Conducting starter culture-controlled fermentations of coffee beans during on-farm wet processing: Growth,metabolic analyses and sensorial effects

In this study, the potential use of Pichia fermentans YC5.2 as a starter culture to conduct controlled coffee bean fermentations during on-farm wet processing was investigated. Inoculated fermentations were conducted with or without the addition of 2% (w/v) sucrose, and the resultant microbial growth and metabolism, bean chemistry and beverage quality were compared with spontaneous (control) fermentation. In both inoculated treatments, P. fermentans prevailed over indigenous microbiota and a restricted microbial composition was observed at the end of fermentation process. The inoculation also increased the production of specific volatile aroma compounds (e.g., ethanol, acetaldehyde, ethyl acetate and isoamyl acetate) and decreased the production of lactic acid during the fermentation process. Sucrose supplementation did not significantly interfere with the growth and frequency of P. fermentans YC5.2 inoculum but maintained high levels of wild bacteria population and lactic acid production similar to the spontaneous process. In roasted beans, the content of sugars and organic acids were statistically (p < 0.05) similar for all the treatments. However, the inoculated fermentations were shown to influence the volatile fraction of roasted coffee beans by increasing the concentration of yeast-derived metabolites compared to control. Sensory analysis of coffee beverages demonstrated that the use of the YC5.2 strain was favorable for the production of high-quality coffees with distinctive characteristics, e.g., intense perception of ‘vanilla’ taste and ‘floral’ aromas. In conclusion, the use of P. fermentans YC5.2 in coffee processing was shown to be a viable alternative to control the fermentation step and to ensure consistent quality of finished products.     

Development of a process for producing ethyl caproate‐ and ethyl lactate‐rich rice shochu

To increase the popularity of rice shochu, a process was developed to produce ethyl caproate‐ and ethyl lactate‐rich rice shochu. On a laboratory‐scale, there was a shochu production trial with Saccharomyces cerevisiae Y‐E. Caproic acid added in the second‐stage fermentation was esterified to ethyl caproate. Both ethyl caproate and ethyl lactate were produced by adding a caproic acid‐producing bacterial (CAPB) consortium and lactic acid bacterium (LAB) to the shochu production process. Yellow koji was more appropriate for producing a flavour‐rich shochu with the addition of a CAPB consortium and LAB than white koji. Optimal addition time for the CAPB consortium and LAB was on the first day of the second‐stage fermentation, judging from concentrations of ethyl caproate and ethyl lactate produced. Additional dosages of CAPB consortium and LAB positively affected the formation of ethyl caproate and ethyl lactate, respectively. Shochu production with the addition of 2% and 4% CAPB consortium led to ethyl caproate concentrations of 27.3 mg/L and 47.9 mg/L in genshu, respectively, and the shochu achieved the best sensory test score from the Japanese shochu brewery panellists. Copyright © 2015 The Institute of Brewing & Distilling     

Isolation and characterization of lactic acid bacteria from jiang‐sun (fermented bamboo shoots), a traditional fermented food in Taiwan

BACKGROUND: In this study, lactic acid bacteria (LAB) were isolated, characterized and identified from jiang‐sun (fermented bamboo shoots; a traditional fermented food in Taiwan). Samples were collected at seven time intervals from a fixed fermenting bucket during the fermentation process of jiang‐sun and its initial ingredients, dochi (fermented soybeans) and bamboo shoots. RESULTS: A total of 57 LAB cultures were isolated; 42 cultures were isolated from jiang‐sun samples and 15 cultures were isolated from dochi and bamboo shoots. These isolates were characterized phenotypically and then divided into three groups (A–C) by restriction fragment length polymorphism analysis and sequencing of 16S ribosomal DNA. Alteration of microbial populations during the fermentation process was observed. While various LAB were found in the dochi and bamboo shoots, it was mostly replaced by Lactobacillus plantarum after 1 day of fermentation. Furthermore, the antibacterial activities of the isolates were determined, and one Enterococcus faecium strain showed inhibitory activity against all the indicator strains. CONCLUSION: Results suggest that L. plantarum is the main LAB present during the fermentation of jiang‐sun. To our knowledge, this is the first report describing the distribution and varieties of LAB that exist in the jiang‐sun fermentation process. Copyright © 2010 Society of Chemical Industry     

Analysis of volatile compounds produced by different species of lactobacilli in rye sourdough using multiple headspace extraction

