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The purpose of this paper is to assess equipment surfaces associated with the production of Baker's compressed yeast for microbial biofilms.

Yeast and bacteria (aerobic plate counts – APC, Enterococcus, E. coli and coliforms) attached to five processing equipment surfaces in a yeast processing factory were enumerated after dislodging from stainless steel squares (“mock” surfaces), or swabbing, after 7, 14, 21 and 28 days of yeast of production. Attached populations were visualized by scanning electron microscopy (SEM).

A similar increasing trend in attached bacterial counts on all equipment surfaces was observed over 28 days using both “mock” surface and swabbing techniques. However, bacterial and viable yeast counts obtained using “mock” surfaces were significantly higher (P<0.05) by ca. 1 to 2.5 log CFU/cm² compared to corresponding counts obtained by swabbing. Overall E. coli and coliform counts were below the lower detection limit (0.7 log CFU/cm²), Enterococcus counts ranged from 2.30 log CFU/cm² to 4.69 CFU/cm², and APC ranged from 2.17 CFU/cm² to 4.89 CFU/cm². Highest attached bacterial counts were consistently recorded on the hopper and extruder. SEM of “mock” surfaces confirmed the accumulation of yeast cells and attachment of rod and coccoid‐shaped bacterial cells. Predominant surface‐associated bacterial populations were Enterococcaceae (70%), Lactobacillus (20%) and Gram‐negative rods (10%).

Biofilms on stainless steel yeast processing equipment surfaces may act as potential sources of during production spoilage contamination of Baker's compressed yeast.

Mixed fermentation with Saccharomyces cerevisiae and non-Saccharomyces yeasts has become an oenlogical tool to improve wines’ organoleptic properties. However, the maximum utilization of this method is dependent upon understanding the influence of mixed cultures on the physiology of S.cerevisiae and non-Saccharomyces yeasts.

In this study, the supernatants from 48 h mixed-culture fermentation were added to the pure cultures of Issatchenkia orientalis and Saccharomyces, respectively. And the authors used RNA sequencing to determine the transcriptome change of I.orientalis and S.cerevisiae in a mixed culture.

The results showed that multiple genes associated with cell growth and death were differentially expressed. Genes related to biosynthesis of amino acids were enriched among those upregulated in the mixed-fermentation supernatant. Meanwhile, the differential expression level of genes encoding enzymes essential for formation of aroma compounds was found in the single and in the mixed fermentation. The high expression level of molecular chaperones Hsp70, Hsp90 and Hsp110 suggests that metabolites of mixed-culture fermentation may lead to aggregation of misfolded proteins. Moreover, upregulation of ethanol dehydrogenase I ADH1 in the mixed-culture fermentations was highlighted.

This is the first time that RNA-seq was used to analyze changes in the transcriptome of mixed cultures. According to the results the authors’ manuscript provided, an integrated view into the adaptive responses of S.cerevisiae and non-Saccharomyces yeasts to the mixed-culture fermentation is benefit for the potential application of S.cerevisiae and non-Saccharomyces yeasts in fruit wine brewing.

In the Indian system of medicine – Ayurveda, Musa paradisiaca has been mentioned as a remedy for various diseases and ailments. Based on the folkloric use, the purpose of this paper is to verify and compare the hypoglycemic potential of unripe, ripe and overripe fruit extract of Musa paradisiaca.

Hypoglycemic activity of fruit extracts has been evaluated using various in vitro methods, namely, determination of glucose adsorption capacity, glucose uptake in yeast cells, amylolysis kinetics and glucose diffusion.

The extracts of unripe, ripe and overripe fruits of Musa paradisiaca adsorbed glucose, and the adsorption of glucose increased remarkably with an increase in glucose concentration. In the amylolysis kinetic experimental model, the rate of glucose diffusion was found to increase with time, and all the extracts of unripe, ripe and overripe fruits of Musa paradisiaca demonstrated significant inhibitory effects on the movement of glucose into external solution across the dialysis membrane as compared to the control. The extracts under study also promoted glucose uptake by the yeast cells in all the five glucose concentrations used in the study.

Here, the authors have verified and compared the hypoglycemic potential of Musa paradisiaca, its unripe fruit extract was found to show a better activity than ripe and overripe fruit extracts.

Banana, being an all season readily available fruit, is widely consumed due to its ready availability and low cost. It acts as a complete food for even low socio-economic classes of society, owing to its rich nutritional values. Even in a processed and unprocessed manner, it is an important constituent of diet. The research suggests that instead of consuming ripe and overripe fruit, the unripe fruit will help in management of diabetes.

This study was conducted with the aim of examining the ability of Saccharomyces cerevisiae to remove AFB₁ from liquid media in order to use data in food and feed systems.

