Sixth Day Of Fermentation Research Articles

Effects of different fermenters on the quality and flavour of fermented mandarin fish (Siniperca chuatsi)

SummaryIn this study, the effect of different fermenters on the quality and flavour of fermented mandarin fish was investigated via pH, salt content, moisture content, thiobarbituric acid, microbial community, free amino acids and volatile compounds. The results demonstrated that the inoculated fermentation effectively suppressed fish fat oxidation, resulting in significantly higher levels of umami amino acids in mandarin fish compared to the natural fermentation group (P < 0.05). Additionally, certain bitter amino acids were also inhibited. Moreover, the total amino acid content of the mixed inoculated fermentation group was significantly elevated compared to other groups, reaching 300.21 ± 5.37 mg/100 g. The synergistic effect of free amino acids and flavour‐enhancing nucleotides significantly influenced the taste of the fermented fish, with the mixed inoculation fermentation group exhibiting a significantly higher Equivalent umami concentration (EUC) value compared to other groups, reaching 216.06 ± 20.13 mgMSG/100 g on the sixth day of fermentation. A total of 47 volatile compounds were detected by using headspace gas chromatography‐ion mobility spectrometry (HS‐GC‐IMS), and the results demonstrated that inoculated fermentation positively influenced the development of fish flavour, and mixed inoculated fermentation proved to be more effective. This study provides a theoretical foundation for the industrial production of fermented fish products and offers potential avenues for technical enhancement.

Enhancing quality of ruminant feed through fungal treatment: Usage of bamboo shoot residues.

In this investigation, we explore the harnessing of bamboo shoot residues (BSR) as a viable source for ruminant feed through fungal treatment, with the overarching objective of elevating feed quality and optimizing bamboo shoot utilization. The white-rot fungi (Wr.fungi), Aspergillus niger (A.niger), and its co-cultures (A.niger&Wr.fungi) were employed to ferment BSR. And the impact of different fermentation methods and culture time on the chemical composition (Crude protein Ash, neutral detergent fibre and acid detergent fibers), enzyme activity (Cellulase, Laccase, Filter paperase and Lignin peroxidase activities), and rumen digestibility in vitro were assessed. The findings reveal a nota ble 30.39% increase in crude protein in fermented BSR, accompanied by respective decreases of 13.02% and 17.31% in acid detergent fiber and neutral detergent fibre content. Enzyme activities experienced augmentation post-fermentation with A.niger&Wr.fungi. Specifically, the peak Cellulase, Laccase, and Lignin peroxidase activities for BSR with Wr.fungi treatment reached 748.4 U/g, 156.92 U/g, and 291.61 U/g, respectively, on the sixth day of fermentation. Concurrently, NH3-N concentration exhibited an upward trend with prolonged fermentation time. Total volatile fatty acids registered a decline, and the Acetate/Propionate ratio reached its nadir after 6 days of fermentation under the A.niger&Wr.fungi treatment. These outcomes furnish a theoretical foundation for the development of ruminant feeds treated via fungal co-culture.

Factors Affecting the Ethanol Production from Sugar Beet Molasses

Sugar beet molasses is one of the important by products in sugar industry, it in dark brown to black colored and rich source of various polysaccharides. So, it can be used in the production of ethanol by<i> Saccharomyces</i> <i>cerevisiae</i>. Data showed that 2% inoculums size was the best size of all tested for molasses media. Where the alcohol production was 4.6 ml /100 media with economic coefficient 53.7% and yield coefficient 46.1%. Also, incubation periods were tested from 2 to 14 days. Maximum alcohol production was noticed at the sixth day of fermentation, it was 4.71% ml/100ml medium. The economic and yield coefficient were 53.7% and 46.1%; respectively. Results showed at 30°C incubation temperature the yeast of Saccharomyces cerevisiae produced high value of ethanol production. 4.61 ml /100ml medium with high value of economic coefficient 53.7% and 46.1% of yield coefficient. While PH 5 was the optimal value for ethanol production from molasses, where alcohol production was 4.61%, economic coefficient and yield coefficient were 53.7% and 46.1%, respectively. Increasing the PH value up to 5.5 did not increase the ethanol production. but ethanol production was recorded decrease value. Data showed that at 20°C incubation temperature and 14.0% initial, sugar the ethanol production was 5.16% with 40% economic coefficient, while at 30°C incubation temperature the maximum ethanol production was 6.3% with economic coefficient 49.0% where the initial sugar was 14.0%.

