Preparation of lactic acid bacteria compound starter cultures based on pasting properties and its improvement of glutinous rice flour and dough

The effects of 5 lactic acid bacteria(LAB)fermentation on the pasting properties of glutinous rice flour were compared,and suitable fermentation strains were selected based on the changes of viscosity,setback value,and breakdown value to prepare LAB compound starter cultures.The results revealed that Latilactobacillus sakei HSD004 and Lacticaseibacillus rhamnosus HSD005 had apparent advantages in increasing the viscosity and reducing the setback and breakdown values of glutinous rice flour.In particular,the compound starter created using the two abovementioned LAB in the ratio of 3:1 had better performance than that using a single LAB in improving the pasting properties and increasing the water and oil absorption capacity of glutinous rice flour.Moreover,the gelatinization enthalpy of the fermented samples increased significantly.For frozen glutinous rice dough stored for 28 days,the viscoelasticity of frozen dough prepared by compound starter was better than that of control dough,and the freezable water content was lower than that of control dough.These results indicate that compound LAB fermentation is a promising technology in the glutinous rice-based food processing industry,which has significance for its application.

Effect of a compound starter cultures inoculation on bacterial profile and biogenic amine accumulation in Chinese Sichuan sausages

Effects of a starter culture composed of Lactobacillus sakei,Pediococcus pentosaceus,Staphylococcus xylosus and S.carnosus at the ratios(m/m)of 1:1:1:1 on bacterial profile and biogenic amine accumulation in Chinese Sichuan sausages were demonstrated.In starter culture-inoculated sausages,Lactobacillus spp.,Pediococcus spp.and Staphylococcus spp.were predominant bacterial genus and their relative abundances ranged from 70.14%to 25.98%,57.66%to 14.08%,and 15.71%to 13.40%during fermentation,respectively.Accordingly,Lactobacillus spp.and Weissella spp.were predominant bacterial genus and their relative abundances ranged from 63.14%to 24.70%and 49.40%to 11.96%during spontaneous fermentation,respectively.Furthermore,the abundances of undesirable microorganisms such as Yersinia spp.,Enterobacter spp.,Acietobacter spp.and Psychrobacter spp.were lower than that of the control.The levels of histamine,putrescine,tyramine and cadaverine in Chinese Sichuan sausages with starter cultures inoculation were significantly lower(P<0.05)than that of the control,and were decreased by 83.09%,69.38%,51.87%and 57.20%,respectively,at the end of the ripening.These results revealed that the starter cultures inoculation was a better alternative for microbial quality improvement and biogenic amine reduction of Chinese Sichuan sausages with good sensory attributes.

Lactobacilli isolates as potential aroma producer starter cultures:Effects on the chemical,physical,microbial,and sensory properties of yogurt

Five lactobacilli isolates from traditional yogurts and a commercial isolate(LB)were utilized for yogurt production and weekly chemical,physical,microbial,and sensory analyzes were performed during the 21-day storage period.All yogurt samples possessed similar gross compositions,and no significant difference was detected between yogurt samples in terms of acidity and syneresis rates,together with lactobacilli and streptococci counts during storage(p>0.05).All samples exhibited pseudoplastic behavior and solid-like properties.The highest complex and apparent viscosity values were determined in LB,KKC2,and EPSC2 yogurts.The EPSC2 strain has stood out,leaving the commercial culture behind,regarding acetaldehyde and acetone production while CBH4 and CBX have fallen behind others considering sensory and aromatic properties.Except for viscosity,EPSC2 and KKC2 exhibited similar or better characteristics,including sensory properties and flavor profiles,than LB.In conclusion,EPSC2 and KKC2 are recommended as potential yogurt starters.

