Natural Fermentation Research Articles

Dynamic Analysis of Fermentation Quality, Microbial Community, and Metabolome in the Whole Plant Soybean Silage

Soybean (Glycine max (L.) Merr.) is an important oilseed crop, known for its rich nutritional content and high-quality protein. To address the shortage of feed protein resources and better utilize soybeans as a raw material, this study investigated the feasibility of using whole-plant soybean (WPS) as silage. As the ensiling period is a critical fermentation parameter, identifying the optimal fermentation duration was a key objective. The research involves fermenting WPS for silage production, conducted over five fermentation durations: 7, 15, 30, 60, and 90 days. The fermentation quality, microbial community, and metabolome of WPS silage were analyzed across these different time points. WPS silage fermented for 30 days exhibited optimal fermentation characteristics, with the highest lactic acid (LA) content observed at 30 days (p < 0.05), while butyric acid (BA) was detected only at 60 and 90 days. At 30 days, Enterococcus genera reached its peak relative abundance and was identified as the dominant genus. Random forest analysis highlighted Pantoea genera as the most influential biomarker. Metabolomic analysis revealed that the metabolic pathways involved in the biosynthesis of essential amino acids valine, leucine, and isoleucine were significantly enhanced during the later stages of fermentation compared to the earlier stages. Under natural fermentation conditions, the optimal fermentation period for WPS silage is approximately 30 days. These findings provide a theoretical basis for the utilization of WPS and the subsequent optimization of fermentation quality.

Silage Making of Napier Grass and Sugarcane Top at Different Proportions: Evolution of Natural Fermentation Characteristics, Chemical Composition, and Microbiological Profile

The co-ensiling technique is widely used to improve silage quality; however, it remains unclear as to what high-quality silages can be made by co-ensiling Napier grass (NG) with Sugarcane top (ST). The aim of this study was to evaluate the fermentation characteristics, chemical composition, and microbiological profile of silage produced from mixtures of NG and ST in varying ratios. Silage was prepared using a small-scale fermentation system, and treatments were designed as control silage (NG ensiled alone) or with 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%ST on a fresh matter basis with six replicates, respectively. Increasing ST in the silage reduced the contents of crude protein, ash, acetic acid, butyric acid, ammonia-N, as well as pH, but increased the contents of dry matter, ether extract, neutral detergent fiber, acid detergent fiber, water-soluble carbohydrate, lactic acid, and lactic acid bacteria. Lactobacillales and Enterobacterales were the dominant orders, with Lactiplantibacillus and Weissella as the dominant genera. Co-ensiling NG with ST enhanced microbial diversity and richness. ST, as a local by-product, is a viable additive to improve NG silage quality and nutrition. This study suggests that good-quality silages can be produced with NG: ST ratios of 40:60 to 20:80 and that these silages offer an opportunity to optimize the nutrient supply for ruminants.

Screening and application of functional autochthonous starter culture from cured meat, which can reduce nitrite content.

Cured meat is a fermented meat product from the traditional Chinese culture made by natural fermentation. In this study, five bacteria strains were screened from cured meat using 16S rDNA technology, and a functional local starter was selected, which was applied to the production of cured meat to standardize the production of cured meat and improve the quality of cured meat. By studying the fermentation characteristics of strain these strains, this study found that the fermentation characteristics of L. mesenteroides and S. lactis are ideal. L. mesenteroides and S. lactis were used as starter cultures in fermented bacon. Then, this study compared the quality of fermented beef with Sichuan bacon, Hunan bacon, and Xinyang bacon. The results suggested that L. mesenteroides and S. lactis can improve the sensory and texture properties of the products and reduce the moisture content, water activity, pH value, and protein content of fermented beef products. More importantly, L. mesenteroides can significantly reduce the nitrite content (25.34%) and nitrosamine content (29.69%) in fermented beef, which provides an excellent guarantee for the safety of cured meat. In this study, a functional fermentation strain-L. mesenteroides could degrade the nitrite content of fermented meat products and improve their sensory and textural properties-was screened to provide some reference value for the later development of functional strains suitable for fermented meat products.

