不同碱添加量澄清甜菜汁面条的理化性质比较

Comparison of the Physicochemical Properties of Clear Beetroot Juice-Enriched Noodle with Different Amounts of Alkali

甜菜汁富含生物活性物质,可作为食用色素和功能性食品原料的来源。本研究将澄清甜菜汁(clear beetroot juice;CBJ)加入面条配方中,以改善面条的营养价值、抗氧化性与颜色的丰富性。本研究以10%CBJ-面条为研究对象,探讨碱添加量(0~0.40%)对其质构、颜色和抗氧化性质的影响。使用质构仪和色差仪分别测定面条的质构和颜色,采用分光光度法测定总甜菜色素、总多酚含量和1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除能力。研究结果表明:与对照组干面条相比,增加碱添加量(0.10%~0.40%)会显著增加干面条的折断力(11.07%~33.35%)和游离态总多酚含量(2.26%~25.28%),但是显著减少总甜菜色素(3.77%~43.20%)和DPPH自由基清除能力(1.08%~18.20%)。此外增加碱添加量会显著增加熟面条的切断力(10.88%~29.23%)和拉伸强度(47.78%~137.21%)。在色泽上,添加0~0.40%碱的CBJ干面条的红色度(a*值)介于16.59至1.98,而相对应地熟面条的红色度介于7.39至1.76,这表明甜菜汁中的甜菜色素对高p H和高温不稳定。因此本研究建议以低碱添加量(0.10%)制备甜菜碱面条,不仅可呈现粉红色面条外观且可保留较多的甜菜色素、总多酚及较高的抗氧化性。

Beetroot juice,rich in bioactive substances,is a good source of food colorings and functional ingredients.In this study,clear beetroot juice(CBJ)was added to the formulated noodle to improve the nutritional value,antioxidant properties and color of the noodle.The 10%CBJ-noodles was used as the research object to study the effects of added alkali level(0~0.40%)on the texture,color and antioxidant properties of the resultant noodles.Texture and color of the noodles were measured by a texture analyzer and a colorimeter,respectively.Total contents of betalains and polyphenols,and the 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical scavenging capacity were determined by spectrophotometry.The research results showed that compared with the control noodle(without alkali),increasing the alkali level(0.10~0.40%)significantly increased the breaking force(11.07~33.35%)and the content of free polyphenolics(2.26~25.28%)of the dried CBJ-noodles,whilst decreasing significantly total betalains(3.77~43.20%)and DPPH radical scavenging capacity(1.08~18.20%).In addition,increasing the level of added alkali increased significantly the cutting force(10.88~29.23%)and tensile strength(47.78~137.21%)of cooked noodles.In terms of color,the redness(a*value)of dried raw and cooked CBJ-noodle with 0~0.40%alkali ranged from 16.59 to 1.98 and from 7.39 to 1.76,respectively.These results indicate that the betalains in CBJ were unstable at a high pH and temperature.Therefore,this research proposes the use of a low alkali level(0.10%)for the preparation of alkaline noodles,which makes the noodles not only having a pink appearance but also possessing higher contents of retained betalains and polyphenols and higher antioxidant activity.