Enhancement of Arabica coffee quality with selected potential microbial starter culture under controlled fermentation in wet process

Coffee is a significant agricultural commodity that is well-known and enjoyed all over the world for its distinct flavor and aroma.The quality of coffee is affected by various parameters.The existing coffee processes,which rely on natural microorganisms,are uncontrollable,resulting in product inconsistency.To overcome this problem,this study aimed to investigate the potential use of selected microbial inoculants in wet method processing and the effects of fermentation time and temperature on coffee quality.Selected yeasts,bacteria,and lactic acid bacteria,isolated from the coffee fermentation process,were used as the starter cultures.Twenty-four conditions were set.At the 0 and 24 h of fermentation,total bacterial and yeast counts,as well as pH,were measured and trend to change during fermentation.After fermentation,coffee beans were subjected to sensory evaluation by Quality-Arabica Graders.Results showed that specific microbial starter culture under controlled conditions successfully improved coffee quality.Ten of the twenty-four types coffee beans tested were classified as specialty coffee with distinct cupping characteristics.Scaling up experiment was done by a mixture of three strains of Pichia kluyveri and Wickerhamomyces anomalus(condition Y4-04)at Doi Saket District,Chiang Mai,Thailand.According to the flavor profile derived from Q-graders,the cupping results was related to the volatile and water-soluble compounds identified by GC-MS and 1H NMR analyses.It suggests that the coffee quality can be improved by using starter cultures and carefully managing fermentation settings.

Effect of Different Ratios of DL-type Starter Culture： Mould Geotrichum candidum on the Viscosity and Sensory Properties of Fermented Milk

A great variety of dairy products with different flavour, texture and health-promoting properties can be obtained from milk using different technologies and starter cultures. Fermented milks are consumed in many parts of the world and are relished for their acidic taste and health benefits. The aim of this study was to compare effects of different ratios of DL-type starter culture： mould Geotrichum candidum grown in milk on its viscosity and sensory properties on the 5th, 10th and 15th day of storage at 4 ~C~ in order to determine the best ratio to prepare fermented milk on basis of Iranian acceptance. We have examined the production of fermented milk by 80： 20, 70： 30, and 60：40 ratios of DL-type starter culture： mould Geotrichum candidum grown in milk. The results obtained from viscosity measurement and sensory evaluation showed no significant difference between these treatments used in the study and were not satisfactory; their viscosity was not accepted and scores attributed to odour and flavor of fermented milks by panelists were low.

Development of Starter Culture for the Production of African Condiments and Seasoning Agents

As a process, food fermentation dates back at least 6000 years and is likely to be derived from microbial interactions of an appropriate nature. Fermentation has allowed our ancestors to survive the winter season in temperate and cooler regions and those in the tropics to survive the periods of drought by improving food shelf-life and safety. Traditional fermentation process is still used as a replacement where there is no refrigeration or other means available for food storage. In general, fermented foods can be defined as foods produced through controlled microbial growth and the conversion of food components through enzymatic actions. They are generally appreciated for characteristics such as pleasant taste, aroma, texture and improved cooking and processing properties. Microorganisms contribute to the development of characteristic properties such as taste, smell, visual appearance, texture, shelf-life and protection by virtue of their metabolic activities. Enzymes indigenous to the raw materials may play a role in enhancing these characteristics. The use of starter cultures is a hallmark of industrial food fermentation and their introduction has been followed by a continuous search to improve them. Examples of desired properties in starter cultures include robustness during manufacturing, fast growth, high biomass yield and product yield and specific organoleptic properties. Quality, safety and acceptability of traditional fermented foods may be significantly improved through the use of starter cultures selected on the basis of multifunctional considerations, also taking into account the probiotic concept and possibilities offered for improved health benefits. Focused studies toward the introduction of starter cultures for small-scale fermentations seem more than justified, and in fact, deserve the highest priority.

