Institute of Systems Biotechnology, Saarland University, Saarbrücken, Germany.
Nestlé Research Center, Lausanne, Switzerland.
Microb Cell Fact. 2022 Mar 26;21(1):48. doi: 10.1186/s12934-022-01773-w.
Sunflower seeds (Helianthus annuus) display an attractive source for the rapidly increasing market of plant-based human nutrition. Of particular interest are press cakes of the seeds, cheap residuals from sunflower oil manufacturing that offer attractive sustainability and economic benefits. Admittedly, sunflower seed milk, derived therefrom, suffers from limited nutritional value, undesired flavor, and the presence of indigestible sugars. Of specific relevance is the absence of vitamin B. This vitamin is required for development and function of the central nervous system, healthy red blood cell formation, and DNA synthesis, and displays the most important micronutrient for vegans to be aware of. Here we evaluated the power of microbes to enrich sunflower seed milk nutritionally as well as in flavor.
Propionibacterium freudenreichii NCC 1177 showed highest vitamin B production in sunflower seed milk out of a range of food-grade propionibacteria. Its growth and B production capacity, however, were limited by a lack of accessible carbon sources and stimulants of B biosynthesis in the plant milk. This was overcome by co-cultivation with Bacillus amyloliquefaciens NCC 156, which supplied lactate, amino acids, and vitamin B for growth of NCC 1177 plus vitamins B and B, potentially supporting vitamin B production by the Propionibacterium. After several rounds of optimization, co-fermentation of ultra-high-temperature pre-treated sunflower seed milk by the two microbes, enabled the production of 17 µg (100 g) vitamin B within four days without any further supplementation. The fermented milk further revealed significantly enriched levels of L-lysine, the most limiting essential amino acid, vitamin B, vitamin B, improved protein quality and flavor, and largely eliminated indigestible sugars.
The fermented sunflower seed milk, obtained by using two food-grade microbes without further supplementation, displays an attractive, clean-label product with a high level of vitamin B and multiple co-benefits. The secret of the successfully upgraded plant milk lies in the multifunctional cooperation of the two microbes, which were combined, based on their genetic potential and metabolic signatures found in mono-culture fermentations. This design by knowledge approach appears valuable for future development of plant-based milk products.
葵花籽（向日葵属）作为一种快速增长的植物性人类营养市场的有吸引力的来源。特别引人关注的是葵花籽压榨饼，这是葵花籽油生产的廉价残余物，具有吸引人的可持续性和经济效益。诚然，由此衍生的葵花籽奶，其营养价值有限，口感不佳，且含有不可消化的糖。特别重要的是缺乏维生素 B。这种维生素是中枢神经系统发育和功能、健康红细胞形成和 DNA 合成所必需的，是素食者需要注意的最重要的微量营养素。在这里，我们评估了微生物的力量，以使其在营养和风味方面丰富葵花籽奶。
在一系列食品级丙酸杆菌中，丙酸杆菌 NCC 1177 在葵花籽奶中表现出最高的维生素 B 产量。然而，由于植物奶中缺乏可利用的碳源和维生素 B 生物合成的刺激物，其生长和 B 生产能力受到限制。通过与解淀粉芽孢杆菌 NCC 156 共培养克服了这一限制，解淀粉芽孢杆菌 NCC 156 提供了乳酸盐、氨基酸和维生素 B，以支持 NCC 1177 的生长，并可能支持丙酸杆菌的维生素 B 生产。经过几轮优化，两株微生物对超高温预处理的葵花籽奶进行共发酵，使 17µg（100g）维生素 B 在四天内无需任何额外补充即可生产。发酵后的牛奶进一步显示出显著增加的 L-赖氨酸水平，L-赖氨酸是最有限的必需氨基酸，还增加了维生素 B、维生素 B、改善了蛋白质质量和风味，并大大消除了不可消化的糖。
使用两种食品级微生物发酵葵花籽奶，无需进一步补充，得到一种具有高维生素 B 水平和多种协同效益的有吸引力的清洁标签产品。成功升级植物奶的秘诀在于两种微生物的多功能合作，这种合作是基于它们在单一培养发酵中的遗传潜力和代谢特征结合的。这种基于知识的设计方法似乎对未来植物性牛奶产品的开发具有价值。