Mixed Cultures of Saccharomyces kudravzevii and S. cerevisiae Modify the Fermentation Process and Improve the Aroma Profile of Semi-Sweet White Wines.

The purpose of the study was to evaluate the impact of the Saccharomyces cerevisiae and S. kudriavzevii mixed culture on the fermentation, chemical and aromatic composition of semi-sweet white wines. The variables tested in the experiment were the initial ratio of yeast in mixed cultures and the time of inoculation of the S. kudriavzevii co-culture. The addition of S. kudriavzevii to the inoculum did not significantly change the chemical composition of the wines obtained. No reduction in ethanol yield was found in mixed culture fermented wines; however, in some variants of the experiment, the ethanol content was higher. The mixed cultures of S. cerevisiae and S. kudriavzevii increased the level of volatile compounds in white grape wines. Wines fermented with the co-culture of S. kudriavzevii were characterized by a more diversified ester profile. The mixed cultures of S. cerevisiae and S. kudriavzevii raised the levels of terpenes in white wines. The most promising results were obtained for mixed culture variants, in which S. kudriavzevii was sequentially inoculated on the sixth day of fermentation.

High-Solid Loading Enzymatic Hydrolysis of Waste Office Paper for poly-3-hydroxybutyrate Production Through Simultaneous Saccharification and Fermentation

Waste paper holds great potential as a substrate for the microbial production of bioplastic (Poly-3-hydroxybutyrate (PHB)). This study aimed to produce PHB by utilizing office paper as a substrate using Cupriavidus necator through batch and fed-batch simultaneous saccharification and fermentation (SSF) approach. For the batch experiment, different loadings of shredded office paper (3, 5 and 10%) with two different pretreatments H2O2 (OPH) and H2O2 and Triton X-100 (OPTH) were carried out. For the fed-batch experiment, paper loading started with 3% and two more additions were made at 36 and 84 h. Both experiments were conducted at 30 °C, 200 rpm and pH 7 using 55.5 FPU/g of cellulase and 37.5 CBU/g of β-glucosidase with a fixed amount of nitrogen source. High PHB yield was observed with OPH in all loadings, though the OPHT showed a better hydrolysis. Maximum PHB yield (4.27 g/L) was achieved with 10% OP on the sixth day of fermentation in batch SSF. Whereas, maximum PHB yield (4.19 g/L) was obtained within a shorter time (66 h)with OPH in the fed-batch experiment. The extracted PHB showed well-matched characteristic features to the standard PHB. Finally, this study proves the feasibility of employing the SSF process for PHB production using waste paper as an alternative approach to overcome the shortcoming of the separate hydrolysis and fermentation (SHF) process.

Phytochemical, Antinutrient and Radical Scavenging Potential of Parkia Biglobosa Seeds as affected by Fermentation and Extraction methods

Plants contain important bioactive compounds which possess radical scavenging ability. Processing methods such as fermentation and the kind of solvents used in extraction induces the plant to make available these bioactive compounds. Parkia biglobosa seeds are commonly fermented into a food spice called ‘‘Dawadawa’’ utilized as a condiment in soups and stews possessing varying nutritional and medicinal benefits. The study evaluated the phytochemical, antinutrients content and antioxidant potential of raw and fermented Parkia biglobosa seeds extracted either with methanol or water. Phytochemical presence in the seeds was influenced by extraction solvent and fermentation. Total Phenolic Content was found to be 30.05-147.52 and 21.59-141.41 mg GAE/g of extract in methanol raw and methanol fermented seeds, respectively. While the aqueous raw and fermented had 14.89-72.80 and 19.84-85.19 mg GAE/g, respectively. The fermented and raw Parkia biglobosa seed extracts exhibited great reducing and free radical scavenging properties by reducing ferric (Fe3+) to ferrous (Fe2+). Furthermore, fermentation reduced phytate and oxalate content in the unfermented seeds from 3.410 mg/g to 0.925 mg/g and 5.717 mg/g to 1.356 mg/g, respectively on the sixth day of fermentation. Thus, fermentation increases the phenolic content and the antiradical activity of Parkia biglobosa seed and enhances its nutritional value due to the reduction in the antinutrient content.