Bacteriocin characterization of autochtonous Lactococcus lactis L54 and its application as starter culture for Beyaz cheese

White brined cheese is one of the most produced and consumed cheese varieties in Mediterranean region.Beyaz cheese is a type of white brined cheese and is usually produced from pasteurized cow’s milk.Cheese produced from raw milk or contaminated after production with foodborne pathogens may have a safety risk.Beyaz cheese provides a favorable environment for growth of Listeria monocytogenes,a psychrotrophic pathogen.Objective of this study was to evaluate use of nisin producing autochtonous Lactococcus lactis L54 to control L.monocytogenes ATCC 7644 in Beyaz cheese during storage for 90 days.Characterization of bacteriocin demonstrated that nisin L54 has a broad inhibition spectrum on both pathogens including L.monocytogenes ATCC 7644,Staphylococcus aureus ATCC 43300,Bacillus cereus ATCC 33019 and several other lactic acid bacteria strains.The safety assessment revealed that L.lactis L54 did not contain tested virulence genes and showed no hemolytic and DNAse activity.Inoculation of L.lactis L54 to Beyaz cheese significantly decreased the L.monocytogenes counts compared to the control and did not show any negative effect on the physicochemical and sensory properties.L.lactis L54 strain was concluded as potential bioprotective,starter or co-starter culture for Beyaz cheese production.

Evolution of free amino acids, biogenic amines and volatile compounds in fermented sausages inoculated with Lactiplantibacillus plantarum and Staphylococcus simulans

Lactic acid bacteria and coagulase-negative staphylococci play an important role in the production of fermented sausages,such as inhibiting the growth of undesirable bacteria and antioxidant.In this study,the effects of inoculation with different starter cultures(Lactiplantibacillus plantarum HN108 and Staphylococcus simulans NJ209)on the free amino acids(FAAs),biogenic amines(BAs)and volatile compounds of fermented sausages were investigated using an amino acid analyzer,ultra performance liquid chromatography and gas chromatography-ion mobility spectrometry,respectively.The pH and carbonyl content of the inoculated group was significantly lower than those in the control group(P<0.05).L.plantarum HN108 significantly reduced the content of FAAs and BAs in fermented sausage production(P<0.05),while S.simulans NJ209 promoted the formation of FAAs(especially bitter amino acids)and exhibited slight BAs-reducing activity.In addition,L.plantarum HN108 promoted the formation of volatile compounds such as ketones,alcohols and alkenes in sausages.In conclusion,L.plantarum HN108 could contribute to reducing the content of putrescine and tyramine and forming the desirable flavor compounds in fermented sausages.Thus,L.plantarum HN108 is expected to be a starter culture that can improve the safety and flavor of fermented sausages.

3D printed lactic acid bacteria hydrogel:cell release kinetics and stability

In this study,a new type of 3 D printed living biological hydrogel was developed by integrating lactic acid bacteria(LAB)into biocompatible and non-toxic polymer materials.Interestingly,the living materials loaded with LAB can be freeze-dried and reused for more than 100 times.The bio-hydrogel can be used to co-culture different LAB and keep its fermentation performance stable in long-term use.The release kinetics model and response surface method were used to simulate and optimize the bacteria release mode in the bio-hydrogel.The results show that the release of bacteria from hydrogel is regulated by the coupling of Fickian diffusion and polymer swelling.The stability of LAB hydrogel was evaluated by reuse experiments.The images of confocal microscopy and scanning electron microscope showed that the bacteria with high cell viability were distributed in the hydrogel and intact structure of the living hydrogel was maintained after 100 times of reuse as yoghurt starter.In conclusion,the 3 D printed LAB bio-hydrogel developed in this study has the advantage of reuse and sustainability,which is expected to open up a new way for the preparation of food culture starter.

