Novel yeasts with potential probiotic characteristics isolated from the endogenous ferment of artisanal Minas cheese.

Artisanal Minas cheese (QMA) is traditionally elaborate using raw milk and endogenous ferment (pingo - whey or rala - grated ripened cheese). In the present study, 91 yeast strains were isolated and identified from pingo and rala. Eight yeast species were identified by the MALDI-TOF mass spectrometry and confirmed by sequencing of the ITS region. The yeasts' protease and lipase activities were evaluated in addition to probiotic properties such as tolerance to low pH and bile salts, hydrophobicity, autoaggregation, co-aggregation with pathogens, and antimicrobial susceptibility. The rala ferment showed a greater variety of species. Yarrowia lipolytica was the dominant specie (52.7% of isolates), followed by the Kluyveromyces lactis and Kodamaea ohmeri (9.9 and 6.6%, respectively). From the total yeasts evaluated, 74 strains showed positive enzymatic activity: 52 strains showed lipolytic (51 Y. lipolytica and one Trichosporon japonicum) and 44 proteolytic activities (18 Y. lipolytica, 13 K. ohmeri, 11 K. lactis, and 2 Wickerhamiella sp.). All evaluated isolates demonstrated tolerance to pH 2.0, and 69 isolates supported the presence of bile salts. From them, 12 isolates showed the capacity of autoaggregation (> 30%) and hydrophobicity (> 90.0%) and were then selected for co-aggregation and antibiotic resistance assays. All selected isolates showed co-aggregation with Salmonella Enteritidis, Escherichia coli, and Listeria monocytogenes greater than 30%. None of the yeast showed sensibility to the evaluated antibiotics and antagonistic activity against the evaluated pathogens. The results demonstrated that pingo and rala have different yeast composition with different enzymatic activity, which may affect the characteristics of the cheese. Furthermore, some yeast strains: Y. lipolytica (9 strains isolated from rala) and K. ohmeri (3 strains isolated from pingo) demonstrated attractive probiotic potential.

Evaluation of potentially probiotic yeasts and Lactiplantibacillus plantarum in co-culture for the elaboration of a functional plant-based fermented beverage.

This work aimed to evaluate the performance of co-cultivation of potential probiotic yeast and lactic acid bacteria (LAB) in producing plant-based fermented beverages. The co-culture comprised LAB Lactiplantibacillus plantarum CCMA0743 with the yeasts Pichia kluyveri CCMA 0615, Pichia guilliermondii CCMA 1753 and Debaryomyces hansenii CCMA 1761 separately. The plant substrate was 75 g oat, 175 g sunflower seeds, and 75 g almonds. The viability of microorganisms in the plant-based matrix was evaluated during fermentation, storage at 4 °C, and under simulated gastrointestinal tract (GIT) conditions. Chemical analysis, antioxidant activity, and sensory profile of the beverages were also determined. The three yeasts and the LAB showed counts greater than 6.0 log CFU/mL after fermentation, and the plant-based matrix protected the yeasts during simulated digestion. P. kluyveri and D. hansenii showed higher survival than P. guilliermondii and L. plantarum after exposure to simulated GIT conditions. The pH of the plant-based matrix reduced from approximately 7 to 3.8. Lactic acid was the main organic acid produced during fermentation. In addition, 113 volatile compounds were detected by gas chromatography-mass spectrometry (GC-MS), including alcohols, aldehydes, alkanes, alkenes, acids, ester, ether, ketones, phenol, and amides. The beverage sensory profile varied with the co-culture. The co-culture D. hansenii and L. plantarum showed higher antioxidant activity than the other co-culture tested, and the homogeneous texture attribute characterized the beverage produced with this combination. Results show the suitability of tested co-cultures to produce a plant-based fermented beverage and indicate more significant potential for D. hansenii and L. plantarum co-culture as a starter for its functionalization.

Sensory and flavor-aroma profiles of passion fruit juice fermented by potentially probiotic Lactiplantibacillus plantarum CCMA 0743 strain.

