利用電子順磁共振頻譜建立經輻射照射處理香辛料之鑑別方法研究

Research on the identification using EPR spectroscopy for spices processed by gamma irradiation

蔡宗憲(Cai, Zong Sian)

指導教授 ： 江啟勳 ； 許芳裕

國立清華大學/原子科學院/核子工程與科學研究所/碩士(2016年)

摘要

香辛料為現今生活之常用所需品，大眾對於輻射以及食品安全的意識抬 頭，使用游離輻射對香辛料進行殺菌的處理方式廣泛利用於國內外，主要是利 用高劑量游離輻射達到香辛料滅菌除細菌、微生物以及增長有效期限，而其他 食品或物品亦會經由輻射照射處理，像是抑制馬鈴薯發芽、輻射誘發農產品變 異、玉石變色、魚類與乳製品的保鮮等等。相較於其他滅菌方法，輻射滅菌有 方便、快速、較不易變質與無化學殘留等優點；雖然台灣已經廣泛的使用經輻 射照射之產品，但尚未建構輻射滅菌之鑑別分析相關技術，國內許多欲出口之 輻射照射食品，常會遇到進口國家的嚴格控管，特別是經歷福島核災事件後的 日本，對於輻射照射處理食品的管控相當嚴格。
本研究選用 Co-60 作為滅菌應用之輻射源，在香辛料方面則選取台灣最常 見以及最常使用輻射滅菌之香辛料，依序為五香粉(Five-spice powder)、肉桂粉 (Cinnamon powder)、咖哩粉 (Curry powder)、辣椒粉 (Chili powder)、八角粉 (Star aniseed powder)、胡荽籽(Coriander seed)、百里香 (Herb powder)、檸檬草 (Lemon grass)、月桂葉 (Cassia powder)、茴香籽 (Fennel powder)、黑胡椒 (Black pepper) 共 11 種香辛料樣品。將個別樣品照射輻射劑量後，再利用電子 順磁共振(Electron paramagnetic resonance, EPR) 光譜儀計讀，藉由 EPR 計讀儀 器之原理，輻射照射後會產生自由基 (Free radicals) 係屬不成對電子 ( unpaired electron)，而 EPR 可以轉換不成對電子產生的數目為訊號強度，再藉由演算法 量化訊號，可以個別分析兩種訊號：峰對峰值(Peak-to-peak value)、曲線下面積 (Area of curve)。
藉由峰對峰值與曲線下面積來分析物質的不成對電子濃度，結果發現香辛 料經由輻射照射後會產生自由基，促使香辛料 EPR 訊號提高，依照不同香辛料 特性會隨著時間產生不同的衰變性質，可以成功的判斷香辛料是否照過輻射滅 菌，以及個別香辛料的 EPR 訊號衰變特性分析。除此之外，本研究發現空石英 管在尚未照射輻射時可作為測讀 EPR 之管樣容器，輻射照射空石英管會產生大 量的 EPR 訊號，由此推估 SiO2 細部的化學鍵結會受到高劑量輻射的破壞，生 成不成對電子；本論文之實驗有分析其照射輻射後的空石英管，於 EPR 訊號方 面屬於穩定的。

關鍵字

電子順磁共振光譜 ； 輻射照射滅菌 ； 香辛料 ； 石英管 ； 峰對峰值

並列摘要

The spices are commonly required food in modern life. The people is rising awareness of food safety including the safety of radiation irradiated food. The sterilization methods using ionizing radiation for spices has been frequently used in Taiwan and abroad. The aims of using high doses of ionizing radiation to irradiate spices are that effectively achieve sterilization of spices. Compared to other sterilization methods, the radiation sterilization has the advantages of easy, fast, relatively non-perishable and non-chemical residue. Although the gamma irradiated products have been commercially used in Taiwan, anyway, identification of radiation sterilization food has not been set yet. The exported gamma irradiated food must meet strict control by the import countries. For example, Japan, after the Fukushima incident, is strictly control the imported radiation irradiated food. The study designed to follow the report of International Atomic Energy Agency (IAEA) that gives the recommendation regarding the criteria of food irradiations.
In this research, Co-60 was selected as the radiation source of sterilization applications. The spices are common used and most frequently irradiated by radiation for sterilization in Taiwan. Eleven investigated samples listed below in sequence: Five-Spice powder, Cinnamon powder, Curry powder, Chili powder, Star aniseed powder, Coriander seed, Herb powder, Lemon grass, Cassia powder, Fennel powder, Black Pepper. In addition, the characteristic of quartz tube is also assessed in the experiments. According to the principle of EPR (Electron paramagnetic resonance), irradiated samples will produce unpaired electron products which include the free radicals. The number of unpaired electrons could be converted to form the signals of EPR. The signals could be analyzed by parameters of either Peak-to-peak value or Area of curve (AOC).
With analysis of Peak-to-peak or Area of curve, unpaired electron concentration related to free radicals of the spices after radiation exposure is proportion to radiation dose. EPR signal of spices is proportion to the number of free radical. EPR signal decay with time, and with different decay characteristic dependent on the types of spices. By the method of this research, whether the spices through radiation sterilization or not can successfully be determined. In addition, the study found that pure quartz tubes, the container of spice samples while perform EPR test, will not produce EPR signals before irradiation, but it will produced large amounts of EPR signals after radiation exposure. This research has analyzed irradiated quartz tubes which the EPR signals were stable.
Key Word：Electron paramagnetic resonance spectroscopy (EPR), Sterilization of irradiation, Spices, Quartz tube, peak-to-peak value.

並列關鍵字

Electron paramagnetic resonance spectroscopy (EPR) ； Sterilization of irradiation ； Spices ； Quartz tube ； peak-to-peak value

參考文獻

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