Contribution of mixed commercial starter cultures to the quality improvement of fish-chili paste,a Chinese traditional fermented condiment

This study evaluated the effects of commercial starter cultures on the microbial counts,protein degradation,biogenic amines and volatile compounds in fermented fish-chili paste.Four inoculated groups with different starter cultures and one group without inoculation were investigated.The results revealed that the application of mixed starter cultures promoted the growth of lactic acid bacteria and yeast,while effectively inhibited the Enterbacteriaceae counts compared with the spontaneously fermented group.The inoculation with mixed starter cultures resulted in higher levels of umami-tasting free amino acids(FAAs)in all inoculated groups.Highest content of sweet-tasting FAAs was found in group HS(Pichia anomala+Staphylococcus xylosus+Staphylococcus carnosus+Pediococcus pentosaceus+Pediococcus acidilactici),and much lower bitter-tasting components were presented in group HW(Pichia anomala+Staphylococcus xylosus+Staphylococcus carnosus),HS and HV(Pichia anomala+Lactobacillus plantarum).In addition,total levels of biogenic amines detected in all inoculated samples were significantly lower compared with control,especially the content of tyramine(P<0.05).For the volatile compounds,more esters as well as less undesirable odor substances such as aldehydes,were exhibited in four inoculated groups.

Influence of the starter culture on the volatile profile of processed cocoa beans by gas chromatography–mass spectrometry in high resolution mode

Cocoa is the main component of chocolate.It is widely accepted that cocoa quality largely depends on the processing,especially the fermentation step.Traditionally,fermentation takes place spontaneously by the endogenous microbiota;however,the process can lead to poor quality and heterogeneity of the final product.In this study,we evaluated the influence of the starter culture on the profile of volatiles during fermentation of commercial volumes of Mexican cocoa.Volatiles were also analyzed in post-fermented cocoa samples obtained after drying,roasting,and conching.Our results revealed a most desirable volatile profile in cocoa fermented with starter culture,mainly due to the higher relative content of alcohols(40%)and aldehydes(3.5%),but also due to a lower acidity(<1%)as compared to endogenous fermentation(acids,65%;alcohols,2%;and aldehydes<0.5%).Additionally,it is remarkable,the higher content of pyrazines in the inoculated samples after processing.

Promotion of Safe Winemaking Practices Using Quantity Comparison and Methanol-reduction Process for Rice Wine and Whisky

Research was conducted to determine the quantity of methanol in liquor locally produced in nine different areas of Kamphaengphet province, Thailand. All samples were investigated for methanol content and, while quantities varied depending on the fermentation process, the amounts of methanol determined were statistically significant. The results showed a clear trend of increasing amounts of methanol; the longer it was fermented, the higher amount of methanol it gained. The appropriate distillation temperature was at 85 ℃ examined from a fermented sample which had the highest level of methanol. As a part of this research, a workshop was conducted for distillers on skill development and knowledge promotion for rice wine, rice whisky and safe wine manufacturer. This included a campaign to promote safer rice wine distillation process wherein alcohol content does not exceed 15%. An evaluation at the completion of the workshop indicated that the participants had gained knowledge and understanding, satisfaction, and knowledge utilization.

Esterase Activities and Biochemical Properties of Lactic Acid Bacteria Isolated from Goat＇s Milk Cheese in Argentina

Twenty-two lactic acid bacteria （LAB） strains isolated from Argentinean goat dairy products were evaluated for its biochemical properties and esterase activities relevant to flavor development. Streptococcus thermophilus （UNSE314）, Lactobacillus （L.） delbrueckii subsp, bulgaricus （UNSE309）, L. rhamnosus （UNSE308）, L. plantarum （UNSE287, UNSE316, UNSE317） and Pediococcus pentosaceus （UNSE315） strains presented high acidifying activity. All strains tested metabolized citrate and produced diacetyl-acetoin in goat milk. Based on these results, 10 strains with the best performance in diverse technological properties were selected to determine esterolytic activity. In all evaluated strains, esterase specific activity （ESA） was detected on ct-naphthyl （ct-NA） acetate and 13-naphthyl （[3-NA） acetate, propionate, eaprylate and ct-NA butyrate. No activity was detected on [3-NA laurate. The highest values were detected when using a-NA instead of fI-NA derivatives as substrate. In Pediocoecus strains, wide variability in ESA were observed, which were species- and strain-specific. These results allow us to select strains with biochemical properties and esterase activities to design starter and adjunct cultures that contribute to flavor development during cheese ripening, thus preserving the typical organoleptic characteristics of Argentinean goat cheeses.

