The reformulation of dairy products to contain less added sugar can contribute to reducing sugar consumption, thereby reducing the risk of non-communicable diseases. The objective of this study was to investigate the microbial ecology of reformulated yoghurt, which was produced using bi-enzymatic modification of lactose to increase its sweetness by a factor of 2–3. Ultimately, this reformulation strategy could reduce the amount of added sugar needed for equal sweetness of the end product. The bi-enzymatic modification relied on utilisation of a β-galactosidase enzyme to convert the milk sugar lactose to galactose and glucose, followed by the enzymatic conversion of the glucose moiety to fructose using a glucose isomerase. The microbial ecology of reformulated yoghurt produced with two mixed starter culture preparations containing either Streptococcus (S.) thermophilus and Lactobacillus (Lb.) delbrueckii or S. thermophilus, Lb. acidophilus and Bifidobacterium sp. strains, was analysed during fermentation and cool storage using 16S rRNA based metagenomics. None of the yoghurt samples showed a significant difference in microbial composition between sweetness-enhanced and regular milk at all sampling time points during manufacture and storage of yoghurt. However, a significant difference between the microbiota of inoculated milk before and after fermentation was observed. In both types of yoghurt, the starter culture genera dominated the microbial ecology at the end of fermentation as expected, reducing the possibility of growth of potentially pathogenic or spoilage bacteria possibly resulting from a changed carbohydrate spectrum.

中文翻译：

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发酵和储存过程中增甜酸奶的微生物组成。

奶制品中重新添加较少糖分的配方可有助于减少糖分的消耗，从而降低非传染性疾病的风险。这项研究的目的是研究重新配制的酸奶的微生物生态学，该酸奶是通过双酶修饰乳糖将其甜度提高2-3倍而产生的。最终，这种重新配制策略可以减少为获得相等甜度的最终产品所需的添加糖量。双酶修饰依赖于利用β-半乳糖苷酶将乳糖乳糖转化为半乳糖和葡萄糖，然后使用葡萄糖异构酶将葡萄糖部分酶促转化为果糖。用两种混合发酵剂制备的酸奶所产生的微生物生态学链球菌（小号）嗜热和乳杆菌（磅）德氏或嗜热链球菌，乳 嗜酸菌和双歧杆菌sp。使用基于16S rRNA的宏基因组学在发酵和冷藏期间分析了这些菌株。在酸奶的生产和储存过程中的所有采样时间点上，没有一个酸奶样品在增甜牛奶和普通牛奶之间显示出微生物组成上的显着差异。但是，观察到发酵前后接种牛奶的微生物群之间存在显着差异。在两种类型的酸奶中，如预期的那样，发酵剂在发酵结束时就占据了微生物生态的主导地位，从而减少了可能由于碳水化合物谱变化而引起潜在致病或腐败细菌生长的可能性。