Carotenoid Production by Rhodosporidium paludigenum Using Orange Peel Extract as Substrate

Carotenoids are fat-soluble pigments that have various benefits in health and beauty. The demand and market of carotenoids are increasing; thus, the faster and cheaper biological production of these pigments using microorganisms is desired. In this study, the optimum medium pH and nitrogen concentration for carotenoid production by Rhodosporidium ( R. ) paludigenum using orange peel extract as substrate were determined. The soluble sugars from orange peels were extracted using distilled water at 100 °C. The yeast inoculum was cultivated in Yeast Peptone Dextrose (YPD) media before fermentation. The independent variables in the fermentation factorial design included initial medium pH (5; 6; and 7) and nitrogen concentration (0; 1; and 1.75 g/L urea in the medium). The decrease in reducing sugar concentration and the increase in biomass dry weight during fermentation demonstrated carbon source consumption by R. paludigenum for growth and carotenoid production. On the sixth day of fermentation (D6), the culture was harvested for the total carotenoid extraction and determination. The highest total carotenoid yield (107.63 µg/g) was achieved by the treatment group with an initial medium pH of 6 without nitrogen supplementation. This result indicated the orange peel extract potential as a substrate for carotenoid production using R. paludigenum as a workhorse. This was the first reported research in natural carotenoid generation using R. paludigenum (strain InaCC Y-236) locally isolated in Indonesia as the producer and orange peel extract as the substrate. Thus, this research would enrich the microbial carotenoid exploration and waste valorization to value-added products at the same time. The study can then be developed further and upscaled for industrial applications.Â

Dynamic Changes of Physicochemical and Aroma Components in the Fermentation Process of Mango-carrot Compound Fruit Wine

The contents of alcohol, sugar, total acid, phenols, dry extract, methanol and aroma substances of mango-carrot compound fruit wine were investigated by physical and chemical detection and gas chromatography-mass spectrometry (GC-MS) to better control the fermentation process and improve the quality of fruit wine. The results showed that the alcohol content increased first and then tended to be stable, the total sugar content decreased continuously, and the alcohol content was 13.37% vol at the end of 8 days fermentation;The content of total phenol and dry extract increased first and then decreased, total phenol reached the maximum of 395.17 mg/L on the third day of fermentation and the dry extract reached the maximum of 24.20 g/L on the fourth day of fermentation;The methanol content increased rapidly and reached the maximum of 103 mg/L on the sixth day of fermentation. Meanwhile, the volatile flavor components of mango-carrot compound fruit wine during fermentation were identified by gas chromatography-mass spectrometry (GC-MS). The mango-carrot juice was detected 23 kinds of aroma components, The main aroma components of mango-carrot juice were terpenes (65.55%), and the characteristic aroma components were 3-carene, terpinolene and β-caryophyllen;The mango-carrot compound fruit wine was detected 55 kinds of aroma components. In the fermentation process of compound fruit wine, the relative content of terpenes gradually decreased, while that of esters was the opposite. The main aroma components of compound fruit wine were esters (72.58%), and the characteristic aroma components were ethyl caprate, ethyl laurate and ethyl caprylate.

Study on the Variation of Microbial Diversity during the Fermentation of Potato Liquor Based on Biolog ECO Technology

There are many kinds of microorganisms in the fermentation process of potato liquor. Using the technology of Biolog Eco, the changes of microbial diversity in different fermentation periods were studied. The results showed that the AWCD value of microorganism in the fermentation process of potato liquor was increasing, and the AWCD value of the sample on the sixth day of fermentation was higher than that of other fermentation time samples. The results showed that the values of dominance index and diversity index of the samples on the sixth day of fermentation were higher than those of the samples in other fermentation periods, but the overall difference was not significant; the value of richness index of the samples before loading was the highest, and the value of richness index decreased after the start of fermentation, and the difference in the later stage of fermentation was small. The utilization of various carbon sources by microorganisms showed that in the process of potato liquor fermentation, microorganisms mainly used carbohydrate, polymer and amino acid carbon sources, but less used carboxylic acid, amine and phenolic acid carbon sources. The results of principal component analysis of microbial community showed that the highest carbon source was D-xylose / pentanose, and the lowest carbon source was D, l-α-Glycerin phosphate.