Study on the safety and excellent probiotic properties of fermentation strains isolated from traditional dry-cured duck for starter development

The indigenous starter cultures isolated from fermented food can compete with spoilage and pathogenic bacteria and improve the flavor and organoleptic properties of products.The purposes of this work were to screen and assess the safety,potential probiotic,and fermentation properties of indigenous starter cultures isolated from dry-cured ducks.The properties of indigenous starter cultures were investigated by antibiotic resistance,virulence genes,in vivo toxicity,simulated gastrointestinal,adhesion capacity to Caco-2 cells,inoculation fermentation,etc.Overall,six strains were isolated and identified,including Lactobacillus sakei D15,Weissella hellenica D20,Lactobacillus curvatus D2,Staphylococcus simulans D12,Staphylococcus equorum D19,and Staphylococcus edaphicus D17.The obtained strains showed high safety.Additionally,most strains displayed excellent probiotic properties,including tolerance to lower pH,lysozyme,bile salt,and a high survival rate of the simulated gastrointestinal phase.The adhesion ability of strain cells to Caco-2 cells was 9.22%-14.21%.And the probiotic properties of strains can be strengthened by the expression of specific enzymes.The inoculation with the isolated strains(LS-D15,LC-D2 and SS-D12)could contribute to the formation of volatile flavor compounds in samples.Overall,results demonstrated that strains possessed excellent safety and probiotic properties,and can be used as starter cultures to enhance the quality and flavor of the dry-cured duck.

Recent developments of lactic acid bacteria and their metabolites on foodborne pathogens and spoilage bacteria:Facts and gaps

Lactic acid bacteria(LAB)are common microorganisms found in various ecosystems including in plants,fermented foods,and the human body.Exploring the biodiversity of lactic acid microflora and characterization of LAB is a new approach to form a variety of starter communities to create innovative nutritional food matrices.There has been growing interest in LAB isolated from non-dairy environments as these bacteria exhibit significant metabolic diversity and have unique taste-forming activities.Disease may be prevented,or treated by LAB but the treatment of disease conditions with LAB is highly dependent on the host's microbiome and diet and varies in both effectiveness and side effects from individual to individual.Future perspectives on the study of LAB may be related to the expansion of our knowledge in the fields of genetics and genetic engineering.The application of genetic science may help to improve existing strains and develop new strains with characteristics designed for specific purposes.Therefore,the preservative effects of LAB and their metabolites,as well as their interaction on the growth of food borne pathogens and food spoilage microorganisms were elucidated.In addition,the competitive models for microbial growth between LAB and other microorganisms as well as the role of LAB in the elimination of toxic compounds in food products were discussed.Moreover,the review provided an overview of the risks and benefits of using LAB in the food industry.

Role of fermentation and microbes in cacao fermentation and their impact on cacao quality

Cocoa seed fermentation involves a well-stabilized succession of microbial processes and the action of enzymes.Microorgan-isms(yeast,lactic acid bacteria,and acetic acid bacteria)play a critical role in cacao fermentation by degrading mucilage pulp by producing a stabilized succession of enzymatic reactions that contribute to its quality.Nowadays,the majority of cacao fermentation practiced in our planet is in the traditional form to produce aroma flavor.The art of using starter culture to substitute naturally occurring microorganisms in cacao fermentation is crucial for the development of the aroma and flavor of cacao for sustainable uniformity and quality improvement and unique cacao flavor development.In this sense,this review presents an overview of cacao fermentation process and its impacts on quality,starter culture and microorganisms involved in cacao fermentation process,cacao bioactive compounds and its health benefits.Moreover,the research perspectives needed and the advance made in terms of fermentation process in order to reduce fermentation period are reviewed.

