ABSTRACT
The aim of this study was to investigate the characteristics of yogurt prepared with the addition of Persian shallot and probiotic bacteria. The effect of Persian shallot on the viability of probiotic bacteria (Lactobacillus acidophilus and Bifidobacterium bifidum) was evaluated. Furthermore, the antimicrobial effects of shallot and probiotic bacteria on Listeria monocytogenes and Escherichia coli species were investigated. The experiments were performed on days 0, 1, 7, 14, and 21. The results showed that the survival of lactic acid bacteria increased significantly in the presence of shallots (p < .05). The addition of two different probiotic bacteria to the yogurt samples inhibited the pathogenic bacteria. While E. coli bacteria had a 3-log reduction, L. monocytogenes did not grow at all in the presence of probiotic bacteria and shallots. Based on these experiments, it was concluded that the addition of shallots not only increased the survival of probiotic bacteria but also reduced the growth of food-borne pathogenic bacteria. In addition, the addition of probiotic bacteria increased the acceptance of sensory properties of yogurt samples.
ABSTRACT
Yogurt is a fermented food obtained by the bacterial fermentation of milk. In the present work, the effect of different concentrations (1, 3 and 5% w/w) of coriander (Coriandrum sativum) seed powder on physicochemical, sensory characteristics and viability of Bifidobacterium bifidum and Lactobacillus acidophilus of probiotic yogurt were investigated at 4 °C for 21 days. Laboratory-made yogurts were obtained by inoculating milk with yogurt bacteria (mixed culture of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) and two probiotic cultures (Lactobacillus acidophilus and Bifidobacterium bifidum). According to the results, the viability of B. bifidum and L. acidophilus increased in synbiotic stirred yogurts with 5% CSP (coriander seed powder) up to 9.15 ± 0.09 log CFU/g at 11 days of the storage period, whereas probiotic bacteria count decreased to 9.02 ± 0.01 by the end. Therefore, our results confirmed that the addition of probiotics and CSP powder improved the physicochemical and sensory characteristics of stirred yogurt and exerted a beneficial effect on probiotic bacteria.
ABSTRACT
One of the most significant challenges within production of probiotic products is the survival and functionality of probiotic bacteria during processing and shelf life. In this research, the probiotic bacterium Bifidobacterium bifidum was used as adjunct culture for the production of Iranian white cheese containing different percentages of Allium ampeloprasum L. ssp. iranicum Wendelbo extracts (1% and 2% in fresh and dried form). The effects of the plant extract on bacterial growth and sensory properties of the model cheese were investigated. The in vitro experiments showed that probiotic bacteria growth was influenced by the presence of the plant extract. The highest bacterial growth (Δ growth = 25.82%) was observed when the probiotic was cultured in the medium supplemented with 1 g/L of plant extract. At time 0, the cheese samples were characterized by a pH value between 5.7 and 6.3 and a probiotic concentration of about 9 log cfu/g. Results showed that after 45 d of shelf life, the cheese model containing 1% dry extract had the best survival of probiotic B. bifidum (7-8 log cfu/g) and the most appreciated sensory properties. The findings of this study support the idea that A. ampeloprasum extract, acting as prebiotic substance, exerts a beneficial effect on probiotic bacteria.
Subject(s)
Allium , Bifidobacterium bifidum , Cheese , Probiotics , Animals , IranABSTRACT
This study was conducted to investigate the microbial, chemical, and sensory quality of chicken drumsticks vacuum-packaged at 4 °C, using chitosan (CH) coating containing ethanol extracts and the essential oils (EO) of Elettaria Cardamomum. The treatments were stored for 16 days in cold conditions and investigated in three-day intervals. Total volatile base nitrogen analysis showed that, on the 6th day, the uncoated treatment showed unacceptable values, while treatments containing the EO and extracts stayed below the specified level even on the 16th day. In addition, during storage, the Peroxide values for the uncoated sample were higher than the documented for the coated groups. Results of the Thiobarbituric acid reactive substances index revealed that the sample containing the EO of E. Cardamomum is the best treatment. Regarding to pH on the 16th day, the microbial growth in the mixed sample was 0.46 units lower than the control group. Microbial analysis showed that coating significantly reduce the growth of all five groups of bacteria at 4 ± 1 °C; thus, on the 6th day, the differences between mesophiles, Enterobacteriaceae, psychrotrophic, and H2S-producing bacteria with the control group were 4.5, 4.5, 2.5, and 2 logs Cfu/g, respectively (p < 0.05). Furthermore, the lactic acid bacteria growth was completely stopped. Finally, it was found that adding EO and extracts could significantly preserve the sensory quality of the samples. Thus, it was concluded that vacuum-packaged CH coatings enriched with the extract and EO of E. Cardamomum can preserve the quality of chicken drumsticks during storage in refrigerators.
