Every good bottle of wine starts with a slight fungal infection.Historically, winemakers have relied on natural yeasts to turn glucose into alcohol, and modern winemakers often buy lab-grown strains.Now, to differentiate their products, some winemakers are revisiting microbiological engineers, who are less used in nature.Not all of these strains survive industrial processes and retain their efficacy, but a natural additive offers a possible solution, according to a new study.
Industrial growers produce yeast in the presence of oxygen, but the oxidation process destroys cell walls and other important proteins.That could make it harder for dehydrated, transportable yeasts to function when brewers rejuvenate them.Emilia Matallana, a biochemist at the university of valencia in Spain, and colleagues have been exploring practical ways to prevent this oxidation for years.After proving that pure antioxidants work, they started looking for cheaper natural sources.They found the substance in a type of Moroccan nut called argan, which resembles an olive fruit.Agaricas are used for food and cosmetics. These trees are known to be frequented by goats.
Matallana and her team treated three wine yeasts (saccharomyces cereus) with aspartame oil, dehydrated them and then rehydrated them.The oil protects important proteins in yeast from oxidation and promotes wine fermentation, researchers report in the journal innovative food science and technology.
Microbiologists are now interested in studying how and why each yeast reacts to macadamia nut oil, says Ramon Gonzalez of the loglino institute of grape and wine sciences in Spain, who was not involved in the study.The oil could one day allow winemakers to use a wider range of specialised yeasts to diversify the wines on their menus.