Hakan Kuleasan

The Effects of Pasteurization, Ultraviolet Radiation and Chemiclal Preservatives on Microbial Spoilage and Scent Composition of Rose Water

Damask Rose (Rosa damescena Mill.) is the major rose species used for rose oil production. Rose water is the major subsidiary product obtained during the distillation process. Rose water has also commercial importance because of its usage as an ingredient in some processed foods and aromatherapy. Microorganisms cause souring and therapeutic effect losses of rose water during its storage. Various preservation techniques were applied in rose water for the prevention of microbial spoilage. The physical methods used for the preservation of rose water were pasteurization, and ultra violet treatment. Phenoxyethanol and sodium benzoate were used as chemical preservatives. After methods were applied, rose water samples were stored at room temperature and spoilage microorganisms such as bacteria, yeasts and molds were enumerated. The changes in the composition of essential oils of rose water samples were also determined. Any of the applications caused a significant change in aroma composition, while inhibiting the microbial spoilage.

Determining potential probiotic properties of human originated Lactobacillus plantarum strains

In this study, twenty Lactobacillus plantarum strains which were isolated from the fecal samples of humans were investigated in vitro for their characteristics as potential new probiotic strains. The L. plantarum strains were examined for resistance to gastric acidity in simulated gastric juice at pH 2.0, 2.5, 3.0, and 3.5. The growth of test cultures with different pH was monitored after 0, 10, 30, 60, 90, and 120 min of incubation using a spectrophotometer at 550 nm. At the same time, samples were serially diluted in sterile PBS, and counts of viable bacteria were determined by plate counts using MRS agar for each pH and time parameter. The strains were also examined for resistance to 0.4% phenol, production of H2O2, adhesion to Caco-2 cell line and antimicrobial activity. It was determined that the artificial gastric juice, even at pH 2.0, did not significantly change the viability of the cultures. Except L. plantarum AA1-2, all strains were detected at 8 ∼ 9 log10 CFU/g. It was found that all L. plantarum strains showed good resistance to 0.4% phenol, and only one strain (AC18-82) produced H2O2. Good adhesion of L. plantarum strains to Caco-2 cells was observed in this experiment. These selected strains also showed antimicrobial activity.

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.

Novel Strategies for the Reduction of Microbial Degradation of Foods

Abstract Microbial quality of fresh and dried foods and spices plays a key role in determining the shelf life of the product. Major cause of spoilage in food products are molds and yeasts. Molds may also produce compounds such as aflatoxins which can cause serious health problems. In addition to spoilage, contaminated vegetables and fresh-cut fruits can serve as a carrier to many infectious microorganisms such as cholera, hepatitis, and giardiasis. Spices and vegetable seasonings are also a potential source of bacterial contamination causing food spoilage. In addition to causing food-borne diseases, degradation of products causes economic losses in considerable amounts. Microbial contamination can be reduced through good agricultural practices, application of advanced processes, and packaging. The main source of microbial contamination of food products are soil, air, water, and human. Among these, air and soil are the major source of mold spores which are responsible from majority of food degradation. The number of spoilage microorganisms increase during inappropriate transportation and storage conditions. Postharvest process is also important to prevent further spoilage. Microbial contamination can be prevented by employing trained staff, application of proper storage conditions, and using advanced processes and packaging materials. Rapid detection of microbial contaminants with new technologies may also extend the shelf life and quality of fresh and processed foods, fruits, and vegetables and also reduce postharvest losses.