介質研磨紅棗作為乳酸菌益生質及改善結腸發炎

Abstract

本研究系統性評估介質研磨技術應用於新鮮紅棗 (Ziziphus jujuba Mill.) 及紅棗干之加工，探討其對懸浮液之物理與化學性質、生物活性化合物含量及潛在功能應用的影響。實驗針對固形物含量與研磨時間進行最佳化分析，結果顯示理想製備參數為：紅棗原料濃度為 5% (固形物基準)，其中新鮮果實需研磨 180 分鐘，紅棗干則以 120 分鐘研磨時間為佳。粒徑分析結果顯示，鮮棗懸浮液之體積平均粒徑由 229.0 ± 1.0 μm 顯著降至 25.0 ± 0.2 μm，數量平均粒徑由 7.2 ± 0.0 μm 降至 0.1 ± 0.0 μm；棗干懸浮液方面，其體積平均粒徑由 146.3 ± 1.5 μm 降至 29.4 ± 0.8 μm，數量平均粒徑亦由 11.3 ± 0.2 μm 降至 0.1 ± 0.0 μm，顯示介質研磨處理能顯著破壞紅棗樣品之結構並有效降低粒徑，達到粒子微細化的效果。此外，研磨處理亦改善懸浮液之 ζ 電位、黏度及分散穩定性，並對色澤與 pH 值造成顯著變化，顯示介質研磨技術對產品物理與化學性質具有多重影響。活性成分方面，新鮮果實經介質研磨後，可提升懸浮液水相中總類黃酮含量由 2.9 ± 0.1 增至 3.8 ± 0.0 mg 兒茶素當量/g 乾物重 (DW)，總三萜類含量亦由 15.4 ± 1.2 提升至 28.0 ± 4.9 mg 齊墩果酸當量/g 乾物重 (DW)。原料類型方面，紅棗干經介質研磨與熱水萃取後所測得之活性成分含量皆優於攪碎處理。在抗氧化活性方面 (DPPH、FRAP、ABTS)，研磨前後樣品變化不大，懸浮液皆具有良好的抗氧化效力。綜合上述結果，選擇鮮棗懸浮液作為後續乳酸菌發酵、細胞實驗與小鼠結腸炎模型試驗之研究樣品。經 Lactiplantibacillus plantarum 發酵後顯示，無論經攪碎或介質研磨處理，懸浮液皆為良好發酵基質，可有效被乳酸菌利用並產生乳酸。進一步以 RAW 264.7 巨噬細胞進行抗發炎試驗，結果顯示鮮棗懸浮液可抑制一氧化氮與促發炎細胞激素 IL-1β 的產生，具備調節發炎反應的潛力。然而，在 DSS 誘導性結腸炎小鼠模型中，儘管介質研磨鮮棗懸浮液顯示安全性，仍未觀察到顯著的保護作用。總結而言，介質研磨技術可有效提升紅棗懸浮液之物理穩定性與活性成分釋放效率，亦展現作為功能性食品或健康促進素材之應用潛力，未來可望進一步應用於營養補充品、保健飲品與疾病管理相關產品的開發與產業化推廣。

This study systematically evaluated media milling for processing fresh (Ziziphus jujuba Mill.) and dried jujube, and examined its effects on the physicochemical properties, bioactive compound content, and functional potential of the resulting suspensions. Optimization of solids content and milling time indicated that the ideal conditions were 5 % (w/w) total solids, with milling times of 180 min for fresh fruit and 120 min for dried fruit. Particle size analysis showed that the volume-weighted mean diameter of the fresh jujube suspension decreased markedly from 229.0 ± 1.0 µm to 25.0 ± 0.2 µm, while the number-weighted mean diameter fell from 7.2 ± 0.0 µm to 0.1 ± 0.0 µm. For the dried jujube suspension, the volume-weighted mean diameter was reduced from 146.3 ± 1.5 µm to 29.4 ± 0.8 µm and the number-weighted mean diameter from 11.3 ± 0.2 µm to 0.1 ± 0.0 µm. These results confirm that media milling effectively disrupts jujube structure and micronizes the particles. Concurrently, milling improved ζ-potential, viscosity, and dispersion stability, and significantly altered color and pH, indicating multiple impacts on product quality. Regarding bioactive constituents, milling fresh fruit increased the total flavonoid concentration in the aqueous phase from 2.9 ± 0.1 to 3.8 ± 0.0 mg catechin equivalents (CE)/g dry weight (DW) and the total triterpenoid content from 15.4 ± 1.2 to 28.0 ± 4.9 mg oleanolic acid equivalents (OAE)/g DW. For dried fruit, both media milling and hot water extraction yielded higher bioactive compound levels than blending. Antioxidant activities (DPPH, FRAP, and ABTS assays) showed only minor changes before and after milling, indicating that all suspensions retained strong antioxidant capacity. Based on these findings, the fresh jujube suspension was selected for further studies involving lactic acid bacteria fermentation, cell assays, and a dextran sodium sulfate (DSS)-induced colitis model. Fermentation with Lactiplantibacillus plantarum demonstrated that both blending and media milled suspensions served as excellent substrates, supporting bacterial growth and lactic acid production. In RAW 264.7 macrophages, the fresh jujube suspension suppressed nitric oxide production and the pro-inflammatory cytokine IL-1β, indicating anti-inflammatory potential. In a DSS-induced colitis model, the media milled suspension was safe but did not confer significant protection. In summary, media milling markedly enhances the physical stability and release of bioactive compounds in jujube suspensions, underscoring its promise as a platform for functional food or health promoting ingredients. The technology could be further leveraged to develop nutritional supplements, functional beverages, and products aimed at disease management and commercialization.