Identification and application of Streptomyces microflavus G33 in compost to suppress tomato bacterial wilt disease

Tomato bacterial wilt caused by Ralstonia solanacearum is the most destructive disease impacting production. Application of bioorganic fertilizer (BOF) containing antagonistic microorganism to suppress tomato bacterial wilt disease may be a promising disease control strategy. Here, we used organic waste materials, specifically biogas residues, cattle manure and rice straw, in composting with antagonistic strain G33 isolated from the rhizosphere soil of a healthy tomato plant to produce BOF. Strain G33 was identified as Streptomyces microflavus by morphological and culturing traits and by 16S rRNA gene sequence analysis. We conducted a field experiment with control treatment, organic fertilizer and BOF-G33 to characterize suppression of tomato bacterial wilt disease. Our results indicate that the optimal combination containing (w/w) 40% biogas residues, 40% cattle manure and 20% rice straw can increase the nutrient contents of the compost product, prolong the thermophilic period and increase the decomposition rate of organic matter and the humification degree. A combination of strain G33 and mature compost produced under optimal conditions resulted in the spore number of 5.75 × 109 CFU/g on the sixth day of fermentation. Field experiments showed that BOF-G33 significantly decreased the incidence of tomato wilt; the disease biocontrol efficiency was 64.4%. In addition, application of the BOF-G33 significantly reduced the pathogenic R. solanacearum populations and increased the abundance of beneficial indigenous flora in the rhizosphere soil, which might have been the key factors in constraining the disease. In conclusion, this study showed that bioorganic fertilizer with Streptomyces microflavus G33 is a potential biocontrol agent for controlling tomato bacterial disease.

Enhancement and bioavailability of phenolic content in Kappaphycus alvarezii through solid substrate fermentation

Known as carrageenan, Kappaphycus alvarezii is a popular species of red edible seaweed which is mainly cultivated for its hydrocolloids. K. alvarezii is a good source of phenolics which are considered to be natural antioxidants that promote myriads of health benefits. Extraction of phenolic compounds using conventional solvent extraction may result in hazards and toxicological effect and low yield of bound phenolics. Therefore, this study was conducted to increase the release of bound phenolics through solid substrate fermentation. In the present study, three different varieties of K. alvarezii were fermented with Aspergillus oryzae through solid substrate fermentation (SSF) at 30 ℃ for 2 to 6 days. The changes of total phenolic content and antioxidant activity due to the effects of SSF were investigated. Results obtained revealed that the highest total phenolic content for green (10.022 mg GAE/g) and purple (4.037 mg GAE/g) varieties of K.alvarezii were on the fourth day of fermentation while for yellow (4.479 mg GAE/g) variety was on the sixth day of fermentation. A remarkable enhancement of antioxidant activity was discovered through DPPH radical scavenging activity on the fourth day of fermentation for all varieties of K. alvarezii tested. Total phenolic content also showed a significant correlation with antioxidant activity of fermented seaweed. Cellulase, xylanase, and β-glucosidase enzymes produced by A.oryzae during SSF were also investigated to see the relationship with the release of phenolic compounds after fermentation. The highest cellulase activity was observed on the fourth day of fermentation. The similar observation was also found for xylanase enzyme in yellow and purple varieties of K. alvarezii , except for green variety where the highest xylanase activity was on the sixth day of fermentation. The maximum β-glucosidase activity in yellow and green varieties was observed on the fourth day of fermentation while purple variety exhibited the maximum β-glucosidase activity on the sixth day. There are positive correlation between the enzymes studied and the polyphenols content in all varieties of K. alvarezii . This study demonstrated that fermented K. alvarezii contained more phenolic content compared to non-fermented seaweed.

