Assessment of In Vitro Antioxidant Capacity of Ginseng Extract and Its Effect on Inhibiting Lipid Oxidation and Physicochemical Properties of Cooked Ground Beef During Refrigerated Storage.

Research background: Ginseng is a medicinal plant that has anti-inflammatory, antidiabetic, anticancer, antiobesity, cardioprotective, antioxidant and antimicrobial properties. However, previous reports lack information on the effects of ginseng extract on the shelf life and quality characteristics of muscle foods. Thus, it is essential to determine the effects of ginseng extract on the meat model system to gain valuable insights to improve the shelf life and quality of muscle foods. Experimental approach: After determining the in vitro antioxidant activity of ginseng extract, the antioxidant effect of ginseng extract on cooked ground beef was investigated. In vitro antioxidant activity was determined using Fe(III) reducing antioxidant power (FRAP), 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging and total phenolic content (TPC) analyses, while lipid oxidation, chemical, microbiological and textural changes were determined during 30 days of storage. Cooking loss, proximate composition and textural features were measured after thermal processing. The pH, CIE colour parameters, thiobarbituric acid reactive substances (TBARS), lipid hydroperoxide (LPO), total aerobic mesophilic bacteria, total coliform bacteria, yeast and mould counts were determined during refrigerated storage. Results and conclusions: The mean values for FRAP expressed as Fe(II) equivalents ((4.7±0.2) mmol/g), DPPH (IC50=(12.11±0.09) mg/mL) and TPC expressed as gallic acid equivalents ((146.0±2.4) mg/g) showed a potential antioxidant capacity of ginseng extract. The addition of ginseng extract increased the cooking loss (p<0.05), but it did not affect the proximate composition of ground beef. It also caused a decrease in pH (p<0.05). Ground beef samples containing 1 % or more ginseng extract had lower TBARS values than control (p<0.05). In addition, LPO values of ground beef with ginseng extract were lower than the control after 30 days of storage (p<0.05). Total aerobic mesophilic bacteria, total coliform bacteria, yeast and mould were not found in any of the groups, except in the control, which had 3.35 log CFU/g total aerobic mesophilic bacteria at the end of storage. Novelty and scientific contribution: The results show that ginseng extract has an important activity in controlling lipid oxidation and can be used in the meat industry to extend shelf life and microbial stability.

In vitro antimicrobial activity of ginseng extract against Staphylococcus aureus, Salmonella Typhimurium and Listeria monocytogenes and its inhibitory effects on these pathogens in cooked ground beef.

Present study is focused on exploring in vitro antimicrobial activity of ginseng extract (GE) against Staphylococcus aureus, Salmonella Typhimurium and Listeria monocytogenes and their biofilm forming ability, then determining its antimicrobial efficiency during the storage (4 and 10 °C) of cooked ground beef contaminated with these pathogens. Results revealed that the minimum inhibitory concentration (MIC) for S. aureus, S. typhimurium and L. monocytogenes were 90, 70 and 40 mg/mL, respectively. GE was also able to inhibit biofilm production by S. aureus and L. monocytogenes, whereas S. typhimurium did not produce biofilm with or without GE application. On the other hand, the results of GE aplication in ground beef indicated that GE incorporation at 0.5% or more reduced S. aureus and S. Typhmurium counts in cooked ground beef at the end of 30 d storage at 4 °C (P < 0.05). Using 1% or more GE totally inhibited S. Typhmurium after 15 d storage at 4 °C (P < 0.05). However, GE application did not affect S. aureus or S. Typhmurium counts in cooked ground beef stored at 10 °C. Furthermore, incorporation of 0.5% or more GE generally inhibited L. monocytogenes growth in cooked ground beef at the end of storage at both 4 and 10 °C (P < 0.05). In general, pH was lower in samples with GE than those without GE regardless of differences in the type of tested pathogen, storage time and temperatures (P < 0.05). Although similar aw was generally obtained on processing day, lower aw was observed in GE containing groups at the end of storage for both storage temperatures (P < 0.05). Oxidation reduction potential (ORP) in all groups generally increased during storage at both storage temperatures (P < 0.05). In conclusion, our results demonstrated that GE has an important role in controlling growth of tested pathogens and may be used as a natural agent by the meat industry to inhibit the growth of food-borne pathogens in cooked processed meat products during storage.

