Lactobacillus casei-fermented milk as an inhibitor on selected foodborne pathogens

The aim of this study was to reduce the growth of vanB resistant Enterococcus faecium, vanA resistant Enterococcus faecalis, Staphylococcus aureus ATCC 43300 and methicillin-resistant Staphylococcus aureus- MRSA ATCC 25923, which are foodborne pathogens that cause the death of a significant number of people every year, by the presence of Lactobacillus casei. For this purpose, the development of pathogens (104 and 106 log cfu/ml) in milk fermented with L. casei (106 log cfu/ml) was followed under in vitro conditions for 72 hours. Moreover, the generation times of each pathogen and the lactic acid content of fermented milk were determined. It was determined that the development of all pathogens could be suppressed by the presence of L. casei considering the change in generation times and the number of pathogens during the 72 hour fermentation period. This effect was greater in samples containing 104 log cfu/ml pathogen compared to samples containing 106 log cfu/ml.

The Use of Olkuska Sheep Milk for the Production of Symbiotic Dairy Ice Cream

The aim of this study was to determine the possibility of using Olkuska sheep milk for the production of ice cream with probiotics and prebiotics. The study examined the effect of the storage and type of bacteria used for the fermentation of ice cream mixes and partial replacement of inulin with apple fiber on the physicochemical properties, viability of probiotic cultures and organoleptic properties of sheep’s milk ice cream stored at −22 °C for 21 days. The addition of apple fiber reduced the pH value of ice cream mixes before fermentation. In ice cream mixes and ice cream with apple fiber, the lactic acid content was higher by 0.1–0.2 g L−1 than in their equivalents with inulin only. These differences persisted during the storage of the ice cream. After fermentation of the ice mixes, the bacterial cell count ranged from 10.62 log cfu g−1 to 12.25 log cfu g−1. The freezing process reduced the population of probiotic bacteria cells in ice cream with inulin from 0.8 log cfu g−1 in ice cream with Lactobacillus acidophilus, 1.0 log cfu g−1 in ice cream with Lacticaseibacillus paracasei and 1.1 log cfu g−1 in ice cream with Lacticaseibacillus casei. Freezing the varieties with apple fiber also resulted in a reduction of viable bacterial cells from 0.8 log cfu g−1 in ice cream with L. paracasei and Lb. acidophilus to 1 log cfu g−1 in ice cream with L. casei, compared to the results after fermentation. The highest percentage overrun was determined in ice cream with L. paracasei and Lb. acidophilus. Ice cream with L. casei was characterized by significantly lower overrun on the 7th and 21st days of storage. Although L. paracasei ice cream had the highest overrun, it did not cause a significant reduction in the probiotic population during storage. After seven days of storage, the first drop differed significantly depending on the type of bacteria used for fermentation of the mixture and the addition of apple fiber. L. casei ice cream had a longer first drop time than L. paracasei and Lb. acidophilus ice cream. Partial replacement of inulin with apple fiber resulted in a significant darkening of the color of ice cream mixes. Depending on the type of bacteria used for fermentation, the addition of apple fiber decreased the value of the L* parameter. Ice cream mixes and ice cream with inulin and apple fiber were characterized by a high proportion of yellow. Partial replacement of inulin with apple fiber reduced the hardness of ice cream compared to inulin-only ice cream. Moreover, the panelists found that ice cream with inulin was characterized by a sweeter taste than ice cream with apple fiber. Moreover, the addition of apple fiber favorably increased the flavor and aroma perception of the mango-passion fruit. Therefore, the milk of Olkuska sheep could be successfully used for the production of symbiotic dairy ice cream.

Yogurt As A Functional Drink Development From Various Local Raw Materials Using Eucheuma Spinosum As Natural Stabilizer

Along with raising public awareness about health and increasing yogurt consumption, it is critical to improve the quality of the yogurt. The innovation of yogurt producing in terms of flavor variety is critical since it can entice consumers to consume yogurt. This innovation is possible through the use of high-nutrient plant components that have not been optimally exploited in the surrounding environment. The purpose of this study was to examine the quality of yogurt produced from a variety of raw materials and stabilized naturally using Eucheuma spinosum seaweed. This study used a completely randomized design with a single factor: the type of raw material utilized in the production of yogurt (corn, sweet potato, pumpkin, banana and pineapple). The parameters analyzed included total lactic acid content, pH, total lactic acid bacteria, bacterial viability, viscosity, and organoleptic qualities such as homogeneity and taste were examined using scoring and hedonic methods. The data were evaluated using an analysis of variance (ANOVA) with a significance level of 5%, and the significantly different data were further tested using an additional test of an honest significant difference (HSD). Results show that yogurt made from corn was the best treatment, with pH value of 4.28, total lactic acid content was 1.67%; viscosity was 74,67cP, total lactic acid bacteria was 11.02 log CFU/ml, the bacterial viability met the concentration as a probiotic drink with the decreasing number 0.21 log CFU/ml, scoring test homogeneity score was 3,21 (slightly homogenous), taste score was 3.08 (slightly sour) and hedonic score for homogeneity and taste were 3.29 and 3.25 respectively.

