Urtubia Urbina, Alejandra Pamela

The seed from the Araucaria araucana (in Spanish, piñon) tree, native to Chile and Argentina, is sold mainly as raw seed. Engineering a process to add value to piñon has the potential to positively impact local indigenous communities with very little ecological impact because it is routinely harvested in the wild. This study evaluated the feasibility of using 100% piñon, or as a blend with barley malt, to produce a beer-like beverage, while also evaluating consumer acceptance of the beverage’s piñon characteristics. Prototypes generated based on 93% piñon and 7% oat (enzymatic treatment of α-amylase, glucoamylase, protease and β-glucanase), as well as 50% piñon and 50% barley (no external enzymatic treatment), were evaluated. Overall acceptability by a consumer acceptance panel (21 consumers) rated the 100% piñon and the piñon–barley malt blend 5/9 and 7/9, respectively. The piñon–barley malt blend prototype stood out for its low level of carbohydrates, high potassium content and banana and clove aromas.

Grapes are a source of native yeasts and lactic acid bacteria (LAB); however, the microbial make up is dependent on the grape cultivar and the regional growth conditions. Therefore, the aim of this study was to characterize the yeast and LAB in seven grape cultivars cultivated in Chile. Grape juices were fermented at 25 °C for 7 days. Samples were collected to analyze sugar, organic acids, and ethanol. Microbial evolution was measured with culture-dependent and molecular approaches. Then, a native isolated Candida oleophila was selected for further sequential fermentations with Saccharomyces cerevisiae. The grape cultivars in the Maule showed a diversity of non-Saccharomyces yeasts, with a greater diversity observed at the beginning of the fermentation. However, species from the Hansenasporia, Metschnikowia, Torulaspora, Lachancea, and Candida genera were detected after 7 days, suggesting tolerance to environments rich in ethanol, capability may be associated to the terroir studied, which is characterized by torrid weather and antique and traditional vineyards. The alcoholic fermentation negatively impacted the LAB population, and after 7 days only Leuconostoc mesenteroides was isolated. In the sequential fermentations, C. oleophila was able to produce fermented grape juices with <1.5 g/L glucose, 12.5% (v/v) alcohol, and low concentrations of malic (<1.00 g/L) and succinic (2.05 g/L) acids, while acetic acid reached values >0.3 (g/L). To our knowledge this is the first time C. oleophila has been reported as a potential starter culture for wine production. However, more studies are necessary to fully characterize the potential of C. oleophila on wine attributes.

Organic nitrogen plays a significant role in the fermentation performance and production of esters and higher alcohols. This study assessed the use of yeast protein hydrolysate (YPH) as a nitrogen source for grape must fermentation. In this study, we prepared an enzymatic protein hydrolysate using yeasts recovered from a previous fermentation of wine. Three treatments were performed. DAP supplementation was used as a control, while two YPH treatments were used. Low (LDH) and high degrees of hydrolysis (HDH), 3.5% and 10%, respectively, were chosen. Gas chromatography and principal component analysis indicated a significant positive influence of YPH-supplementations on the production of esters and higher alcohols. Significantly high concentrations of 3-methyl-1-penthanol, isoamyl alcohol, isobutanol, and 2-phenylethanol were observed. Significant odorant activity was obtained for 3-methyl-1-pentanol and ethyl-2-hexenoate. The use of YPH as nitrogen supplementation is justified as a recycling yeasts technique by the increase in volatile compounds.

En este estudio se caracterizó la microbiota natural (levaduras y bacterias ácido lácticas) observada durante la fermentación espontánea de variedades de uva de Chile, con el fin de evaluar su potencial para producir vinos con menor contenido de etanol. El potencial de fermentación de las levaduras seleccionadas se determinó en términos de consumo de azúcar y producción de etanol. Las cepas con potencial para producir vinos reducidos en etanol se estudiaron adicionalmente en inoculaciones secuenciales con Saccharomyces cerevisiae. Se identificaron nueve especies no Saccharomyces y solo tres géneros de bacterias ácido lácticas. Durante las etapas finales de fermentación, S. cerevisiae y L. mesenteroides fueron dominantes, mientras que solo Candida, Metchnikowia, Torulaspora y Lachancea spp. se observaron después de 14 días de fermentación. La fermentación de cultivo puro con cepas aisladas seleccionadas mostró aproximadamente un 50% de utilización de azúcar, con una producción de etanol que varió desde 6.25 a 9.25% v/v. Nuestros resultados sugieren que las levaduras nativas R. glutinis, M. pulcherrima y H. uvarum, aisladas en este estudio, son potenciales para producir vinos reducido en etanol. Sin embargo, se necesitan más estudios sobre la contribución en sabor y el aroma.