臺灣飼料用甘藷蛋白質含量與胰蛋白酶抑制活性分析

Protein Content and Trypsin Inhibitor Activity Analysis of Taiwanese Animal-feed Sweet Potatoes

本研究分析臺灣飼料甘藷的蛋白質含量與胰蛋白酶抑制活性，所分析的甘藷品種包括台南(TN)18號、台農(TNG)10、17和31號，再加上CYY98-08及CYY99-68兩個實驗品系，台農10號的蛋白質含量為2.1%，是蛋白質含量最低的飼料甘藷，而台南18號和CYY98-08則是臺灣蛋白質含量較高的飼料甘藷，因為甘藷的蛋白質含量偏低，當製成甘藷飼料時可以混入蛋白質含量較高的大豆粕或大豆渣，但大豆粕及大豆渣的粉末總體密度皆小於甘藷（約在0.7~0.75g/mL之間），在進行混合時，容易因密度不同而導致混合不均。大豆粕的蛋白質含量約40%，而大豆渣的蛋白質含量約為20%左右，若台農10號甘藷和50%的大豆粕混合，可使混合飼料的蛋白質含量達20%以上，但若混合50%的大豆渣，混合飼料的蛋白質含量只能達到10%。台農10號的胰蛋白酶抑制活性大約為50%，而台南18號及台農17號則有較高的胰蛋白酶抑制活性，實驗品系中以CYY99-68的胰蛋白酶抑制活性最低，在台農10號甘藷的混合飼料中，加入50%大豆粕的混合飼料，其胰蛋白酶抑制活性大約是94%左右，而加入50%大豆渣的混合飼料，其胰蛋白酶抑制活性只有30%左右，無論大豆粕或大豆渣都可以成功地和台農10號甘藷混合，只是進行飼料混合加工時，可根據混合飼料的蛋白質需求標準選擇適合的混合原料。

The protein content and trypsin inhibitor activity of six Taiwanese animal-feed sweet potato varieties, including TN18, TNG10, TNG17, TNG31, CYY98-08, and CYY99-68, were analyzed in this study. TNG10 sweet potatoes contain less protein (2.1%) than other sweet potatoes. On the other hand, TN18 and CYY98-08 contain more proteins. Because the protein content of sweet potatoes was not enough, soybean meal and soybean dregs can be mixed with sweet potatoes to increase the protein content. Soybean meal and soybean dregs had lower bulk density than sweet potatoes (0.70~0.75 g/ml). The difference in bulk density resulted in the difficulty of well-mixing. The protein content of soybean meal and soybean dregs was 40% and 20%, respectively. When 50% soybean meal was mixed with TNG10 sweet potatoes, the protein content of the mixture was 20%. When 50% soybean dregs were mixed with TNG10 sweet potatoes, the protein content was only 10%. The trypsin inhibitor activity of TNG10 sweet potatoes was about 50%. TN18 and TNG17 sweet potatoes had higher trypsin inhibitor activity. However, CYY99-68 had lower trypsin inhibitor activity than other sweet potato varieties. When TNG10 sweet potatoes were mixed with 50% soybean meal, the trypsin inhibitor activity of the mixture was approximately 94%. When TNG10 sweet potatoes were mixed with 50% soybean dregs, the trypsin inhibitor activity was 30%. Both soybean meal and soybean dregs were successfully mixed with TNG10 sweet potatoes. Sweet potatoes can be mixed with either soybean meal or soybean dregs to meet the protein requirement.