School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
Department of Biological Sciences, Cork Institute of Technology, Rossa Avenue, Cork, Ireland.
Int J Food Microbiol. 2018 Dec 2;286:31-36. doi: 10.1016/j.ijfoodmicro.2018.07.013. Epub 2018 Jul 20.
The interest for plant-based dairy substitutes is expanding rapidly and consumers are opting for nutritious and healthy dairy alternatives. The reduction of sugar using different exogenous enzymes in combination with lactic acid fermentation in a quinoa-based milk substitute was explored in this study. Different amylolytic enzymes were used to release sugar from the raw material, which were further metabolised to mannitol, due to fermentation with two heterofermentative lactic acid bacteria. Using these two biotechnological techniques enables the reduction of sugar, while also preserving some of the sweetness. Leuconostoc citreum TR116, and Lactobacillus brevis TR055 were isolated from sourdough. Both strains showed high viable cell counts with L. citreum TR116 > 8.4 and L. brevis TR055 > 9.3 log cfu/mL, and a reduction in pH to 3.7 and 3.5 respectively. When fructose was available, mannitol was produced in conjunction with acetic acid in addition to lactic acid. Due to these processes, the original glucose value was reduced from 50 mmol/100 g to approximately 30 mmol/100 g, which equates to a glucose reduction of 40%. In respect to mannitol production, both strains performed well: L. citreum TR116 showed a conversion factor of 1:1 from fructose to mannitol, while L. brevis TR055 showed a lower yield, with a conversion factor of 1:0.8. Glycaemic load was reduced by more than a third, bringing it down to the low range with a value of about 10. Overall, enzymatic modification in conjunction with mannitol-producing lactic acid bacteria shows great potential for further possible application in the development of nutritious and sugar reduced plant-based milk substitutes.
植物性乳制品替代品的需求正在迅速增长，消费者更倾向于选择营养健康的乳制品替代品。本研究探索了在以藜麦为基础的牛奶替代品中使用不同外源性酶结合乳酸发酵来减少糖的方法。使用不同的淀粉分解酶从原料中释放糖，然后由于与两种异型乳酸发酵菌的发酵，这些糖进一步代谢为甘露醇。使用这两种生物技术可以减少糖的含量，同时保留部分甜味。Leuconostoc citreum TR116 和 Lactobacillus brevis TR055 是从酸面团中分离出来的。这两种菌株的活菌数都很高，L. citreum TR116 为 8.4log cfu/mL 以上，L. brevis TR055 为 9.3log cfu/mL 以上，pH 值分别降低到 3.7 和 3.5。当有果糖存在时，除了乳酸外，还会生成甘露醇和乙酸。由于这些过程，原始葡萄糖值从 50mmol/100g 降低到约 30mmol/100g，相当于葡萄糖减少了 40%。在甘露醇生产方面，两种菌株的表现都很好：L. citreum TR116 显示果糖到甘露醇的转化率为 1:1，而 L. brevis TR055 的转化率较低，为 1:0.8。血糖负荷降低了三分之一以上，降至低值，约为 10。总的来说，酶法修饰结合产甘露醇的乳酸菌在开发营养丰富且低糖的植物性乳制品替代品方面具有很大的应用潜力。
