本文以崂山奶山羊乳为研究对象，对山羊乳的一般理化性质进行分析，并重点探讨了山羊乳的热稳定性。采用热凝固时间法(HCT)测定不同泌乳期、温度、pH值及相关助剂对山羊乳热稳定性的影响。结果表明，山羊乳的pH接近中性、酸度为11~23 °T，且与泌乳期呈正相关关系。羊乳的稳定性随泌乳期的延长而增强，随加热温度的升高而急剧减弱。pH对羊乳的热稳定性影响较大，pH越大，HCT值越大，当待测乳样的pH值超过6.5时，乳样不再发生沉淀。在pH＝6.0、140 ℃加热条件下，加入适量浓度为0.01~0.20 mol/L的柠檬酸盐、磷酸盐、EDTA均可改善羊乳的稳定性，且添加物浓度越大，改善效果越好。添加钙离子亦可改变羊乳的热稳定性，其稳定性随钙离子浓度的升高而降低。羊乳热稳定性随蔗糖浓度的增大呈现出先升高后降低的趋势，添加浓度为35%的蔗糖时，待测羊乳的HCT值最高，羊乳的热稳定性最好。

The general physicochemical properties of Laoshan goat milk were analyzed and the heat stability of goat milk was discussed. The effects of lactation period, heating temperature, pH and additives on the heat stability of goat milk were studied by analyzing the heat coagulation time (HCT) of the milk. The results showed that pH of goat milk was close to neutral with titration acidity of 11~23°T, and it positively correlated with lactation period. The heat stability of goat milk enhanced along with the extension of lactation period and sharply reduced with the temperature increased. The influence of pH was enormous on heat stability, and HTC value was increased with pH increased. The solidification did not appear in the milk samples when pH＞6.5. Some additives such as citrate, phosphate and EDTA (0.01~0.20 mol/L) were used to overcome destabilization and the higher concentration of additives, the greater improvement of heat stability. On the contrary, calcium content had a negative impact on heat stability of milk. In addition, the result showed a special relationship between heat stability and sucrose concentration. With the increasing of sucrose concentration, the heat stability of milk ascended first and then descended. The heat stability and HTC value exhibited the highest by addition of 35% sucrose.

山东省科技发展计划项目（2013GNC11306）；山东省自然科学基金资助项目（ZR2010CQ005）