Sensory Characteristics of Two Kinds of Alcoholic Beverages Produced with Spent Coffee Grounds Extract Based on Electronic Senses and HS-SPME-GC-MS Analyses

In this work, the hydrothermal extract of spent coffee grounds (SCG) was used to make alcoholic beverages with commercial S. cerevisiae strain D254. The sensory characteristics of the SCG alcoholic beverages were analyzed using sensory description, electronic nose, electronic tongue, and gas chromatography-mass spectrometry (GC-MS). The results suggested that the supplement of 0.20% (NH4)2HPO4 was effective at improving growth and alcohol fermentation of Saccharomyces cerevisiae D254 in SCG extract. SCG fermented beverages (SFB) and SCG distilled spirits (SDS) produced at the optimized fermentation conditions had appropriate physicochemical properties and different sensory characteristics. Fermentation aromas, especially esters, were produced in SFB, increasing the complexity of aroma and lowing the irritating aroma. The combination of original and fermentation components might balance the outstanding sourness, astringency, and saltiness tastes of SFB. The fermentation aroma was partially lost and the sourness, bitterness, astringency, and saltiness tastes were relieved in distillation, leading to the relatively more prominent aroma typicality of coffee and a soft taste. These findings lay a foundation for producing new high-quality coffee-flavored alcoholic beverages or flavoring liquors.

Role of enzymatic catalysis in the production of alcohol

В статье приведены данные о регуляторной роли ферментов в направленной биокаталитической конверсии полимеров зерна для приготовления качественного сусла и интенсификации процессов генерации дрожжей и спиртового брожения. The article provides data on the regulatory role of enzymes in the directional biocatalytic conversion of grain polymers to prepare a high-quality wort and intensify the processes of yeast generation and alcohol fermentation.

Wine Aroma Characterization of the Two Main Fermentation Yeast Species of the Apiculate Genus Hanseniaspora

Hanseniaspora species are the main yeasts isolated from grapes and grape musts. Regarding genetic and phenotypical characterization, especially fermentative behavior, they can be classified in two technological clusters: the fruit group and the fermentation group. Among the species belonging to the last group, Hanseniaspora osmophila and Hanseniaspora vineae have been previously isolated in spontaneous fermentations of grape must. In this work, the oenological aptitudes of the two species of the fermentation group were compared with Saccharomyces cerevisiae and the main species of the fruit group, Hanseniaspora uvarum. Both H. osmophila and H. vineae conferred a positive aroma to final wines and no sensory defects were detected. Wines fermented with H. vineae presented significantly higher concentrations of 2-phenylethyl, tryptophol and tyrosol acetates, acetoin, mevalonolactone, and benzyl alcohol compared to H. osmophila. Sensorial analysis showed increased intensity of fruity and flowery notes in wines vinificated with H. vineae. In an evolutionary context, the detoxification of alcohols through a highly acetylation capacity might explain an adaption to fermentative environments. It was concluded that, although H. vineae show close alcohol fermentation adaptations to H. osmophila, the increased activation of phenylpropanoid metabolic pathway is a particular characteristic of H. vineae within this important apiculate genus.

Transcriptomics Analysis of Formic Acid Stress Response in Saccharomyces Cerevisiae

Formic acid is a representative small molecule acid cell inhibitor in lignocellulosic hydrolysate, which can inhibit the growth of yeast cells in the process of alcohol fermentation. However, the mechanism of formic acid cytotoxicity remains largely unknown. This study aimed to study the cytotoxicity of formic acid stress to Saccharomyces cerevisiae. We evaluated the effects of formic acid on growth metabolism and cell morphology of yeast cells, and comprehensively and systematically analyzed the molecular mechanism of formic acid stress tolerance through transcriptome technology. The results showed that when the concentration of formic acid was 1.8 g/L, the growth of yeast cells was significantly inhibited, the cell surface was wrinkled, and the adhesion between cells was observed, and the cell wall and cell membrane of yeast were destroyed by changing the structure of proteins and carbohydrates, resulting in cell damage. Transcriptome sequencing results showed that formic acid stress inhibited protein biosynthesis, induced oxidative stress, resulted in autophagy, impaired intracellular ATP production and increased consumption, and then impaired normal physiological and metabolic functions of cells. Yeast cells provide sufficient ATP by accelerating glucose metabolism, enhancing electron transport and ATP synthesis more energy to resist formic acid stress, and reduce the expression of genes related to energy metabolism such as intracellular amino acids to achieve an energy-saving strategy, In addition, it can also induce sexual reproduction and spore formation to improve cell tolerance to formic acid. This study initially revealed the molecular response mechanism of S. cerevisiae under formic acid stress, and provided a scientific basis for further research on methods to improve the tolerance of cell inhibitors in lignocellulose hydrolysate.