Biogas Production from Cow Dung for Sustainable Energy Generation

Microbial degradation of organic material under aerobic and anaerobic conditions is a key process within the natural metabolism of ecosystem. This term is often used in relation to energy, waste management and is now commonly associated with the anaerobic generation of methane. Microbial degradation and Biogas production from cow dung was investigated. Fresh cow dung was collected from Abattoir, Katsina State, Nigeria. The sample was collected in a large clean plastic container. Batch type anaerobic digesters were designed using Karki’s Biogas model. The produced biogas was collected by water displacement method. The production started on the sixth day of fermentation and followed an increasing trend. It reached its peak on the seventeenth day before a gradual fall in production rate. The Physico-chemical and microbiological analysis of the animal wastes were carried out before, during and after the digestion process. The pH range was 6.51 - 7.89. The temperature remained at mesophilic range (25-45oC) throughout the study. Data on % total solids, and ash content were also determined. The total aerobic and anaerobic bacterial counts ranged from 8.5 × 106 - 2.3 × 107 and 1.5 × 106- 1.2 × 107 cfu/ml, respectively. The bacteria isolated were Klebsiella sp, Escherichia coli, Bacillus sp, Pseudomonas aeruginosa, Staphylococcus aureus and Clostridium sp. Biogas production from cow dung is a good and cheap alternative source of energy. The use of biogas will not only serve as a source of fuel but will also help in the management of waste. Large scale production of biogas from wastes should be undertaken as the wastes around you can be converted to wealth.

STUDIES ON THE POSSIBILITIES TO USE AGRICULTURAL AND FOOD WASTES TO PRODUCE ETHANOL ALCOHOL. 1-FACTORS AFFECTING THE ETHANOL PRODUCTION FROM SUGAR BEET MOLASSES

The conditions production of bioethanol from beet molasses was investigated by Saccharomyces cerevisiae Meyen ex E.C. Hansen (1883) . Data showed that 2% inoculums size was the best size of all tested for molasses media size. Where the alcohol production was 4.6 ml /100 media with economic coefficient 53.7% and yield coefficient 46.1%. Also, incubation periods were tested from 2 to 14 days. Maximum alcohol production was noticed at the sixth day of fermentation, it was 4.71% ml/100ml medium. The same observation was found with the economic and yield coefficient, it was 53.7% and 46.1% respectively. Results showed at 30˚C incubation temperature the yeast of Saccharomyces cerevisiae produced high value of ethanol production. 4.61 ml /100ml medium with high value of economic coefficient 53.7% and 46.1% of yield coefficient. While PH 5 was the optimal value for ethanol production from molasses, where alcohol production was 4.61%, economiccoefficient and yield coefficient were 53.7% and 46.1%, respectively. Increasing the PH value up to 5.5 did not increase the ethanol production. but ethanol production was recorded decrease value. Data showed that at 20 ˚C incubation temperature and 14.0% initial, sugar the ethanol production was 5.16% with 40% economic coefficient, while at 30˚C temperature incubation the maximum ethanol production was 6.3% with economic coefficient 49.0% where the initial sugar was 14.0% in media. Conclusively, food and Agricultural wastes can be used for ethanol production usingSaccharomyces cerevisiae under anaerobic condition. Maximum Yield of ethyl was 6.3% with economic coefficient 49.9%

Determination of hydroxytyrosol produced by winemaking yeasts during alcoholic fermentation using a validated UHPLC–HRMS method

Hydroxytyrosol (HT) is a phenolic compound of recognized bioactivity that has been described in wines but little is known about its origin. This work demonstrates that yeast involved in wine making, i.e. Saccharomyces cerevisiae strains and the non-Saccharomyces Torulaspora delbrueckii, can synthesise HT, as this compound was identified in the intracellular media of three strains by means of a developed and validated UHPLC–HRMS method with LOQ and LOD of 0.108 and 0.035ngmL−1 respectively. Controlled fermentations were performed with different varieties of grapes (Corredera, Moscatel, Chardonnay, Palomino fino, Sauvignon Blanc, Vijiriega, and Tempranillo) and synthetic must. The Saccharomyces cerevisiae strain QA23 was the most efficient producer of HT from tested yeasts. On the other hand, the grape variety influences HT wine concentrations. Furthermore, the maximum concentration of HT is reached between the fourth and sixth day of fermentation. This work reveals that yeasts have a great potential for the production of HT.