Profiles of volatile organic compound (VOC) produced by nine individual lactic acid bacteria (LAB) during rye sourdough fermentation were compared by automated SPME and GC/MS‐Tof. The dough samples were inoculated with individual strains, placed inside the headspace vials and incubated during next 24 h. The production or loss of VOC‐s was followed by adsorbing volatiles onto 85‐m Car/PDMS fibre in every 4 h. Volatile profiles differed among LAB species and divided LAB into two main groups – hetero‐ and homofermentative. Hetrofermentative LAB (Lactobacillus brevis; Leuconostoc citreum; Lactobacillus vaginalis, Lactobacillus panis) showed high production of acetic acid, CO₂, ethanol, ethylacetate, producing also hexyl acetate, ethyl hexanoate and isopentyl acetate. Whereas homofermentative LAB species (Lactobacillus helveticus; Lactobacillus casei; Lactobacillus sakei; Lactobacillus curvatus) produced a considerable amount of 2,3‐butanedione. Production of l ‐leucine methyl ester was unique for Lb. sakei, Lb. casei and Lb. curvatus strains. Lb. helveticus was the only LAB that produced benzaldehyde.     

Development of fermented Hericium erinaceus juice with high content of L‐glutamine and L‐glutamic acid

Fermented plant beverages (FPB) with a high content of desirable principle components are served as functional foods from several years. Hericium erinaceus is famous for its antimicrobial, antioxidant, antihypertensive and antidiabetic nature. Accordingly, the current study was aimed to produce fermented H. erinaceus juice with a high content of L‐glutamine (Gln) and L‐glutamic acid (GA) through lactic acid bacteria (LAB) isolated from fermented Thai foods. LAB isolates were screened and identified the potent protease‐producing bacteria Enterococcus faecalis (G414/1) that facilitate the production of Gln and GA through protein hydrolysis. Box–Behnken design (BBD) and response surface methodology (RSM) were adapted for the optimisation of conditions for the increased production of Gln and GA during fermentation of H. erinaceus. We succeeded with an optimum concentration of cofactor (CaCl₂), pH and temperature for improved protease activity and subsequent Gln and GA production. The ability of isolated E. faecalis strain to produce Gln and GA was demonstrated in this study. Further, upstream processes like strain improvement and media optimisation will direct the way to produce enriched H. erinaceus based FPB.     

Growth inhibition of Fusarium graminearum and deoxynivalenol detoxification by lactic acid bacteria and their application in sourdough bread

Eight lactic acid bacteria (LAB) strains were screened for their ability to inhibit Fusarium graminearum (F. graminearum) growth and remove deoxynivalenol (DON). Furthermore, the selected LAB strains were applied as starter cultures to evaluate their performance during the breadmaking process. Lactobacillus plantarum (L. plantarum) AR524 exhibited strong inhibitory activity against F. graminearum growth in a pH-dependent manner and removed up to 40.9% of DON, mainly through cell wall binding. Compared with the control, L. plantarum AR524 inhibited 60.19% of F. graminearum growth and removed 50.53% of DON during breadmaking. The texture properties of the bread were also remarkably improved by L. plantarum AR524, and its shelf life was extended from 3 days to 6 days without the application of any chemical preservatives. Therefore, L. plantarum AR524 shows excellent potential for application as a bioprotective starter culture in bakery products.     

Effect of added sulphur dioxide levels on the fermentation characteristics of strawberry wine

The aim of this study to evaluate the effects of sulphur dioxide (SO₂) on strawberry wine fermentation and on the quality of the final wine product. Major aroma compounds, reducing sugars, ethanol, titratable acid and microflora were analyzed during the fermentation of strawberry wine supplemented with 0–100 mg/L SO₂. As the amount of added SO₂ increased, the consumption of reducing sugars and soluble solids and ethanol production decreased during early fermentation, but increased during late fermentation. During the fermentation process, the concentrations of 2‐phenethanol, isobutanol and isopentanol significantly increased and those of n‐propanol, isoamyl acetate and ethyl lactate decreased with increasing amount of added SO₂. The production of n‐butanol, ethyl acetate and ethyl butyrate was slightly dependent on the amount of added SO₂. Yeast cells were the dominant microbe in the fermenting strawberry pulp, and indigenous bacteria and fungi populations decreased rapidly or disappeared because of their sensitivity to SO₂. It was concluded that 60–80 mg/L SO₂ should be added during strawberry wine fermentations to improve wine quality. Copyright © 2016 The Institute of Brewing & Distilling     

Potential for prevention of non‐O157 Shiga toxin‐producing Escherichia coli contamination in traditionally fermented African maize gruel by fermentative probiotic Lactobacillus plantarum