Formulasi sediaan Cuka Buah Kopi Menggunakan Ragi (Saccharomyces cerevisiae) dan Bakteri (Acetobacter aceti)

Indonesia is the third largest coffee producing country in the world, with a variety of compounds that are beneficial to the body. Vinegar fermentation is one way to add value to the benefits of fruits and vegetables because it can form useful new chemical compounds. Vinegar has a variety of benefits that have been studied such as reducing hyperglycemia, hyperinsulinemia, hyperlipidemia and obesity. Previous research in 2013 had made acetic acid from Arabica coffee pulp waste. This study aims to obtain a coffee fruit vinegar formula that conforms to the quality standards of acetic acid SNI 01-4371-1996. The material used is whole coffee with a two-stage fermentation method, namely alcohol fermentation using S. cerevisiae for 4 days and vinegar fermentation using A. aceti for 3 days. The results showed that the formula with 25% coffee fruit and 20% sugar is the best formula compared to other formulas with organoleptic test results in brown, sour and sweet taste and a little distinctive aroma of coffee, 5.03% acetic acid content, 0% alcohol content, pH 3,242. Abstrak. Indonesia merupakan negara ketiga penghasil kopi terbesar di dunia, dengan berbagai kandungan senyawa yang bermanfaat bagi tubuh. Fermentasi cuka merupakan salah satu cara untuk menambah nilai manfaat dari buah dan sayur karena dapat membentuk senyawa kimia baru yang bermanfaat. Cuka memiliki berbagai manfaat yang telah diteliti seperti menurunkan hiperglikemia, hiperinsulinemia, hiperlipidemia dan obesitas. Penelitian sebelumnya pada tahun 2013 telah dilakukan pembuatan asam asetat dari limbah cair kulit kopi arabika. Penelitian ini bertujuan untuk mendapatkan formula cuka buah kopi yang sesuai standar mutu asam asetat SNI 01-4371-1996. Bahan yang digunakan adalah buah kopi secara utuh dengan metode fermentasi dua tahap yaitu fermentasi alkohol menggunakan S. cerevisiae selama 4 hari dan fermentasi cuka menggunakan A. aceti selama 3 hari. Hasil penelitian menunjukan bahwa formula dengan 25% buah kopi dan 20% gula merupakan formula terbaik dibandingkan dengan formula lain dengan hasil uji organoleptis berwarna coklat, rasa asam dan manis serta sedikit aroma khas kopi, kadar asam asetat 5,053%, kadar alkohol 0%, pH 3,242.

Anthocyanin and Phenolic Acids Contents Influence the Color Stability and Antioxidant Capacity of Wine Treated With Mannoprotein

Wine is consumed by humans worldwide, but the functional components are lost and the color changes during its production. Here, we studied the effects of mannoprotein (MP) addition (0, 0.1, and 0.3 g/L) upon crushing and storage. We measured anthocyanins, phenolic acids profiles, color characteristics, and antioxidant activities of wine. The results showed that the addition of MP before fermentation significantly increased the total phenolic content (TPC), total anthocyanin content, total tannin content (TTC), total flavonoid content, and total flavanol content in wine, whereas the addition of MP during storage had the opposite effect. The addition of MP before alcohol fermentation significantly increased the amount of individual anthocyanins and individual phenolic acids, maintained the color, and increased the antioxidant capacity of wine. In addition, the addition of 0.3 g/L MP during storage increased the content of individual phenolic acids and TPC of wine. However, the addition of 0.1 g/L MP during storage significantly reduced the TPC, TAC, TTC, and individual anthocyanin content (except for malvidin-3-glucoside and malvidin-3-acetly-glucoside); meanwhile, the treatment attenuated the color stability and antioxidant capacity of wine. The results demonstrated that the addition of MP before alcohol fermentation could increase the functional components and improve the color stability and antioxidant capacity of wine.

