不同穀物澱粉之性質對冷藏烏龍麵品質的影響

Abstract

摘 要 本論文主要在探討由不同來源（小麥、玉米、及稻米）之穀粉或澱粉，以重組麵粉方式進行澱粉取代試驗，探討其他來源榖類澱粉對烏龍麵條製品品質及貯藏性質的影響。試驗將分成二個主軸：首先是探討不同來源澱粉的理化性質，接者則是探討不同穀類澱粉來源及不同米澱粉取代比例對麵條品質及質地之影響。結果顯示：不同來源之穀物澱粉其粒徑大小、形狀、支鏈澱粉分子結構、糊液黏度性質與熱性質有顯著差異。大致上可以分成糯性（直鏈澱粉含量＜2%）與非糯性澱粉（直鏈澱粉含量介於13~25%），非糯性澱粉一般均具有較高的最終黏度、回凝黏度及較低的膨潤性質。但即使均為糯性品系，各個品種之間亦有明顯的差異。糯性玉米澱粉之支鏈澱粉微細結構中屬於B1-chain之中長鏈（DP 13-24）部分所佔比例顯著高於米澱粉及小麥澱粉，以致於其糊化溫度及糊化熱焓值均為最高；糯性小麥則有最高的尖鋒黏度及最低的起始糊化溫度。至於在決定烏龍麵條食用性質方面，影響因子複雜，主要會受到麵粉原料之糊化溫度、直鏈澱粉含量、支鏈澱粉結構及澱粉膨潤性質之影響。試驗結果顯示，以米澱粉取代者其麵帶結構最為緻密，也最薄。因此，煮麵時間相對於其他樣品縮短許多，致使烹煮損失率也顯著降低。但由於其最適煮麵時間較短，麵條水分含量及膨脹率則較其他樣品為低。重組麵粉之麵條質地及貯存試驗結果顯示，以糯性澱粉取代者具有最小之截切力，其中以TCW 70（67%）取代者為最低，其次是以糯性小麥及糯性玉米澱粉取代者，但後者烹煮時間不似前者，煮麵時間並未明顯縮短。麵條經冷藏貯藏5天後，由熱性質分析之結果得知，TCW 70（67%）重組麵粉麵條之回凝速率最快，因此截切力急速上升，但經由沸水復熱1 min後，其截切力可以回復到比新鮮麵條更軟狀態。在不同米澱粉取代度，如TCW 70（20%）、TCW 70（40%）、TCS 10（20%）、TCS 10（40%），經4℃貯存一天後，可降低麵條之回凝程度。整體而言，建議以20%的TCW 70、TCS 10米澱粉取代小麥麵粉以製備烏龍麵條為最佳。因為，相較於其他榖物澱粉的取代，此麵條有較短的烹煮時間並可以抑制貯存初期的回凝現象。

Different sources of cereal starch (including rice, wheat and corn) were used as the substituted starch of reconstituted flour for Udon noodle making. The purposes of this study were to investigate the physicochemical properties of different cereal starches first, and then evaluated the cooking, eating and storage qualities of noodle made from reconstituted flours. The results indicated that there were significant differences of cereal starches from different sources in particle size and shape of starch granules, microstructure of amylopectin, pasting and thermal properties of starch slurry. Based on the amylose content of starch, waxy starches contained less then 2% of amylose and non-waxy starches contained 13-25% of amylose. Generally speaking, non-waxy starches had higher final viscosity and setback and lower swelling power. However, there were significant differences in their pasting properties among different waxy starches. According to the analysis of microstructure of amylopectin, the proportion of B1-chain length (DP 13-24) of waxy corn starch was higher than that of rice starches and wheat starches. This resulted in the highest gelatinization onset temperature and enthalpy. Waxy wheat starch had the highest peak viscosity and lowest pasting temperature among all of starches. The influential factors of cooking, eating and storage qualities of Udon noodle made from reconstituted flour were very complex; the major factors include the gelatinization temperature of starch in reconstituted flour, amylose content of starch, microstructure of amylopectin and swelling power of flour. The dough sheets made from rice starches were the most compact and the least thickness among those made from reconstituted flours. The optimal cooking time of noodle was much shorter for those made of rice starch reconstituted flour than others. The low cooking loss of noodles made of rice starch reconstituted flours (both waxy and non-waxy) was attributed to the short cooking time required for them. While, the short cooking time resulted in low moisture content and low swelling index of boiled noodle. Compared to noodle made of non-waxy starch reconstituted flours, cooking properties of noodle made of TCW 70 (67%） starch reconstituted flours had the lowest cutting force, followed by that made of waxy wheat starch and waxy corn starch reconstituted flours. However, the cooking time of noodle made of waxy wheat starch and waxy corn starch reconstituted flours was not significantly decreased. After five-day’s storage, degree of retrogradation of noodle made of TCW 70 (67 %) reconstituted flour was high and contributed to the large cutting force. Decreasing in the replacement ratio of TCW 70 and TCS 10 starch in reconstituted flours, such as 40% and 20% of replacements, decreased the degrees of retrogradation of noodles after 1–day’s storage at 4℃. After reheating with boiling water, the stored noodles retrieved their original softness with the order of decreasing in softness with the increases in the degree of replacements of rice starches in reconstituted flour. The reconstituted flour with TCW 70 (20%) and TCS 10 (20%) starch were recommended for the Udon noodle making due to their short cooking time and high swelling index in fresh cooked noodles and decreased the degrees of retrogradation of noodles after 1–day’s storage at 4℃.