The binding of AFB₁ to Saccharomyces cerevisiae in the late exponential and early stationary phases was studied for viable, heat killed and acid killed yeast. AFB₁ at concentrations (5, 10 and 20 μg/l) was added to the yeast culture (10⁹ cfu/ml) in yeast mold broth medium and incubated at 25°C for 4, 12 and 24 hrs. The aflatoxin binding capacity of the strain was quantified by the amount of unbound AFB₁ using ELISA technique.

The detoxification rate for different treatments reported as follows: acid treated cells > heat treated cells > viable cells. Also, the most reduction in AFB₁ concentration happened within the first four hours of incubation with no significant increase in AFB₁ binding on further incubation because of saturation of active sites in yeast cells. According to the results, either form of Saccharomyces cerevisiae (viable or nonviable) is effective in aflatoxin binding from medium and the binding has a physical nature.

The findings reduce the public concern about aflatoxin B₁ contamination in foods and feeds having high risk of aflatoxin contamination.

No research had been done to assess the ability of Saccharomyces cerevisiae in the mentioned forms to detoxify AFB₁.

The purpose of this paper is to assess the potential of papaya juice fermentation and to evaluate the kinetic changes of volatile organic compounds (VOCs) produced during fermentation by three commercial wine yeasts.

Laboratory‐scale fermentations were carried out in papaya juice using three commercial wine yeasts Saccharomyces cerevisiae var. bayanus strains EC‐1118 and R2, and S. cerevisiae MERIT.ferm. Brix, pH, optical density and yeast cell count were determined during fermentation. VOCs were analysed by headspace‐solid phase microextraction with gas chromatography‐mass spectrometry‐flame ionization detector (HS‐SPME‐GC‐MS/FID).

During fermentation, the three wine yeasts grew actively and showed similar growth patterns. Changes in Brix and pH were similar among the three yeasts. A range of VOCs were produced during fermentation including fatty acids, alcohols, acetaldehyde, esters and acetoin. Esters were the most abundant VOCs produced. Some VOCs indigenous to the papaya juice such as benzaldehyde, β‐damascenone and benzyl isothiocyanate were consumed during fermentation. Some VOCs increased initially, and then decreased during fermentation. Overall, the profiles of VOC changes during fermentation were similar among the three yeasts with some differences observed.

The paper suggests that papaya fermentation with S. cerevisiae yeasts are likely to result in papaya wine with similar flavours. New approaches are required to produce papaya wine with distinct flavours and to enable differentiation of papaya wines by exploiting non‐Saccharomyces yeasts in conjunction with Saccharomyces yeasts and/or by adding selected nitrogen sources.

Increased ethanol accumulation during ethanol fermentation generates stress in yeast cells, which finally reduces the fermentation performance and efficiency. Trehalose, a potential stress protectant, has been reported to regulate the response of yeast to diverse environmental stresses. This study aimed to explore how exogenous trehalose application affects the survival, transcriptome and antioxidant enzymes of Wickerhamomyces anomalus grown under ethanol stress conditions.

Exogenous trehalose was applied to the growth condition of W. anomalus, and optical densitometric method was used to detect contents of intracellular trehalose and MDA and activities of CAT and SOD. The survival was evaluated using spot analysis. Differentially expressed genes (DEGs) were identified through transcriptomics analysis.

The results showed that ethanol stress induced the accumulation of intracellular trehalose, with further exogenous trehalose application improving the survival and alleviating oxidative stress in ethanol-stressed W. anomalus. Transcriptomic results showed that trehalose has pleiotropic regulating effects on ethanol-stressed W. anomalus since most DEGs annotated to energy metabolism, amino acid metabolism, translation, folding, sorting and transport were affected post trehalose addition. Therefore, it is found that trehalose protected W. anomalus against ethanol stress, and these findings provide interesting insights into the mechanistic role of trehalose in improving ethanol stress tolerance of W. anomalus.

(1) Protective effect of exogenous trehalose addition on the survival of ethanol-stressed W. anomalus was proved. (2) Exogenous trehalose addition could partly alleviate oxidative stress induced by ethanol stress and affect transcriptome in W. anomalus.

The yeast Saccharomyces cerevisae is the most important ingredient of leavened products and is best known for its characteristic physiological property: the rapid fermentation of sugar to ethanol and carbon dioxide. The purpose of this paper is to exploit this feature to determine the effect of three commercially available yeast types: Instant, Dried, and Fresh on sugar utilization during the fermentation process and bread quality.

Three commercially available yeast types – Instant, Dried, and Fresh were used at three levels, i.e. 0.50, 0.75 and 1.00 percent in order to assess sugar utilization during the fermentation process and bread quality after baking.

The rate of utilization of glucose was much faster than fructose and sucrose. Instant yeast at 1.00 percent exhibited maximum sugar utilization during the fermentation process. It also contributed to improving the bread texture, loaf volume, grain texture, crust and crumb color. Dried and Fresh types could not depict any significant difference in their sugar utilization behavior and bread quality. The results indicated that yeast quality as well as quantity is one of the major indices of bread quality.