Several non-dairy probiotic beverages are already available to consumers and have been considered suitable carriers for probiotic bacteria. This study aimed to investigate the effect of Lactiplantibacillus plantarum CCMA 0743 in single and co-culture on the volatile compounds and sensory profiles of fermented passion fruit juice. The viability of strains inoculated in juice and MRS matrices was evaluated in a simulated gastrointestinal condition. The bacterial viability after 28 days of refrigerated storage of the juices was also evaluated. L. plantarum CCMA 0743 showed high viability (6.18 Log CFU/mL) after passage throughout simulated digestion in the passion fruit juice matrix. Both juices maintained high probiotic counts (>8.0 Log CFU/mL) during storage. Also, the yellow color was stable after 28 days of storage. Volatile compounds of passion fruit juices were modified after the fermentation process, such as ketones and alcohol formation degradation. The sensory profile of passion fruit juice was modified by single and co-culture fermentations. The fermented samples were mainly correlated with the terminologies "salty, acidic and bitter tastes" and "sweetener aftertaste". Overall, passion fruit juice proved to be an adequate food matrix to deliver the evaluated strains. However, individual strains or strain-strain interactions with the food matrix affect the fermented product, demonstrating that strain and matrices evaluations are essential for developing novel products with acceptable characteristics.

Lactiplantibacillus plantarum CCMA 0743 and Lacticaseibacillus paracasei subsp. paracasei LBC-81 metabolism during the single and mixed fermentation of tropical fruit juices.

Fruit juices have shown promising results as new probiotic carriers. This study aimed to evaluate acerola, jelly palm, and passion fruit juices as substrates for fermentation using Lactiplantibacillus plantarum CCMA 0743 and Lacticaseibacillus paracasei LBC-81 in single and mixed cultures. First, the juices were evaluated as substrate and selected based on bacterial growth performance during fermentation. Afterward, the impact of fermentation on sugars, organic acids, and bioactive compounds was also appraised. Phytochemical modification of three different juices fermented by lactic acid bacteria at 37 °C/24 h was evaluated. After 18 h of fermentation, passion fruit juice showed higher cell viable counts of single and mixed L. plantarum CCMA 0743 culture, above 9.00 Log CFU/mL, and pH between 4.07 and 4.10. Sugars consumption and organic acid production were influenced by juice composition and culture used. The mixed culture reduced the total sugars in the passion fruit juice by approximately 53.0% (8.51 g/L). Lactic acid was the main product of the sugars fermentation, with higher concentrations detected in passion fruit juice (8.39-11.23 g/L). Bioactive compounds were analyzed on the selected substrate. The fermentative process reduced antioxidant activity and carotenoid content. However, single L. plantarum CCMA 0743 culture increased the yellow flavonoid content of passion fruit juice by approximately 3.0 µg/mL. L. plantarum CCMA 0743 showed high and suitable cell, viable counts, to claimed probiotic products, increasing bioactive compounds in passion fruit juice. Therefore, this strain and passion fruit substrate showed attractive potential to produce alternative and functional fermented fruit beverages.

Brazilian cocoa hybrid-mix fermentation: Impact of microbial dominance as well as chemical and sensorial properties.

High-yield resistant hybrids are used in cocoa fermentation and result in chocolates with different sensorial profiles. This work aimed to characterize the fermentation microbiologically and physicochemically. Hybrids CEPEC 2004, FA13, PH15, and CEPEC 2002 were used for fermentation. The yeast, acetic acid bacteria, lactic acid bacteria, and mesophilic bacteria population were evaluated in their respective medium. Carbohydrates and acids were detected using a high-performance liquid chromatography system, and volatiles were analyzed using gas chromatography-mass spectrometry equipment. Finally, a consumer acceptance test followed by a check-all-that-apply question and a temporal dominance of sensations assessment was performed in chocolate. The fermentation resulted in a typical succession: yeast-dominated at first, followed by lactic acid, acetic acid, and mesophilic bacteria. In the pulp, carbohydrates and citric acid were consumed. Low concentrations of acetic acid (0.09-1.75 g/kg) were detected. Acids, esters, and alcohols were the most abundant groups. The chocolate profile resulted in sweet, acidic, and fruity, satisfying consumers' tastes. PRACTICAL APPLICATION:  The cocoa hybrid-mix fermentation can improve the fermentation process and chocolate quality.  The mixture generated a different sensory profile in comparison to other fermentations.  The fruity chocolate was accepted and liked by consumers.

Probiotic Properties of Lactobacilli and Their Ability to Inhibit the Adhesion of Enteropathogenic Bacteria to Caco-2 and HT-29 Cells.