Non‐O157 Shiga toxin‐producing Escherichia coli (STEC) are a frequent cause of STEC‐related infections such as diarrhoea. Fermentation by presumptive probiotic Lactobacillus plantarum strain B411 isolated from cereal fermentation was investigated to prevent the growth of acid‐adapted (AA) and non‐acid‐adapted (NAA) non‐O157 STEC in traditionally fermented maize gruel, a widely used complementary food in Africa. L. plantarum strain B411 possessed probiotic characteristics and antimicrobial activity against selected pathogenic bacteria. Growth of AA and NAA non‐O157 STEC strains was substantially inhibited by 3.6 and 4.8 log reductions, respectively, in the maize gruel fermented with the L. plantarum B411, while their growth was only inhibited by 1.0 and 1.2 log reductions, respectively, by traditional fermentation alone. Inclusion of fermentative strains of L. plantarum exhibiting probiotic activity is a feasible method to ensure safety of traditionally fermented African cereal porridges through inhibition of non‐O157 STEC.     

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.     

Production and Application of Xylanase from Penicillium sp. Utilizing Coffee By-products

The lignocellulosic coffee by-products such as coffee pulp, coffee cherry husk, silver skin, and spent coffee were evaluated for their efficacy as a sole carbon sources for the production of xylanase in solid-state fermentation using Penicillium sp. CFR 303. Among the residues, coffee cherry husk was observed to produce maximum xylanase activity of 9,475 U/g. The process parameters such as moisture (50%), pH (5.0), temperature (30 °C), particle size (1.5 mm), inoculum size (20%), fermentation time (5 days), carbon source (xylose), and nitrogen source (peptone) were optimized and the enzyme activity was in the range of 19,560–20,388 U/g. The enzyme production was further improved to 23,494 U/g with steam as a pre-treatment. The extracellular xylanase from the fungal source was purified to homogeneity from culture supernatant by ammonium sulfate fractionation, DE32-cellulose with a recovery yield of 25.5%. It appeared as a single band on SDS-PAGE gel with a molecular mass of approximately 27 kDa. It had optimum parameters of 50 °C temperature, pH 5.0, K _m 5.6 mg/mL, and V _max 925 μmol mg⁻¹ min⁻¹ with brichwood xylan as a substrate. The crude enzyme hydrolysed lignocellulosic substrate as well as industrial pulp. Production of xylanase utilizing coffee by-products constitutes a renewable resource and is reported for the first time.     

Spray drying conditions for orange juice incorporated with lactic acid bacteria

This work aimed to develop an orange juice powder by spray drying with lactic acid bacteria (Lactobacillus plantarum 299v and Pediococcus acidilactici HA‐6111‐2), testing their survival both during drying and storage (room temperature and 4 °C). Initially, the best conditions for spray drying were chosen to allow the best survival of each LAB: (i) inlet air temperature of 120 °C and (ii) 0.5:2 ratio of the orange juice soluble solids and drying agent added (prebiotics: 10 DE maltodextrin or gum Arabic). Survival of LAB was not affected by drying process, and it was higher when cultures were stored at 4 °C. A slightly higher protection was conferred by 10 DE maltodextrin, in the case of L. plantarum and at 4 °C. Pediococcus acidilactici was more resistant during storage at 4 °C, with logarithmic reductions lower than 1 log‐unit. It was demonstrated that it is possible to produce a functional nondairy product, orange juice powder supplemented with prebiotic compounds, containing viable LAB for at least 7 months, when stored at 4 °C.     

Improving the quality of Sichuan pickle by adding a traditional Chinese medicinal herb Lycium barbarum in its fermentation

Sichuan pickle is a traditional Chinese food fermented mainly by lactic acid bacteria (LAB). In this study, effect of adding Lycium barbarum on Sichuan pickle fermentation was investigated using kinetic modelling and correlation analysis. It was found that L. barbarum addition not only increased the amount of LAB, the total acid content and antioxidant capacity, but also improved the organoleptic quality and reduced nitrite content of the pickle considerably. Model‐based analyses revealed that L. barbarum addition increased the growth rate and decreased the death rate of LAB. The increase in antioxidant capacity of the pickle, especially the phenolics, can at least partly be attributed to its transferring from the L. barbarum. Correlation analysis results suggest that the nitrite reduction in pickle is closely related with pH value decrease and the increase in acids, and LAB, yeast and acids may all make contribution to the antioxidant capacity of the pickle.     

