Physicochemical and microbiological description of Caxiri – a cassava and corn alcoholic beverage

Caxiri is a fermented alcoholic beverage made from cassava, corn and sweet potatoes by indigenous people in Brazil. Saccharomyces cerevisiae Rhodotorula mucilaginosa, Lactobacillus fermentum, Bacillus subtilis and L. helveticus were the main microbial species detected. Maltose was the main carbohydrate found (19.12 g L^?1), and lactic acid (15.09 g L^?1) and ethanol (92.16 g L^?1) were also found in high concentrations. Gas chromatography‐flame ionisation detector was used to identify thirteen volatile compounds. Among these volatiles, the higher concentrations were decanoic acid (123.04 μg L^?1) for the acids, diethyl malate (88.32 μg L^?1) for the esters, furfural (109.31 μg L^?1) for the aldehydes, 2‐phenylethanol (1022.76 μg L^?1) for the alcohols and 1,1‐diethoxyethane (226.24 μg L^?1) for the others. This study contributes to increasing knowledge of the microbiota present in the alcoholic fermentation produced from cassava, corn and sweet potatoes.     

Effects of sugar concentration on mango wine composition fermented by Saccharomyces cerevisiae MERIT.ferm

This study investigated the effect of initial sugar concentrations (^°Brix of 17, 23 and 30) on mango wine composition fermented by Saccharomyces cerevisiae MERIT.ferm. It was found that growth rate and maximum cell population were inversely correlated with initial sugar levels with the fastest growth rate and largest cell population in the low sugar fermentation. However, the cell population in the low and medium sugar fermentation declined significantly (from 8.7 and 8.2 log to 2 and 2.8 log, respectively) relative to the high sugar fermentation in which cell populations remained stable upon reaching the stationary phase (7.7 log). Glycerol production increased with increasing sugar content in low (13.4 g L^?1), medium (14.5 g L^?1) and high (15.9 g L^?1) sugar fermentation. In addition, high sugar fermentation had a negative impact on volatile production with significantly lower amounts of acetate esters (1.5 mg L^?1) but more acetic acid (0.54 g L^?1) compared to the low (5.0 mg L^?1 and 0.44 g L^?1, respectively) and medium (3.7 mg L^?1 and 0.49 g L^?1, respectively) sugar fermentations. Furthermore, volatiles especially terpene hydrocarbons (α‐caryophyllene was released) present in mango juice were significantly metabolised after fermentation, while numerous new volatile compounds (such as isobutyl alcohol, isoamyl alcohol, ethyl and acetate esters) were produced. Some terpene alcohols were released and converted into corresponding acetyl esters. This may indicate that the mango wines fermented with different levels of sugars would have different flavour aromas.     

Microbiological and physicochemical properties of dry‐cured neck inoculated with probiotic of Bifidobacterium animalis ssp. lactis BB‐12

The effect of inoculum level of Bifidobacterium animalis ssp. lactis BB‐12 probiotic strain and ripening period on the quality of dry‐cured neck was studied. The microbiological parameters (Enterobacteriaceae, LAB and TVC) and physicochemical attributes (pH value, a_w, TBARS index, colour) were determined directly after fermentation at 15 °C for 3 weeks, after 6 and 12 months of ripening at 4 °C. The highest LAB count and a lower pH value were found in the meat inoculated with probiotic strain at 6.6 log cfu g^?1 (B2) followed by inoculation with probiotic strain at 6.3 log cfu g^?1 (B1). Level of inoculation had not had an influence on water activity, TBARS index and total colour parameters. Changes of fat oxidation during half‐year of ripening were limited in probiotic meat samples compared to naturally fermented control meat (C). Based on the results, it can be concluded that the most favourable physicochemical and microbiological parameters of the dry‐cured neck were obtained after 6 months of ripening. At that time, the Bifidobacterium BB‐12 at both levels is a good potential starter for meat fermentation.     

