Abstract UHT hydrolysed-lactose milk (HLM) is prone to chemical changes, giving rise to off-flavours in the product. To investigate this better, headspace solid-phase micro-extraction gas chromatography (HS-SPME/GC–MS) was applied to monitor the volatiles profile of HLM during production and shelf-life. Optimum extraction conditions for volatiles were explored, focussing on compounds affecting milk aroma. This study is the first investigating industrial scale manufacturing under controlled conditions, allowing direct associations between specific reactions and changes in milk volatiles. The effect of UHT treatment on milk flavour was shown, while the lactase, potentially containing undesirable proteases and odours, did not alter the milk “volatilome” after addition. Commercial samples exhibited different trends in the volatiles along the shelf-life due to differences in production systems, lactase purity and packaging. Merging all results, HS-SPME/GC–MS successfully mapped the phenomena causing modifications in the volatiles profile of UHT HLM at each step of the product life-cycle.

中文翻译：

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顶空固相微萃取气相色谱法在超高温水解乳糖乳生产和储存过程中挥发物特征评估中的应用

摘要 UHT 水解乳糖奶 (HLM) 容易发生化学变化，导致产品变味。为了更好地研究这一点，采用顶空固相微萃取气相色谱 (HS-SPME/GC-MS) 来监测 HLM 在生产和保质期内的挥发物分布。探索了挥发物的最佳提取条件，重点是影响牛奶香气的化合物。这项研究是首次在受控条件下调查工业规模制造，允许特定反应与牛奶挥发物变化之间的直接关联。显示了 UHT 处理对牛奶风味的影响，而乳糖酶可能含有不良蛋白酶和气味，添加后不会改变牛奶的“挥发物”。由于生产系统、乳糖酶纯度和包装的差异，商业样品在保质期内表现出不同的挥发物趋势。合并所有结果，HS-SPME/GC-MS 成功地绘制了在产品生命周期的每个步骤中导致 UHT HLM 挥发物谱发生变化的现象。