ABSTRACT
In this study, antibacterial, antioxidant, and anticancer effects of Cu nanoparticles (CuNPs) fixed on cellulosic walnut shell material were investigated. Firstly, three types of walnut shell-supported copper nanoparticles with various sizes (CuNP-WS1 15-22 nm, CuNP-WS2 60-80 nm and, CuNP-WS3 aggregated of metallic nanoparticles) were synthesized. Antibacterial properties of CuNPs were studied on three strains of bacteria; Staphylococcus aureus, Escherichia coli, and Listeria monocytogenes. DPPH (1, 1-Diphenyl-2-picrylhydrazyl) method was used to examining antioxidant properties. Cytotoxic effects of the synthesized nanoparticles on the cancer cell line were studied. Antimicrobial properties of CuNPs showed that these nanomaterials affect both Gram-positive and Gram-negative bacteria. The antioxidant properties of CuNPs increased significantly by increasing the concentration to 10%. CuNPs appeared to have a dose-dependent cytotoxic effect on K562 cells. However, the IC50 of the synthesized nanoparticles against the K562 (25.24 ± 5 µg/mL) cancer cells was lower significantly (P < 0.01) of the IC50 of these compounds against PBMCs (42.54 ± 6.2 µg/mL).
ABSTRACT
The aim of the current study was to investigate the effects of pomegranate peel extract (PPE) and chitosan-starch (CH-S) composite film incorporated with Thymus kotschyanus essential oil (TEO) on the shelf-life of beef during storage period of 21 days at 4 °C. The physico-mechanical parameters, the color and Fourier Transform Infrared spectra values of the films were determined. Changes in odor, color, pH, thiobarbituric value for lipid oxidation levels and Pseudomonas spp. total viable counts, lactic acid and Listeria monocytogenes were determined during the storage time. All treated films showed lower elongation, strength and transparency values compared with chitosan - starch (CH-S) group. Results showed that CH-S-PPE 1%-TEO 2% treatment had the highest inhibition effect against L. monocytogenes. The bacterial counts and lipid oxidation were successfully inhibited using PPE and TEO. CH-S-PPE 1% group containing up to 2% TEO had the best acceptable sensory characteristic. Beef samples wrapped with CH-S film containing PPE and TEO also had longer shelf life.
Subject(s)
Chitosan/chemistry , Oils, Volatile , Pomegranate/chemistry , Red Meat/analysis , Animals , Cattle , Edible Films , Food Storage , Listeria monocytogenes/drug effects , Plant Extracts , Pseudomonas , Red Meat/microbiology , Starch , Thymus Plant/chemistryABSTRACT
The present study aimed at extending shelf life of rainbow trout fillet. Fish and seafoods are the most valuable nutrients, however, high levels of moisture, free amino acids, unsaturated fatty acids, and the content of nutrients make them to be categorized as spoilable and unstable foods. The objective of this research was to study of the shelf life of rainbow trout fillets using Salvia officinalis L. extract. Chemical and microbial analyses were performed on treatments. The usage of hydro-ethanol extract of S. officinalis L. significantly decreased microbial growth in fish fillet and there were significant differences among concentrations of the extract (p ≤ 0.05). The presence of extract of S. officinalis L. resulted in an inhibitory effect on the formation of TVB-N and FFA in comparison with the control group at all analytical times. In conclusion, the shelf life of fish fillets was increased noticeably using extract at 4 ± 1 °C.
ABSTRACT
The impact of dipping in combination of propolis extract (PE) and chitosan (CH) coating enriched with Zataria multiflora essential oil (ZEO) on chemical, microbial and organoleptic properties of poultry meat was determined at 4⯰C. GC-MS analysis showed that the most components of PE were Dihydrochrysin (9.69%) and b- Pinostrobin (7.41%). The results of mesophilic total viable plate counts (TVC), lactic acid bacteria (LAB), Psychotropic bacteria and Pseudomonas spp. showed detectably lower (pâ¯<â¯0.05) microbial count in CH-PE 1%-Z 0.5% and CH-PE 1%-Z 1% samples at the last day of storage. The results of chemical characteristics (pH, total volatile base nitrogen (TVB-N), 2-thiobarbituric acid reactive substances (TBARS)) in all treated samples compared with the control, revealed that there is a synergistic effect between CH, PE and ZEO. In the sensorial assessment, treatments containing 1% PE- 0.5% ZEO and 1% PE- 1% ZEO were mostly acceptable by the sensory analyst. These results offer a successful approach that chitosan coating enriched with combination of ZEO and PE can be an improving method to reducing deterioration of fresh packed chicken meat.