The Potential Effects on Microbiota and Silage Fermentation of Alfalfa Under Salt Stress

This study investigated the fermentation quality of alfalfa grown in different salt stress regions in China. Following the production of silage from the natural fermentation of alfalfa, the interplay between the chemical composition, fermentation characteristics, and microbiome was examined to understand the influence of these factors on the fermentation quality of silage. The alfalfa was cultivated under salt stress with the following: (a) soil content of <1%0 (CK); (b) 1–2%0 (LS); (c) 2–3%0 (MS); (d) 3–4%0 (HS). The pH of the silage was high (4.9–5.3), and lactic acid content was high (26.3–51.0 g/kg DM). As the salt stress increases, the NA+ of the silages was higher (2.2–5.4 g/kg DM). The bacterial alpha diversities of the alfalfa silages were distinct. There was a predominance of desirable genera including Lactococcus and Lactobacillus in silage produced from alfalfa under salt stress, and this led to better fermentation quality. The chemical composition and fermentation characteristics of the silage were closely correlated with the composition of the bacterial community. Furthermore, NA+ was found to significantly influence the microbiome of the silage. The results confirmed that salt stress has a great impact on the quality and bacterial community of fresh alfalfa and silage. The salt stress and plant ions were thus most responsible for their different fermentation modes in alfalfa silage. The results of the study indicate that exogenous epiphytic microbiota of alfalfa under salt stress could be used as a potential bioresource to improve the fermentation quality.

Effects of N Fertilization During Cultivation and Lactobacillus plantarum Inoculation at Ensiling on Chemical Composition and Bacterial Community of Mulberry Silage

As unconventional forage source, mulberry (Morus alba L.) has been cultivated to alleviate animal feed shortages. This study aimed to investigate the effects of N fertilization during cultivation and Lactobacillus plantarum inoculation at ensiling on the chemical composition and bacterial community of mulberry silage. Mulberry was separately cultivated under two N fertilization rates (N1, 390 kg/ha/year; N2, 485 kg/ha/year) in 2016–2019, harvested on 30 April (the first-cut) and 15 June (the second-cut) in 2019, and then chopped for producing small bag silage. The silage was treated without (control) or with L. plantarum (LP, a recommended application rate of 105 cfu/g on fresh matter basis). After storage of 60 days in dark room at ambient temperature, silage was sampled for analysis of chemical and microbial compositions. Higher (P < 0.05) final pH value and acetic acid content and lower (P < 0.05) lactic acid content were found in silage of mulberry under N2 fertilization, resulting in more dry matter loss than that under N1 fertilization. Compared with control, inoculation of LP at ensiling increased (P < 0.05) lactic acid content and decreased (P < 0.05) final pH value, acetic acid and propionic acid contents of silage, by advancing the dominance of Lactobacillus and reducing the abundance of Enterococcus and Enterobacter. In particular, inoculation of LP at ensiling decreased (P < 0.05) dry matter loss and butyric acid content of first-cut silage. In conclusion, inoculation of LP at ensiling could reduce the undesirable effects from high N fertilization rate during cultivation on silage quality of mulberry harvested at different growing seasons.

Ketamine ameliorates depressive-like behaviors in mice through increasing glucose uptake regulated by the ERK/GLUT3 signaling pathway

To investigate the effects of ketamine on glucose uptake and glucose transporter (GLUT) expression in depressive-like mice. After HA1800 cells were treated with ketamine, 2-[N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)Amino]-2-Deoxyglucose (2-NBDG) was added to the cells to test the effects of ketamine on glucose uptake, production of lactate, and expression levels of GLUT, ERK1/2, AKT, and AMPK. Adult female C57BL/6 mice were subjected to chronic unpredictable mild stress (CUMS), 27 CUMS mice were randomly divided into the depression, ketamine (i.p.10 mg/kg), and FR180204 (ERK1/2 inhibitor, i.p.100 mg/kg) + ketamine group. Three mice randomly selected from each group were injected with 18F-FDG at 6 h after treatment. The brain tissue was collected at 6 h after treatment for p-ERK1/2 and GLUTs. Treatment with ketamine significantly increased glucose uptake, extracellular lactic-acid content, expression levels of GLUT3 and p-ERK in astrocytes and glucose uptake in the prefrontal cortex (P < 0.05), and the immobility time was significantly shortened in depressive-like mice (P < 0.01). An ERK1/2 inhibitor significantly inhibited ketamine-induced increases in the glucose uptake in depressive-like mice (P < 0.05), as well as prolonged the immobility time (P < 0.01). The expression levels of p-ERK1/2 and GLUT3 in depressive-like mice were significantly lower than those in normal control mice (P < 0.01). Ketamine treatment in depressive-like mice significantly increased the expression levels of p-ERK1/2 and GLUT3 in the prefrontal cortex (P < 0.01), whereas an ERK1/2 inhibitor significantly inhibited ketamine-induced increases (P < 0.01).Our present findings demonstrate that ketamine mitigated depressive-like behaviors in female mice by activating the ERK/GLUT3 signal pathway, which further increased glucose uptake in the prefrontal cortex.