We evaluated the probiotic properties of lactic acid bacteria using resistance, safety, and functional assays. A preliminary subtractive screening of nineteen strains was performed based on their survival in simulated gastric and intestinal juice, and cell surface characteristics (hydrophobicity and auto-aggregation). Five strains were selected for further characterization, which included the assessment of their co-aggregation to pathogens, phenol tolerance, antimicrobial activity, and safety. Moreover, their adhesion to Caco-2 and HT-29 cells and the ability to inhibit pathogenic bacteria adhesion were evaluated. All strains had high (≥ 80.0%) survival rates in gastric and intestinal juices. Among them, Lactobacillus brevis CCMA 1284, L. plantarum CCMA 0743, and L. plantarum CCMA 0359 exhibited higher hydrophobicity (95.33, 96.06, and 80.02%, respectively), while L. paracasei CCMA 0504 and L. paracasei CCMA 0505 had the highest auto-aggregation values (45.36 and 52.66%, respectively). However, these last two strains were positive for the DNAse test, which is a safety concern. The CCMA 0359 and CCMA 1284 strains did not show antimicrobial activity, while the CCMA 0505 strain had a higher percentage of adhesion (4.75%) to Caco-2 cells. In the simulated competition and exclusion assays, the CCMA 0743 strain was able to reduce Salmonella adhesion to both cells (Caco-2 and HT-29), but only the CCMA 0743 and CCMA 0505 strains inhibited Escherichia coli adhesion to HT-29 cells in the competition assay. According to the results of these evaluated attributes, this strain showed to be an excellent candidate for probiotic use.

Physiological and genetic characterization of indigenous Saccharomyces cerevisiae for potential use in productions of fermented maize-based-beverages.

The Saccharomyces cerevisiae has been used for many years in the elaboration of food and beverage products, mainly associated with fermentation processes. The objective of this study was to characterize different indigenous S. cerevisiae strains and guide the notable strains for potential use in productions of fermented maize-based beverages. Initially, 81 strains isolated from different spontaneous food fermentations were evaluated. About 31% of strains showed phytase activity, an important characteristic for their application in cereals beverages production. All strains were able to grow in pH values 2.0, 3.0, and 5.0 and the presence of 5, 15, and 30% of glucose, but none could grow at 42 °C. Only 29.6% of the evaluated strains were able to efficiently grow in up to 1.0 mol L-1 of NaCl. The Rep-PCR and RAPD-PCR tools showed that the strains were differently grouped by the two techniques, and the grouping was not completely correlated with isolation source. A total of 65 volatile compounds were identified from the maize beverage produced. The profiles of volatile compounds produced by the strains were strain specific. S. cerevisiae strains isolated from the same source showed different chemical and genetic profiles, emphasize the importance to characterize the performance of each strain when searching for starter culture to develop or improve fermented beverages.

Yeasts isolated from Brazilian fermented foods in the protection against infection by pathogenic food bacteria.

The consumption of probiotics has increased due to the reported health benefits, mainly in preventing or treating gastrointestinal pathology. This study investigated the antimicrobial capacity of yeasts, Saccharomyces cerevisiae and Pichia kluyveri, previously isolated from fermented foods (indigenous beverage, kefir and cocoa) against the adhesion of foodborne pathogens to Caco-2 cells. Co-aggregation of yeasts with pathogens and were evaluated by quantitative analysis and using scanning electron and laser confocal microscopies. All yeasts strains were able to co-aggregate with the tested pathogens, however, this activity was strain-dependent. The inhibition tests showed that the adhesion of Escherichia coli EPEC, Listeria monocytogenes and Salmonella Enteritidis to Caco-2 was reduced by all the yeasts studied. Most of the evaluated yeasts showed inhibition rates equal to or greater than the commercial probiotic Saccharomyces boulardii. The yeasts were able to reduce up to 50% of the bacterial infection, as observed for CCMA0615 towards EPEC in exclusion assay; CCMA0731, CCMA0732 and CCMA0615 towards L. monocytogenes in exclusion and competition assays; and CCMA0731 in exclusion and CCMA0731, CCMA0732, CCMA0615 in competition assay towards S. Enteritidis. No antimicrobial compounds were produced by the yeasts, showing that competition for nutrients and/or receptors in the intestinal mucosa was the mechanism to bacterial inhibition.

Probiotic Potential, Antioxidant Activity, and Phytase Production of Indigenous Yeasts Isolated from Indigenous Fermented Foods.