Antimicrobial effect of dried koruk (Vitis vinifera L.) pomace against food-borne pathogens inoculated in kofte.

This study aimed to investigate the antimicrobial effects of various concentrations of dried koruk pomace (1%, 1.5%, and 2%) used in kofte formulations. To detect the inactivation effect of dried koruk pomace on food-borne pathogens, kofte samples were separately inoculated with Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium at high and low levels. During the storage period, E. coli O157:H7, L. monocytogenes, and S. Typhimurium counts of the samples inoculated with high levels were decreased in the range of 1.1-1.3 log CFU/g, 0.1-0.2 log CFU/g and 1.1-1.2 log CFU/g, respectively. When low inoculum levels were used, E. coli O157:H7 and S. Typhimurium counts of the samples were reduced to an undetectable level at the beginning and after 2 months of storage, respectively. Although L. monocytogenes counts of the samples were reduced to an undetectable level immediately, the counts were increased during storage till the end of the fifth month. The results indicated that dried koruk pomace was more effective in eliminating E. coli O157:H7 and S. Typhimurium than L. monocytogenes inoculated in kofte. The results suggest that using dried koruk pomace in kofte formulations is an effective method to improve the safety of the products, especially when low levels of contamination occur.

Effects of Aloe vera utilization on physochemical and microbiological properties of Turkish dry fermented sausage.

The study aimed to determine the minimum inhibitory concentration of Aloe vera extracts obtained by different extraction methods on eight strains from five different pathogens (Pseudomonas fluorescens, Listeria monocytogenes, Salmonella spp., Escherichia coli and Staphylococcus aureus) in the first phase and utilize Aloe vera extract in sausage processing in the second phase. Sausages were evaluated for thiobarbituric acid reactive substances (TBARS), physicochemical and microbiological properties. The first phase results indicated that the highest inhibition was determined in Listeria monocyctogenes 472 regardless of tested Aloe vera extract doses and extraction methods (Tukey HSD, P < 0.05). The highest Listeria monocyctogenes 472 levels reached was 0.38 log10 cfu/g. The second phase results revealed that Aloe vera containing treatments of sausage had lower pH than others after storage (ANOVA, P < 0.05). Dry matter, protein, fat and ash contents of sausage dough increased in all treatments after fermentation (ANOVA, P < 0.05). After 30 d storage, 48 and 45% TBARS reductions were obtained in sausages with only nitrite and those with only Aloe vera extract compared to control respectively. The lowest TBARS (68% reduction) were obtained in Aloe vera extract and nitrite incorporated sausages (Tukey HSD, P < 0.05). Result showed that the use of Aloe vera extract and nitrite combination in sausage formulation is a useful approach to control lipid oxidation in the product. Supplementary information: The online version contains supplementary material available at 10.1007/s13197-021-05183-5.

Assessment of the effect of marination with organic fruit vinegars on safety and quality of beef.

