Fermented Cabbage Research Articles

TWO-STEP CONTROLLED FERMENTATION USING NISIN Z-PRODUCING LACTOCOCCUS LACTIS SSP. LACTIS AND SELECTED STRAINS OF THE GENUS LACTIPLANTIBACILLUS SPP.

Spontaneous fermentation of Brassica vegetables is an ancient method that improves the foods' sensory properties, safety, and shelf life. However, in recent years, there has been a growing interest in studying controlled fermentation with lactic acid bacteria selected based on their technological properties. This study reported the inhibitory activity of a Lactococcus lactis ssp. lactis of marine origin and the evolution of a two-step controlled fermentation using the cited strain and two selected Lactiplantibacillus strains. Lc. lactis ssp. lactis was studied by phenotypic and genotypic methods. The inhibitory activity was assayed against common contaminants and pathogens. The strain behaviour in Chinese cabbage and white cabbage fermentation was studied by monitoring the cell count and inhibitory activity against Listeria innocua ATCC 33090. The two-step controlled fermentation of Chinese and white cabbage was conducted using, in the first step, the Lactococcus strain and, in the second step, the two Lactiplantibacillus strains. The evolution of the processes was monitored by cell counts and pH measurements. PCR amplification confirmed the presence of nisin Z gen in the Lc. lactis ssp. lactis strain. The bacteriocin exerted inhibitory activity against Gram-positive related species but not against Gram-negative ones. The results obtained in the controlled fermentation suggested that the combination of the selected strains is compatible and may improve the fermented matrices' safety.

Lacrimispora brassicae sp. nov. isolated from fermented cabbage, and proposal of Clostridium indicum Gundawar et al. 2019 and Clostridium methoxybenzovorans Mechichi et al. 1999 as heterotypic synonyms of Lacrimispora amygdalina (Parshina et al. 2003) Haas and Blanchard 2020 and Lacrimispora indolis (McClung and McCoy 1957) Haas and Blanchard 2020, respectively.

A Gram-stain-negative, endospore-forming, rod-shaped, indole-producing bacterial strain, designated YZC6T, was isolated from fermented cabbage. Strain YZC6T grew at 10-37 °C, pH 5.5-8.5, and with up to 2 % (w/v) NaCl. The major cellular fatty acids were C16 : 0 and C18 : 1 cis 11 dimethyl acetal. Phylogenetic analysis of the 16S rRNA gene revealed that strain YZC6T belonged to the genus Lacrimispora and was closely related to Lacrimispora aerotolerans DSM 5434T (98.3 % sequence similarity), Lacrimispora saccharolytica WM1T (98.1 %), and Lacrimispora algidixylanolytica SPL73T (98.1 %). The average nucleotide identity based on blast (below 87.8 %) and digital DNA-DNA hybridization (below 36.1 %) values between the novel isolate and its corresponding relatives showed that strain YZC6T could be readily distinguished from its closely related species. Based on genotypic, phenotypic, and chemotaxonomic data, a novel Lacrimispora species, Lacrimispora brassicae sp. nov., was proposed, with YZC6T as the type strain (=MAFF 212518T=JCM 32810T=DSM 112100T). This study also proposed Clostridium indicum Gundawar et al. 2019 as a later heterotypic synonym of Lacrimispora amygdalina (Parshina et al. 2003) Haas and Blanchard 2020 and Clostridium methoxybenzovorans Mechichi et al. 1999 as a later heterotypic synonym of Lacrimispora indolis (McClung and McCpy 1957) Haas and Blanchard 2020.