While many bacteria have been used as probiotics by industries, only two yeasts, Saccharomyces cerevisiae var. boulardii and Kluyveromyces fragilis (B0399), have been used for this purpose. In the present work, a total of 116 yeasts isolated from Brazilian indigenous fermented food, cocoa fermentation, and kefir were in vitro characterized for probiotic attributes. From 116 isolates, 36 were tolerant to gastrointestinal conditions evaluated by tolerance to pH 2.0, bile salts (0.3% w/v), and 37 °C temperature. From those, 15 isolates showed a similar or higher percentage (P < 0.05) of hydrophobicity, autoaggregation, and coaggregation with E. coli than the reference strain S. boulardii. All these strains showed a high percentage of adhesion to Caco-2 cells (> 63%) and antioxidant activity (ranging from 18 to 62%). Phytate hydrolysis was evaluated for these yeasts and 13 strains showed positive results, which is important for nutrient availability in plant-based foods. These results are important insights for characterization of novel probiotic yeast strains as well as to aggregate functional value to these food products.

Fermentation of yam (Dioscorea spp. L.) by indigenous phytase-producing lactic acid bacteria strains.

The use of lactic bacteria in the development of functional foods has increased in recent years. In addition to their probiotic characteristics, they can ferment a variety of substrates, such as cereals, roots, and tubers. Phytase producer lactic acid bacteria strains and their behavior during the fermentation process of yam-based food were studied. Leuconostoc lactis CCMA 0415, Lactobacillus plantarum CCMA 0744, and Lactobacillus fermentum CCMA 0745 were selected due to phytase production, pH reduction, and growth during 24 h of fermentation. Oxalate activity was not detected in all assays, suggesting its concentration was reduced due to the bleaching process. Among the selected strains, L. lactis CCMA 0415 appeared to be a promising strain in yam-based fermentations because it maintained a cell viability above 8 log CFU/mL and did not reduce diosgenin concentrations (around 8.0 µg/mL) after fermentation for 24 h, thereby, generating a potentially functional yam food. Furthermore, this strain promoted the decrease of pH value from 6.1 to 3.8 and produced 8.1 g/L lactic acid, at 6 h of fermentation. The L. lactis CCMA 0415 was reported as a starter culture in fermented products based on cereals, roots, and tubers.

Combination of probiotic yeast and lactic acid bacteria as starter culture to produce maize-based beverages.

Cereal-based fermented beverages are non-dairy products which are considered possible carriers for probiotic strains and alternatives for use by vegans and lactose-intolerant consumers. In the present work, the commercial probiotic, Lactobacillus paracasei LBC-81, was used singly and in co-culture with potential probiotic yeasts, Saccharomyces cerevisiae CCMA 0731, S. cerevisiae CCMA 0732, and Pichia kluyveri CCMA 0615, to ferment a maize-based substrate. All tested strains showed viability higher than 6 log CFU/mL, as recommended for food probiotic products, except for the yeast P. kluyveri which decreased during fermentation and storage time. A reduction in pH value, from approximately 7 to 4, was observed. This decrease was due organic acid production, which did not affect the microbial viability. Lactic and acetic acids were the main organic acids produced during fermentation, and they decreased over 28 days of storage (<0.5 and 0.1 g/L for lactic and acetic acids, respectively). Ethanol was detected in the S. cerevisiae assays; however, the content was <5 g/L in a non-alcoholic beverage. Seventy volatile compounds were detected, including acids, alcohols, aldehydes, esters, ketones, and other compounds. Sensory analysis showed score of 5.93-4.57, respectively for appearance and taste. This is an important result, considering that the beverage had no flavoring additive and lacked a sweet taste. Therefore, probiotic beverages were successfully obtained by maize fermentation inoculated with co-culture of S. cerevisiae (CCMA 0731 or CCMA 0732) and L. paracasei LBC-81.

Microbial community and physicochemical dynamics during the production of 'Chicha', a traditional beverage of Indigenous people of Brazil.