Influence of Pediococcus pentosaceus Starter Cultures on Biogenic Amine Content and Antioxidant Activity in African Sourdough Flatbread Fermentation.

This study investigated the impact of Pediococcus pentosaceus strains not only on biogenic amine (BA) content, but also on antioxidant indices, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and total phenolic content, in kisra, an African sourdough flatbread. Among forty-six lactic acid bacteria (LAB) strains isolated from naturally fermented kisra sourdough, two strains (K-B21, K-B01) identified as P. pentosaceus, were selected due to their low BA-producing and high BA-degrading ability for kisra fermentation. Inoculation with P. pentosaceus K-B21 or P. pentosaceus K-B01 completely prevented the formation of tyramine and cadaverine during kisra fermentation. The levels of putrescine, histamine, spermine, and spermidine in kisra were reduced by about 90%, >31%, 55-61%, and 9-25%, respectively, by the two strains, compared to the control (natural fermentation). Additionally, DPPH scavenging activity was 83-84% in the control and inoculated groups of kisra. The total phenolic content was 1977.60 μg/g in the control and insignificantly lower in the inoculated groups (1850-1880 μg/g) than the control. These results suggest that P. pentosaceus K-B21 and K-B01 are promising candidates for use as sourdough starter cultures to produce kisra bread of higher quality, including both its safety and health functionality.

Comparative Analysis of Microbial Diversity and Metabolic Profiles during the Spontaneous Fermentation of Jerusalem Artichoke (Helianthus tuberosus L.) Juice.

Jerusalem artichoke juice is valued for its nutritional content and health benefits. Spontaneous fermentation enhances its flavor, quality, and functional components through microbial metabolic activities. This study used high-throughput sequencing to analyze microbial community changes, and LC-MS and GC-MS to detect secondary metabolites and flavor compounds during fermentation. During natural fermentation, beneficial bacteria like Lactobacillus and Pediococcus increased, promoting lactic acid production and inhibiting harmful bacteria, while environmental bacteria decreased. Similarly, fungi shifted from environmental types like Geosmithia and Alternaria to fermentation-associated Pichia and Penicillium. A total of 1666 secondary metabolites were identified, with 595 upregulated and 497 downregulated. Key metabolic pathways included phenylpropanoid biosynthesis, with significant increases in phenylalanine, tryptophan, and related metabolites. Lipid and nucleotide metabolism also showed significant changes. Flavor compounds, including 134 identified alcohols, esters, acids, and ketones, mostly increased in content after fermentation. Notable increases were seen in Phenylethyl Alcohol, Ethyl Benzenepropanoate, 3-Methylbutyl Butanoate, Ethyl 4-Methylpentanoate, 5-Ethyl-3-Hydroxy-4-Methyl-2(5H)-Furanone, Ethyl Decanoate, Hexanoic Acid, and 1-Octanol. γ-aminobutyric acid (GABA) and other functional components enhanced the health value of the juice. This study provides insights into microbial and metabolic changes during fermentation, aiding in optimizing processes and improving the quality of fermented Jerusalem artichoke juice for functional food development.

Biosynthesis of antibacterial bacterial cellulose in-situ using yellow wine wastewater through co-fermentation

Bacterial cellulose (BC) is extensively used in many fields due to its excellent physical properties; however, its high production cost and low output remain a challenge. The production of conventional yellow wine typically results in the generation of a substantial quantity of rice soaking wastewater (RSW). In this study, BC producing strain was isolated and identified from Kombucha. BC was produced directly using unsterilized RSW as the medium. High-yield BC was obtained by co-fermentation of isolated Novacetimonas hansenii S-08 with natural fermentation flora from RSW. The culture conditions were optimized by combining RSW medium and seed liquid of HS medium at a ratio of 5:1, using unsterilized RSW as a medium containing 40 g/L fructose corn syrup and 2 % ethanol. The results of FTIR, XRD, TGA, SEM analysis, and mechanical properties showed that the physical properties of BC-RSW were comparable with ordinary BC. The BC-RSW had strong inhibitory effects on both Gram-positive and Gram-negative bacteria. In conclusion, the wastewater produced by yellow wine enterprises could be directly used as an alternative medium for the sustainable biosynthesis of antibacterial BC in situ.