Subject(s)
Chitosan/chemistry , Food Packaging , Lamiaceae/chemistry , Plant Oils/chemistry , Poultry Products , Propolis/chemistry , Animals , Chickens , Food PreservationABSTRACT
In the present study, the antioxidant and antimicrobial effects of essential oil (EO) and extract of Pimpinella affinis on the shelf life of rainbow trout during storage at refrigerator temperature based on three indicators of microbial, chemical and sensory quality parameters were evaluated. For this purpose, fish samples were stored in zein coatings containing 1.00% EO and 2.00% extract and in combination treatment containing 1.00% of each of them in refrigerator for 12 days. All of treatments were analyzed for microbiological count (Enterobacteriaceae, psychrophilic bacteria, mesophilic bacteria and pseudomonas bacteria) and chemical including pH, thiobarbituric acid reactive substances (TBARS), total volatile base nitrogen, peroxide value (POV) and free fatty acids (FFAs) and sensory (odor, color and texture) characteristics. Results showed that the highest levels of three factors including TBARS, POV and FFAs were related to the control sample and the least amount of these parameters was observed in EO and extract combination treatments. This effect of combined treatment was also observed in the reduction of total volatile basic nitrogen and pH parameters. Total bacterial counts during storage in fish treated with the extract and EO were remained below the acceptable level and microbial spoilage was significantly decreased compared to control. According to the sensory evaluation, treatments containing EO and extract showed improvement in this index compared to control treatment during storage. Based on the results of this study, it can be concluded that the EO and extract of P. affinis as active ingredients in zein coating successfully improve the quality and shelf life of the fish in the refrigerator.
ABSTRACT
Incorporation of natural ingredients antioxidants in edible fats can profitably affect their oxidative stability during production and storage. The purposes of the current work were to assess the antioxidant and antimicrobial effect of walnut kernel septum membranes hydroalcohol extract (WHE) in traditional butter (TB). Antioxidant characterization of the extract was screened through methods of DPPH, reducing power and total phenolic assays. After preparation of traditional butter from yogurt, WHE was incorporated into TB at three different concentrations; 0.05%, 0.1% and 0.5% and compared with a control, BHT and tocopherol treated samples (200 mg of BHT and tocopherol/kg). Microbiological studies (Staphylococcus aureus, Coliforms, Psychrotrophic bacteria, yeasts and molds) were done during 90 days of storage time. Changes in Anisidine value (AV), acid value, peroxide value (PV) free fatty acids (FFA), Schaal and Totox value were monitored at 45-day intervals. Sensory evaluation was done using 10 semi-trained panelists based on the 5-point hedonic scale. It was found that the total phenolic content of WHE was 368.86 mg GAE/g. The BHT had higher antioxidant activity than WHE inhibiting 92.3% of the DPPH radical at 600 µg/mL. Peroxide value of TB treated with tocopherol, BHT and WHE 0.5% was 0.29 ± 0.07, 0.39 ± 0.07 and 0.52 ± 0.04 respectively. Furthermore, the WHE incorporated butter has shown low levels of free fatty acids, Schaal and Totox value when compared to control treatment. The WHE 0.5% incorporated sample had the most antimicrobial activity and it inhibited the growth of all the microorganisms (except Staphylococcus aureus) used in the study. Among the treated TB, the samples treated with the control and WHE 0.05% had the highest sensory attributes score. The study showed that WHE could be an excellent natural origin of antimicrobial and antioxidant agents which can be used in butter.
ABSTRACT
Beef is susceptible to rapid spoilage due to its high amount of protein (18.00%) and moisture (72.00%). Food industries have recently found methods to extend beef shelf-life. The influence of beef dipping in hydro-alcoholic extract of sumac (SE) and chitosan (CH) coating incorporated with Zataria multiflora essential oil (ZEO) on microbial, chemical and sensory quality of beef was evaluated during refrigerated storage. Total viable counts (TVC), lactic acid bacteria, Pseudomonas spp., Enterobacteriaceae and yeasts-molds, total volatile nitrogen (TVN), thiobarbituric acid reactive substance values (TBARS) and peroxide value (PV) were founded to be significantly lower in all treatment groups compare to control groups during storage time. The highest level of antimicrobial effects induced by chitosan, SE 4.00% and ZEO. We found that in TVC (3.69 log CFU g-1 reduction compared with control group (sterile distilled water), Enterobacteriaceae (3.61 log CFU g-1 reduction) and lactic acid bacteria (2.67 log CFU g-1 reduction), respectively. Sumac gave a pleasant effect on sensory attributes and chitosan coating enriched with ZEO significantly improved sensory scores except for flavor factor. The results revealed the bio preservative properties of chitosan, hydro-alcoholic extract of sumac and Z. multiflora Boiss essential oil during refrigeration in normal packaging of beef.
ABSTRACT
Thyme Essential oils (EO) with antimicrobial and antioxidant properties are widely used in pharmaceutical, cosmetic, and perfume industry. It is also used for flavoring and preservation of several foods. Nowadays, packaging research is receiving a considerable attention due to the development of eco-friendly materials made from natural polymers such as starch and chitosan. In this study Thymus kotschyanus EO concentrations ranging from 0 to 2.0%, incorporated in starch-chitosan composite (S-CH) film were used. Antimicrobial and antioxidant properties significantly increased with the incorporation of EO (p < 0.05). Incorporating EO, increased total color differences (DE), yellowness index (YI) and whiteness index (WI) which were significantly higher than control and its transparency was reduced. Our results pointed out that the incorporation of Thymus kotschyanus EO as a natural antibacterial agent has potential for using the developed film as an active packaging.
