豌豆蛋白的分離及其加工上特性的研究

近年來由於全球暖化及糧食短缺，尋找肉類蛋白替代品成為一個十分熱門的關注議題，而豌豆本身含有大量的複合式碳水化合物、優良蛋白質及微量元素，成為了市場上關注的新焦點。多項研究表明豌豆蛋白與大豆蛋白具有相似的功能特性，但豌豆蛋白的低致敏特性更受到食品工業的重視，近年來常作為食品添加劑應用於食品中。這些商業性蛋白大都以高溫噴霧乾燥進行量產，在過程中常使蛋白受到熱破壞而變性，因此，本研究先利用鹼萃取－等電沉澱法自綠豌豆與黃豌豆中萃取出蛋白質，並用冷凍乾燥法進行乾燥，探討以不同pH值及粉水比對於蛋白質萃取率及純度的影響，之後使用最適之萃取條件以低溫（60°C）噴霧乾燥進行蛋白粉量產，比較商業性蛋白粉與自製蛋白粉之功能特性，最終利用國產單軸擠壓機進行高水分組織化試驗。研究結果顯示，在冷凍乾燥組中，綠豌豆於pH 11.5與粉水比1:10條件下有最高之蛋白質萃取產率15.75%；黃豌豆於pH 10.5與粉水比1:20條件下有最高之蛋白質萃取產率13.50%，兩者的蛋白質純度皆超過85%。噴霧乾燥組中，黃豌豆及綠豌豆蛋白質萃取產率落在10~12%間，蛋白質純度約為83%。由SDS-PAGE的結果，發現自製蛋白粉之球蛋白含量顯著高於商業性蛋白粉；蛋白質溶解度測定中，商業性蛋白粉之蛋白溶解度顯著低於自製蛋白粉，整體隨pH上升呈現先下降再上升的趨勢，於pH 5下有最低之蛋白質溶解度；乳化活性測試結果與蛋白質溶解度具有相似的趨勢，同樣於pH 5下蛋白粉具有最低之乳化活性；乳化穩定性測試結果，發現冷凍乾燥之蛋白粉乳化穩定性較高，整體來說乳化穩定性與pH值無顯著關係；發泡性與發泡穩定性測試中，pH值變化對自製蛋白粉的發泡性與發泡穩定性並無顯著影響，整體數值表現偏低。在高水分組織化試驗中，商業性蛋白粉於150°C、50%進料含水率下便有明顯組織化，當上升至160°C時硬度與截斷力皆具有顯著性上升；自製蛋白粉於相同的溫度及條件下，硬度與截斷力顯著大於商業性濃縮蛋白組，整體交聯現象較商業性蛋白強韌。

關鍵字

豌豆；豌豆蛋白；鹼萃取等電沉澱法；功能特性；組織化蛋白

並列摘要

In recent years, due to global warming and food shortages, the search for meat protein substitutes have become a very popular topic. Pea contains a large number of complex carbohydrates, proteins and micronutrient, which has become a new focus in the market. Several studies have shown that pea protein and soybean protein have similar functional properties, but the hypoallergenic properties of the pea protein are more valued by the food industry. In recent years, pea protein is often used as food additives. Most of these commercial proteins are mass-produced by high-temperature spray-drying in the process, proteins were destroyed and denatured. Therefore, in this study, proteins from green peas and yellow peas were first extracted by using alkaline extraction-isoelectric precipitation method, and then dried by freeze-drying method. Effects of different pH values and powder-water ratios on protein extraction rate and purity were studied. Furthermore, an optimum extraction condition was obtained and used with the spray-drying at a temperature of 60°C for a mass production of self-extraction pea protein. The functional characteristics of the self-extraction pea protein were compared with those of commercial protein, and then processed by an indigenous single-screw extruder for high-moisture texturization test. The results showed that in the freeze-drying group, green pea has the highest extraction yield (15.75%) under the conditions of pH 11.5 and powder to water ratio 1:10; yellow pea has the highest extraction yield (13.50%) under the condition of pH 10.5 and powder to water ratio 1:20, and the protein purity of both were more than 85%. In the spray-drying group, the extraction yield of yellow pea and green pea felt between 10 and 12%, and the protein purity was about 83%. The results of SDS-PAGE showed that the content of globulin in self-extraction protein was significantly higher than commercial protein. In the determination of protein solubility, the commercial proteins were significantly lower than the self-extraction protein, and the figure showed as a U-shaped curve. It has the lowest protein solubility at pH 5. And about the protein functionality, the trend of emulsifying activity test was similar to protein solubility, but the emulsifying stability was not. In the foaming properties test, the commercial protein was significantly higher than the self-extraction protein, and the self-extraction protein has no significant difference at different pH values. In the high-moisture texturized protein test, the commercial protein is clearly texturized at 150°C and 50% feed moisture content. When it raised to 160°C, the hardness and the cutting force were significantly increase. And at the same process conditions, the self-extraction proteins had significantly higher hardness and cutting force than commercial protein groups. Overall, the self-extraction protein’s gelling ability were higher than commercial protein.