白切鸡，又叫白斩鸡，是我国传统的低温酱卤类肉制品，盛行于两广和华东地区，其具有外皮色泽光亮、爽口弹牙，肉质熟而不烂、细腻嫩滑的特点，通常以热鲜黄羽肉鸡为原料制作而成，可最大程度的保持原料鸡的鲜美风味。清远麻鸡作为我国特色黄羽肉鸡品种之一，其皮下和肌间脂肪发达，是制作白切鸡的上好原料。近年来冷鲜鸡成为消费的主流，原料肉鸡经屠宰后，随着宰后时间的延长，鸡胴体经历了尸僵、解僵成熟等过程，可提高肉的嫩度与保水性，完成肌肉向可食用肉的转化，同时发生一系列生化反应如糖酵解、蛋白质降解、脂质氧化等影响风味前体物质的时序性变化。肉鸡的宰后成熟时间相对较短，且品种间差异较大，宰后成熟过程对白切鸡风味影响的研究相对较少。

食品的口腔加工过程是一个复杂的动态过程，它不仅涉及食品在口腔中的分解、消化和吞咽，更是消费者感知食品质地与风味的全过程。鸡皮作为白切鸡较为特色的食用部位，其脂肪含量较高，影响口腔加工过程中食团的形成、唾液的分泌以及风味物质的释放与感知。因此本文以清远麻鸡为原料，探究了宰后成熟过程对白切鸡风味的影响，并通过口腔加工实验，探究食用方法对白切鸡风味感知的影响，为黄羽肉鸡的生产加工和食用提供一定的理论依据。主要研究内容和结果如下：

• 宰后成熟对黄羽肉鸡水溶性风味前体物质的影响

为探讨宰后成熟时间对鸡肉水溶性风味前体物质的影响，采用清远麻鸡为原料，测定宰后0~4℃成熟48小时，pH、三磷酸腺苷（ATP）相关联物等风味核苷酸、游离氨基酸和分子量小于3000 KDa的水溶性低分子肽的含量。结果表明，鸡胸和鸡腿的pH分别在4 h，3 h到极限值5.64，6.21。无论是在胸肉中还是在腿肉中，ATP在3小时内均迅速下降。鸡腿在宰后成熟2 h的K值最低，表明其鲜度最好。3 h和4 h的鸡肉的等鲜浓度（EUC）值相对较高，但相应的电子舌鲜味响应值并不高，进一步说明水溶性低分子肽在宰后成熟过程中发挥了重要作用。结合聚类分析和偏最小二乘判别分析（PLS-DA），初步推断冷鲜鸡在宰后0~4℃成熟的最佳时间为2 h，为冷鲜鸡的进一步加工研究提供理论依据。

• 宰后成熟对白切鸡的质构、风味与味觉特征的影响

清远麻鸡是我国著名的黄羽肉鸡，以其皮下和肌间脂肪发达、皮薄骨软而闻名。然而，以其为原料进行传统低温加工制作的白切鸡的质构、风味等品质指标尚未揭示。宰后成熟是影响质构、风味等品质的一个重要过程，为了探索制作白切鸡的最佳的宰后成熟时间，采用多元分析方法对主要理化特性（pH值、质构、味觉特征和挥发性气体）进行了研究，发现鲜味、甜味、pH值、硬度和粘聚性是造成不同成熟时间制作白切鸡样品感官差异的关键指标，4个游离氨基酸、3种核苷酸、7种低分子量水溶性肽以及8种挥发性物质被确定为影响风味的主要成分。偏最小二乘判别分析（PLS-DA）结果表明，成熟1 h和2 h制作的白切鸡样品在口感上有明显优势，但1 h的样品电子舌苦味值较高。感官喜好排序实验将样品分为三类，其中宰后成熟2 h制作的白切鸡排序最好，8 h制作的白切鸡排序最差，其余样品处于中等水平。综合各指标，宰后成熟2 h制作的白切鸡最为突出，为黄羽肉鸡的深加工提供一定理论依据。

• 白切鸡的口腔加工过程中的食团特性与味觉感知

食物的感官感知是一个动态过程，与口腔加工过程中风味物质的释放密切相关。它不仅受食物本身材质的影响，还会因个体口腔环境差异而有所不同。本章研究了不同类型组合鸡肉样品（鸡胸CB、鸡胸+鸡皮CBS、鸡腿CT、鸡腿＋鸡皮CTS）在咀嚼过程中的感官特性、粒径、表观粘度、电子鼻和电子舌特征变化。相关分析结果表明，鸡肉样品的物理特性决定了其口腔加工行为。鸡皮的添加在口腔加工中起到一定的润滑作用，在咀嚼初期可增大食团颗粒粒径，咀嚼后期增强食团的流动性，减少达到吞咽点的时间，同时提高了电子鼻中芳香族化合物的响应信号。但在脂肪含量较高的鸡腿类样品中，鸡皮的影响则适得其反，同时其对鸡肉样品的鲜味和甜味的感知有一定的掩蔽作用。综上所述，鸡皮在鸡肉口腔加工中发挥了重要作用，鸡腿在白切鸡食用综合评价中更受喜爱。宰后成熟与口腔加工过程对白切鸡风味感知的影响均具有显著性差异，其具体影响机制值得进一步深究。

综上所述，以我国特色黄羽肉鸡清远麻鸡为原料，宰后成熟2 h制作的白切鸡风味最佳，在食用过程中鸡皮降低了白切鸡肉鲜甜味感知，增强了芳香物质的释放，其劲道爽口的口感及对挥发性香气成分的影响有待深度探究。

