 93.75% had a similar overall odour to the control sausages,good sensory characteristics and the highest overall acceptability.更多还原