Enhancing Shelf-Life of Banana Fruit Using Fermented Cabbage Extract

Biochemical changes along with microbial contamination may shorten the shelf life of post harvested fruits and vegetables. Generally, various physical and chemical treatments are being used to preserve the post harvested fruits. However, those treatments are hardly good for human health as well as the environment. Interestingly, lactic acid bacteria (LAB) produce antimicrobial peptides that are harmful to food spoilage bacteria and extend shelf life by killing them. Therefore, the present study is designed to investigate spontaneous fermentation by the autochthonous LAB in the cabbage leaves and the application of fermented cabbage extract to enhance the shelf-life of banana fruits. The result showed that the fermented cabbage extract was acidic (pH = 3.6 after 40 hours) in nature and increased its acidity over time. In 24 hours, 1 mgL-1 lactic acid was produced by LAB in cabbage leaves. In fermented cabbage extract, 3.85 mg per 100g vitamin-C was measured, antioxidant properties expressed by the DPPH and it was 3.02 mgml-1. Anthocyanin and flavonoids were present in cabbage extract but no tannin was observed. After 48h fermentation, the fermented cabbage extract was applied immediately to the harvested mature banana fruits. The brown surface of the banana was considered as an indicator before rotting. The brown surface in the control banana appeared on Day 7 after exposing to cabbage extract. On the other hand, such surface appeared on treated banana on Day 11. By Day 11, control banana group had already succumbed to rot. This result indicates that the treated banana took an additional 4 days to reach the state. Taken all together, it may be concluded that fermented cabbage extract possesses a promising role to extend the shelf life of banana fruits and to reduce the postharvest loss through eco-friendly natural approach without compromising quality and safety. J Bangladesh Agril Univ 22(2):241-248, 2024

Unraveling the In Vitro Anti-Advanced Glycation End-Product (Anti-AGE) Potential of Fermented Red Cabbage and Beetroot: Insights into Composition and Activities.

This study verified the in vitro activity of red cabbage and beetroot against the formation of advanced glycation end-products (AGEs) and their relationship with the biomolecules' content. Fermentation of cabbage increased the total phenolic (~10%) and flavonoid contents (~14%), whereas decreased total phenolics/flavonoids in beetroot. Fermented cabbage exhibited higher ability against AGEs, i.e., 17% in the bovine serum albumin-methylglyoxal (BSA-MGO) model and 25% in the BSA-glucose model, while beetroot exhibited 23% and 18%, respectively. The major compounds of cabbage products were cyanidin 3-(sinapoyl)(sinapoyl)-diglucoside-5-glucoside, sinapic acid, and epicatechin. Syringic acid and epicatechin were predominantly present in fermented beetroot. 2,17-bidecarboxy- and 2,15,17-tridecarboxy-betanin were the major betalains. Fermented vegetables can be effective inhibitors of the AGE formation/accumulation and could be recommended in the prevention of diet-related diseases.

Determination of Post-Fermentation Waste from Fermented Vegetables as Potential Substitutes for Preservatives in o/w Emulsion.

Post-fermentation wastes are rich sources of various biologically active compounds with antimicrobial activity, whose potential is not being fully exploited. One of the possible applications of post-fermentation waste may be its use as a natural preservative that effectively combats pathogens found in formulations. The study aims included the following: (1) compare the antimicrobial and antioxidant activity of fermented vegetable extracts (FVEs), (2) examine the inhibition of cosmetic-borne pathogens by FVEs, and (3) estimate the preservative effectiveness of FVEs in o/w emulsions. It was found that fermented white cabbage, cucumber, celery, and the mixture of fermented white cabbage, cucumber, and celery (1:1:1) showed antibacterial and antifungal activity against all the tested reference microbial strains. The addition of fermented cucumber, celery, and the mixture of fermented white cabbage, cucumber, and celery (1:1:1) to the o/w emulsion fulfilled criterion A of the preservative effectiveness test for S. aureus, E. coli, and A. brasiliensis, but did not fulfill the criterion for P. aeruginosa and C. albicans. The tested FVEs have comparable activity to inhibit pathogens in o/w emulsion as sodium benzoate. The results of our study prove that FVEs can be valuable raw materials supporting the preservative system, which, in turn, can significantly reduce the concentration of preservatives used in o/w emulsion.

Dry fermented vegetable products of long-term storage and their integration into the diet of astronauts