Development of a beverage from red grape juice fermented with the Kombucha consortium

Kombucha is a health-promoting fermented beverage traditionally made by fermenting a sweetened tea with a symbiotic culture of yeast species and acetic acid bacteria. The aim of this work was to develop a beverage using red grape juice as an alternative substrate. Grape juice contains various nutrient elements and phytochemicals, such as polyphenols, which possess a wide range of biological activities. We investigated the chemical characteristics and sensory and antimicrobial activities of the fermented grape juice Kombucha beverage. The pH decreased from 3.95 to 2.9 during the fermentation process and remained fairly constant thereafter, and the acetic acid bacteria and yeast counts in the broth increased up to 6 days of fermentation and subsequently decreased. Phenolic and anthocyanin contents and the antioxidant activity of the fermented beverage were higher after fermentation, with the maximum increase observed on the sixth day of fermentation when values were approximately 2.47- and 1.59-fold higher than pre-fermentation values, respectively, as assessed by 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis (3-ethylbenzothiazoline-6- sulfonic acid) radical scavenging assays. Fourier transform infrared spectroscopy was used for the qualitative analysis of the grape juice before and after fermentation. Distinct peak variations in the spectral region between 2500 and 1650 cm−1 were observed, which matched the appearance of organic acids and changes in phenolic compounds. Fermented juice Kombucha showed antibacterial activity toward all tested bacteria, which can be primarily ascribed to the increased production of acetic acid, but also to the biosynthesis of other metabolites, during the fermentation process. The 6-day fermented juice was the most appreciated by the taste panel based on the overall quality evaluation; with prolongation of fermentation the fermented juice acquired a distinct sour flavor.

Use of elephant grass (Pennisetum purpureum) acid hydrolysate for microbial oil production by Trichosporon cutaneum

ABSTRACTElephant grass (Pennisetum purpureum) dilute acid hydrolysate contains 34.6 g/L total sugars. The potential of lipid production by oleaginous yeast Trichosporon cutaneum grown on elephant grass acid hydrolysate was investigated for the first time. During the fermentation process on the elephant grass acid hydrolysate, glucose, xylose, and arabinose could be well utilized as carbon sources by T. cutaneum. Interestingly, xylose was almost no use before glucose was consumed completely. This illustrated that simultaneous saccharification of xylose and glucose by T. cutaneum did not occur on elephant grass acid hydrolysate. The highest biomass, lipid content, lipid yield, and lipid coefficient of T. cutaneum were measured after the sixth day of fermentation and were 22.76 g/L, 24.0%, 5.46 g/L, and 16.1%, respectively. Therefore, elephant grass is a promising raw material for microbial oil production by T. cutaneum.

The effects of N+ ion implantation mutagenesis on the laccase production of Ceriporiopsis subvermispora

In order to obtain genetically stable, high-yield, laccase-producing strains, Ceriporiopsis subvermispora was induced by N+ ion implantation and subcultured. The results revealed that, with energy of 30 keV and a dose of 80×1014 ions/cm2, a relatively high increase in mutations and positive mutations were achieved. Three screened high-yield strains (NL3, NL4, and NL6) were obtained and subcultured. The results of the comparison showed that, NL4 had stable genetic traits and the highest laccase activity (323 U/L). In the course of fermentation, NL4 entered a vigorous growth period 24 h ahead of the original strain, and produced a large amount of laccase during the stationary phase. Up until the sixth day of fermentation achieved the highest laccase activity of 377 U/L, and a corresponding biomass dry weight of 4.2 mg/mL. The relative laccase activity of the per gram dry cells was 89.76 U, which was 4.79 times that of the original strain. The results indicated that N+ ion implantation was an ideal technique for microbial breeding, which could be applied for the improvement of Ceriporiopsis subvermispora.

INVESTIGATION OF CHEMICAL QUALITY OF SUGARCANE (SACCHARUM OFFICINARUM L.) WINE DURING FERMENTATION BY SACCHAROMYCES CEREVISIAE