The microbial community of artisanal corn fermentation called Chicha were isolated, purified and then identified using protein profile by Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF) and confirmed by partial ribosomal gene sequencing. Samples from Chicha beverage were chemically characterized by gas and liquid chromatography (HPLC and GC-MS). Aerobic mesophilic bacteria (AMB) (35.8% of total of isolated microorganisms), lactic acid bacteria (LAB) (21.6%) and yeast (42.6%) were identified. Species of the genera Klebsiella, Bacillus, Staphylococcus, Micrococcus, Enterobacter, and Weissella were identified. Rhodotorula mucilaginosa, Lodderomyces elongisporus, Candida metapsilosis, and C. bohicensis were the yeasts found. The LAB isolates detected were responsible for the high concentrations of lactic acid found during the fermentation process (1.2 g L- 1), which is directly related to the decrease in pH values (from 6.95 to 3.70). Maltose was the main carbohydrate detected during corn fermentation (7.02 g L- 1 with 36 h of fermentation). Ethanol was found in low concentrations (average 0.181 g L- 1), making it possible to characterize the beverage as non-alcoholic. Twelve volatile compounds were identified by gas chromatography; belonging to the groups acids, alcohols aldehydes, acetate and others. MALDI-TOF was successfully used for identification of microbiota. Weissella confusa and W. cibaria were detected in the final product (after 36 h of fermentation), W. confusa is often classified as probiotic and deserve further application studies.

Effect of symbiotic interaction between a fructooligosaccharide and probiotic on the kinetic fermentation and chemical profile of maize blended rice beverages.

There is an important demand for the development of new non-dairy probiotic beverages in the functional food market. This work aimed to develop new fermented beverages from maize and rice. Lactobacillus plantarum CCMA 0743, Torulaspora delbrueckii CCMA 0235, and the commercial probiotic Lactobacillus acidophilus LACA 4, were used as a mixed starter culture. Two prebiotic concentrations, 20 and 50g/L fructooligosaccharide (FOS) were tested. The growth of L. acidophilus LACA 4 was favored by 50g/L FOS and after refrigerated storage at 4°C for 28days, its population remained above 107CFU/mL. Lactic and acetic acids were the main organic acids detected, at around 3.7 and 0.5g/L, respectively. Ethanol was present at <5g/L in non-alcoholic beverages. Fifty-five volatile compounds including acids, alcohols, aldehydes, esters, ketones, pyrazines and others, were detected. The sensorial analysis demonstrated that >50% of consumers liked slightly or liked extremely the beverages (scores from 6-9). Therefore, potential symbiotic cereal beverages were successfully obtained using a mix of lactic acid bacteria and yeast as a starter culture. This is an important step in the commercial production of alternative beverages from common food substrates for consumers.

Nondairy beverage produced by controlled fermentation with potential probiotic starter cultures of lactic acid bacteria and yeast.

This work aimed to develop a nondairy fermented beverage from a blend of cassava and rice based on Brazilian indigenous beverage cauim using probiotic lactic acid bacteria (LAB) and yeast. The indigenous strains Lactobacillus plantarum CCMA 0743 (from cauim) and Torulaspora delbrueckii CCMA 0235 (from tarubá), and the commercial probiotic, L. acidophilus LAC-04, were used as starter cultures in single and co-cultivations. The bacteria populations were around 8.0 log (CFU/mL) at the end of all fermentations as recommended for probiotic products. Higher residual starch contents were noted in the single LAB cultures (10.6% [w/w]) than in co-cultures (<6% [w/w]), showing that co-culture may help the digestibility. For all different assays (single and co-culture), lactic acid was the main organic acid detected (>1.6g/L) and ethanol was lower than 0.5% (w/v) consisting in a non-alcoholic beverage. The assays containing yeast showed the highest antioxidant activity (around 10% by DPPH and ABTS methods). Therefore, a nondairy fermented beverage was successfully obtained, and the co-culture of LAB and T. delbrueckii could increase the product's functional properties.

Lipid production by yeasts grown on crude glycerol from biodiesel industry.

The main carbon source used for growth by four yeast strains (Yarrowia lipolytica CCMA 0357, Y. lipolytica CCMA 0242, Wickerhamomyces anomalus CCMA 0358, and Cryptococcus humicola CCMA 0346) and their lipid production were evaluated, using different concentrations of crude and pure glycerol and glucose. Whereas crude glycerol (100 g/L) was the main carbon source used by Y. lipolytica CCMA 0357 (nearly 15 g/L consumed at 120 hr) and W. anomalus CCMA 0358 (nearly 45.10 g/L consumed at 48 hr), pure glycerol (150 g/L) was the main one used by C. humicola CCMA 0346 (nearly 130 g/L consumed). On the other hand, Y. lipolytica CCMA 0242 used glucose (100 g/L) as its main source of carbon (nearly 96.48 g/L consumed). Y. lipolytica CCMA 0357 demonstrated the highest lipid production [about 70% (wt/wt)], forming palmitic (45.73% of fatty acid composition), stearic (16.43%), palmitoleic (13.29%), linolenic (10.77%), heptadecanoic (4.07%), and linoleic (14.14%) acids. Linoleic acid, an essential fatty acid, was produced by all four yeast strains but in varying degrees, representing 70.42% of the fatty acid profile of lipids produced by C. humicola CCMA 0346.