Relevance. Fermentation makes it possible to improve the properties of the final product, increase its nutritional value and organoleptic characteristics. It has been scientifically proven that the use of fermented foods (with high nutritional and biological value) on a regular basis has a positive effect on human health, increases immunity, improves the functioning of the gastrointestinal tract. Dry fermented products with a long shelf life can be recommended as part of the diet in space. The aim is to creation of a dry base for fermented long-term storage beverages based on cabbage and table carrots, applicable in the diet of space nutrition. Objects and methods of research. The objects of the study were the domestic hybrid of white cabbage F1 Severyanka and the domestic variety of carrot table Margosha, and the dry fermented products obtained from them. Results. It was found that, according to biochemical and organoleptic quality indicators, the domestic hybrid of white cabbage F1 Severyanka and the domestic carrot variety Margosha are suitable for various types of processing, including fermentation and manufacture of dried fermented products. The comparison of the number of microorganisms in fermented cabbage and cabbage dehydrated by LTVD (low temperature vacuum drying) and VFD (vacuum freeze drying methods was carried out. The survival rate of microorganisms was 1.62 times higher in LTVD. The ways of accelerating the fermentation process of table carrots are considered. The expediency of using starter cultures obtained on the basis of the fermented product has been confirmed. It has been found that using starter cultures in the form of a fermented product dried by the LTVD method accelerates fermentation and allows you to reach the desired pH level 1.33 times faster than the base one and does not affect the final organoleptic characteristics.

Protective effect of diindolylmethane-enriched dietary cabbage against doxorubicin-induced cardiotoxicity in mice.

Chemotherapy with doxorubicin (Dox) can lead to cardiotoxic effects, presenting a major complication in cancer therapy. Diindolylmethane (DIM), derived from cruciferous vegetables like cabbage, exhibits numerous health benefits. However, its clinical application is limited because of low bioavailability and suboptimal natural concentrations in dietary sources. To address this limitation, we developed a processing methodology, specifically fermentation and boiling, to enhance DIM levels in cabbage. High-performance liquid chromatography (HPLC) analysis revealed a threefold DIM increase in fermented cabbage and a substantial ninefold increase in fermented-boiled cabbage compared to raw cabbage. To evaluate the clinical implications, we formulated a DIM-enriched diet and administered it to mice undergoing Dox treatment. Our in vivo results revealed that Dox treatment led to cardiotoxicity, manifested by changes in body and heart weight, increased mortality, and severe myocardial tissue degeneration. Dietary administration of the DIM-enriched diet enhanced antioxidant defenses and inhibited apoptosis in the cardiac tissue by interfering with mitoptosis and increasing antioxidant enzyme expression. Interestingly, we found that the DIM-enriched diet inhibited the nuclear translocation of NF-kB in cardiac tissue, thereby downregulating the expression of inflammatory mediators such as TNF-α and IL-6. Further, the DIM-enriched diet significantly reduced serum cardiac injury markers elevated by Dox treatment. These results suggest that the DIM-enriched cabbage diet can serve as a complementary dietary intervention for cancer patients undergoing chemotherapy. Further, our research highlights the role of plant-based diets in reducing treatment side effects and improving the quality of life for cancer patients.

Effect of Probiotic Fermented Cabbage Waste on Broiler Chicken Performance to Increase Production

Cabbage waste fermented liquid (Brassica oleracea) is a type of fermented liquid that contains lots of vitamins and other important nutrients that are beneficial for broilers. This study aims to determine the effect of adding fermented cabbage waste to the percentage of weight and length of the digestive organs of broilers including the weight of the proventriculus and ventriculus. This research was carried out from March to May 2021 at the Laboratory of UIN Agriculture Research and Development Station (UARDS) Faculty of Agriculture and Animal Husbandry, Sultan Syarif Kasim State Islamic University, Riau. The research material used 80 DOC broilers (CP 707). The research method was an experiment using a completely randomized design (CRD) with 4 treatments and 5 replications. The treatments consisted of P0 (control drinking water), P1 (2 ml of fermented cabbage waste/liter of drinking water), P2 (3 ml of fermented cabbage waste/liter of drinking water), and P3 (4 ml of fermented cabbage waste/liter of water). drinking water). The parameters measured were the percentage of weight of the proventriculus and ventriculus. The results of the analysis of variance showed that the administration of fermented cabbage waste in drinking water to broilers did not have a significant effect (P>0.05) on the percentage of weight and length of the digestive organs of broilers. The conclusion of this study is that the administration of fermented cabbage waste liquid to a level of 4 ml/liter of drinking water in broilers has not been able to increase the weight and length of the digestive organs of broilers

Anti-Inflammatory Effect of Fermented Cabbage Extract Containing Nitric Oxide Metabolites with Silica.