Uncovering the multiscale structure and physicochemical properties of starch extracted from naturally fermented mung bean liquid by wet milling

In this study, mung bean liquid (MBL) was prepared by wet milling and then naturally fermented for 0, 24, 48, 72, and 96 h. Afterward, the starch extracted from MBL was analyzed. The pH of MBL decreases from 6.54 to 4.91 during fermentation. Moreover, the mung bean starch (MBS) granules changed significantly with pitted surfaces, pores and channels. The particle size, molecular weight (Mw) and long chain amylopectin (B2) content of the MBS decreased, whereas the short chain (A) increased from 20.57% to 22.70% with increasing fermentation time. Natural fermentation had no effect on the crystalline type (A) of the MBS but increased the relative crystallinity from 26.53% to 29.23%. However, the intensity ratios of the 995/1022 cm-1 and 1047/1022 cm-1 FTIR spectra increased with fermentation time, reaching maxima of 0.95 and 0.80 after 48 h, respectively. In addition, Fermented MBS increased the trough viscosity (TV), final viscosity (FV), elastic modulus (G') and viscous modulus (G'') but decreased the peak viscosity (PV) and breakdown (BD). Thermal properties revealed that fermentation increased the gelatinisation enthalpy (ΔH) from 9.49 to 10.26 J/g.

Flavor and nutritional characteristics of surimi product with Lactiplantibacillus plantarum as a reinforcing starter culture

Considering the microbial injury that occurred during the prior salt-curing stage of fermented surimi product (FSP) production, Lactiplantibacillus was investigated as a reinforcing starter in the post-fermentation stage to enhance the flavor, nutritional and safety characteristics of FSP. The results indicated that the addition of Lactiplantibacillus significantly influenced microbial community structures, leading to notable shifts in the physicochemical properties and metabolite profiles. With an abundance of 86.56%, the reinforcing Lactiplantibacillus emerged as the dominant microorganism at 6 months post-fermentation, which correlated with a 20% increase in ester content, thereby enriching the flavor of FSP. Metabolite analysis revealed that while Lactiplantibacillus caused the degradation of dipeptides, it significantly increased the contents of amino acids, N-acetyl-amino acids and organic acids in FSP. Furthermore, biogenic amines and nitrites decreased by 17% and 37%, respectively. This study provides valuable insights into the implementation of reinforcing starter cultures to mitigate the effects of microbial damage in multi-step natural food fermentation.

Enhancing the formation of functional glucosinolate degradation products in fermented broccoli stalk by-product with lactic acid bacteria

Broccoli stalk by-product (BsBP) is rich in glucosinolates (GSLs). Its fermentation process is generally characterized by the degradation of GSLs and formation of bioactive isothiocyanates (ITCs), in which lactic acid bacteria (LAB) play an important role. The GSLs-degrading capacity of 61 LAB strains was investigated in vitro. Lacticaseibacillus paracasei YC5, Pediococcus pentosaceus RBHZ36, and Lactiplantibacillus plantarum ND1, with high potential to transform GSLs into ITCs, were screened. The functional GSL degradation products (total content of sulforaphane, indol-3-carbinol, and ascorbigen) increased 22.0–33.5 % compared to natural fermentation after 24 h when BsBP was fermented by the three screened strains in pure culture. LAB fermentation also helped to increase the quantity of indolic GSL degradation products in BsBP brine, suggesting that LAB fermentation promoted BsBP GSLs transformation into bioactive ITCs. The proposed use of the LAB strains characterized in this study provided a fermented BsBP and brine with high profile of functional GSL degradation products.