The effects of baobab pulp powder on the micro flora involved in tempe fermentation

Locally prepared tempe that underwent natural fermentation was characterized by the growth of Lactobacillus plantarum, Streptococcus lactis , Bacillus sp., Salmonella sp., Klebsiella sp., Lactococcus lactis , Rhizopus sp. and Staphylococcus sp., while fermentation carried out with the addition of varying levels of baobab pulp powder had mainly lactic acid bacteria (LAB)— Lactobacillus plantarum, Lactobacillus fermentum , Lactobacillus acidophilus and Rhizopus sp. dominating. Increasing concentrations of baobab pulp powder led to an increase in the population of lactic acid bacteria (LAB) from 2.3×10² to 3.3×10⁴ while it reduced the population of inoculated Rhizopus from 10² to only six colonies on malt extract agar (MEA).     

Evolution of fermenting microbiota in tarhana produced under controlled technological conditions

The purpose of this study was to evaluate the evolution of lactic acid bacteria (LAB) and yeasts during the fermentation of tarhana produced with some pasteurised ingredients and carried out at 30 and 40 °C. The chemical parameters were those typical for tarhana production. Coliform bacteria were not detected during fermentation, while LAB and yeasts were in the range 10⁷-10⁸ colony forming units (CFU) g⁻¹. Plate counts showed an optimal development of both fermenting microbial groups and the differences in cell concentrations were not significant (P > 0.05). LAB were isolated during fermentation and grouped on the basis of phenotypic and polymorphic characteristics. LAB isolates were identified by a combined genetic approach consisting of 16S/23S rRNA intergenic spacer region (ITS) and partial 16S rRNA gene sequencing as Pediococcus acidilactici, Lactobacillus plantarum and Lactobacillus brevis. Hence, the pasteurisation of the vegetable ingredients, excluded wheat flour, enhanced the hygienic conditions of tarhana without influencing the normal evolution of LAB. However, the fermentation at 40 °C favoured pediococci, while the production at 30 °C was mainly characterised by lactobacilli. Yeasts, identified by the restriction fragment length polymorphism (RFLP) of the 5.8S ITS rRNA gene, were mainly represented by the species Saccharomyces cerevisiae in both productions.     

Microbiological and physicochemical characterisation of green table olives of Halkidiki and Conservolea varieties processed by the Spanish method on industrial scale

The microbiological and physicochemical changes of industrially fermented Halkidiki and Conservolea green table olives were determined. Samples were analysed to monitor the population of lactic acid bacteria (LAB), yeasts and Enterobacteriaceae, together with changes in pH, acidity, salinity, colour, lactic acid, acetic acid and ethanol. LAB and yeast species diversity was evaluated at the beginning (1 day), middle (75 days) and final (135 days) stages of fermentation by RAPD-PCR genomic fingerprinting. Results revealed vigorous lactic acid processes as indicated by the dominance of LAB over yeasts. No Enterobacteriaceae could be detected after 30 days. Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) dominated in the beginning of fermentation in both varieties. In the end, Lactiplantibacillus pentosus (formerly Lactobacillus pentosus) and Pediococcus ethanolidurans prevailed in Halkidiki and Conservolea varieties, respectively. As for yeasts, Kluyveromyces lactis/marxianus and Pichia manshurica prevailed at the onset of fermentation in Halkidiki and Conservolea varieties, whereas in the end Pichia membranifaciens dominated in both varieties.     

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     

Synergistic effects of combinatorial Lactiplantibacillus plantarum fermentation and vegetable oils supplementation on the lycopene level,antioxidant capacities and flavor volatiles of tomato pulp

The objective of this study was to investigate the effects of Lactiplantibacillus plantarum (L. plantarum) fermentation and three types of vegetable oils (corn oil, peanut oil, and olive oil) supplementations on the physicochemical properties, bioactive components, and flavor volatiles of tomato pulp. Tomato pulp supplemented with oils was excellent food matrices for L. plantarum growth, and the colony counts remained above 8.3 log CFU/mL at the end of fermentation. The contents of total phenol, carotenoids and lycopene were dramatically increased after fermentation, and oils supplementation exhibited a synergistic promotion effect, especially for the combination of L. plantarum fermentation and 3% olive oil supplementation exhibiting the highest lycopene level (30 mg/mL), the strongest DPPH radical scavenging activity (84.24%) and FRAP (16.45 mmol Trolox/L). Furthermore, synergistic L. plantarum fermentation and oils supplementation decreased aldehydes content, and increased alcohols, esters, and ketones formation, meaning the improved flavor characteristics of fermented tomato pulp.Industrial relevanceIn this study, a functional beverage of tomato pulp was prepared by the combination of L. plantarum fermentation and vegetable oils supplementation. Colony counts, lycopene level, antioxidant capacities, and flavor characteristics were dramatically improved at the end of fermentation. This study provides an innovative technology to improve the release of lycopene from plant tissue and provide a functional beverage of tomato pulp with high health benefits.     