The findings of the research can be used by bakers in order to select the proper yeast type and its level for production of quality bread. It also gives an idea about sugar type best suited for bread production.

The paper describes unique research work, as both yeast types, along with their levels, are tested for their fermentation capacity on different types of sugars, as fermentation is an important step in bread making.

The present study was carried out to standardize the method for preparation of naturally carbonated fermented paneer whey beverage by incorporating pineapple and strawberry fruit juice and to check their suitability in the beverage by evaluating the organoleptic characteristics and shelf life of product.

Beverage was inoculated with yeast culture Clavispora lucitaniae at 0.5 per cent v/v and fermented at 35 ± 1°C for 36 h aerobically. Standardization of total soluble solids (TSS) (16, 15, 14, 13 and 12oBrix) and juice concentration (15, 20, 25 and 30 per cent) of beverage was done on the basis of organoleptic evaluation, and the beverage with TSS 12oB and 30 per cent juice was selected best for further storage study. Two types of beverages were prepared: paneer whey beverage blended with pineapple juice and paneer whey beverage blended with strawberry juice, and were stored at refrigerated (4 ± 1oC) and ambient (25 ± 5oC) conditions. Effect of storage on physico-chemical, microbiological and sensory attributes were studied periodically after every 15 days for 90 days of storage period.

There was significant decrease in brix:acid ratio (p = 0.0008) from 12.0 to 9.3, total sugar (p = 0.017) from 10.8 to 6.8, ascorbic acid (p = 0.002) from 17.8 to 9.3 mg/100 mL and lactose (p = 0.037) from 3.1 to 0.6 per cent content over 90 days of ambient storage period. Total yeast count increased during the initial stages of fermentation and started declining after 60 days of storage. The alcohol production started after 15 days and reached 0.7 per cent after 90 days for paneer whey beverages blended with strawberry juice. The more variations were found in the physico-chemical and microbiological properties of the beverage at ambient storage than refrigeration storage. Highest score for color, flavor, mouthfeel and overall acceptability was found on third days, which decreased further during the storage. The comparative study of the paneer whey beverage blended with strawberry juice stored at ambient and refrigeration temperature showed that maximum decrease was found for score of appearance/color, flavor, mouthfeel and overall acceptability at ambient temperature as compared to refrigeration temperature. Beverage stored at refrigeration temperature was found more acceptable than the beverage which was stored at ambient temperature irrespective of all types of beverages.

The refrigerated beverage was found more acceptable up to 90 days, whereas beverage stored under ambient conditions was found acceptable up to 60 days. The products so obtained had naturally produced CO₂, and little alcohol content added effervescence, sparkle, tangy taste and flavoring characteristics.

The purpose of this paper is to identify and analyse the fermentative properties of a strain of indigenous Wickerhamomyces anomalus (W. anomalus) from Rosa roxburghii Tratt (R. roxburghii).

Morphological and molecular methods were used to determine the species of the selected strain W. anomalus C11. The physiological tolerances to glucose, ethanol, citric acid and sulphur dioxide (SO₂) were further assessed by checking the growth of cells, and the oenological performances were proved to measure the related fermentative properties of R. roxburghii wines.

The W. anomalus C11 strain could be grown faster than commercial S. cerevisiae X16 in its logarithmic growth period and had preferable tolerances to glucose, ethanol, citric acid and SO₂. Moreover, this strain of native R. roxburghii yeast W. anomalus C11 produced less sulphuretted hydrogen and had a higher β-glucosidase activity. Furthermore, W. anomalus C11 could reduce the volatile acids, reduce the sourness and enhance volatile aroma richness and complexity of R. roxburghii wines including types of aroma and content thereof. Taken together, the R. roxburghii native yeast W. anomalus C11 may have potential for use in R. roxburghii winemaking.

(1) The fermentative properties of a strain of indigenous W. anomalus (named as C11) from R. roxburghii was evaluated. (2) The strain of W. anomalus C11 had preferable tolerances to glucose, ethanol, citric acid and SO₂. (3) This strain of native R. roxburghii yeast W. anomalus C11 produced less sulphuretted hydrogen and had a higher ß-glucosidase activity. (4) W. anomalus C11 could reduce the volatile acids, reduce the sourness and enhance volatile aroma richness and complexity of R. roxburghii wines including types of aroma and content thereof.

The Government's proposals for the establishment of a Greater London Council were contained in the White Paper on London Government, published last November. In the main, the Government support the recommendations of the Royal Commission, although many of these were controversial and aroused much opposition, particularly from the London County Council itself. The present two‐tier form of local government is to be replaced by a Greater London Borough as the primary unit responsible for its own area and an elected Greater London Council with larger and broader functions for a very much larger area. This will consist of the present area of the London County Council, Middlesex and parts of Hertfordshire, Essex, Kent and Surrey, coinciding with the approximate area of the metropolitan police district.