Optimization of the malting process of oat (Avena sativa L.) as a raw material for fermented beverages

Abstract

The influence of the three malting parameters (germination time, germination temperature, and degree of steeping) on the quality of two oat (Avena sativa L.) cultivars was investigated applying response surface methodology. Each predictor variable was tested at three levels, germination of 6 to 8 days; germination temperatures of 12, 15, or 18°C; and degrees of steeping of 43%, 45% or 47%. All analyses were based on methods described in EBC or MEBAK. The oats used were obtained in 2007 from Nordsaat Saatzucht GmbH, Böhnshausen, Germany. A series of malt quality attributes were evaluated including extract, apparent attenuation limit, Kolbach index, α-aminonitrogen, color, β-glucan, and viscosity. Oat malt was optimized based on barley malt specifications, which are considered appropriate in the beverage production industry for optimal processing. For cv. Ivory, the optimal malting program was achieved after 8 days of germination with moisture content of 46%, and at 17°C. Similarly, cv. Typhon required a germination period of 8 days, a moisture content of 47% and temperature of 16°C. The models showed that the value of R 2 was high and p-value was significant. Therefore it can be said that the model is highly significant. This project demonstrates that oat is an alternative cereal with potential to be used as raw material in malting and brewing purposes.Additional key words: alternative cereal; malt, response surface methodology; wort quality. ResumenOptimización del malteado de avena (Avena sativa L.) como materia prima de bebidas fermentadas Con la ayuda de la metodología de superficie de respuesta, se estudió la influencia de tres variables del malteado (tiempo y temperatura de germinación, y grado de humedad) en la calidad de dos cultivares de avena (Avena sativa L.). Cada variable fue evaluada a tres niveles, de 6 a 8 días de germinación; temperaturas de germinación de 12, 15, o 18°C; y grados de humedad del 43, 45 ó 47%. Todos los análisis estuvieron basados en los métodos descritos por la EBC o por la MEBAK. Los cultivares, obtenidos de Nordsaat Saatzucht GmbH, Böhnshausen, Alemania, fueron de la cosecha del 2007. Se evaluaron una serie de atributos de calidad de la malta incluyendo extracto, límite de atenuación aparente, índice de Kolbach, α-aminonitrógeno, color, β-glucano y viscosidad. La optimización del malteado de la avena se realizó siguiendo las especificaciones de la malta de cebada, consideradas las más apropiadas en la industria de producción de bebidas para un buen procesado. Para el cv. Ivory, el programa de malteado óptimo se alcanzó a los 8 días de germinación con un grado de humedad del 46% y a 17°C. De manera similar, el cv. Typhon necesitó un periodo de germinación de 8 días, un grado de humedad de 47% y una temperatura de 16°C. Los modelos mostraron valores R 2 altos y p significativos. Por lo tanto, se puede decir que el modelo es altamente significativo. Este proyecto muestra que la avena es un cereal con potencial como materia prima para el malteado y la producción de cerveza.

Influence of malting conditions on sorghum (Sorghum bicolor (L.) Moench) as a raw material for fermented beverages

“…At the lower temperature limit of the tested range (25℃), higher kolbach index was obtained compared to the higher limit (data not shown). The reason for this behavior could be that the warm germination conditions lead to a displacement of soluble nitrogen towards root and acrospires growth (Muñoz-Insa et al. 2011).…”

Multi-Response Optimization of the Malting Process of an Italian Landrace of Rye (Secale cereale L.) Using Response Surface Methodology and Desirability Function Coupled with Genetic Algorithm

“…Response surface methodology was used to generate the experimental domain and for data analysis. A face-centered central composite design (FCCD), broadly used in research on micro-malting optimization [ 37 , 38 , 39 ], was chosen to set up the experiments. This experimental design is shaped in the form of a cube with the axial points located at the center of the cube faces, with α = 1.…”

Brewing with up to 40% unmalted oats (Avena sativa) and sorghum (Sorghum bicolor): a review

“…Oats were the most widespread brewing grain in the Middle Ages ; nowadays, they are only used in some speciality beers such as oatmeal stouts (flavour, mouthfeel) . Hence, very few brewing‐related studies on malted oats and even fewer on unmalted oats exist in the literature at present. In contrast, there are numerous publications on the use of unmalted sorghum in brewing .…”

“…Oats were the most widespread brewing grain in the Middle Ages (235); nowadays, they are only used in some speciality beers such as oatmeal stouts (flavour, mouthfeel)(236). Hence, very few brewing-related studies on malted oats(154,155,(236)(237)(238)(239)(240)(241)(242)(243) and even fewer on unmalted oats(3,43,63,54,(244)(245)(246)(247) exist in the literature at present. In contrast, there are numerous publications on the use of unmalted sorghum in brewing(4,5,49,136,(248)(249)(250)(251)(252)(253)(254)(255)(256)(257)(258)(259)(260)(261)(262)(263)(264).…”