介質研磨與果膠酶對紅棗多酚釋出的影響

Abstract

紅棗（Ziziphus jujuba Mill.），是鼠李科（Rhamnaceae）棗屬植物棗樹的果實。東方人栽培、食用紅棗已有三千多年的歷史，傳統中醫認為紅棗可“補虛益氣、養血安神、健脾和胃”。紅棗中主要的功能性化合物為多酚（polyphenol）和黃酮（flavanoid），提供抗氧化、抗發炎、提高免疫力等作用。本研究因食材在地性、取得方便性以及來源明確性，選擇台灣公館鄉的雞心棗（鮮棗）進行研究。提取紅棗多酚的常用方法是熱水萃取法和超音波萃取法，多酚在植物體內的存在形式有自由態和包覆結合態，需要酸鹼分段式萃取結合態多酚。熱水萃取法因高溫對酚類物質造成破壞，超音波和酸鹼分段式萃取法繁瑣、不適於量產。本研究比較介質研磨和果膠酶處理鮮棗漿，對紅棗中多酚釋出的影響。結果顯示，介質研磨180 min懸浮液粒徑從240.20～272.47 μm下降至25.79 μm，總酚含量最高增加46.17%，總黃酮含量最高增加76.15%。果膠酶處理後懸浮液粒徑下降至150.9～182.1 μm，固形物含量11.77%的組別黏度均下降50%以上，總酚和總黃酮含量分別增加16.01%和9.92%。以單一多酚類物質之含量而言，介質研磨120 min表兒茶素和芸香苷分別增加46.8%和54.3%，接近總酚含量增加百分比。果膠酶處理後表兒茶素和芸香苷含量分別增加9.92%和7.02%。綜上所述，介質研磨可有效減小鮮棗漿粒徑、破壞植物細胞結構，增加紅棗總酚的釋出；酵素處理可增加紅棗總酚釋出，但仍需經濟分析。本研究的成果為紅棗的高附加價值之加工基礎。

Jujube (Ziziphus jujuba Mill.) is the fruit of jujube tree of the Rhamnaceae family, which has been cultivated and consumed jujube in oriental regions for more than 3,000 years. In traditional Chinese medicine, it is believed that jujube can “replenish vital energy, nourish blood and calm, strengthen the spleen and stomach”. The main bioactive compounds are polyphenols and flavonoids, which provide antioxidant, anti-inflammatory and immune-enhancing effects. In this study, base on locality, convenience and source clarity of the sample, we chose fresh jujube fruit from Miaoli, Taiwan. Traditionaly, jujube extraction methods are hot water extraction and ultrasonic extraction. Polyphenols presence in plants in three types: free, trapped and bound. Therefore, it is necessary to extract trapped and bound type polyphenols by acid-base method. The hot water extraction method causes damage to phenolic compounds due to high temperature, the ultrasonic and acid-base extraction is too complicated, to be commerciallized. In this study, fresh jujube pulp was treated by media milling or pectinase to destruct plant cells, to release polyphenols. The particle size of the suspension decreased from 240.2~272.47 μm to 25.79 μm after 180 min-media milling with an increase in total phenolic content by 46.17% and an increase in the total flavonoid content by 76.15%. Pectinase resulted in the decrease in particle size (150.9~182.1 μm) and viscosity (more than 50%) of 11.77% solid content. In the meanwhile, the content of total polyphenols and flavonoids were increased by 16.01% and 9.92%, respectively. Epicatechin and lutin increased by 46.8% and 54.3% respectively after 120 min-media milling. After pectinase treatment, the epicatechin and lutin content increased by 9.92% and 7.02%, respectively. Media milling could effectively reduce the particle size of fresh jujube pulp, destroy plant cell structure, and increase the release of total phenols from jujube; enzyme treatment has potential as a processing method to increase the release of total phenols from jujube. The result of this research would provide a foundation for processing of high value jujube.