The aim of the present study was to determine the effects of organic fruit vinegars (blackberry, pomegranate, rosehip, and grape) used as marination liquids (MLs) on food-borne pathogens inoculated on beef, as well as on the quality characteristics (physical, chemical, microbiological and sensory properties) of beef during marination process at 4 °C for 24 h. In the first part of the study, meat samples separately inoculated with Salmonella Typhimurium, Listeria monocytogenes and Escherichia coli O157:H7 (≅6 log CFU/mL) were marinated in four different MLs and the count of S. Typhimurium, L. monocytogenes and E. coli O157:H7 on samples decreased in the range of 1.040-1.225, 1.420-1.913 and 1.232-1.435 log CFU/g, respectively. Marination with rosehip vinegar (MLR) was determined as the most effective treatment against all pathogens. In the second part of the study, proximate composition, color parameters, cooking yield, marinate absorption, pH, texture profile, aerobic plate count and sensory properties of marinated meat samples were determined. The moisture content of the samples marinated with grape vinegar (MLG) (73.50%) was found lower than of the samples marinated with other formulations (in the range of 75.95-76.65%) (P < 0.05). Marination by various MLs resulted in significant differences between the L*, a* and b* values of meat samples (P < 0.05). The hardness value of the samples was decreased by marination with MLR (P < 0.05) and was determined as 25.70 N. There were no significant differences between the meat samples marinated with the four different MLs in terms of cooking yield, marinate absorption and pH (P > 0.05). Aerobic plate count was reduced in the range of 0.589-0.950 log CFU/g for 24 h marination (P > 0.05). The highest sensory evaluation scores in terms of flavor were determined in meat samples marinated with MLG (P > 0.05). Therefore, different fruit vinegars used as MLs improved the safety and quality of meat at different levels.

Screening physicochemical, microbiological and bioactive properties of fruit vinegars produced from various raw materials.

In the present study, variety of fruit vinegars were investigated in terms of their physicochemical, microbiological and bioactive properties. Total phenolic and flavonoid contents were in the range of 933-1162 mg GAE/L and 66.64-470.86 mg/L in terms of catechin equivalents, respectively. During the evaluation of antioxidant activity via DPPH and ABTS assay, samples showed the activity as in the range of 0.047-0.302 and 0.413-0.885 µg TE/mL, respectively. The counts of AAB, LAB and yeast-mold were found in the range of < 2-6.32, < 1-5.39 and < 1-3.97 log CFU/mL, respectively. Antimicrobial activity of vinegars was tested against nine bacteria by broth microdilution assay. Most of the samples were found inhibitive against test cultures at concentrations between 3.12 and 6.25% (Minimum Inhibitory Concentration, v/v), while apple vinegar was inhibitive at higher concentrations. These results indicated the high potential of fruit vinegars as antioxidant and antimicrobial agents that could be used as functional food ingredients.

Effects of beta-glucan addition on the physicochemical and microbiological characteristics of fermented sausage.

The objective of this study was to investigate the effects of added beta-glucan (ß-glucan) levels on the lipid oxidation, physicochemical, microbiological, textural and sensorial properties of fermented sausage produced with various amounts of beef fat during fermentation and storage periods. To determine the effects of ß-glucan, twelve sausage treatments included four controls (no ß-glucan) with or without beef fat and starter culture addition and eight ß-glucan incorporated groups produced with addition of starter culture, various levels of ß-glucan (0, 1, 2%) and different levels (0, 10, 15, 20%) of beef fat were manufactured. The results indicated that addition of ß-glucan decreased thiobarbituric acid reactive substances (TBARS) values compared to control groups which had 20% beef fat (P < 0.05). ß-glucan enhanced the growth of lactic acid bacteria during fermentation and storage periods (P < 0.05). The addition of ß-glucan caused a decrease in water activity and pH values of sausage during the fermentation and storage (P < 0.05). Color values, fatty acid composition, protein, fat, moisture and ash content were not influenced by the use of ß-glucan (P < 0.05). Higher levels of ß-glucan in sausage formulation caused an increase in the hardness values of sausage (P < 0.05).

Isolation, identification and determination of technological properties of the halophilic lactic acid bacteria isolated from table olives.

