Phytic acid concentration in selected raw materials and analysis of its hydrolysis rate with the use of microbial phytases during the mashing process

Cambios en la concentración de ácido fítico, fósforo libre y hierro soluble durante la fermentación de repollo blanco y repollo chino

Se estudió la evolución de la concentración de ácido fítico, fósforo libre y hierro soluble durante la fermentación de repollo blanco y repollo chino. En ambos casos, la máxima población de bacterias ácido lácticas se logró a los cinco días del proceso y luego disminuyó continuamente hasta el final. El pH inicial del repollo blanco y repollo chino fue de 6,1 y durante los primeros cinco días disminuyó a 3,7 y 4,3 respectivamente, luego permanecieron estables hasta los 30 días. En el repollo blanco, la concentración de ácido fítico disminuyó y el fósforo libre se incrementó durante los primeros cinco días, después no se detectaron cambios significativos. En el repollo chino, la degradación del ácido fítico se observó durante los primeros 15 días, mientras que el fósforo libre aumentó hasta el final del proceso. Ambos vegetales mostraron una concentración inicial de hierro comparable, luego, se observó un incremento hasta el final del proceso, siendo este fenómeno más notable en el repollo chino. Los resultados obtenidos sugieren que la degradación del ácido fítico producida durante la fermentación por la actividad de fitasas vegetales y bacterianas, no sólo origina la liberación de fósforo libre, sino que mejora la bioaccesibilidad del hierro. Palabras claves. biodisponibilidad de nutrientes, fermentación espontánea, Brassica

Enzyme complexes for activating yeast generation and ethanol fermentation

Introduction. Recent studies have shown the benefits of phytolytic enzymes to prepare grain wort in ethanol production. However, there is a lack of data on the effect of phytases and their amount on the conversion of grain polymers, the ionic composition of wort and mash, and the efficiency of yeast generation and ethanol fermentation. Study objects and methods. Wheat and corn wort samples were treated with a complex of hydrolases, including phytases. Capillary electrophoresis determined the ionic composition of wort and mash. Gas chromatography measured the content of volatile metabolites. Results and discussion. The key enzymes were phytases and proteases. They improved the conversion of grain polymers and stimulated the growth and metabolism of yeast cells. Their synergism enriched the wort with assimilable nitrogen, phosphorus, and other valuable minerals. In addition, it intensified the growth of the Saccharomyces cerevisiae yeast, increased the rate of carbohydrate consumption, and reduced the formation of side metabolites 1.7–1.9 times, mainly due to higher and aromatic alcohols. The concentration of phosphates remained practically unchanged during the fermentation of grain wort treated with phytases. However, by the end of fermentation, it was 2.4–5.1 times higher than in the mash samples without phytolytic treatment. Finally, we identified a complex of enzymes and optimal amounts of phytases that have a stimulating effect on ethanol fermentation. Conclusion. Phytases, whether used individually or together with proteases, enriched grain wort with soluble macro- and microelements, improved yeast metabolism, directed ethanol synthesis, and decreased the formation of fermentation by-products.

Hydrotropic pretreatment on distillery stillage for efficient cellulosic ethanol production

Effectiveness of hydrotropic delignification using sodium cumene sulfonate for pretreatment of rye, wheat and maize stillage for further use in the production of bioethanol was evaluated. The highest stillage biomass extractives was obtained for a biomass particle size <1.0 mm, when exposed to 131 °C for 1 h at 20% v/v hydrotrope concentration. It has been shown that hydrotropic treatment causes changes in the stillage biomass structure (increase in porosity) and reduces the lignin content in biomass by 7-17%. Delignification with a hydrotrope also increased the concentration of fermentable sugars in the media prepared with stillage biomass, which led to a higher final ethanol concentration (up to ca. 3.5 g/L). Hydrotropic treatment is an effective way of pretreatment of stillage biomass. It provides a high degree of biomass bioconversion and creates the prospect of integrating the 1st and 2nd generation ethanol production process to more fully utilize the raw material.

Effects of a complex phytase-containing enzyme preparation on the rye wort fermentation process