The aim of this study was to evaluate the anti-inflammatory effect of fermented cabbage extract (FC) containing nitric oxide metabolites with silica (FCS) on 1-fluoro-2,4-dinitrofluorobenzene (DNFB)-induced atopic dermatitis (AD) in BALB/c mice. Atopic dermatitis-like allergic contact dermatitis was induced by DNFB challenge in the ear after DNFB sensitization on the dorsal skin of mice. FCS alleviated the severity of atopic dermatitis-like skin lesions. In addition, epidermis thickness of the ear and penetration of inflammatory cells in atopic dermatitis-like skin lesions were decreased after topical application of FCS. The serum levels of TNF-α and IL-4 were measured in atopic dermatitis mice using ELISA kits, which were observed to be significantly decreased after topical application of FCS. This study demonstrates that the FCS can be used as a potential therapeutic for the treatment and prevention of AD.

Comparative evaluation of quality characteristics of fermented napa cabbage subjected to hot air drying, vacuum freeze drying, and microwave freeze drying

Fermented napa cabbage (FNC) is a traditional probiotic-enriched food. In this study, the potential of different drying techniques, including hot air drying (HAD), vacuum freeze drying (FD), and microwave freeze drying (MFD), for the production of dehydrated FNCs was evaluated. To reach a moisture content of 0.12 g⋅ g−1 (d.w.b.), MFD took 2 h, which was half of the time needed for HAD. FD process required the longest drying time, which was 18 h. Therefore, MFD consumed significantly less power compared to FD and HAD, which was 12.63% of FD power usage and 30% of HAD power usage. Both MFD and FD products exhibited better rehydration ability than the HAD product due to their honeycomb-like structure with less shrinkage. MFD and FD were able to preserve the living probiotics, bioactive components, and antioxidant capacities of FNCs better than HAD. The taste and aroma of dehydrated FNC products were maintained better by microwave-induced oxidation reaction and Maillard reaction during MFD treatment, based on the quantitative results regarding amino acids, volatile compounds, and sensory evaluation. In general, MFD is a promising method for obtaining high-quality dehydrated FNCs as probiotic foods.

The Influence of Fermentation Vessels on Yeast Microbiota and Main Parameters of Sauerkraut

The aim of this study was to compare the yeast microbiota occurring during cabbage fermentation, along with selected parameters important for the quality of sauerkraut, depending on the vessel used. For this purpose, glass jars were used, in which anaerobic conditions are quickly created, and stoneware vessels, whose appearance and characteristics are similar to tanks used on an industrial scale. WL nutrient agar with chloramphenicol and 10% NaCl was used to enumerate yeast. Isolates were differentiated using RAPD-PCR and identified by sequencing of the 5.8S-ITS rRNA gene region and PCR-RFLP. Selected organic acids, sugars, and polyols were analyzed using UHPLC-UV-Vis and -RI. Sauerkraut obtained in stoneware vessels was characterized by the presence of a larger amount of yeast, including those considered spoilage, such as Rhodotorula and Wickerhamomyces. It also contained 50% less lactic acid and a few times more acetic acids than that obtained using glass jars. A pH around 3.8 and 1.5% lactic acid, which are parameters indicating the end of fermentation of sauerkraut, were obtained in glass jars on the tenth day of fermentation. The yeast Wickerhamomyces anomalus may be an indicator of the presence of oxygen during sauerkraut fermentation, while Clavispora lusitaniae may indicate anaerobic conditions.