Isolation, identification and technological properties of halophilic lactic acid bacteria (HLAB) from olive samples which were collected from different places in Turkey were examined in the present work. According to the genetic analysis of the isolates, it was determined that 42 (%57.53) Lactobacillus plantarum, 20 (%27.39) Lactobacillus acidipiscis, 7 (%9.58) Enterococcus faecium, 2 (%2.73) Lactobacillus alimentarius, 1 (%1.36) Lactobacillus farciminis, 1 (%1.36) Lactobacillus namurensis. L. plantarum, L. alimentarius, L. farciminis and L. namurensis were able to tolerate 8% NaCl. Twenty-seven isolates showed lipolytic activity between 0.2 and 1.09 U ml-1. Thirty isolates had pectolytic activity as 3.24-5.29 U ml-1. A total of twelve L. acidipiscis, L. alimentarius, L. farciminis and L. plantarum strains showed positive decarboxylase activity by decarboxylating tyrosine. Results indicated that L. plantarum Z64A, Z64B, Z66A, Z83B, Z100A and L. acidipiscis Z112D showed high salt resistance, no biogenic amine production, low pectinolytic and low lipolytic activity. HLAB are dominant bacteria in the fermented foods containing high levels of salt. There are no many studies about the presence of HLAB in table olives and their technological properties. The present work showed that HLAB isolates of L. plantarum, L. acidipiscis and E. faecium were the predominant species found in table olives collected from the western part of Turkey. The selected strains which have high salt resistance, low pectinolytic and lipolytic activity are potentially good candidates as starter culture source in olive fermentations.

In-vitro microbial production of conjugated linoleic acid by probiotic L. plantarum strains: Utilization as a functional starter culture in sucuk fermentation.

Twenty-three probiotic Lactobacillus plantarum strains were screened in-vitro to determine their ability to produce conjugated linoleic acid (CLA). L. plantarum AA1-2 and L. plantarum AB20-961 were identified as potential strains for CLA production. Optimum conditions for these strains to produce high levels of CLA were determined by evaluating the amount of added hydrolyzed sunflower oil (HSO) and initial pH levels in a nutrient medium. The highest CLA production was obtained in medium with pH6.0 and 2% HSO (P<0.05). Those strains were then used as starter culture in sucuk fermentation. Five sucuk treatments included a control (no starter culture), two sucuk groups with L. plantarum AA1-2 at the initial pH of 5.8 or 6.0 and two sucuk groups with L. plantarum AB20-961 at the initial pH of 5.8 or 6.0. Results indicate that L. plantarum AB20-961 produced higher amount of CLA in sucuk at initial pH of 5.8 and 6.0 levels during first 24h of fermentation compared with other groups. CLA isomer concentration decreased in all sucuk groups during the rest of the fermentation period (P<0.05) and remained quite stable during the storage. This study demonstrated that probiotic L. plantarum AB20-961 can be used in sucuk manufacturing without posing any quality problems.

Assessment of technological characteristics of non-fat yoghurt manufactured with prebiotics and probiotic strains.

Microbiological, physicochemical, aroma and organic acid characteristics of non-fat yoghurt incorporated with ß-glucan and probiotic Lactobacillus plantarum strains (AB6-25, AC18-82 and AK4-11) combination as adjunct culture were investigated during a 21 day storage period at 4 °C. Four treatment yoghurts contained 0.25, 0.5, 1 and 1.5 % ß-glucan. Treatments also included probiotic combination and commercial culture. Treatments were compared with three controls produced containing commercial culture, commercial culture and probiotic combination, and commercial culture, Lactobacillus acidophilus and inulin. The results indicated that ß-glucan promote the viability of lactobacilli. However, the addition of ß-glucan (except 0.25 %) resulted in enhanced syneresis (P < 0.05). In general, the use of 0.25 % ß-glucan had no significant effect on pH, fat, protein and organic acid content of non-fat yoghurt. The results obtained from this research demonstrated that the use of 0.25 % ß-glucan has no adverse effect on the characteristics of non-fat yogurt produced with probiotic combination.

Ultrasound in the meat industry: general applications and decontamination efficiency.