A complex of amylases, proteases, and hemicellulases is known to enhance deep conversion of polysaccharides and proteins, especially in the processing of difficult-to-ferment raw materials, such as rye, providing grain wort with soluble carbohydrates, amino acids, and peptides. Grain is also a source of phosphorus, whose bioavailability can be increased by hydrolysing the grain with phytase-containing enzyme preparations. However, their catalytic action during the preparation of grain wort for alcohol production has hardly been studied. This study aimed to investigate the effect of a new complex phytasecontaining enzyme preparation on yeast metabolism and the efficiency of rye wort fermentation. The work was carried out in the Russian Research Institute of Food Biotechnology. The Glucavamorin complex enzyme preparations derived from recombinant strains were the object of our research. The preparations differed in the activity level of the main enzyme, lucoamylase, and minor hemicellulase enzymes, as well as in the presence of phytase. The results confirmed their biocatalytic ability to efficiently hydrolyse polymers of rye grain. An increased content of hemicellulases in Glucavamorin-Xyl improved the rheological properties of rye wort. The greatest effect was achieved with the phytase-containing Glucavamorin-Ply. This preparation improved the phosphorus nutrition of yeast, which increased its biomass by 30% and decreased the level of fermentation by-products by 18–20%. Alcohol yield tended to increase and its strength reached 10.5–10.9% vol. When using a phytase-containing enzyme complex, it was possible to reduce the amount of the main enzyme, glucoamylase, without causing the key fermentation indicators to degrade.

Changes in the Concentration of Carbonyl Compounds during the Alcoholic Fermentation Process Carried out with Saccharomyces cerevisiae Yeast

The aim of the study was to determine the influence of the source material and the applied S. cerevisiae strain on the concentrations of carbonyl fractions in raw spirits. Acetaldehyde was the most common aldehyde found, as it accounted for 88-92% of the total amount of aldehydes. The concentration of acetaldehyde in maize, rye and amaranth mashes was highly correlated with fermentation productivity at a given phase of the process, and reached its highest value of 193.5 mg/l EtOH in the first hours of the fermentation, regardless of the yeast strain applied. The acetaldehyde concentration decreased over the time with the decreasing productivity, reaching its lowest value at the 72nd hour of the process. The final concentration of acetaldehyde depended on the raw material used (ca 28.0 mg/l EtOH for maize mashes, 40.3 mg/l EtOH for rye mashes, and 74.4 mg/l EtOH for amaranth mashes). The effect of the used yeast strain was negligible. The overall concentration of the analyzed aldehydes was only slightly higher: ca 30.3 mg/l EtOH for maize mashes, 47.8 mg/l EtOH for rye mashes, and 83.1 mg/l EtOH for amaranth mashes.

Thermostable phytase in feed and fuel industries

Phytase with wide ranging biochemical properties has long been utilized in a multitude of industries, even so, thermostability plays a crucial factor in choosing the right phytase in a few of the sectors. Mesophilic phytases are not considered to be a viable option in the feed industry owing to its limited stability in the required feed processing temperature. In the recent past, inclusion of thermostable phytase in fuel ethanol production from starch based raw material has been demonstrated with economic benefits. Therefore, considerable emphasis has been placed on using complementary approaches such as mining of extremophilic microbial wealth, encapsulation and using enzyme engineering for obtaining stable phytase variants. This article means to give an insight on role of thermostable phytases in feed and fuel industries and methods for its development, highlighting molecular determinants of thermostability.

Extracellular Phytase Production by the Wine Yeast S. cerevisiae (Finarome Strain) during Submerged Fermentation

One of the key steps in the production of phytases of microbial origin is selection of culture parameters, followed by isolation of the enzyme and evaluation of its catalytic activity. It was found that conditions for S. cerevisiae yeast culture, strain Finarome, giving the reduction in phytic acid concentration of more than 98% within 24 h of incubation were as follows: pH 5.5, 32 °C, continuous stirring at 80 rpm, the use of mannose as a carbon source and aspartic acid as a source of nitrogen. The highest catalytic activity of the isolated phytase was observed at 37 °C, pH 4.0 and using phytate as substrate at concentration of 5.0 mM. The presence of ethanol in the medium at a concentration of 12% v/v reduces the catalytic activity to above 60%. Properties of phytase derived from S. cerevisiae yeast culture, strain Finarome, indicate the possibility of its application in the form of a cell’s free crude protein isolate for the hydrolysis of phytic acid to improve the efficiency of alcoholic fermentation processes. Our results also suggest a possibility to use the strain under study to obtain a fusant derived with specialized distillery strains, capable of carrying out a highly efficient fermentation process combined with the utilization of phytates.

Triticale: Nutritional composition and food uses

Triticale (× Triticosecale Wittmack), a man-made cereal from wheat and rye hybridization, is mainly used as animal feed. In recent years, there has been increasing interest in utilising triticale for food production. Some chemical constituents (e.g., starch and non-starch polysaccharides) of triticale as well as the genetic variability in nutritional composition have been much studied. Various food and beverage products of triticale have been developed, including bakery products (e.g., bread and cookie), pasta, malt, spirit, yoghurt, and biodegradable and edible films. Focusing on the literatures from the last 5years, this mini-review summarises the recent advances in the nutritional composition and diverse food uses of triticale. There is a wide variation in the chemical composition of triticale, which suggests the potential of triticale asa cereal alternative for various food and beverage applications.