Selection of autochthonous lactic acid bacteria from goat dairies and their addition to evaluate the inhibition of Salmonella typhi in artisanal cheese.

This study aimed to select autochthonous lactic acid bacteria (LAB) with probiotic and functional properties from goat dairies and test their addition to artisanal cheese for the inhibition of Salmonella typhi. In vitro tests, including survival in the gastrointestinal tract (GIT), auto- and co-aggregation, the hemolytic test, DNase activity, antimicrobial susceptibility, antibacterial activity, tolerance to NaCl and exopolysaccharide (EPS), gas and diacetyl production were conducted for sixty isolates. Based on these tests, four LAB isolates (UNIVASF CAP 16, 45, 84 and 279) were selected and identified. Additional tests, such as production of lactic and citric acids by UNIVASF CAP isolates were performed in addition to assays of bile salt hydrolase (BSH), ß-galactosidase and decarboxylase activity. The four selected LAB produced high lactic acid (>17 g/L) and low citric acid (0.2 g/L) concentrations. All selected strains showed BSH and ß-galactosidase activity and none showed decarboxylase activity. Three goat cheeses (1, 2 and control) were produced and evaluated for the inhibitory action of selected LAB against Salmonella typhi. The cheese inoculated with LAB (cheese 2) decreased 0.38 log10 CFU/g of S. Typhy population while in the cheese without LAB inoculation (cheese 1) the pathogen population increased by 0.29 log units. Further, the pH value increased linearly over time, by 0.004 units per day in cheese 1. In the cheese 2, the pH value decreased linearly over time, by 0.066 units per day. The cocktail containing selected Lactobacillus strains with potential probiotic and technological properties showed antibacterial activity against S. typhi in vitro and in artisanal goat cheese. Thus, goat milk is important source of potential probiotic LAB which may be used to inhibit the growth of Salmonella population in cheese goat, contributing to safety and functional value of the product.

The impact of yeast starter cultures on the microbial communities and volatile compounds in cocoa fermentation and the resulting sensory attributes of chocolate.

Theobroma cacao seeds are the main raw material for chocolate production. During their fermentation, a succession of microorganisms are responsible for the physicochemical changes occurring in the pulp and inside the beans. The aim of this study was to investigate the effects of yeast inoculation (Saccharomyces cerevisiae UFLA CA11, Pichia kluivery CCMA0237, and Hanseniaspora uvarum CCMA0236) on the profile of the volatile compounds and microbial communities in cocoa fermentation. The resulting chocolate was also evaluated by temporal dominance of sensations (TDS) analyses. The dominant microorganisms during spontaneous fermentation were S. cerevisiae, H. uvarum, H. guilliermondii, Lactobacillus fermentum, Pediococcus sp., and Acetobacter pasteurianus. Similarly, S. cerevisiae, P. kluyveri, Candida sp., Pediococcus sp., and A. pasteurianus were the predominant microorganisms assessed by Denaturing Gradient Gel Electrophoresis (DGGE) in inoculated fermentation. Sixty-seven volatile compounds were detected and quantified by gas chromatography/mass spectrometry (GC/MS) at the end of fermentation and chocolates. The main group of volatile compound found after the inoculated and spontaneous fermentations was esters (41 and 39 %, respectively). In the chocolates, the main group was acids (73 and 44 % from the inoculated and spontaneous fermentations, respectively). The TDS analyses showed a dominance of bitter and cocoa attributes in both chocolates. However, in the inoculated chocolate, lingering fruity notes were more intense, while the chocolate produced by spontaneous fermentation was more astringent. Thus, the inoculation of yeast influenced the microbial profile, which likely affected the volatile compounds that affect sensory characteristics, resulting in chocolate with dominant bitter, cocoa, and fruity attributes.