This review summarizes the findings of research focused on ultrasound as a "green", nonchemical technology in the meat industry to improve meat quality and safety. An overview of the importance of the decontamination in meat processing and microbial inactivation using ultrasound combined with some other applications is provided along with results of high power ultrasound studies which have been applied and adapted in the meat industry. The research results revealed that ultrasound by itself or in combination with other processing and/or preservation methods has a potential for improving the general quality, marination and tenderness of meat, preventing microbial growth and recontamination in meat and meat products as well as for the determination of defects in carcasses and cleaning process equipment. This review will provide an interpretation of ultrasound applications, an up-to-date summary of published articles, and an overview of the microbial inactivation in meat and poultry and their products by ultrasound. Since there is a need for not only a pathogen-free product but also a quality product; this review also can be accepted as a report on the results of research in the field of meat quality improvements with ultrasound applications.

Effects of probiotics on methionine choline deficient diet-induced steatohepatitis in rats.

BACKGROUND/AIMS: Intestinal bacteria induce endogenous signals that play a pathogenic role in hepatic insulin resistance and non-alcoholic fatty liver disease. Probiotics could modulate the gut flora and could influence the gut-liver axis. We aimed to investigate the preventive effect of two probiotic mixtures on the methionine choline-deficient diet-induced non-alcoholic steatohepatitis model in rats. METHODS: Two studies, short-term (2 weeks) and long-term (6 weeks), were carried out using 60 male Wistar rats. The 2-week study included six groups. Rats were fed with methionine choline-deficient diet or pair-fed control diet and were given a placebo or one of two probiotic mixtures (Pro-1 and Pro-2) by orogastric gavage. In the 6-week study, rats were allocated into four groups and were fed with methionine choline-deficient diet or pair-fed control diet and given a placebo or Pro-2. At the end of the 2- and 6-week periods, blood samples were obtained, the animals were sacrificed, and liver tissues were removed. Serum alanine aminotransferase activity was determined; histologic and immunohistochemical analysis was performed for steatosis, inflammation, protein expression of tumor necrosis factor-α, and apoptosis markers. RESULTS: In both studies, methionine choline-deficient diet caused an elevation of serum alanine aminotransferase activity, which was slightly reduced by Pro-1 and Pro-2. In the 2- and 6-week studies, feeding with methionine choline-deficient diet resulted in steatosis and inflammation, but not fibrosis, in all rats. In the 2-week study, in rats fed with methionine choline-deficient diet and given Pro-1, steatosis and inflammation were present in 2 of 6 rats. In rats fed with methionine choline-deficient diet and given Pro-2, steatosis was detected in 3 of 6 rats, while inflammation was present in 2 of 6 rats. In the 6-week study, in rats fed with methionine choline-deficient diet and given Pro-2, steatosis and inflammation were present in 3 of 6 rat livers. In both the 2- and 6-week studies, methionine choline-deficient diet resulted in tumor necrosis factor-α, proapoptotic Bax, caspase 3, caspase 8, and anti-apoptotic Bcl-2 expression in all rat livers. Pro-1 and Pro-2 treatment influenced protein expression involved in apoptosis and tumor necrosis factor-α in varying degrees. CONCLUSIONS: Pro-1 and Pro-2 decrease methionine choline-deficient diet-induced steatohepatitis in rats. The preventive effect of probiotics may be due, in part, to modulation of apoptosis and their anti-inflammatory activity.

Effect of probiotics on aspirin-induced gastric mucosal lesions.