Soft-boiled chicken, also known as white sliced chicken (Baiqieji), is a traditional low-temperature soy sauce and pot-roast meat products in China. It is popular in Guangdong province, Guangxi province and the east part of China, and has the characteristics of bright skin color, good springiness and chewness, tender and smooth texture, umami taste. Usually, it is made from fresh yellow-feathered broilers, which is considered to maintain the intrinsic flavor of raw chicken to the greatest extent. Qingyuan partridge broilers (Qingyuna Maji), as one of the characteristic yellow-feathered broilers in China with abundant subcutaneous and intermuscular fat, is a good raw material for soft-boiled chicken. In recent years, chilled chickens have become the mainstream of consumption. After slaughtering, with the extension of post-mortem aging time, the chicken carcass undergoes the processes of rigor mortis and aging, which improves the tenderness and water retention of chicken, complete the transformation from muscle to edible meat. During the transformation, a series of biochemical reactions such as glycolysis, protein degradation and lipid oxidation take place, which affect the formation of flavor. The post-mortem aging span of broilers is relatively short with obvious differences among different breeds, resulting in relatively few researches on the formation of chicken characteristic flavor during the post-mortem aging process.

The oral processing process of food is a complex dynamic process, which involves the decomposition, digestion and swallowing of food in the oral cavity, as well as the whole process of consumers' perception of food texture and flavor. As a characteristic edible part of soft-boiled chicken, chicken skin has a high fat content, which affects the formation of food boluses, the secretion of saliva, the release and perception of flavor substances during oral processing. Therefore, the current study took Qingyuan partridge broilers as the material to explore the effect of post-mortem aging time on the characteristic flavor of soft-boiled chicken, and investigated the influence of chicken skin on the flavor perception of soft-boiled chickens through oral processing experiments, providing a certain theoretical basis for the production, processing and consumption of yellow-feathered broilers.

• Effects of post-mortem aging process on characteristic water-soluble taste-active precursors of yellow-feathered broilers

In order to explore the effect of post-mortem aging on water-soluble flavor precursors of chicken, pH, adenosine triphosphate (ATP) degradation, flavor nucleosides, free amino acids and water-soluble low molecular weight peptides were determined using Qingyuan partridge yellow-feathered broilers as material during 0-4°C in 48 hours of post-mortem aging. The results showed that the pH value fell to the limit pH 5.64 (4 h) in chicken breast and 6.21 (3 h) in thigh. Regardless of chicken breast or thigh, ATP dropped rapidly within 3 h. It was found that the K-value in chicken thigh was the lowest at 2 h indicating the freshness was the best. Considering the equivalent umami concentration (EUC), the value at 3 h and 4 h was relatively high, but the corresponding electronic tongue umami value was not high, which further revealed that the water-soluble low molecular taste peptide played an important role on the post-mortem aging process. Combined with cluster analysis and partial least squares discriminant analysis (PLS-DA), it was preliminarily inferred that the optimal time for chilled chicken during 0-4°C post-mortem aging was 2 h, which could provide a theoretical basis for the further processing of fresh chicken.

• Exploration of texture, flavor and taste of soft-boiled chicken at different post-mortem aging time

As a well-known yellow-feathered broiler, Qingyuan partridge chicken was famous for its phenotype with ample subcutaneous and intermuscular fat, thin skin and soft bones. However, the texture and flavor of soft-boiled chicken prepared by low-temperature marinated Qingyuan partridge chicken is under investigation. Post-mortem aging was a momentous process affecting the quality indexes including texture and flavor. In order to explore the optimal post mortem aging time, the primary physical and chemical characteristics including pH, texture, taste and flavor substances were investigated and analyzed by multivariate methods. The results demonstrated the characteristic taste of umami and sweetness, pH, hardness and cohesiveness were crucial indicators that contributed to the sensory scores of different samples. Four free amino acids, three nucleotides, seven low-molecular weight water-soluble peptides and eight volatile aromas were identified as the main ingredients affecting the flavor. The result of partial least squares discriminant analysis (PLS-DA) indicated that the samples corresponding to1and 2 h had obvious advantage in taste, but the sample produced at 1 h had a higher value of bitterness. The soft-boiled chickens were divided into three categories by sensory ordering experiment, among which the samples prepared at 2 h ranked the first, with 8 h the worst, and the rest of the samples were in the middle level. It was determined that the soft-boiled chicken corresponding to post-mortem aging at 2 h was the most outstanding comprehensively, which could provide a theoretical basis for the further processing of yellow-feathered chicken.

• Taste characteristics and sensory perception of chicken bolus during oral processing

The sensory perception of food is a dynamic process, which is closely related to the release of flavor substances during oral processing. It's not only affected by the food material, but also subject to the individual oral environment. The sensory properties, particle size, viscosity, characteristic values of electronic nose and electronic tongue of different combinations of chicken samples (CB, CBS, CT, CTS) during mastication were investigated. The results of correlation analysis showed that the physical characteristics of the sample determined its oral processing behavior. The addition of chicken skin plays a certain role in lubrication during oral processing. The particle size of the bolus was heightened at the early stage of chewing, and the fluidity was enhanced at the late, which reduced the chewing time to the swallowing point and raised the corresponding signal of aromatic compounds in the electronic nose. But the effect of chicken skin on chicken thigh with relatively high fat content, was the opposite in electronic nose, which had a certain masking effect on the perception of umami and sweet taste. To sum up, chicken skin played a critical role in chicken oral processing and chicken thigh was more preferred in the comprehensive evaluation of soft-boiled chicken.

In conclusion, the soft-boiled made from yellow-feathered broiler Qingyuan partridge chicken had the best flavor and taste when the post-mortem aging time was at 2 h. The chicken skin reduced the perception of umami and sweet taste during oral processing of soft-boiled chicken, its smooth and chewy characteristic and influence on volatile aroma components needed to be further explored.