Perspective on the use of synthetic biology in rudimentary food fermentations

Rudimentary food fermentation can be defined as a spontaneous process of conversion of food components through enzy-matic action.A great variety of fermented foods are produced using spontaneous approaches;however,cocoa and coffee represent the most important agricultural commodities on international markets.As a manner to increase the efficiency of these processes,starter cultures have been developed and applied under field conditions.The selection process begins with the recovery of microbial strains from spontaneous fermentation through phenotypic and metabolic traits.Next,mutation-based breeding is used to develop and improve well-adapted starter cultures.With advances in synthetic biology,especially in the last decade,the development of robust cellular fabrications with high fermentative capacity has become easier-largely due to the development of genomic approaches,such as next-generation sequencing techniques,CRISPR-Cas system and bioinformatics tools.This review brings prospects on the use of synthetic biology to design new robust strains for use in cocoa and coffee fermentations,but which can be extended to other rudimentary foods.In addition,metabolic traits and target genes(e.g.,UvrA,RecA,GPD1,and GPP2)are proposed as a starting point for the improvement of cocoa and coffee starters.Finally,the regulatory and safety requirements for these food crops are addressed.This review aims to stimulate research on the process of fermentation and the associated synthetic biology tools to produce fermented food efficiently and sustainably.

Bacteriocinogenic lactic acid bacteria from Thai fermented foods: Potential food applications

Fermentation is an ancient preservation process which has been widely used in many countries across the world,especially in Southeast Asia.Many types of traditional fermented food products that contain lactic acid bacteria(LAB)appear to contain an abundance of bacteriocin producers.Until now,thirteen types of traditional Thai fermented food are recognized as isolation sources of bacteriocinogenic LAB.Furthermore,twenty-four bacteriocins from Thai fermented food isolates have been identified and fully charactized.Additionally,six bacteriocinogenic LAB strains have been applied to food products,as starter cultures or bacteriocin preparations,in order to increase product quality and safety.However,research into this form of application of bacteriocins produced by Thai fermented food isolates in food products remains very limited.Hence,the aim of this article is to provide a comprehensive review on bacteriocin from Thai fermented food isolates(i.e.,definition,types diversity,and various isolation sources of bacteriocinogenic LAB).Additionally,the potential application of bacteriocins as either starter cultures or preservatives has also been summarized.

Application of microbial cross-over for the production of Italian grape ale (IGA), a fruit beer obtained by grape must addition

In the last years,the production of grape ale beer has become a trendy choice among brewers in Italy,resulting in a new beer type known as Italian Grape Ale(IGA),a sort of bridge beverage between beer and wine.In this study,three autochthonous Saccharomyces cerevisiae strains(CHE-3,P4 and TA4-10),previously isolated from different food types,were tested in comparison with the commercial strain US-05.Fermentations were conducted at a laboratory scale on malt extracts with 15%and 25%grape must adjuncts,and on malt wort(control).After fermentation,the CHE-3,P4 and TA4-10 strains showed significantly higher CO_(2) production than US-05.The main analytical parameters(organic acids,real and apparent attenuation,ethanol content,glycerol level and carbohydrate profile)and the volatile compounds related to the organoleptic quality of the experimental beers were strongly influenced both by the grape must addition to the fermentation medium and the used strains.The addition of grape must enhanced the CO_(2) production,especially when 25%of grape must was added to the wort.By comparing the tested strains,the highest aromatic expression was observed with 15%grape must adjunct.The present results confirm the importance of media composition and microbial biodiversity to gain more different beers especially in the craft beers sector.Moreover,the outcome data show the significance of microbial cross-over,a novel approach based on the exploitation of microorganisms traditionally used in other agro-food chains also for brewing novel beer types.