摘要
对全脂大豆粉和脱脂大豆饼分别通过干热和湿热处理，研究不同工艺条件下脲酶活性变化的规律和对有效赖氨酸含量的影响。结果表明，在同一温度下，全脂大豆及大豆饼的脲酶活性与处理时间呈极显著线性负相关（Ｐ＜０．０１）；在同一时间下，与温度呈曲线下降关系。未经加热的生大豆和生豆饼的脲酶活性ΔｐＨ约为２．２，它们均对湿热敏感，而对干热耐性较高。干热处理时，１３５℃开始对脲酶失活有显著作用，但两小时后ΔｐＨ仍有１．２；当温度至１５０℃时脲酶可在６０分钟左右完全失活。湿热处理时，脲酶失活时间为：１００Ｃ（０ＭＰａ蒸汽压）时，处理１０－１５分钟：１１２℃（０．０５ＭＰａ蒸汽压）时１０分钟：１２０℃（０．１０ＭＰａ蒸汽压）和１２８℃（０．１５ＭＰａ蒸汽压）时５分钟即可。由于在两种加热处理方式下，大豆粉及大豆饼中的有效赖氨酸含量和抗营养因子含量均随着时间延长而呈线性下降，即加热时间延长伴随着正负两种效应，因此，最佳的处理时间是使脲酶活性接近失活的时间。热处理对大豆营养成分的含量没有影响，适度热处理可使大豆各种氨基酸的回肠表现消化率大幅度提高。
Raw soybean and soybean meal were treated by dry heat or wet heat to study the variation of urease activity( UA) and influence on the available lysine content under differ- ent treatment conditions. The results indicated that the urease activity in raw soybean and soybean meal, and treat time were linear in negative regression at the same temperature, and the urease activity in them and temperature were negative related in curve at the same time. The basic UA of non - treated raw soybean and soybean meal was 2. 20(ΔpH). Both of them was highly sensitive to wet heat, and strongly resistant to dry heat. Under dry heat treat condition, starting temperature for marked effect on UA was 135℃, however, UA re- mained 1.20(ΔpH) even after 2 hours of treatment. UA could be totally ceased within 60 minutes while temperature up to 150℃. Under different wet heat treatment condition, the time spend for UA totally cease was: 10 - 15 minutes at 100℃ (0 MPa vapor pressure); 10 minutes at 11 2℃(0.5MPa vapor pressure); 5 minutes at 121℃(0.1MPa vapor pressure) and 128℃(0.15MPa vapor pressure). Under two heat treatments, urease activity and available lysine contents in both raw soybean and soybean meal decreased linearly with the increment of treat time. Consequently the best treat time for them was on that UA could be near ceased. The nutritive con tent in soybean was not changed by heat treatment. The apparent ileum digestibilites of amino acids in soybean greatly increased by properly heat treatment. This paper put forword a mathmatical model to predict nutrient value of soybean and soy- bean meal according to technological parameter established.
出处
《动物营养学报》
CAS
CSCD
1998年第1期12-19,共8页
CHINESE JOURNAL OF ANIMAL NUTRITION
基金
国家自然科学基金
关键词
大豆
热处理
营养价值
heat treat, Soybean, Anti-nutritive factor, Nutritive value
