- 學位論文
酵素處理與食用膠添加對文旦柚皮果醬抗氧化性與耐熱性之影響
Effect of enzyme treatment and edible gums addition on antioxidant and heat-resistant property of Wentan pomelo peel jam
摘要
根據研究結果顯示柚類果皮之各項機能性成分均較果肉高出甚多，且柚皮富含類黃酮，具有許多生理活性。經naringinase水解後，因naringin醣苷鍵的切除而提高抗氧化能力，且naringin對熱穩定，會隨著溫度升高而增加其溶解度，因此利用柚皮水萃液製成高糖酸比的果醬，另添加具耐熱性質的食用多醣膠質及修飾澱粉，以改善果醬烤焙時水分喪失、塌陷等現象，探討抗氧化能力之變化以及烤焙後果醬耐熱性、質地剖面分析、色澤、水活性變化等。naringinase與柚皮作用方面，在不同的柚皮濃度 (0.5-2.5 g/ mL) 、時間 (0.5-2.5 hrs) 、溫度 (室溫-70℃) 、pH値 (3.5-5.5) 下反應。實驗結果顯示，naringinase水解柚皮確實可以提高抗氧化能力，且當水解條件為柚皮濃度2 g/100 mL、pH 4.5、60℃、萃取2小時，有較佳的總酚 (81.97 mg/100 mL) 及還原力 (1996 μmol/L) 的表現。而利用不同水溶液製得之柚皮果醬經烤焙後其抗氧化能力之變化，酵素柚皮水萃液會高於柚皮水萃液以及未經萃取的組別，且柚皮果醬經高溫烤焙後，抗氧化能力皆有上升的趨勢。 利用不同食用膠多醣膠質 (果膠、結蘭膠、果膠混卡特蘭膠、果膠混關華豆膠、果膠混三仙膠、果膠混結蘭膠、果膠混鹿角菜膠) 及澱粉的添加 (糯玉米、預糊化、架橋澱粉) ，製作而成的模式果醬經烤焙後，其受熱變化情形如下：於200℃下顯現出結蘭膠的耐熱性 (97%) 較佳，單純的果膠及果膠混三仙膠其耐熱性質較差；修飾澱粉 (預糊化澱粉、架橋澱粉) 隨著添加比例0.23%、0.46%、0.7%的提高，其耐熱性隨之上升。質地剖面分析方面，經烤焙後其內聚性下降、彈性無明顯變化，其餘的參數如：硬度、黏著性、膠黏性、咀嚼性則都呈現上升的趨勢。除了咀嚼性之外，其餘參數皆是以修飾澱粉變動的幅度最小，顯示其對樣品具有維持質地的能力。烤焙後色澤、水活性變化方面，架橋澱粉於加熱時伴隨著梅納反應的發生，而使色澤上有所差異，故其色差較不添加澱粉的組別為大；由於架橋澱粉顆粒有增強對熱之抵抗力，使得經烤焙後自由水有較佳的保留，使得其水活性變動較不添加澱粉的組別來的小。
並列摘要
Many studies of citrus peel found that the concentration of functional ingredients was higher than pulp. The pomelo peel including rich kinds of flavonoid components and has the physiological regulation mechanism. Naringinase hydrolyzing for pomelo peel increase antioxidant activity because of ablation for glycoside. Naringin to the thermally stable can increase its solubility along with the rishing temperature. Therefore, use pomelo peel water extraction to make the high Ratio of °Brix to Titratable acidity jam, then add the heat-resistance gum and modified starch to improve the jam roast condition when the moisture content losing and collapse. The effects of antioxidant activity, heat-resistant properties, texture profile analysis, color and water activity change will be studied. The experiment results showed that naringinase hydrolyzing for pomelo peel can increase antioxidant activity. When hydrolyzing conditions by concentration 2 g/100 mL, pH 4.5, 60℃ and 120 minutes which have better results of total phenol (81.97 mg/100 mL) and FRAP (1996 μmol/L). The antioxidative acticity of different water solutions altered. Water extract of pomelo peel with naringinase have antioxidative acticity higher than those of water extract of pomelo peel and unextracted group. Pomelo peel jam can increase antioxidant activity with high temperatute baking. Making model jam with different gums (pectin, gellan gum, pectin mixed with curdlan, pectin mixed with guar gum, pectin mixed with xanthan gum, pectin mixed with carrageenan, pectin mixed with gellan gum) and additive starchs (cross-linked starch, pre-gelatinized starch) the baking results are as follows: gellan gum has the better heat-resistant properties (97%), pectin and pectin mixed with xanthan gum has low value. Modify starch (cross-linked starch, pre-gelatinized starch) with rising additive ratio (0.23%, 0.46%, 0.7%) can help enhancing heat-resistant properties. Regarding texture profile analysis, cohesiveness value is decreased, springiness value doesn’t change obviously; the hardness, adhesiveness, gumminess and chewiness value are increased after baking. All parameters, except chewiness, have minuscule alteration of modify starch. The results revealed that modify starch have the capacity to maintain the sample quality. Regarding color and water activity, the cross-linked starch with cause the deep color and differ with unadded group accompanied Maillard reaction during heating. Cross-linked starch has high heat-resistant ability that free water can get better conservation and the effect of water activity is lower than unadded group.