MICROBIOLOGICAL QUALITY AND ACCEPTANCE OF GAMMA IRRADIATED FERMENTED MUSHROOM AND CABBAGE DURING STORAGE

For developing countries, safe shelf-stable foods without refrigeration would offer advantages. Gamma ray, an ionizing radiation is known to be a safe technology for treating food products in extending their shelf-life. Studies were carried out to overcome arisen problems of the safe shelf-stable food and to evaluate the suitability of irradiation in preserving local fermented mushrooms (Pekasam Cendawan) and local fermented cabbages. Generally, local fermented mushrooms can be kept in room temperature and under chilled condition only for one and three days respectively. Similarly, local fermented cabbages require chilled condition for storage to avoid the packages bloated upon displayed and storage. Fresh packed fermented products were obtained from local producers and irradiated at doses of 2.0 kGy, 5.0 kGy and 10 kGy, using 60Co gamma irradiation source at MINTec-Sinagama. The irradiated and non-irradiated samples were displayed at room temperature storage periods for 2 weeks, 1 month, 3 months and 6 months. Microbiological analysis was carried out to determine status of bacteria (Total Plate Count) and fungi counts. The results were expressed as colony forming units per gram (cfu/g). Colour changes of the products were recorded using Colorimeter (Minolta) for lightness (L), redness (a) and yellowness (b) values. Acceptability of the irradiated fermented products were determined through sensory evaluation by using 30 members (male and female) of untrained panellists. The fungal and microbial counts in both samples irradiated at 5 and 10 kGy were more lowered than samples irradiated at 2 kGy. After storage at 3 months, the fungal and microbial counts were increased in the both control samples of fermented mushrooms and cabbages but maintained low in both irradiated samples. The control samples of fermented mushrooms (not irradiated) were spoiled after displayed one day in room temperature and after chilled for 3 months. Both irradiated samples at 2 kGy and 5 kGy were more accepted in sensory evaluation especially the texture and taste and no significant changes (P<0.05) in lightness, redness, and redness of fermented cabbage samples during 3 months storage. However, fermented mushroom samples irradiated at 5 kGy become darker after 3 months storage. Irradiation reduced the bloatness in the packaged fermented cabbages by reducing the count of bacteria in the products. These results showed the ability gamma irradiation for decontamination of selected fermented food and reliable process for food storage in commercial industries.

Effects of adding isolated Lactobacillus plantarum, Leuconostoc mesenteroides, and their mixtures on the quality indices of pickled Chinese cabbage

Pickled Chinese cabbage traditional fermented vegetables is popular in China, especially the northeast, owing to their special flavors. Spontaneous fermented Chinese cabbage usually has rich and mellow flavor because of abundant microorganism in the fermentation broth. In our study, LAB were screened from spontaneous Chinese cabbage and identified including morphology, physiology and biochemistry, and molecular levels. 11 of these were used as a single inocula to ferment Chinese cabbage, and acid contents, soluble sugar contents, Vc contents, cellulose contents and nitrite contents of these pickled Chinese cabbage were measured. Overall, three superior strains mixture(X1, M2, and D2) were inoculated to improve the fermentation characteristics of pickled Chinese cabbage. Furthermore, pickled Chinese cabbage with the mixture had the highest acid and Vc contents, the lowest nitrite content, and medium fiber content. The sensory quality mixed inocula was also the best compared with products prepared with single strain and spontaneous fermentation.
 Keywords: Lactobacillus plantarum; Leuconostoc mesenteroides; pickled Chinese cabbage, mixed LAB

Lactiplantibacillus brownii sp. nov., a novel psychrotolerant species isolated from sauerkraut

A Gram-stain-positive, rod-shaped, facultatively anaerobic and homofermentative strain, named WILCCON 0030T, was isolated from sauerkraut (fermented cabbage) collected from a local market in the Moscow region of Russia. Comparative analyses based on 16S rRNA gene sequence similarity and whole genome relatedness indicated that strain WILCCON 0030T was most closely related to the type strains Lactiplantibacillus nangangensis NCIMB 15186T, Lactiplantibacillus daoliensis LMG 31171T and Lactiplantibacillus pingfangensis LMG 31176T. However, the average nucleotide identity and digital DNA–DNA hybridization prediction values with these closest relatives only ranged from 84.6 to 84.9 % and from 24.1 to 24.7 %, respectively, and were below the 95.0 and 70.0% thresholds for species delineation. Substantiated by further physiological and biochemical analyses, strain WILCCON 0030T represents a novel species within the genus Lactiplantibacillus for which we propose the name Lactiplantibacillus brownii sp. nov. (type strain WILCCON 0030T=DSM 116485T=LMG 33211T).

Phytochemicals, antioxidant capacities and volatile compounds changes in fermented spicy Chinese cabbage sauces treated by thermal and non-thermal technologies

