植物性脂肪之製備及流變性質

Abstract

隨著動物保護、環境保護及健康意識逐漸抬頭，植物肉已經成為極具潛力的新穎食品。植物肉主要由蛋白質、油及水組成，其他成份包含充填劑、著色劑、香料等。市面上大多植物肉產品中的油脂通常以乳化狀態存在，然而實際上的畜肉有「肥肉」、「油」及「瘦肉」之分。本研究針對研發植物肉產品的「脂肪」，為了同時具備肥肉的外觀、口感及質地，實驗分成「肥肉」及「油」兩部份，並以豬背脂 (pork back fat) 為模擬目標。「肥肉」部份，使用可可脂及椰子油，並以熱穩定的海藻酸鈣凝膠作為植物性肥肉主體，以硬度為指標，使用反應曲面法 (Response surface methodology, RSM) 建立模型、優化凝膠配方，並進一步分析膠體的鬆弛模量 (Relaxation modulus)。結果顯示以26.36%油、3.32%卵磷脂、3.56%海藻酸鈉、0.64%碳酸鈣及2.32%葡萄糖酸內酯之凝膠硬度與豬背脂硬度無顯著差異(p>0.05)，接著以此配方做五次驗證試驗，證實模型的正確性。另外，膠體在7℃時比豬背脂更偏向黏彈性固體；常溫下壓縮8%形變量、維持30分鐘依然穩定不破裂，可確保在後續加工過程的穩定性。在油的部份，則利用15%~25%的卵磷脂作為油脂結構劑 (Fat structurant)，加入微量的水 (0.1~1.8%)，結構化常溫液態之芥花油 (Canola oil)，成功提升芥花油熔點至65℃以上，在25℃呈現橡膠態的油膠 (Oleogel)，可模擬常溫不具流動性的豬油，高溫烹調則熔化溢出。綜合上述，本研究成功利用純植物性原料 (Plant-based) 研發具豬背脂質地之肥肉，及巨觀性質近似豬油的油膠，後續可進一步與組織化蛋白質 (Textured vegetable protein, TVP) 混合，開發出具有肥肉紋路的植物肉。

Because of the universal value such as animal welfare, environment protection, and healthy life, plant-based meat has become a novel food. In the plant meat, the major ingredients include water, protein, oil, binding agent and colorant. Oil in most of the plant-based meat products exists as emulsion. However, there are “oil”, “fat” and “lean meat” in real meat. In order to simulate the appearance, mouthfeel and the texture of the fat and oil in the real meat, we divided the experiment into two parts, one was to simulate the “fat” and the other was for “oil”. For fat, the hardness of pork back fat was used as the target. We used calcium alginate, a temperature independent gel to provide the three-dimensional structure of the “fat”. The response surface methodology (RSM) was used to establish the model and optimize the formulation. The viscoelastic property of the “fat” was also analyzed using relaxation modulus. The results indicated that the optimal formulation for the “fat” was 26.36% oil, 3.32% lecithin, 3.56% sodium alginate, 0.64% calcium carbonate and 2.32 %glucono-δ-lactone (GDL). And the hardness of this plant- based “fat” was not significantly different (p>0.05) from pork back fat. However, the “fat” was more elastic than the pork back fat at 7℃ and more stable under 8% strain for 30 minutes at 25℃, which indicated the “fat” might be more resilient during the following processing. In the part of “oil”, we investigated lecithin oleogel to simulate lard. Canola oil was structured by 15%~25% lecithin with micro amount of water (0.1~0.8%). The result showed that the melting points of all the prepared oleogels were above 65℃ and existed in rubbery state in the room temperature, showing the similar macroscopic properties with lard. In conclusion, we successfully used plant-based materials to develop the plant-based fat and oil. The “fat” had the similar hardness as pork back fat and the oleogel had similar macroscopic properties of lard. These plant-based fat and oil products can be further mixed with textured vegetable protein (TVP) to manufacture plant-based ground meat.