Fermentation of Allium chinense Bulbs With Lactobacillus plantarum ZDY 2013 Shows Enhanced Biofunctionalities,and Nutritional and Chemical Properties

In this study, fermentation of Allium chinense bulbs was carried out with Lactobacillus plantarum ZDY 2013. A decrease in pH from 6.8 to 3.5 and a stable lactic acid bacteria population were observed during 7‐d fermentation. The total phenolic content increased by 2.7‐fold in the aqueous and ethanol extracts of A. chinense bulbs after fermentation. Antioxidant capacity including 2,2‐diphenyl‐1‐picrylhydrazyl radical‐scavenging effect and reducing power of both extracts was significantly (P < 0.05) improved after fermentation. Antagonistic test against 6 pathogens showed that fermentation significantly (P < 0.05) enhanced the antimicrobial activity in both extracts of fermented bulbs, especially in the ethanol extracts of fermented bulbs against L. monocytogenes. Analysis of the free amino acid (FAA) profile by ion‐exchange chromatography revealed that fermentation significantly (P < 0.05) increased total FAA content. In addition, among 27 kinds of volatile components analyzed by headspace–solid phase microextraction–gas chromatography–tandem mass spectrometry, sulfur‐containing compounds accounted for 65.23%, but decreased to 43.65% after fermentation. Our results suggested that fermentation of A. chinense bulbs with L. plantarum could improve their biofunctionalities, and nutritional and chemical properties.     

Comparison of the antioxidant activities of roasted and explosive puffed coffees

We investigated the explosive process effect on antioxidant activities of coffee bean. The total polyphenol contents of powdered extract of explosive puffing coffee bean at 0.75 MPa (PEP 7.5) and powdered extract of explosive puffing coffee bean at 0.9 MPa (PEP 9.0) were at a significantly higher than that of the powdered extract of roasting coffee bean (PER) (P < 0.05). PEP 7.5 showed the highest levels of 3‐CQA (86.23 μg mg^?1), 4‐CQA (43.71 μg mg^?1), and 5‐CQA (31.66 μg mg^?1), and PEP 9.0 had also similar levels of chlorogenic acids, with 3‐CQA (77.99 μg mg^?1), 4‐CQA (43.71 μg mg^?1), and 5‐CQA (30.32 μg mg^?1). PEP 7.5 and PEP 9.0 showed relatively higher antioxidant capacities in DPPH, ABTS, taurine, FRAP, and β‐carotene/linoleic acid assays. PEPs partly recovered the HepG2 cell damage induced by t‐BOOH. These results suggest that puffed coffee has beneficial health effects, and could be used for the development of novel processed coffee products.     

On-farm implementation of a starter culture for improved cocoa bean fermentation and its influence on the flavour of chocolates produced thereof

Cocoa bean fermentations controlled by means of starter cultures were introduced on several farms in two different cocoa-producing regions (West Africa and Southeast Asia). Two starter culture mixtures were tested, namely one composed of Saccharomyces cerevisiae H5S5K23, Lactobacillus fermentum 222, and Acetobacter pasteurianus 386B (three heaps and one box), and another composed of L. fermentum 222 and A. pasteurianus 386B (seven heaps and one box). In all starter culture-added cocoa bean fermentation processes, the inoculated starter culture species were able to outgrow the natural contamination of the cocoa pulp-bean mass and they prevailed during cocoa bean fermentation. The application of both added starter cultures resulted in fermented dry cocoa beans that gave concomitant milk and dark chocolates with a reliable flavour, independent of cocoa-producing region or fermentation method. The addition of the lactic acid bacterium (LAB)/acetic acid bacterium (AAB) starter culture to the fermenting cocoa pulp-bean mass accelerated the cocoa bean fermentation process regarding citric acid conversion and lactic acid production through carbohydrate fermentation. For the production of a standard bulk chocolate, the addition of a yeast/LAB/AAB starter culture was necessary. This enabled an enhanced and consistent ethanol production by yeasts for a successful starter culture-added cocoa bean fermentation process. This study showed possibilities for the use of starter cultures in cocoa bean fermentation processing to achieve a reliably improved fermentation of cocoa pulp-bean mass that can consistently produce high-quality fermented dry cocoa beans and flavourful chocolates produced thereof.