The Physicochemical and Nutritional Analysis of Coconut Oil (Cocos nucifera) Extracted from the Tall Tree Variety

Aims: Coconut (Cocos nucifera) known as the ‘tree of life’ is an ancient fruit belonging to the palm family Arecaceae family and the only species in the genus Cocos. This study aims to characterize and show the nutritional qualities of coconut oil from the tall tree variety. Methodology: The production methods include natural Fermentation, centrifugation, freeze-thawing, and solvent extraction. In physical and chemical properties, the moisture content, impurity, specific gravity, refractive index, oil yield, flash, fire, smoke point, melting point, thiobarbituric acid number, saponification, peroxide, iodine, and fatty acid value were analyzed and all fall within close ranges. Results: The fat-soluble vitamins ranged from 18.65 ± 5.09 (vitamin A), 4.28 ± 0.68 (vitamin E), 4.11 ± 3.11(vitamin D) and 1.03 ± 0.21 (vitamin K) all in mg/100ml. Mineral analysis shows that coconut oil contains calcium, zinc, and iron with concentrations of 2.53 ± 0.23, 1.21 ± 0.19, and 0.53 ± 0.13 in mg/100ml respectively. Fatty acid analysis shows that coconut oil contains lauric, myristic, palmitic, caprylic, oleic, capric, stearic, linoleic, and caproic acid of which lauric acid was the highest with a range of 48.40 ± 0.23. Conclusion: The result shows that coconut is a good source of nutrients and the fatty acids make it a good moisturizer.

Bioethanol production from pineapple fruit waste juice using bakery yeast

The declining oil production stemming from decreasing raw material reserves has clashes with rising demands and has created a supply-demand gap in the overall energy sector. Excessive consumption of fossil fuel oil exacerbates environmental issues, potentially leading to global climate change and increased natural disasters. Consequently, there are efforts in looking for alternate renewable fuel sources. The study included physical pre-treatment, natural hydrolysis, natural fermentation, fermentation of pineapple waste juice using bakery yeast, and subsequent distillation. The pineapple wastes produced juice with 12.67 °Brix and pH range of 3.16–3.18. The present study reports bioethanol production from pineapple waste mixed with bakery yeast (Saccharomyces cerevisiae) and pineapple wastes juice without bakery yeast, revealing that the yeast-amended mixture yielded bioethanol with alcohol content of 45 % compared to 36 % from pineapple juice alone. Re-distillation enhanced bioethanol content from 25 % - 45 %–85 % which aligns well with E85 fuel specifications, indicating bioethanol's suitability as fuel. Thus, bioethanol derived from pineapple fruit wastes presents a promising renewable energy solution. This study investigates the production of bioethanol from pineapple waste juice by comparing two methods: one using bakery yeast and the other without yeast. Both methods are conducted at room temperature to evaluate their efficiency and effectiveness in converting pineapple waste juice into bioethanol.

Solid-state fermentation with Bacillus subtillis co-cultured with probiotic Lactobacillus spp. enhances the bioactive peptides, nutritional and antioxidative potentials of tamarind seed

