纖維強化饅頭之流變學：應力鬆弛與質地剖面分析   全文下載

Rheology of Fiber-Enriched Steamed Bread: Stress Relaxation and Texture Profile Analysis

小麥麩皮是廣泛使用在食品工業上之膳食纖維來源。本研究使用質地分析儀評估小麥麩皮取代量（0 - 30%）、吸水率（46 - 62%）和蒸炊電功率 （4 - 12 kW）對饅頭之應力鬆弛與質地參數之影響。研究結果顯示饅頭之應力鬆弛數據非常符合Peleg-Normand模型與三元件之Maxwell模型。在10 - 40%不同應變條件下測試，普通饅頭和纖維強化饅頭在低應變下具有較高之彈性。饅頭之應力鬆弛試驗以在20%應變條件下執行測量較合適。一般而言增加小麥麩皮取代量導致饅頭之彈性下降與硬度上升。然而感官品評試驗結果顯示未添加小麥麩皮饅頭之質地和整體接受性與添加10和20%小麥麩皮饅頭者均沒有顯著差異。中和高的吸水率（54 - 62%）可製得彈性與質地較佳的饅頭。在最低功率（4 kW）下蒸炊所製得之饅頭具有最低的彈性。饅頭質地參數與應力鬆弛參數之間具有顯著相關性。本研究結果建議在54%的吸水率與12 kW的蒸炊電功率條件下可製得彈性與質地佳之含20%麩皮強化饅頭。

Wheat bran is one of the major dietary fiber sources widely used in the food industry in order to produce fiber-enriched foods. The effects of wheat bran substitution (0 - 30%), water absorption (46 - 62%) and electric power (4 - 12 kW) of steamer on stress relaxation and textural parameters of steamed breads were evaluated by the Texture Analyzer. The results showed that mechanical stress relaxation data of steamed breads were fitted well by both the Peleg-Normand and three-element Maxwell models. At 10 - 40% strains tested, common and bran-enriched steamed breads were more elastic measured at low strain. It was suitable to perform the stress relaxation test of steamed bread at 10 - 30% strains. Generally, increasing the substitution of flour by bran resulted in less elasticity and higher hardness of steamed bread. Results of sensory evaluation indicated no significant difference in textural and overall acceptability among various steamed breads with 0, 10 and 20% of wheat bran. Medium and high water absorptions (54 - 62%) produced fiber-enriched steamed bread with better elasticity and texture. The elasticity of the steamed bread was the lowest at 4 kW electric power of steamer. Significant correlations were found between textural characteristics and stress relaxation parameters. This study suggests that 20% bran-enriched steamed bread, with better elasticity and sensory acceptability, can be produced at 54% of water absorption and 12 kW of electric power of the steamer.