Isolation,characterisation and fermentation optimisation of glucansucrase‐producing Leuconostoc mesenteroides DRP105 from sauerkraut with improved preservation stability

A total of fifty‐six strains of lactic acid bacteria isolated from Chinese sauerkraut juice from Shenyang were screened for glucansucrase production. Among them, strain DRP105 was detected to produce highest yield of glucansucrase in MRS broth, which was identified to be Leuconostoc mesenteroides. Based on Plackett–Burman Experiment, sucrose, sodium acetate and initial pH were found to be the most significant factors for glucansucrase production of L. mesenteroidesDRP105. Afterwards, effects of the three main factors on glucansucrase activity were further investigated by central composite design, and the optimum composition was sucrose 35.74 g L^?1, sodium acetate 6.46 g L^?1 and initial pH 5.90. Optimum results showed that glucansucrase activity was increased to 6.26 ± 0.09 U mL^?1 in 24 h fermentation, 33.19% higher than before. Our study also suggested that Tween 80 and dextran have potential to improve glucansucrase stability at temperature (30 °C) higher than enzyme storage temperature in crude fermented broth.     

Comparison of vacuum impregnation and soaking techniques for addition of the probiotic Lactobacillus acidophilus to minimally processed melon

This study aimed to evaluate the vacuum impregnation (VI) and soaking methods in the addition of Lactobacillus acidophilusLA‐3 to minimally processed melon (MPM). The melons were washed, sanitised in chlorine solution (200 mg L^?1), peeled and cutted into cubes. Lactobacillus acidophilusLA‐3 (1.4 × 10¹⁰ CFU g^?1) were added to the MPM through both techniques. The L. acidophilusLA‐3 count in MPM was similar to those commonly found in dairy products having probiotic claim, but VI was more efficient than soaking in maintaining the viability (8.61 and 7.98 Log CFU g^?1, respectively). The pH, acidity and soluble solids were not affected by probiotic culture and the incorporation technique; however, the VI affected the firmness of fruit. The MPM was within Brazilian standards for their microbiological characteristics. MPM may be used as a carrier of probiotic bacteria, being one more alternative for individuals who consume probiotic products.     

Selected factors influencing the ability of Bifidobacterium to form biogenic amines

The ability of typical probiotic culture of Bifidobacterium to produce biogenic amines could be considered a contrastive feature to the beneficial dietary effect on human health. The aim of this pilot study was to evaluate the decarboxylase activity of Bifidobacterium animalis subsp. lactis CCDM 239 influenced by selected factors (pH 4.5 and 5.0; the contents of NaCl 0–20.0 g L^?1, glucose and lactose 0–10.0 g L^?1) at in vitro conditions. The kinetics of the biogenic amine production under the above‐mentioned conditions was also monitored. The biogenic amine content detection was carried out in the supernatants of inoculated broth [MRS enriched with amino acids: arginine, ornithine, lysine, tyrosine; 3 g L^?1 after the cultivation (48 h, 37 ± 1 °C)]. RP‐HPLC after the precolumn derivatisation with dansyl chloride was used. In most cases, the low concentrations of tyramine were monitored (<15 mg L^?1). Simultaneously, it was found out that the addition of certain fermentable saccharide concentrations and NaCl in their mutual combination seemed to have supporting effect on the decarboxylase activity of the tested Bifidobacterium.     

Bioconversion of agro‐industrial by‐products to lactic acid using Lactobacillus sakei and two Pediococcus spp. strains

The aim of this study was to evaluate the bioconversion efficiency of rich in cellulose agro‐industrial by‐products such as wheat bran (WB), spent distiller's grain with solids (DGS), brewer's spent grain (BSG) and lupin (Lupinus angustifolius L.) wholemeal fraction (LF) to lactic acid (LA) using acid tolerant lactic acid bacteria (LAB) strains Lactobacillus sakei KTU05‐06, Pediococcus acidilactici KTU05‐7 and P. pentosaceus KTU05‐9. Carbohydrase preparation Depol^? 692L was used for the hydrolysis of non‐starch polysaccharides. Analysed raw materials were suitable substrates for LAB propagation and L‐lactic acid production. The lowest pH (3.6) was found in LF medium after 48 h fermentation with P. acidilactici and P. pentosaceus strains. The lowest pH (3.86) was measured in WB fermented with L. sakei, and in DGS and BSG (pH 3.8 and 3.9 respectively) fermented with P. acidilactici. The highest endoxylanase activity was excreted by the P. acidilactici and P. pentosaceus (84 and 69 XU g^?1 respectively), and the highest α‐amylase activity was of L. sakei (255.6 AU g^?1) after 24 h incubation in WB medium. The L‐lactic acid concentration of 86.11 g kg^?1 was reached after the bioconversion of hydrolysed WB in combination with 48 h fermentation by P. pentosaceus KTU05‐9 strain. LA contents between 222 and 282 mg kg^?1 was produced from lupin processing residues via fermentation using P. acidilactici and P. pentosaceus KTU05‐9 strains. The major challenge within the presented study is the viability of tested LAB in cereal waste media and effective LA production at a low pH (3.6–3.8).     