The effect of natural or controlled solid-state fermentation using single or mixed probiotic strains on the nutritional, bioactive and phytochemical constituents, and antioxidant activities of tamarind seeds was evaluated. Tamarind seeds were subjected to either controlled solid-state fermentation (37 °C, 72 h) using either Bacillus subtilis only or Bacillus subtilis co-cultured with probiotics Lactobacillus spp. (Lactobacillus fermentum, Lactobacillus rhamnosus GG, Lactobacillus brevis, and Lactobacillus delbrueckii) or natural fermentation while unfermented tamarind seeds served as control. The changes in the nutritional composition, peptide content, antioxidative properties (Ferric reducing antioxidant power (FRAP) and DPPH radical scavenging activities) and total viable count of probiotics in fermented tamarind seed were evaluated using standard methods. The peptide content, crude protein, fat, and fibre (100.19 mg/g, 51.35, 9.50 and 5.10%), and FRAP and DPPH (0.55 and 21.60%) in unfermented tamarind seed were significantly (p < 0.05) lower than fermented tamarind seed (271.00–308 mg/g, 12, 62.84–64.02, 12.21–13.11 and 6.01–6.90, and 1.42–2.92 and 26.66–35.70%, respectively), after 72 h of fermentation. The total viable count in the tamarind seed fermented with Bacillus subtilis only was 1.2 × 109 CFU/g while that co-cultured with probiotics ranged from 6 × 108 to 9.9 × 108 CFU/g after 72 h of fermentation. This study showed that a controlled solid-state fermentation using probiotics Lactobacillus co-cultured with Bacillus subtilis can significantly increase the peptide contents, and enhance the nutritional and antioxidant activities of tamarind seed while producing a condiment with significant probiotic potential.

Physico-chemical and functional properties of the lao fermented bamboo shoots (Nor Mai Som) inoculated with potential probiotic bacteria, Pediococcus pentosaceus BBS1 and Lactiplantibacillus plantarum BBS13

Pediococcus pentosaceus BBS1 and Lactiplantibacillus plantarum BBS13 strains were used as starter cultures in Nor mai som fermentation, to determine their physiochemical action, changes in their population, and in reducing cyanide compounds.When BBS1 and BBS13 were added to the fermentation set-ups, the pH values decreased from the initial pH of > 4.6 to pH 3.0 at the end of the fermentation period. The lactic acid levels in all treatments increased from the start of the process through the end of fermentation. During fermentation, lactic acid bacteria (LAB) and total viable count (TVC) populations in all Nor mai som samples showed similar counts of >9 log CFU/g in 24 h of incubation. Thereafter, the counts declined until the completion of the fermentation. Interestingly, Enterobacteriaceae were undetectable in all samples with inoculated starter cultures, whereas their growth in spontaneous fermentation was still found at 3.95 log CFU/g on day 3. Each treatment with the inoculated strains showed cyanide reduction in the range of 62.09 % to 90.31 % at day 10, compared to natural fermentation which registered a reduction of only 49.75 % for the same period. The findings herein indicate that BBS1 and BBS13 when used as starter cultures play a significant role in accelerating the process within 5 days compared to the treatment without inoculation which takes 15 days. BBS1 and BBS13 contribute to the improvement of product quality and may be economically advantageous in large-scale manufacture. This suggests the opportunity to utilize them in various products, including Nor mai som, livestock feeds, and plant-derived fermented products.

Physicochemical, Nutritional, and Antioxidant Properties of Traditionally Fermented Thai Vegetables: A Promising Functional Plant-Based Food.

Fermented plant-based products were gathered from various regions in Thailand and categorized into 10 types of traditional commercial vegetables. Different vegetable materials and natural fermentation methods influence the diverse physical, chemical, nutritional, and functional attributes of the products. All the traditionally fermented Thai vegetable samples collected showed physicochemical properties associated with the fermentation process, contributing to the nutritional and functional quality of the final products. Achieving consistent research results is challenging due to the intricate nature of food matrices and biochemical processes during fermentation. The roles of microorganisms, especially probiotics, are crucial in delivering health benefits through fermented foods. Traditionally fermented Thai vegetable foods contain high levels of total soluble solids, titratable acidity, and salinity in pickled shallot and ginger as a result of the natural fermentation process and the ingredients used. The research findings were confirmed using a hierarchical cluster analysis (HCA)-derived dendrogram pattern. The nutritional compositions, total phenolic contents, and antioxidant activities varied among the different types of vegetables. The correlations among lipid, protein, fiber, total soluble solid (TSSs), total titratable acidity (TTA), and salinity as potential biomarkers in fermented vegetable products were examined. The results suggest that traditionally fermented Thai vegetable products significantly impacted food research by enhancing the quality and preserving the authenticity of traditionally fermented Thai vegetables.