Evaluation of Anthocyanin Profile and Color in Sweet Cherry Wine: Effect of Sinapic Acid and Grape Tannins during Aging

Cherries are rich in bioactive phenolic compounds and are often fermented into cherry wines. The degradation of anthocyanins during storage will cause color deterioration. The study aimed to utilize sinapic acid and grape tannins in cherry wine to maintain a high fraction in the colored forms of anthocyanins, in order to maximize the color intensity, the latter being associated with good product quality. The effects on the anthocyanin profile and on color parameters of copigments, utilizing spectral measurement combined with UPLC-MS quantitative analysis, have been evaluated in sweet cherry wines. The copigmentation effect of sinapic acid and grape tannin was accompanied by the bathochromic shift and the hyperchromic effect, which lead to an increase in color intensity (lower L*, higher a* and b*). During the aging process, sinapic and grape tannin increased the content of pyranoanthocyanins in cherry wine, especially the addition of sinapic acid makes the cherry wine generate 10-syringyl-pyranocyanidin-3-rutinoside. These results demonstrate that sinapic acid is suitable for adding before alcohol fermentation, while grape tannins can be added before aging.

Screening and Evaluation of Purine-Nucleoside-Degrading Lactic Acid Bacteria Isolated from Winemaking Byproducts In Vitro and Their Uric Acid-Lowering Effects In Vivo

In Taiwan, adult hyperuricemia affects as many as 1 in 4 males and 1 in 6 females, who are predominantly young adults aged 19–45. In this study, lactic acid bacteria (LAB) with acid tolerance, bile salt tolerance and high affinity to intestinal cells were extracted from the side products of alcohol fermentation (distillers’ grains). These bacteria were evaluated for their ability to lower uric acid levels. Qualitative identification and quantitative analysis were performed using high-performance liquid chromatography (HPLC) on the purine-degrading enzymes to select purine-decomposing LAB for animal testing. When the final concentration of purine compounds reached 0.1% and 1%, seven strains of LAB showed potential in degrading purine compounds. HPLC was used to analyze their purine-degrading abilities, and the three best performing LAB strains, (107) 8–16, (107) tau 1–3, and (107) 6–10 were screened for further animal testing with Wistar rats. By the third week, the results showed that strain (107) 6–10 could prevent formation and reduce the levels of blood urea nitrogen (BUN) in yeast extract/potassium oxonate-induced hyperuricemia. The multi-strain lactic acid bacteria (MLAB) performed best for uric acid reduction in the serum and down regulated BUN. Yeast extract/potassium oxonate-induced hyperuricemia had no impact on serum creatinine, while LAB did not affect the creatinine concentration. In summary, MLAB not only protects kidney function but is also effective in regulating uric acid concentration in the body. Hence, MLAB can be used as a functional food supplement that prevents or aids the treatment of hyperuricemia in a rodent model.

Metabolic, Organoleptic and Transcriptomic Impact of Saccharomyces cerevisiae Genes Involved in the Biosynthesis of Linear and Substituted Esters

Esters constitute a broad family of volatile compounds impacting the organoleptic properties of many beverages, including wine and beer. They can be classified according to their chemical structure. Higher alcohol acetates differ from fatty acid ethyl esters, whereas a third group, substituted ethyl esters, contributes to the fruitiness of red wines. Derived from yeast metabolism, the biosynthesis of higher alcohol acetates and fatty acid ethyl esters has been widely investigated at the enzymatic and genetic levels. As previously reported, two pairs of esterases, respectively encoded by the paralogue genes ATF1 and ATF2, and EEB1 and EHT1, are mostly involved in the biosynthesis of higher alcohol acetates and fatty acid ethyl esters. These esterases have a moderate effect on the biosynthesis of substituted ethyl esters, which depend on mono-acyl lipases encoded by MGL2 and YJU3. The functional characterization of such genes helps to improve our understanding of substituted ester metabolism in the context of wine alcohol fermentation. In order to evaluate the overall sensorial impact of esters, we attempted to produce young red wines without esters by generating a multiple esterase-free strain (Δatf1, Δatf2, Δeeb1, and Δeht1). Surprisingly, it was not possible to obtain the deletion of MGL2 in the Δatf1/Δatf2/Δeeb1/Δeht1 background, highlighting unsuspected genetic incompatibilities between ATF1 and MGL2. A preliminary RNA-seq analysis depicted the overall effect of the Δatf1/Δatf2/Δeeb1/Δeht1 genotype that triggers the expression shift of 1124 genes involved in nitrogen and lipid metabolism, but also chromatin organization and histone acetylation. These findings reveal unsuspected regulatory roles of ester metabolism in genome expression for the first time.