To extend shelf life of fermented spicy Chinese cabbage sauce at room temperature, the effects of electron beam irradiation (EBI), high pressure processing (HPP), pasteurization (PT) and autoclave sterilization (AS) treatments on the colony counts of Lactobacillus plantarum, phytochemicals, antioxidant activities and volatile compounds were investigated. Results showed that thermal and non-thermal treatments could significantly decrease the colony counts of Lactobacillus plantarum, in which EBI and AS treatments inactivated Lactobacillus plantarum thoroughly. EBI and HPP treatments were superior to PT and AS treatments in terms of volatile compounds, bioactive compounds and antioxidant activities. The total contents of volatile compounds in sauces treated by EBI and HPP were significantly increased by 43.92%–61.87% and 71.53%–84.46%, respectively, and the new formed substance 2,3-butanedione endowed sauces with sweet and creamy aroma. In addition, HPP treatment improved the extractable contents of total phenolics and carotenoids, retained capsicum red pigment content, and significantly enhanced antioxidant capacities of sauces. Sauce treated by HPP at 200 MPa exhibited the highest total carotenoid content, DPPH radical scavenging activity and FRAP, increasing by 9.27%, 2.24% and 16.13%, respectively, compared with CK. EBI treatment exhibited higher total phenolic content and FRAP, which positively depended on the dose. Therefore, HPP and EBI treatments were suggested as potential technologies to improve shelf-life stability and volatile compounds of fermented spicy Chinese cabbage sauce.

Analysis of The Addition of Natural Preservative Ingredients To The Saving Time of Squid (Loligo Sp.) (Study Of Various Studies Conducted)

Squid is one of Indonesia's marine fisheries resources that is nutritious and in high demand by the public, hence the need for good quality squid. The obstacle experienced in fulfilling the demand for squid is the quality of squid. Various research have been conducted to determine preservatives that are effective enough to maintain the freshness of squid for a long time and extend the shelf life. This research was conducted using a literature study technique, comparing and selecting the most effective of several natural preservatives used. Some of the preservatives compared were lactate solution from cabbage fermentation, yogurt, chitosan solution, picung seeds, and cucumber. This study aims to determine the effective preservatives that have the longest shelf life for squid. The results of the literature study showed that yoghurt was the most effective preservative for extending the shelf life of squid until day 11 with total lactic acid bacteria colonies of 4.8x 105 cfu/gram and pH value of 6.8 in low temperature storage. The concentration used was 1.5%.

Investigating the role of Lactiplantibacillus plantarum vs. spontaneous fermentation in improving nutritional and consumer safety of the fermented white cabbage sprouts.

Brassicaceae sprouts are promising candidates for functional food because of their unique phytochemistry and high nutrient density compared to their seeds and matured vegetables. Despite being admired for their health-promoting properties, white cabbage sprouts have been least explored for their nutritional significance and behavior to lactic acid fermentation. This study aimed to investigate the role of lactic acid fermentation, i.e., inoculum vs. spontaneous, in reducing intrinsic toxicants load and improving nutrients delivering potential of the white cabbage sprouts. White cabbage sprouts with a 5-7cm average size were processed as raw, blanched, Lactiplantibacillus plantarum-inoculated fermentation, and spontaneous fermentation. Plant material was dehydrated at 40°C and evaluated for microbiological quality, macronutrients, minerals, and anti-nutrient contents. The results indicate L. plantarum inoculum fermentation of blanched cabbage sprouts (IF-BCS) to increase lactic acid bacteria count of the sprouts from 0.97 to 8.47 log CFU/g. Compared with the raw cabbage sprouts (RCS), inoculum fermented-raw cabbage sprouts (IF-RCS), and spontaneous fermented-raw cabbage sprouts (SF-RCS), the highest content of Ca (447mg/100g d.w.), Mg (204mg/100g d.w.), Fe (9.3mg/100g d.w.), Zn (5mg/100g d.w.), and Cu (0.5mg/100g d.w.) were recorded in IF-BCS. L. plantarum-led fermentation of BCS demonstrated a reduction in phytates, tannins, and oxalates contents at a rate of 42%, 66%, and 53%, respectively, while standalone lactic acid fermentation of the raw sprouts reduced the burden of anti-nutrients in a range between 32 and 56%. The results suggest L. plantarum-led lactic acid fermentation coupled with sprout blanching is the most promising way to improve the nutritional quality and safety of the white cabbage sprouts.

The Impact of Different Cooking Methods on the Flavor Profile of Fermented Chinese Spicy Cabbage.

