The Profiles of Low Molecular Nitrogen Compounds and Fatty Acids in Wort and Beer Obtained with the Addition of Quinoa (Chenopodium quinoa Willd.), Amaranth (Amaranthus cruentus L.) or Maltose Syrup

Replacement of a part of malt with unmalted materials is a common practice in beer production. These materials may differ in chemical composition than barley malt, which in turn can contribute to changes in the final composition of the wort. Consequently, it may affect yeast metabolism and final parameters of the obtained products. In this research, two unmalted pseudocereals were used: quinoa (Chenopodium quinoa Willd.) and amaranth (Amaranthus cruentus L.). Maltose syrup was tested as a reference material due to its commercial usage as a substitute of malt in production of worts. Replacement of a part of the malt with quinoa or amaranth favorably influenced the profiles of amino and fatty acids. Due to the fact that the type and concentration of individual amino acids and fatty acids in the fermented wort significantly affect the flavor compounds synthesized by yeast, differences in the profiles of esters and higher alcohol have been noted in beers produced with pseudocereals.

Heterologous Expression of a Thermostable α-Glucosidase from Geobacillus sp. Strain HTA-462 by Escherichia coli and Its Potential Application for Isomaltose–Oligosaccharide Synthesis

Isomaltose–oligosaccharides (IMOs), as food ingredients with prebiotic functionality, can be prepared via enzymatic synthesis using α-glucosidase. In the present study, the α-glucosidase (GSJ) from Geobacillus sp. strain HTA-462 was cloned and expressed in Escherichia coli BL21 (DE3). Recombinant GSJ was purified and biochemically characterized. The optimum temperature condition of the recombinant enzyme was 65 °C, and the half-life was 84 h at 60 °C, whereas the enzyme was active over the range of pH 6.0–10.0 with maximal activity at pH 7.0. The α-glucosidase activity in shake flasks reached 107.9 U/mL and using 4-Nitrophenyl β-D-glucopyranoside (pNPG) as substrate, the Km and Vmax values were 2.321 mM and 306.3 U/mg, respectively. The divalent ions Mn2+ and Ca2+ could improve GSJ activity by 32.1% and 13.8%. Moreover, the hydrolysis ability of recombinant α-glucosidase was almost the same as that of the commercial α-glucosidase (Bacillus stearothermophilus). In terms of the transglycosylation reaction, with 30% maltose syrup under the condition of 60 °C and pH 7.0, IMOs were synthesized with a conversion rate of 37%. These studies lay the basis for the industrial application of recombinant α-glucosidase.

Xarope de Maltose como Potencial Substrato para o Crescimento de Monascus Ruber

Diversas fontes de carbono vêm sendo utilizadas como substrato para o crescimento do Monascus ruber, as mais usuais são glicose, sacarose, amido e o arroz, têm sido amplamente consumido na China, Japão, Ásia, Indonésia e países do Sudeste Asiático. E o xarope de maltose apresenta-se como um substrato potencial alternativo para o fungo Monascus, bem interessante por ser um subproduto da indústria de alimentos. Deste modo, o objetivo deste trabalho foi avaliar o reaproveitamento do resíduo agroindustrial xarope de maltose como um potencial para fabricação de pigmentos, determinando a velocidade de crescimento radial pelo fungo Monascus ruber CCT 3802, em cultivo sólido sob diferentes concentrações de substrato. As análises de velocidade de crescimento radial foram realizadas em meio ágar dextrose de batata (PDA) sob diferentes concentrações de xarope de maltose (5, 20, 50, 80 e 95 g/L), além da placa padrão contendo apenas PDA. Diante dos resultados pode-se observar que o micro-organismo cultivado no meio contendo 50 g/L de xarope de maltose obteve crescimento de 0,0607 mm h-1, ou seja, 1,4568 mm dia-1 representando maior velocidade de crescimento radial quando comparado com as demais concentrações. Portanto, a utilização do xarope de maltose como substrato para o Monascus ruber é promissor observando que as diferentes concentrações obtiveram influência em seu crescimento. Palavras-chave: Crescimento Radial. Fermentação Sólida. Xarope de Maltose. Abstract Several sources of carbon have been used as a substrate for the growth of Monascus ruber, the most common of which are glucose, sucrose, starch and rice, have been widely consumed in China, Japan, Asia, Indonesia and Southeast Asian countries. And maltose syrup presents itself as an alternative potential substrate for the Monascus fungus, quite interesting as it is a by-product of the food industry. Thus, the objective of this work was to evaluate the reuse of the agro - industrial maltose syrup residue as a potential for pigment manufacture, determining the radial growth rate by the Monascus ruber CCT 3802 fungus in solid culture under different substrate concentrations. Radial growth rate analyzes were performed on potato dextrose agar (PDA) under different concentrations of maltose syrup (5, 20, 50, 80 and 95 g/L), in addition to the standard plate containing only PDA. In view of the results, it can be observed that the microorganism cultured in the medium containing 50 g/L of maltose syrup obtained growth of 0.0607 mm h-1, that is, 1.4568 mm day-1 representing higher speed of radial growth when compared to the other concentrations. Therefore, the use of maltose syrup as a substrate for Monascus ruber is promising by observing that the different concentrations have influenced its growth. Keywords: Radial Growth. Solid Fermentation. Maltose Syrup.

Sugar Profile of Syrups from Malted and Unmalted Rice of Different Varieties

Rice syrup was produced from ten varieties of locally available rice in Nigeria. Flours of malted and unmalted rice from different varieties were treated with a combination of starch hydrolyzing enzymes (Amyloglucosidase, Bacterial α-amylase and Fungal α-amylase); and the starch hydrolysates were either filtered and/or centrifuged at the end of hydrolysis. The resulting rice syrup was evaluated for sugar compositions (maltose, glucose, maltotriose, sucrose, raffinose and stachyose) using HPLC. The results showed that syrups from malted rice had significantly higher (p<0.05) maltose and maltotriose concentration than syrups from unmalted rice. The resultant syrup is a ‘High Maltose Syrup’ since maltose was found to be the predominant sugar in the rice syrup with concentration of above 50% especially for malted samples. Rice syrup can be widely applied as a potential raw material in beverage and confectionery industries as well as a good adjunct for brewing since the sugar profile of the rice syrup was similar to that of barley wort.