Evaluating the Dermatological Benefits of Snowberry (Symphoricarpos albus): A Comparative Analysis of Extracts and Fermented Products from Different Plant Parts.

Skin ageing is influenced by both intrinsic and extrinsic factors, with excessive ultraviolet (UV) exposure being a significant contributor. Such exposure can lead to moisture loss, sagging, increased wrinkling, and decreased skin elasticity. Prolonged UV exposure negatively impacts the extracellular matrix by reducing collagen, hyaluronic acid, and aquaporin 3 (AQP-3) levels. Fermentation, which involves microorganisms, can produce and transform beneficial substances for human health. Natural product fermentation using lactic acid bacteria have demonstrated antioxidant, anti-inflammatory, antibacterial, whitening, and anti-wrinkle properties. Snowberry, traditionally used as an antiemetic, purgative, and anti-inflammatory agent, is now also used as an immune stimulant and for treating digestive disorders and colds. However, research on the skin benefits of Fermented Snowberry Extracts remains limited. Thus, we aimed to evaluate the skin benefits of snowberry by investigating its moisturising and anti-wrinkle effects, comparing extracts from different parts of the snowberry plant with those subjected to fermentation using Lactobacillus plantarum. Chlorophyll-free extracts were prepared from various parts of the snowberry plant, and ferments were created using Lactobacillus plantarum. The extracts and ferments were analysed using high-performance liquid chromatography (HPLC) to determine and compare their chemical compositions. Moisturising and anti-ageing tests were conducted to assess the efficacy of the extracts and ferments on the skin. The gallic acid content remained unchanged across all parts of the snowberry before and after fermentation. However, Fermented Snowberry Leaf Extracts exhibited a slight decrease in chlorogenic acid content but a significant increase in ferulic acid content. The Fermented Snowberry Fruit Extract demonstrated increased chlorogenic acid and a notable rise in ferulic acid compared to its non-fermented counterpart. Skin efficacy tests revealed that Fermented Snowberry Leaf and Fruit Extracts enhanced the expression of AQP-3, HAS-3, and COL1A1. These extracts exhibited distinct phenolic component profiles, indicating potential skin benefits such as improved moisture retention and protection against ageing. These findings suggest that Fermented Snowberry Extracts could be developed into effective skincare products, providing a natural alternative for enhancing skin hydration and reducing signs of ageing.

Enhancement of poly‑γ‑L‑diaminobutanoic acid production in Bacillus pumilus by repeated pH shocks.

This study investigated the effect of pH on poly-γ-L-diaminobutanoic acid (γ-PAB) production by Bacillus pumilus in batch fermentation. In the natural fermentation where pH was not controlled, pH decreased from initial 7.0 to 3.0 in 18h and γ-PAB production was 428.6mg/L. In the pH-controlled fermentation, B. pumilus tended to proliferation at higher pH, while γ-PAB synthesis was favorable at lower pH, in which the optimal pH for γ-PAB production was 4.2, and γ-PAB yield reached 2284.5mg/L. Adopting a pH shock strategy which lasted 9h in the pre-fermentation phase, biomass (OD600) and γ-PAB yield of B. pumilus were obtained as 61.3 and 2794.6mg/L, respectively, which were 10.8% and 22.4% higher than those in batch fermentation without pH shock. Subsequent fermentation of repeated pH shocks showed that a further higher productivity could be achieved, in which the final OD600 reached 65.1, and γ-PAB production reached as high as 3482.3mg/L, which were increased by 6.2% and 17.1% compared with those in single pH shock, respectively. This study demonstrated that B. pumilus can synthesize more γ-PAB at suboptimal pH and provided a novel approach to regulate γ-PAB synthesis.