Chinese spicy cabbage (CSC) is a common traditional fermented vegetable mainly made of Chinese cabbage. In addition to eating raw, boiling and stir-frying are the most common cooking methods for CSC. To identify the impacts of boiling or stir-frying on the quality of CSC, the physicochemical properties, flavor compounds, and sensory properties of CSC were analyzed. A total of 47 volatile flavor compounds (VFCs) were detected by gas chromatography-mass spectrometry. Sulfide was determined as the main flavor compound of CSC, mainly contributed by cabbage, garlic, and onion odors. The content of sulfide decreased significantly after cooking. Nonanal, geranyl acetate, and linalool were newly generated after boiling with odor activity value (OAV) > 1, and contributed fatty, sweet, fruity, and floral odors to BL-CSC. 1-Octen-3-one, 1-octen-3-ol, octanal, nonanal, and (E)-2-nonenal were newly generated after stir-frying with OAV > 1, and contributed mushroom, fatty, and green odors to SF-CSC. Diallyl trisulfide, nonanal, (E)-β-ionone, β-sesquiphellandrene, and (E)-2-decenal were considered as the potential key aroma compounds (KACs) to distinguish the CSCs after different heat treatment. After cooking, the total titratable acidity of CSC increased and the sensory properties changed significantly. This study provides valuable information and guidance on the sensory and flavor changes of thermal processing fermented vegetables.

Hydrogen Production from Gelatin, Cotton, Wheat Straw, and Sour Cabbage and Their Mixtures—Short Communication

The influence of microaeration, pH, and substrate during dark fermentation of sour cabbage, gelatin, and wheat straw was investigated, and the results of dark fermentation of these three substrates and their mixtures are presented in this research. The fermentation of cabbage, gelatin, and wheat straw was investigated under varying pH and aeration conditions. We investigated concentrations of volatile suspended solids (VSS) of 20 g VSS/L of a substrate at a stable pH of 6.0 and a not aligned pH value. Sour cabbage resulted in the highest volume of hydrogen for 450 mL/g VSS with a pH of 6.0. The mixing of substrates caused lower hydrogen production than sour cabbage or wheat straw alone.

Presence of an ultra-small microbiome in fermented cabbages.

Ultramicrobacteria (UMB), also known as ultra-small bacteria, are tiny bacteria with a size less than 0.1 µm3. They have a high surface-to-volume ratio and are found in various ecosystems, including the human body. UMB can be classified into two types: one formed through cell contraction and the other that maintains a small size. The ultra-small microbiome (USM), which may contain UMB, includes all bacteria less than 0.2 µm in size and is difficult to detect with current methods. However, it poses a potential threat to food hygiene, as it can pass through sterilization filters and exist in a viable but non-culturable (VBNC) state. The data on the USM of foods is limited. Some bacteria, including pathogenic species, are capable of forming UMB under harsh conditions, making it difficult to detect them through conventional culture techniques. The study described above focused on exploring the diversity of USM in fermented cabbage samples from three different countries (South Korea, China, and Germany). The samples of fermented cabbage (kimchi, suancai, and sauerkraut) were purchased and stored in chilled conditions at approximately 4 °C until filtration. The filtration process involved two steps of tangential flow filtration (TFF) using TFF cartridges with different pore sizes (0.2 µm and 100 kDa) to separate normal size bacteria (NM) and USM. The USM and NM isolated via TFF were stored in a refrigerator at 4 °C until DNA extraction. The extracted DNA was then amplified using PCR and the full-length 16S rRNA gene was sequenced using single-molecule-real-time (SMRT) sequencing. The transmission electron microscope (TEM) was used to confirm the presence of microorganisms in the USM of fermented cabbage samples. To the best of our knowledge, this is the first study to identify the differences between USM and NM in fermented cabbages. Although the size of the USM (average 2,171,621 bp) was smaller than that of the NM (average 15,727,282 bp), diversity in USM (average H'=1.32) was not lower than that in NM (average H'=1.22). In addition, some members in USM probably underwent cell shrinkage due to unfavorable environments, while others maintained their size. Major pathogens were not detected in the USM in fermented cabbages. Nevertheless, several potentially suspicious strains (genera Cellulomonas and Ralstonia) were detected. Our method can be used to screen food materials for the presence of USM undetectable via conventional methods. USM and NM were efficiently separated using tangential flow filtration and analyzed via single-molecule real-time sequencing. The USM of fermented vegetables exhibited differences in size, diversity, and composition compared with the conventional microbiome. This study could provide new insights into the ultra-small ecosystem in fermented foods, including fermented cabbages.