高壓處理微化甘藍膳食纖維與其功能性之研究

Abstract

甘藍 (Brassica oleracea var. capitata) 為十字花科蕓薹屬作物，是臺灣產量與產值皆第一大的蔬菜，但易有生產過剩問題發生。膳食纖維依照其溶解度可分為可溶性膳食纖維 (Soluble dietary fiber, SDF) 與不可溶性膳食纖維 (Insoluble dietary fiber, IDF) ，SDF具有較多生理功效但植物中多為IDF，因此本實驗目的為利用高靜水壓 (High hydrostatic pressure, HHP)與高壓均質 (High pressure homogenization, HPH) 技術微化初秋甘藍的膳食纖維，提升其SDF比例。 以酶-重量法測定SDF可由控制組6.43% 提高至最佳處理條件為HPH 1 Cycle 10.92%，SDF/IDF由0.27提高至0.44，而HHP最佳條件為600 MPa的0.35，表示HPH相較於HHP具有較好的微化效果。粉體性質方面，與SDF/IDF增加具有相同增加趨勢的性質有保油能力、水溶性指標、吸水膨脹力、乳化性、乳化安定性；隨SDF/IDF增加而降低的性質則有保水能力、吸水性指標、體積密度。處理後的粉末一般成分不會有明顯差異，且可以完整保留總酚含量，而類黃酮與維生素C則有降解的現象，進而影響了粉末的抗氧化性質，唯有亞鐵離子螯合率在均質後有上升的趨勢。經過HPH處理粉末可溶性的還原糖及總糖增加，且粒徑非常顯著的降低則是影響粉體產生不同性質的原因，以掃描式電子顯微鏡觀察，HPH處理後粉末微結構由片狀變成細碎顆粒狀且表面具有凹凸刻痕。此外，生理功效方面，陽離子交換能力不受高壓加工影響，膽固醇吸附力在HPH處理後可以顯著增加，亞硝酸鹽吸附力則在HHP處理後有顯著提升的效果。 總結所述，高壓處理具有微化甘藍粉末的效果，且改變其粉體性質並可以增加生理功效，進而成為具有多種功能性的膳食纖維原料，並期待其能提供甘藍產量過剩時解決剩餘物的一種新的加工利用方式。

Cabbage (Brassica oleracea var. capitata) belong to Brassica species, in the family Brassicaceae, and are the most widely grown vegetable crop in Taiwan. However, cabbage overproduction and price fluctuation occur every winter. Dietary fiber (DF) can be classified into soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) based on water solubility. Although SDF has more physiological benefits than IDF, the plant components generally contain the latter in high contents. Therefore, this study aims to micronize “early autumn” cabbage powder and increase the portion of SDF content using high hydrostatic pressure (HHP) and high-pressure homogenization (HPH) technologies. Using the enzyme-gravimetric method, SDF was increased from 6.43% in the control group to 10.92% in the optimal treatment condition in HPH 1 Cycle, and SDF/IDF ratio increased from 0.27 to 0.44. The highest SDF/IDF ratio in HHP was 0.35 at 600 MPa, indicating that HPH had a better micronization effect than HHP. The properties of powder proportional to the increase in SDF/IDF ratio included oil retention capacity, water solubility index, water swelling capacity, emulsion activity, and emulsion stability. The properties inversely proportional to the increase in SDF/IDF ratio included water retention capacity, water absorption capacity, and bulk density. After high-pressure treatments, the general powder composition of the powder was minorly influenced, and the total phenol content was completely retained. Flavonoids and vitamin C were degraded, which further affected the antioxidant properties of the powder. However, the ferric-reducing antioxidant efficiency increased after homogenization. After HPH treatment, the contents of reducing sugar and total sugar in the cabbage powder increased, and the particle sizes were substantially smaller. The smaller particle size was the main reason for the different properties of the powder. The microscopic structure after HPH treatment changed from flaky to broken and irregular granules with many irregularities on the surface. As for functional properties, high-pressure treatment had no significant effect on cation exchange capacity, while HPH treatment significantly increased the cholesterol adsorption capacity, and HHP treatment improved nitrite ion adsorption capacity. In summary, high-pressure-micronized cabbage powder has improved powder properties and physiological effects. Thus, the cabbage powder is a potential raw material as dietary fiber with multiple functions. This could serve as a solution for the problem of cabbage overproduction.