BACKGROUND/AIMS: We aimed to investigate the role of a probiotic mixture, including 13 different bacteria, in the prevention of aspirin-induced gastric mucosal injury. METHODS: Forty rats were allocated into 4 groups: normal control, aspirin, probiotic control, and probiotic plus aspirin. Normal control and aspirin groups received 0.2 ml of skim milk by daily gavage for 14 days. Probiotic control and probiotic plus aspirin groups were administered 0.2 ml/day of probiotic mixture (1.3 x 10(10) cfu/ml) suspended in skim milk by daily gavage for 14 days. On day 15, gastric lesions were induced by administration of aspirin (200 mg/kg) in the aspirin and probiotic plus aspirin groups. Normal control and probiotic control groups were given saline. RESULTS: Pretreatment with probiotic mixture reduced aspirin-induced gastric damage scores (4.50 ± 0.43 and 2.60 ± 0.40, p<0.01) and exerted tendency of downregulation of proinflammatory cytokines elicited by aspirin (p>0.05). We also found that the probiotic mixture increased sIgA production approximately 7.5-fold in the stomach, and significantly reduced the malondialdehyde (MDA) increase in the gastric mucosa elicited by aspirin (p<0.001). Additionally, pretreatment with the probiotic mixture alleviated aspirin-induced reduction of mast cell count in the gastric mucosa. CONCLUSIONS: Probiotic mixture pretreatment attenuates the aspirin-induced gastric lesions by reducing the lipid peroxidation, enhancing mucosal sIgA production, and stabilizing mucosal mast cell degranulation into the gastric mucosa.

Preventive effect of probiotics and α-tocopherol on ethanol-induced gastric mucosal injury in rats.

The protective effect of a probiotic mixture of 13 different bacteria and α-tocopherol on 98% ethanol-induced gastric mucosal injury was evaluated. Levels of gastric mucosal pro- and anti-inflammatory cytokines, malondialdehyde, and secretory immunglobulin A were measured. Rats were allocated into four groups: control, ethanol, probiotic, and α-tocopherol. The control and ethanol groups received skim milk for 14 days. Probiotic and α-tocopherol groups were administered probiotic mixture suspended in skim milk and 100 mg/kg α-tocopherol, respectively, by daily gavage for 14 days. On Day 15, gastric lesions were induced by administration of ethanol 98% (1 mL) to all rats except those in the control group. Probiotic, but not α-tocopherol, seemed to inhibit ethanol-induced gastric mucosal tumor necrosis factor-α, interferon-γ, and interleukin-2 production (P > .05). Ethanol caused the elevation of mucosal interleukin-4 level (compared to the control, P < .05). Probiotic pretreatment significantly suppressed the ethanol-induced increase of gastric mucosal interleukin-4 levels. Pretreatment with either probiotic or α-tocopherol inhibited the ethanol-induced increase of mucosal malondialdehyde concentration (P < .01 and P < .05, respectively). Probiotic pretreatment enhanced the gastric mucosal secretory immunoglobulin A concentration (P < .001). In conclusion, probiotic mixture and α-tocopherol reduced ethanol-induced gastric mucosal lipid peroxidation, suggesting that they may be beneficial for gastric lesions induced by lower ethanol concentration.

Identification of lactic acid bacteria isolated from the fecal samples of healthy humans and patients with dyspepsia, and determination of their ph, bile, and antibiotic tolerance properties.

The research of novel probiotic strains is important in order to satisfy the increasing request of the market and to obtain functional products in which the probiotic cultures are more active and have better probiotic characteristics than those already on the market. In this study, the probiotic potential of Lactobacillus and Enterococcus strains isolated from human feces was investigated. One hundred seven strains of lactic acid bacteria were isolated from the fecal samples of 19 adult volunteers with stomach problems and the fecal samples of 12 healthy adult volunteers. The strains were identified by 16S rRNA analysis and examined for resistance to gastric acidity (pH 3.5) and bile salts (0.3% bile salt). The antibiotic susceptibility of the strains was also determined. The counts of lactic acid bacteria in the fecal samples ranged from 1.7 x 10(7) to 3.1 x 10(10) CFU/g. The species present in those samples were found to be Lactobacillusplantarum, L. fermentum, Enterococcus faecium and E. durans. Results indicated that L. plantarum (AA1-2, AA17-73, AC18-88, AK4-11, and AK7-28), L. fermentum (AB5-18, BB16-75, and AK4-180), E. faecium (AB20-98 and BK11-50) and E. durans (AK4-14 and BK9-40) showed good pH and bile tolerance. These strains are potentially good candidates for use as health-promoting bacteria.