Studies on the mashing conditions of teff (Eragrostis tef) malt as a raw material for lactic acid‐fermented gluten‐free beverage

Formation of extracts and fermentable sugars during mashing can be limited by incomplete starch gelatinisation. The aim of this research was to develop mashing programme for 100% teff malt as a potential raw material for gluten‐free lactic acid‐fermented beverage. Isothermal mashing at temperatures ranging between 60 and 84 °C was conducted, and the highest extract (85%) was observed for the wort samples produced at temperatures higher than 76 °C. Sixty‐minute rest at 71 °C resulted in higher fermentable sugars than other tested conversion rest temperatures. Inclusion of lower mashing‐in temperature in the mashing programme also substantially improved the concentrations of free amino nitrogen (128 mg L^?1) and fermentable sugar (58 g L^?1) in the final wort. Therefore, 30‐min rest at 40 °C followed by 60‐min rest at 71 °C and 10‐min rest at 78 °C was found to be a suitable mashing programme for teff malt.     

Control of lactic acid bacteria in fermented beverages using lysozyme and nisin: test of traditional beverage boza as a model food system

The objective of this study was to increase quality and limited shelf‐life of boza (3–15 days), a traditional Balkan origin fermented beverage using lysozyme (LYS) and/or nisin (NIS). For this purpose, the effectiveness of NIS, LYS and LYS:NIS combinations was first tested in a broth medium at 4 °C for 3 weeks on Lactobacillus plantarum, one of the frequently isolated lactic acid bacteria in boza. Stability of LYS and NIS in boza, their effects on LAB counts, and chemical and sensory properties of boza were then evaluated during cold storage at 4 °C. Results of LAB counts as well as pH, d ‐ and l ‐lactic acid, and titratable acidity measurements showed that LAB in boza containing NIS (250 μg g^?1) or LYS:NIS (500:250 μg g^?1) could be controlled without reducing LAB counts below 6 log CFU mL^?1 during 2 weeks shelf‐life. In contrast, LYS (500 μg g^?1) alone could not control LAB in boza to delay its acidic spoilage. Positive effects of NIS and LYS:NIS application on quality of boza were also proved with sensory analysis by panelists and e‐nose measurements. This work showed that use of natural GRAS agents in preservation of fermented beverages containing probiotic LAB is possible without affecting their characteristic aroma and flavour.     

Impact of buffering capacity on the acidification of wort by brewing‐relevant lactic acid bacteria

Acidified wort produced biologically using lactic acid bacteria (LAB) has application during sour beer production and in breweries adhering to the German purity law (Reinheitsgebot ). LAB cultures, however, suffer from end product inhibition and low pH, leading to inefficient lactic acid (LA) yields. Three brewing‐relevant LAB (Pediococcus acidilactici AB39, Lactobacillus amylovorus FST2.11 and Lactobacillus plantarum FST1.7) were examined during batch fermentation of wort possessing increasing buffering capacities (BC). Bacterial growth was progressively impaired when exposed to higher LA concentrations, ceasing in the pH range of 2.9–3.4. The proteolytic rest (50°C) during mashing was found to be a major factor improving the BC of wort. Both a longer mashing profile and the addition of an external protease increased the BC (1.21 and 1.24, respectively) compared with a control wort (1.18), and a positive, linear correlation (R ² = 0.957) between free amino nitrogen and BC was established. Higher levels of BC led to significant greater LA concentration (up to +24%) after 48 h of fermentation, reaching a maximal value of 11.3 g/L. Even higher LA (maximum 12.8 g/L) could be obtained when external buffers were added to wort, while depletion of micronutrient(s) (monosaccharides, amino acids and/or other unidentified compounds) was suggested as the cause of LAB growth cessation. Overall, a significant improvement in LA production during batch fermentation of wort is possible when BC is improved through mashing and/or inclusion of additives (protease and/or external buffers), with further potential for optimization when strain‐dependent nutritional requirements, e.g. sugar and amino acids, are considered. Copyright © 2017 The Institute of Brewing & Distilling     