Antioxidant capacity of cocoa beans and chocolate assessed by FTIR.

The total antioxidant capacity (TAC) and total phenolic compounds (TPC) of cocoa beans and chocolate produced from spontaneous and inoculated fermentations of different cocoa varieties were evaluated. Fourier transform infrared spectroscopy (FTIR), as well as conventional methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), was used to determine TAC and TPC. Chocolate showed higher (p<0.05) TPC (47.17-57.16mgGAE/g) and TAC (1.66-2.33mMTE/g and 8.86-11.35mMTE/g as measured by DPPH and ABTS, respectively) than cocoa beans (6.30-26.05mgGAE/g, 0.24-1.17mMTE/g and 1.29-4.83mMTE/g for TPC, DPPH and ABTS, respectively). Partial least square (PLS) model for infrared data showed a good calibration coefficient (R2cal>0.94), indicating that the FTIR technique represents a fast and reliable tool to evaluate TPC and TAC in cocoa beans and chocolate.

Microbiological and chemical parameters during cassava based-substrate fermentation using potential starter cultures of lactic acid bacteria and yeast.

Traditional Brazilian indigenous fermented foods and beverages are potential sources of new food products that promote health, but they are still produced by natural fermentation. In the present work, Lactobacillus fermentum CCMA 0215 isolated from the indigenous fermented cassava beverage yakupa was used as single or mixed starter culture with five different yeast strains (Torulaspora delbrueckii CCMA 0234 and CCMA 0235, Pichia caribbica CCMA 0198, and Saccharomyces cerevisiae CCMA 0232 and CCMA 0233) to ferment cassava. Fermentations using each yeast as single starter culture were also performed. The microbial population and metabolites produced during cassava fermentation were investigated. In all assays, the inoculated microorganisms fermented cassava, judged by lowering the pH from 6.0 to 4.0-5.0 within 24h. Lactic acid bacteria (LAB) and yeast population increased during fermentation. Lactic acid was the main organic acid produced, reaching a maximum value of 4.5g/L at 24h in the co-culture with L. fermentum CCMA 0215 and T. delbrueckii CCMA 0234. Other organic acids, such as malic, tartaric, and succinic acids, were detected in low concentrations (less than 0.5g/L). Ethanol and glycerol were produced in all assays inoculated with yeasts (single and co-cultured with LAB), reaching the maximum concentration of approximately 2.3g/L and 0.6g/L, respectively. Twenty-two volatile compounds were detected after 48h of fermentation, varying widely between single and co-cultures. The compounds 2-phenylethyl alcohol, 1-butanol, 3-methyl (isoamyl alcohol), and acetoin were detected in single and co-cultures. This study demonstrated co-cultures of yeasts and LAB had the ability to improve the aroma profile of the final product and the safety of the product by lowering the pH.

In vitro determination of volatile compound development during starter culture-controlled fermentation of Cucurbitaceae cotyledons.

The effects of Lactobacillus plantarum UFLA CH3, Pediococcus acidilactici UFLA BFFCX 27.1, and Torulaspora delbrueckii UFLA FFT2.4 inoculation on the volatile compound profile of fermentation of Cucumeropsis mannii cotyledons were investigated. Different microbial associations were used as starters. All associations displayed the ability to ferment the cotyledons as judged by lowering the pH from 6.4 to 4.4-5 within 24h and increasing organic acids such as lactate and acetate. The population of lactic acid bacteria (LAB) and yeasts increased during fermentation. In the fermentation performed without inoculation (control), the LAB and yeast populations were lower than those in inoculated assays at the beginning, but they reached similar populations after 48 h. The Enterobacteriaceae population decreased during the fermentation, and they were not detected at 48 h in the L. plantarum UFLA CH3 and P. acidilactici UFLA BFFCX 27.1 (LP+PA) and L. plantarum UFLA CH3, P. acidilactici UFLA BFFCX 27.1, and T. delbrueckii UFLA FFT2.4 (LP+PA+TD) samples. The assays inoculated with the yeast T. delbrueckii UFLA FFT2.4 exhibited the majority of volatile compounds (13 compounds) characterized by pleasant notes. The LP+PA+TD association seemed to be appropriate to ferment C. mannii cotyledons. It was able to control the Enterobacteriaceae population, and achieved high concentrations of esters and low concentrations of aldehydes and ketones.