不同明胶添加量馒头的质构、营养价值及微观结构差异

Differences in Texture, Nutritional value and Microstructure of Steamed Buns with Different Amounts of Gelatin

摘要:

该研究分析了不同明胶添加量引起的馒头的质构、营养价值及微观结构变化。通过TPA质构分析、感官评定、比容及氨基酸组分测定分析馒头的质构、营养及微观结构等。研究表明，明胶添加量增大，馒头硬度、胶着度及咀嚼性先减小后增大，黏聚性和回复性先升高后降低。明胶添加量为3%时，其硬度、胶着性及咀嚼性最小，弹性、黏聚性及回复性最大，此时馒头比容（1.96）和感官评分（81.72）显著提高，各指标均为最优。添加明胶馒头蛋白质含量比普通白馒头高17.62%，必需氨基酸含量高46.06%，赖氨酸评分高52.12%，总必需氨基酸评分高22.00%。GC-MS检测添加明胶的馒头酯类含量升高40.61%，烷烃类提高48.60%，芳香杂环胺类提高34.03%。α-螺旋含量在面团中有所变化；β-折叠含量在蒸制后馒头中显著增大；β-转角含量均有不同程度的下降（P<0.05），说明添加明胶使蛋白质二级结构中无序的β-转角向有序的β-折叠或α-螺旋结构转换，蛋白质结构更趋于稳定。添加明胶能显著改善馒头的质构特性、感官品质及营养价值。

Abstract:

The changes in the texture, nutritional value, and microstructure of the steamed buns caused by the addition of different amounts of gelatin were studied. The texture, nutrition value and microstructure of the steamed buns were analyzed by TPA, sensory evaluation, specific volume measurement and amino acid composition analysis. The results showed that with the increase of gelatin content, the hardness, adhesiveness and chewiness of the steamed bun decreased firstly then increased, and the cohesiveness and resilience decreased firstly then increased. When the content of gelatin was 3%, the hardness, adhesiveness and chewiness of the finished steamed bun were the lowest, while the elasticity, cohesiveness and resilience were the greatest, with the specific volume (1.96) and sensory score (81.72) Therefore, the indexes of the finished steamed bread all reach the optimal value. Compared with the ordinary white steamed bun, the gelatin-fortified steamed bread had higher protein content (increased by 17.62%), essential amino acid content (increased by 46.06%), lysine score (increased by 52.12%), and overall essential amino acid score (increased by 22.00%). The results of GC-MS analysis showed that the gelatin-fortified steamed bun had increased contents of esters, alkanes and aromatic heterocyclic amines (by 40.61%, 48.60% and 34.03%, respectively). The addition of gelatin led to a change in the content of α-helix, a significant increase in the content of β-sheet after steaming, and different degrees of decrease in the content of β-turns (P<0.05). These results indicated that the addition of gelatin made the disordered β-turns of the protein secondary structure convert to the ordered β-sheets or α-helical structure, and the protein structure became more stable. Thus, the addition of gelatin can significantly improve the textural characteristics, sensory quality and nutritional value of steamed bun.