Co‐inoculation of yeast and lactic acid bacteria to improve cherry wines sensory quality

This study examined the effect of co‐inoculation of yeast and lactic acid bacteria (LAB) on the chemical and sensory characteristics of cherry wines, in comparison with a traditional sequential culture. Three LABs were investigated, including two O. oeni (SG26 and Viniflora) and one L. plantarum (PL18). All co‐inoculations significantly shortened the fermentation time (average 8 days earlier) to reach a stable level of residual sugar (<2 g L^?1) and L‐malic acid (<0.5 g L^?1), and no inhibitory effect on the yeast proliferation was observed. For volatiles determined, co‐culture with SG26 produced the greatest amount of volatile components (138.5 mg L^?1), whereas sequential inoculation with PL18 had the lowest level (119.6 mg L^?1). PCA result revealed that different LABs had diverse influences on the volatile profile of cherry wines, and sensory analysis confirmed that these samples presented distinct sensory profiles, and particularly, a stronger note of fruity was perceived when co‐culture was used.     

Effect of milk supplementation and culture composition on acidification, textural properties and microbiological stability of fermented milks containing probiotic bacteria

In the present work, the combined effect of milk supplementation and culture composition on acidification, textural properties, and microbiological stability of fermented milks containing probiotic bacteria, was studied. Three powders (whey, casein hydrolysate, and milk proteins) were tested as supplementation. Two strains of probiotic bacteria, Lactobacillus acidophilus (LA5) and Lactobacillus rhamnosus (LC35), were used in pure culture, and in mixed culture with Streptococcus thermophilus (ST7). Acidifying activity was enhanced with mixed cultures, compared to pure cultures resulting in a shorter time to reach pH 4.5. Acidifying activity was greatly improved with casein hydrolysate, with a reduction of the fermentation time by about 55% by comparison with the other supplementations. The stability of probiotic bacteria was weakly affected by milk supplementation and culture composition. However, pure cultures were more stable than mixed cultures. The texture of the fermented products was not dependent on culture composition, but strongly dependent on milk supplementation. Sweet whey supplementation gave products with lower firmness and viscoelasticity than products supplemented with casein hydrolysate or milk proteins (decrease by 70%). It was observed that all products containing probiotic counts over 2.2×10⁷ CFU mL⁻¹ are suitable for the development of a lactic beverage containing probiotics.     

Effects of inulin,fructooligosaccharides/glucose and pH on the shape of the death kinetic of Lactobacillus reuteri DSM 20016

The viability of Lactobacillus reuteri, Lb. delbrueckii subsp. bulgaricus and Lb. paracasei was assessed in a laboratory medium containing inulin (5 g L^?1) or glucose + FOS (fructooligosaccharides) (2.5 + 2.5 g L^?1). Data were modelled through the Weibull equation pinpointing that prebiotics determined a decrease in the shape parameter. In the 2nd step, L. reuteri was used as the test microorganism; pH, storage temperature and the amounts of FOS + glucose and inulin were combined through a 4‐variable/5‐level central composite design. Temperature, pH and glucose + FOS affected the microbiological shelf life; inulin was not significant. The maximum value of shelf life was found at pH 8.5 and with 5.0 g L^?1 of glucose + FOS. The combination of pH and prebiotics affected the shape parameter with a shift from a convex to a concave trend and vice versa: their effect was different depending on the use of a single prebiotic or a mix.     