ABSTRACT The purpose of this study was to examine the changes in the contents of sugar, ethanol, organic acids, volatile compounds, pH and acidity in sugarcane wine during fermentation using Saccharomyces cerevisiae and the consumer preference test was also conducted to investigate the optimal fermentation. According to the results, the maximal population of S. cerevisiae reached to 8.12 log cfu/mL at the sixth day of fermentation. The maximum ethanol content, 15.16%, was obtained at the ninth day, while the sucrose and glucose concentrations were almost exhausted at the same time. As for organic acids, citric acid was detected as the most abundant one at the second day of fermentation, followed by lactic and succinic acids. The volatile compounds were analyzed by SPME/GC‐MS, and the concentrations of alcohols, esters and acids were all highest in sugarcane wine at the sixth day of fermentation. The results have demonstrated that sugarcane wine fermentation with S. cerevisiae at the sixth day is enough to reach the highest aroma quality as indicated by the highest esters/alcohols in the wine and the most abundant amount of aroma‐related compounds. The overall preference of consumer test also supports the above result with the sugarcane wine fermented at day 6 having highest scores.PRACTICAL APPLICATIONSSugarcane with high content of sugar is a potential material for making vinegar through alcoholic and acetous fermentation. Because the sugarcane wine as well as sugarcane vinegar is seldom available in Taiwan or other places, it is beneficial to study how to effectively use the sugarcane other than just consumed as a kind of fresh fruit or a juice drink. The economic value of wine is highly depended on its composition changes and consumer's preference. Although there are a few reports working on the chemical compounds during fermentation of sugarcane wine, there is little concerning the consumer‐type preference parallel to the chemical analysis during fermentation. Following the identification of winemaking fermenting yeast strain, Saccharomyces cerevisiae, isolated from liquor rice dregs and the establishment of the fermenting condition for making sugarcane wine carried out in our previous studies, in this study, we analyzed the composition of volatile compounds in sugarcane wine and characterized the associated changes in chemical properties during fermentation. In addition, the consumer preference test was also carried out to verify the results of chemical property analysis. It is hoped the strategy of this study to be a reference prior to industry scale for manufacturing process and quality improvement of sugarcane wine and other wines.

Improvement on Citric Acid Production in Solid-state Fermentation by Aspergillus niger LPB BC Mutant Using Citric Pulp

Citric acid (CA) production has been conducted through a careful strain selection, physical-chemical optimization and mutation. The aim of this work was to optimize the physical-chemical conditions of CA production by solid-state fermentation (SSF) using the Aspergillus niger LPB BC strain, which was isolated in our laboratory. The parental and mutant strain showed a good production of CA using citric pulp (CP) as a substrate. The physical-chemical parameters were optimized and the best production was reached at 65% moisture, 30 degrees C and pH 5.5. The influence of the addition of commercial and alternative sugars, nitrogen sources, salts, and alcohols was also studied. The best results (445.4 g of CA/kg of CP) were obtained with sugarcane molasses and 4% methanol (v/w). The mutagenesis induction of LPB BC was performed with UV irradiation. Eleven mutant strains were tested in SSF where two mutants showed a higher CA production when compared to the parental strain. A. niger LPB B3 produced 537.6 g of CA/kg of CP on the sixth day of fermentation, while A. niger LPB B6 produced 616.5 g of CA/kg of CP on the fourth day of fermentation, representing a 19.5% and 37% gain, respectively.

Study on microbial protein and the mechanism of solid-state fermentation with periodical dynamic changes of air

The effect of different extraction and purification conditions on the microbial protein obtained from solid-state fermentation (SSF) and the effect of periodical dynamic changes of air on protein have been studied. The mechanism of solid-state fermentation with periodical dynamic changes of air is also discussed. Compared with static solid-state fermentation, periodical dynamic changes of air afford a higher protein mass; from 1 g of the fermentation microbe, 5.3 mg of the intracellular protein (an increase of 34.63%) and 9.09 mg of the extracellular protein (an increase of 17.8%) were obtained on the sixth day of fermentation. The filter paper activity and carboxymethyl cellulose activity (FPA and CMCase) of the extracellular protein are 1.739 μmol/s and 109.592 μmol/s, respectively, which represent increases of 60.1% and 21.2% over the corresponding values for static solid-state fermentation. The FPA and CMCase of the intracellular protein are 0.245 μmol/s and 6.392 μmol/s, respectively, which represent decreases of 22.2% and 38.7% over the corresponding values for static solid-state fermentation. The enzyme activity of the microbial extracellular protein in solid-state fermentation with periodical dynamic changes of air on the fifth day is nearly equal to that on the sixth day without periodical dynamic changes of air, so the period of fermentation can be shortened. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) experiments suggest that pulsating air pressure stimulation leads to a decrease in the amount of protein component with molecule mass of about 80400Da, and an increase in the amount of protein component with molecule mass of about 28520Da.