Microbial succession and flavor impact during natural fermentation of Tartary buckwheat sourdough

In this study, the succession process and driving mechanisms of microbial communities during the fermentation of Tartary buckwheat sourdough were explored using high-throughput sequencing and microbiome co-occurrence network analysis. A gas chromatograph–mass spectrometer (GC–MS) was used to monitor the dynamic evolution of flavor compounds in Tartary buckwheat sourdough at different fermentation stages. Using GC–MS and principal component analysis, 47 volatile compounds were identified as the main differential volatile compounds during fermentation. The predominant bacterial genera observed in the natural fermentation of Tartary buckwheat sourdough included Enterococcus, Weissella, Cronobacter, Lactococcus, and Pediococcus. Among fungi, Alternaria, Botrytis, Trichothecium, and Vishniacozyma were the dominant genera. The correlation analysis results revealed that Weissella, Pediococcus, Lactobacillus, Acinetobacter, and Vishniacozyma were the core functional microbes involved in flavor formation. Organic acids were the primary driving force for microbial succession. This study provides a better understanding of the relationship between microbial communities and volatile components in the natural fermentation process of Tartary buckwheat sourdough as well as useful information for improving the flavor quality of Tartary buckwheat sourdough products, thereby helping to choose starter cultures with flavor modulation ability.

Effect of bacterial diversity on the quality of fermented apple juice during natural fermentation of Hanfu apples

Effect of bacterial diversity on the quality of fermented apple juice during natural fermentation of Hanfu apples

An Investigation of Volatile Flavor Compounds and Lipolysis-Oxidation in Coppa as Affected by the Inoculation of Coagulase-Negative Staphylococcus during the Air-Drying Stage.

This study aimed to explore the effects of coagulase-negative Staphylococcus inoculation on flavor generation and lipolysis-oxidation in Coppa. Acid lipase, neutral lipase, phospholipase, and lipoxygenase (LOX) activities, as well as free fatty acids, volatile compounds, and sensory evaluation, were determined during the fermentation and air-drying processes of Coppa over 40 days. Staphylococcus carnosus and Staphylococcus xylosus or a combination of both strains were selected for this study, and natural fermentation was treated as a control. The results showed that Staphylococcus inoculation significantly enhanced lipase and LOX activities, and mixed strains had a superior effect. Palmitic acid, stearic acid, linoleic acid, and oleic acid were identified as the predominant free fatty acids in Coppa, with the mixed fermentation group exhibiting the highest contents. Acids, aldehydes, alcohols, ketones, esters, and phenols were found for the volatile compounds in Coppa. These findings thus suggested a positive role of Staphylococcus inoculation in activating lipolysis-oxidation and contributing to the flavor formation of Coppa during the air-drying stage.

Isolation and Identification of Fungi from Natural Fermentation of Guava Seeds

Guava, a tropical fruit, is high in macro- and micronutrients. However, only 50% of the fruit’s parts are edible, while the peel and seeds are considered agro-industrial waste. Ruminants may benefit from the nutritional value of dehydrated guava seeds. Guava seeds processed by natural/spontaneous fermentation could boost amino acid content while also preventing antinutritional factors. However, more research is needed to determine the benefits and safety of using fermented guava seeds. The purpose of this study was to investigate fungi isolated from the natural/spontaneous fermentation of guava seeds. Guava seeds were fermented using sterile water and banana leaves, and incubated at 37 °C for 72 hours. Isolation was done on PDA medium for moulds and YMEA medium for yeast. The isolated fungi were characterized by their colony and cell morphology, as well as their physiological characteristics. Results showed that the yeasts from the genera Schizosaccharomyces, Pichia, and Cryptococcus were found to be primary microbes that play a role in the fermentation process, while the moulds from the Mucoraceae family are likely spoilage microbes that appear after the fermentation period.