Influence of ammonia and lysine supplementation on yeast growth and fermentation with respect to gluten-free type brewing using unmalted sorghum grain

Because gluten-free type brewing with unmalted sorghum does not provide adequate nitrogen for complete fermentation, wort supplementation with ammonia (as diammonium phosphate, DAP) or lysine on yeast performance was investigated. By Phenotype Microarray, under aerobic conditions, greater yeast growth was indicated with DAP than lysine both as a single source and combined with sorghum wort amino acids. With sorghum fermentation, both DAP and lysine improved maltose and maltotriose uptake. However, DAP supplementation also maintained yeast numbers (24.0–21.3 × 10⁶ cells mL⁻¹), whereas there was a decline with lysine supplementation. Lysine supplementation also resulted in adverse effects on yeast cell morphology. Neither DAP nor lysine supplementation resulted in evident genetic change to the yeast, but the change in substrate from barley malt wort to unmalted sorghum wort slightly altered the yeast genetically. Therefore, ammonia as DAP has potential as a nitrogen supplement for improving yeast fermentation performance in sorghum gluten-free brewing.     

Comparison of releasing bound phenolic acids from wheat bran by fermentation of three Aspergillus species

Wheat bran was fermented at 28 °C for 7 days under 70% humidity by Aspergillus niger, Aspergillus oryzae and Aspergillus awamori. Total phenolic content (TPC) of the unfermented sample was 1531.5 μg g^?1 wheat bran. After the fermentation of Aspergillus awamori, Aspergillus oryzae and Aspergillus niger, TPC reached 5362.1, 7462.6 and 10 707.5 μg g^?1, respectively. The antioxidant activity in the extractions of fermented wheat bran also increased significantly compared with the unfermented sample (P < 0.05). Aspergillus niger showed the greatest capacity to release bound ferulic acid (416.6 μg g^?1). Aspergillus oryzae and Aspergillus awamori had the advantages of releasing more chlorogenic acid (84.0 μg g^?1) and syringic acid (142.3 μg g^?1), respectively. The destructive effect of Aspergillus niger on wheat bran structure was the strongest, followed by that of Aspergillus oryzae. This effect of Aspergillus niger may be due to its higher cellulase, xylanase, arabinofuranosidase and β‐xylosidase activities. Besides, Aspergillus oryzae possessed higher β‐glucosidase activity, and Aspergillus awamori had higher α‐amylase and feruloyl esterase activities. Aspergillus niger may be the best to release bound phenolic acids in the three Aspergillus species. These will provide the helpful information for understanding mechanism of the fermentation by Aspergillus species releasing bound phenolic in wheat bran.     

Use of waste materials for Lactococcus lactis development

BACKGROUND: Lactococcus lactis is an interesting microorganism with several industrial applications, particularly in the food industry. As well as being a probiotic species, L. lactis produces several metabolites with interesting properties, such as lactic acid (LA) and biosurfactants. Nevertheless, L. lactis is an especially demanding species since it has strong nutritional requirements, implying the use of complex and expensive culture media. RESULTS: The results showed the potential of L. lactis CECT‐4434 as a LA and biosurfactant producer. The economical cost of L. lactis cultures can be reduced by replacing the MRS medium by the use of two waste materials: trimming vine shoots as C source, and 20 g L^?1 distilled wine lees (vinasses) as N, P and micronutrient sources. From the hemicellulosic fraction, 14.3 g L^?1 LA and 1.7 mg L^?1 surfactin equivalent were achieved after 74 h (surface tension reduction of 14.4 mN m^?1); meanwhile, a simultaneous saccharification and fermentation process allowed the generation of 10.8 g L^?1 LA and 1.5 mg L^?1 surfactin equivalent after 72 h, reducing the surface tension by 12.1 units at the end of fermentation. CONCLUSIONS: Trimming vine shoots and vinasses can be used as alternative economical media for LA and cell‐bound biosurfactant production. Copyright © 2010 Society of Chemical Industry     

Enhancement of the antioxidant and starch hydrolase inhibitory activities of king coconut water (Cocos nucifera var. aurantiaca) by fermentation with kombucha ‘tea fungus’

