添加葡萄糖酸內酯及檸檬酸對泰式發酵香腸Nham之影響

食品發酵為最古老的食品加工方法之一，發酵肉製品製作過程中，除了添加乳酸菌酛外，亦可能添加可產酸之物質，降低pH值。葡萄糖酸內酯 (glucono-δ-lacton, GDL) 與檸檬酸 (citric acid, CA) 常添加於發酵產品中，不僅可以增加食物風味及延長食品保存，GDL亦具有抑制病原菌微生物之效果，然而若添加過量時會造成產品質地崩解品質下降，因此，本試驗旨在探討添加不同比率之GDL與檸檬酸對泰式發酵香腸Nham之理化、微生物、質地、感官品評及及電泳結果之影響。結果顯示：第4天發酵完成後，各組pH值皆顯著下降 (P 0.05)。發酵完成後各組滴定酸度皆顯著上升 (P 0.05)。製程第0天時，各組之L*值與a*值皆無顯著差異，發酵完成後各組皆有上升之趨勢；發酵後以及貯存期間b*值無顯變化，且各組間無顯著差異 (P > 0.05)，貯藏期結束後各組皆有下降之趨勢。物性分析結果顯示，發酵完成後樣品之硬度、彈性、脆度及咀嚼性皆顯著上升 (P 0.05)。品評結果部分，隨著貯存時間延長，各組之顏色、氣味、質地、風味、酸度、鹽度及總接受度評分皆無顯著差異 (P > 0.05)。綜觀上述，添加GDL與檸檬酸於Nham中對理化、微生物、物性、感官品評及電泳結果之表現並無顯著差異，未來應考量添加GDL與檸檬酸對於病原性微生物之作用，以生產安全衛生及品質優良之泰式發酵香腸。Food fermentation is one of the oldest food processing and preservation methods. Glucono-δ-lacton (GDL) and citric acid have been applied in the meat industry to improve flavors and extend shelf life of fermented products. However, too excess addition of GDL might deteriorate the qualities of products. The objective of this study was to investigate the influence of adding different amounts of GDL and citric acid on the physicochemical, microbiological, textural, and sensory properties of Nham sausages which inoculated with Lactobacillus plantarum as a starter culture. The results showed that the pH values decreased significantly (P 0.05). The L* and a* values did not significantly differ at day 0 and tended to increase after finishing of fermentation. Less change was observed in b* value after fermentation and during storage. There was no significant difference on b* values between treatments (P > 0.05) and they tended to decrease after storage. For the texture profile, the hardness, springiness, fracturbility and chewiness of samples increased significantly after fermentation, yet the cohesiveness of samples did not significantly differ between days 0 and 4. The hardness of samples did not significantly differ during storage. The control had the highest hardness whereas the ones with addition of GDL and citric acid had lower hardness. The VBN values increases significantly during the fermentation (P 0.05). There was no significant difference on the sensory characteristics between treatments. The NPN values of all treatments increased rapidly during the fermentation, and the ones of GDL04+CA01 and GDL08+CA01 decreased during storage. For the SDS-PAGE, the intensity of the myosin heavy chain (MHC) band decreased thereafter. The actin band (around 45 kDa) also decreased in intensity after fermentation and storage. In conclusion, adding GDL and citric acid did not detriment the physicochemical, microbiological, and textural qualities of the Nham sausages inoculated with L. plantarum. Further studies should be addressed on the protectium against the pathogens base on the addition of GDL and citric acid in order to produce safe Nham sausage with better qualities.誌謝. i 中文摘要 ii Abstract iii 圖次. vii 表次. viii 附錄目次 ix 壹、 前言 1 貳、 文獻探討 2 一、發酵食品定義與起源 2 二、菌酛 (starter culture) 2 (一) 乳酸菌之定義與用途 2 (二) 添加菌酛目的 2 (三) 乳酸菌之發酵作用與食品中之運用 3 (四) L. plantarum之運用以及與生物胺之關係 3 三、發酵香腸 5 (一) 發酵香腸之加工特性 5 (二) 發酵香腸分類 5 (三) 菌酛在發酵香腸中之利用 5 四、泰式發酵香腸Nham 6 五、GDL之介紹 8 (一) GDL之結構與功能性 8 (二) GDL使用 8 六、檸檬酸之介紹 9 (一) 檸檬酸之結構與功能性 9 (二) 檸檬酸之使用 9 參、 材料與方法 11 一、原料肉 11 二、泰式發酵香腸Nham的配方與製備 11 三、乳酸菌酛之活化與製備 11 四、分析項目 13 (一) 產品失重率 (weight loss) 13 (二) 水分含量 (moisture content) 13 (三) 灰分 (ash) 13 (四) 粗脂肪 (crude fat) 13 (五) 粗蛋白 (crude protein) 13 (六) pH值 (pH value) 14 (七) 酸度 (titratable acidity) 14 (八) 色澤 (color) 14 (九) 水活性 (Water activity) 15 (十) 質地剖面分析 (Texture profile analysis, TPA) 15 (十一) 揮發性鹽基態氮 (Volatile basic nitrogen, VBN) 15 (十二) 總生菌數 (total plate count) 16 (十三) 乳酸菌數 (lactic acid bacteria counts, LAB) 16 (十四) 非蛋白態氮 (nonprotein nitrogen, NPN) 16 (十五) SDS-PAGE 17 (十六) 感官品評 (sensory tralnation) 18 (十七) 統計分析 18 肆、 結果與討論 19 一、失重率、一般成分、pH值及酸度 19 二、顏色 23 三、水活性 25 四、物性分析 25 五、揮發性鹽基態氮 29 六、總生菌數及乳酸菌數 31 七、非蛋白態氮 33 八、SDS-PAGE 35 十、感官品評 39 伍、結論 41 陸、參考文獻 42 柒、附錄 4