Nutritionally Enhanced Probioticated Whole Pineapple Juice

Nutritionally enhanced probioticated whole pineapple juice (WPJ, comprising juice of pineapple pulp and peel) beverages were produced by fermentation of WPJ with the probiotic bacterium Lactobacillus plantarum WU-P19. The 12 h fermented juice contained between 2.1 × 109 and 3.7 × 109 live cells of the probiotic per milliliter, depending on the beverage formulation. The beverage had a pH of around 4.1 and a lactic acid content of ~12.8 g L−1. It had a total sugar (glucose, sucrose, fructose, maltose) content of ~100.2 g L−1. During fermentation, some of the initial glucose and fructose were consumed by the probiotic, but sucrose and maltose were not consumed. The original WPJ was free of vitamin B12, but fermentation enhanced vitamin B12 content (~19.5 mg L−1). In addition, fermentation enhanced the concentrations of vitamins B2, B3, and B6, but the bacterium consumed some of the vitamin B1 originally present. From a nutritional perspective, the final probioticated beverage was a good source of vitamin B12, vitamin C and vitamin B6. In addition, it contained nutritionally useful levels of vitamins B1, B2, and B3. The calorific value of the final beverage was 56.94 kcal per 100 mL. The product was stable during 21-day refrigerated (4 °C) storage.

Production and Characterization of Exopolysaccharides from Loss Cooked Sweet Potatoes (Ipomoea batatas) by Lactobacillus Plantarum

The aim of the work was to produce and characterize the exopolysaccharides from loss cooked sweet potato (Ipomoea batatas) using fermentation with Lactobacillus. The cooked sweet potato was fermented according to the factorial design with the following factors: the time (21.51h-38.48h) and the amount of Lactobacillus (1.58*106-5*106UFC). Responses were represented by production yield, pH, and titrable acidity. Characterization of the exopolysaccharides was then done by determination of total sugars, solubility index and viscosity. The results show that the pH of unfermented cooked potatoes was between 6.23 to 6.63. The pH of fermented potatoes varies from 3.96 to 4.06. The lactic acid content was found from 7.75 to 9.9% for the fermented samples. The production yields are 1.90% for the samples fermented for 21.5 hours with 3.5*106UFC of bacteria and 5.62% for those fermented for 30 hours with the same volume of inoculum. The average viscosity of the products was 4mPas regardless of the fermentation time. Chemical characterization indicates glucose contents of 68.21 and 94.01% in fermented potato for 24h and 21h respectively. The solubility index gives values of 70.3 ± 0.16 and 88.11 ± 0.23 for fermentation times of 21h and 24h respectively. Results of this work indicated that cooked sweet potatoes ferment for 21h was a promising substrate for production of exopolysaccharides.

Selective Thermotolerant Lactic Acid Bacteria Isolated From Fermented Juice of Epiphytic Lactic Acid Bacteria and Their Effects on Fermentation Quality of Stylo Silages

The aim of the present study was to isolate and identify lactic acid bacteria (LAB) from fermented juice of tropical crops such as Napier grass, Ruzi grass, Purple guinea grass, Stylo legume, and Leucaena and their application to improve the quality of tropical crop silage. Fifteen strains of LAB were isolated. The LAB strains were Gram-positive and catalase-negative bacteria and could be divided into three groups, i.e., Pediococcus pentosaceus, Lactiplantibacillus (para)plantarum, and Limosilactobacillus fermentum according to the biochemical API 50CH test. Based on the analysis of 16S rRNA sequence, the strains isolated in the group L. (para)plantarum were distinguished. Two isolates (N3 and G4) were identified as Lactiplantibacillus plantarum. Three isolates (St1, St2, and St3) were identified as L. paraplantarum. In addition, the identification of other isolates was confirmed in the group P. pentosaceus (R1, R4, R5, R8, R11, and L1) and the group L. fermentum (N4, G6, G7, and N4). All selected strains were able to grow at 50°C. All LAB strains showed antimicrobial activity against Escherichia coli ATCC 25922, Shigella sonnei ATCC 25931, Pseudomonas aeruginosa ATCC 27853, and Bacillus cereus ATCC 11778. Four selected LAB strains (St1, St3, N4, and R4) were tested for their capacity to successfully ensile Stylo legume (Stylosanthes guianensis CIAT184). Stylo silages treated with LAB were well preserved, the NH3–N and butyric acid contents were lower, and the lactic acid content was higher than those in the control (p &lt; 0.05). The acetic acid content was the highest in R4-treated silage among the treatments (p &lt; 0.05). The crude protein (CP) content of St1-silage was significantly (p &lt; 0.05) higher than the others. The inoculation of thermotolerant LAB selected from fermented juice of epiphytic lactic acid bacteria (FJLB) was found to be highly instrumental to obtain well-preserved silage from the Stylo legume.