Enhancement of antioxidant and starch hydrolase inhibitory properties of king coconut water when subjected to fermentation with the ‘tea fungus’ was evaluated. pH, colour, viscosity, ethanol content, antioxidant activity, total phenolic content, ferulic and p‐coumaric acid contents and starch hydrolase inhibitory activities were analysed for 7 days in fermented and unfermented king coconut water samples. The fermented sample had a statistically significant decrease (P < 0.05) in pH. Colour values indicated the fermented beverage to increase in ‘yellowness’ over time. A statistically significant increase in the total phenolic content and the antioxidant activity (P < 0.05) was observed from day 1 onwards in the fermented sample. The starch hydrolase inhibitory activities in the fermented beverage had statistically significantly increased (P < 0.05) by day 7. Overall, the study highlights an enhancement of the antioxidant and starch hydrolase inhibitory properties of king coconut water as a result of the kombucha‐based fermentation.     

Influence of the addition of Helianthus tuberosus L. fermented with different lactobacilli on acrylamide content in biscuits

The aim of the study was to investigate the effect of the addition of Helianthus tuberosus L. fermented with different lactobacilli (Lactobacillus sakei KTU05‐6, Pediococcus acidilactici KTU05‐7 and Pediococcus pentosaceus KTU05‐9) on acrylamide content in biscuits. Results of study indicated that submerged fermented Helianthus tuberosus L. tubers had the significantly (P ≤ 0.05) lower pH, higher total titratable acidity and from 1.2 to 1.3 times higher protease and from 1.2 to 2.0 higher alpha‐amylase activities compared with treated by solid‐state fermentation. The acrylamide content in all biscuit samples enriched with submerged fermented Helianthus tuberosus L. was measured lower than 10 μg kg^?1. Submerged fermentation with selected lactobacilli provided specific characteristics of fermented Helianthus tuberosus products which had effect on the asparagine reduction in plant additives, thus reducing acrylamide content in biscuits enriched with Helianthus tuberosus L.     

Optimisation of culture conditions and development of a novel fed‐batch strategy for high production of β‐galactosidase by Kluyveromyces lactis

The aim of this study was to enhance β‐galactosidase production by Kluyveromyces lactis CICC1773. Firstly, the optimum culture conditions were obtained by response surface methodology, and the maximum β‐galactosidase activity reached 20.6 U mL^?1, about two‐fold increase than that of the initial conditions (initial fermentation medium and conditions). To further improve β‐galactosidase production, a new fed‐batch strategy based on pH feedback control was developed successfully in a 7‐L fermenter, using 400 g L^?1 lactose as feeding medium. As a result, the β‐galactosidase activity and productivity reached up to 111.61 U mL^?1 and 5.31 U/(mL·h), enhanced by 15.3‐fold and 17.6‐fold superior than the results of initial conditions, respectively. To our knowledge, β‐galactosidase activity obtained was the highest value among the results reported by nonrecombinant strains. These results demonstrated that the new fed‐batch strategy based on optimum culture conditions could be automatic control easily and be conductive to further scale up for industrial fermentation.     

Optimization of the Fermentation of Cantaloupe Juice by Lactobacillus casei NRRL B-442

This study was carried out to optimize the fermentation pH and temperature and also the fermentation time for development of a new probiotic fermented drink with cantaloupe juice. The fermented juice was subjected to a storage study during 42?days at 4?°C. The initial pH and temperature influenced the growth of Lactobacillus casei in cantaloupe juice. However, on the microbial viability only the effect of temperature was significant. Optimum conditions for a satisfactory growth and viability of L. casei in cantaloupe juice were as follows: pH?=?6.1 and temperature?=?31?°C. The fermentation time of 8 hours was selected as the optimal fermentation time to prepare the probiotic cantaloupe juice. The cell viability was 8.3 log CFU mL^?1 at the end of the fermentation. This level was kept over the 42?days of refrigerated storage. The consistent growth and viability of the probiotic microorganism in cantaloupe juice during fermentation and storage suggested that melon is a suitable vehicle for L. casei delivering. The fermented juice arises as a good alternative to the traditional dairy based products.