Journal of Food Technology and Nutrition
Year:2010 | Volume:7 | Issue:4 (28)|Papers Count:12

Introduction: In edible oil refining, either by chemical or physical process, the bleaching treatment is a critical step. The adsorbants used for bleaching can remove pigments and other impurities, such as soap, trace metals, phospholipids, and oxidation products. The removal of these impurities improves the sensory quality and the oxidative stability of the deodorized oil.Materials and methods: The aim of this study was to investigate the adsorption effects of three activated bleaching earths (Persian bentonite, Pakestanish bentonite and German tonsil 131) on color, peroxide value, soap, free fatty acid percent (FFA%), chlorophyll, induction period, trace metals, anisidine value and phosphorus in alkali- refined soybean, sunflower, canolla and palm oils.Results: The results showed that bleaching decreased colour, peroxide value, soap, chloroplyll, Fe, Cu, P, while the amount of acidity, anisidine value and induction period increased. Although the bleaching earths employed in this study had different chemical and physical properties, their effects on the oil components were insignificant and soyabean oil proved to be more responsive to bleaching by different earth.Conclusion: It might be concluded that interm of economy, availability and bleaching power, the Persian bentonite might be regarded as the most suitable earth.

Introduction: Vitex agnus-castus (VAC) as a plant in herbal medicine has been known since centuries ago. Recently the effects of this herb for treatment of Premenstrual Syndrome (PMS) and Menopause discomforts have been investigated and were found to be positive. In this research the effects of VAC leaf extract on the amount of the serum lipids have been studied.Materials and Methods: The mature male Charls river strain Rats (with about 210-250 gr. weight) were divided into 3 groups; first experimental group: 20mg extract, second experimental group: 40 mg extract, and third Sham group: 2 ml distilled water per Rat daily.The research was carried out for one month and during each day the experimental groups were fed VAC leaf extract and sham group distilled water. By blood - letting from rats’ hearts, the serum concentration of cholesterol and triglyceride were measured by enzymatic method. Data were analyzed by one way ANOVA, MANOVA and Tukey fellow up test at level of significance p<0.05.Results: The study showed that oral administration of the VAC leaf extract in male rats did not have a significant effect on the serum cholesterol in three groups compared with each other, and the serum triglyceride in both experimental groups compared with sham group did not have a significant difference, P>0.05. While in the second experimental group (high dosage) the serum triglyceride increased significantly compared with the first experimental group (low dosage), P<0.05.Conclusion: As in previous studies some compounds with chemical structure similar to steroid hormones like phytoestrogens and ecdysteroids that are capable of binding to estrogen receptors have been isolated from VAC. It is concluded that these compounds with a dependence on dosage related to these receptors have affected lipids’ metabolism.Furthermore, the existence of anti oxidant compounds such as flavonoids and iridoids were beneficial in the normalizing of serum lipid levels, and some compounds in this herb that bind to the receptors in hypothalamus and anterior pituitary with endocrine mechanism counterbalanced and regulated serum level of lipid that no significant differences in both experimental groups compared to the sham group were found.

Introduction: During the last few years, a large number of research projects have been conducted on optimization of drying process of mushroom slices to obtain high quality product with extended shelf life. One of the most useful pretreatments for drying is osmotic dehydration. The main advantage of this process is its influence on the principal drying method, shortening of the drying process, resulting in lower energy requirements.Considering that heat is not applied in this stage, osmotic dehydration offers higher retention of initial food characteristics, such as colour, aroma, nutritional constituents, and flavor compounds. The combination of pulsed vacuum osmotic dehydration (PVOD) and microwave drying of mushroom slices has been studied.Materials and Methods: The effects of some variables such as temperature (30-50oC), osmotic solution (brine 5-15%), contact time (60-180 min), vacuum pressure (500-700 mbar) on water loss and solid gain in osmotic dehydration of sliced button mushroom were studied. The osmotic dehydration carried out on the reduced pressure and optimization of dehydration process was done by response surface methodology with central composite design.Results: The analysis of variance showed that a linear model predicted well the experimental data. The applied pressure had the main effect on water loss and solid gain.Optimization conditions were based on the higher water loss and lower solid gain.Conclusion: Optimal conditions were 46oC for osmotic temperature, 7% for salt concentration, 85 min for osmotic time and 638.69 mbar for pressure system.

Introduction: This study was designed to evaluate and determine the antibacterial activity of date palm (Phoenix dactylifera L.) fruit and pit against multidrug-resistant staphylococcus aureus.Materials and Methods: Date fruits were obtained from a local date market in Iran. The pits were separated from the flesh and their ethanol and acetone extracts were prepared. Fifty six strains of Staphylococcus aureus were isolated from nosopharyngial of hospitalized patients. The antibiotical resistance of the extracts was determined using Kirby-Bauer method. Twelve multidrug-resistant of these strains were selected and antibacterial activities of the extracts were evaluated by disc-diffusion method.Results: The results showed that the extracts of date fruit did not have antibacterial activity against the bacteria tested, but the pit extracts affected some of the isolated strains. The acetone extract of pits had higher inhibition effect than their ethanolic extract.Conclusion: This study indicated that date palm pit extract, had an antibacterial activity against tested microorganisms and we can support the idea of proposing the use of this substance as a natural antibacterial agent in treatment of infected wounds and other diseases.

Introduction: Serum separation is one of the most important problem in ketchup industry .For this reason different hydrocolloid are usually used in ketchup formulation and carboxy methyl cellulose (cmc) is the most popular one however this isn’t effective in decreasing synersis and might have some allergic and carcinogenic side effects. Therefore natural hydrocolloid such as mucilage of mustard might be considered as a substitute for cmc.Materials and Methods: In this study cmc is replaced by different concentrations (0-1.5%) of yellow mustard powder (Sinapis Alba, Brassica Alba) and the effects on the particle size (by lazer diffractometer) and synersis (by centrifuge, 4600 g for 20 minutes) of the product were studied.Results: Samples with 1.5 % mustard showed the lowest amount of synersis (13.9%) and particle size (104.37) among the samples examined, also d43 of the samples containing 0.5 and 1.5 % mustard have decreased to 14 % and 17% respectively as compared to the control.Conclusion: According to the results high concentration of mustard has an effective role in controlling the synersis and decreasing the particle size.

Introduction: Pumpkin is a plant with oily seeds belonging to the Cucurbitaceae family.This study is concerned with the evaluation of physicochemical characteristics of oil extracted from different varieties of pumpkin seeds.Materials and Methods: In this research work six varieties of pumpkin seeds were subjected to oil extraction. The extracted oils were subjected to a series of physical and chemical tests consisting of fatty acid composition, refractive index, iodine value, saponification value, nonsaponifiable matter, colour, acid value, peroxide value and induction period determinations.Results: The extracted oils accounted for 34-47% of the total weight of the seeds. The fatty acid profile indicated that oleic and linoleic acids were the predominant mono and poly unsaturated fatty acids present, which is quite important in term of nutrition. One of the samples (D) due to the high oil content (45%), fatty acid composition and high resistance to oxidation (21.97 h) at 110oC might be regarded as the best sample.Conclusion: It was concluded that pumpkin seed oil due to its high content of mono and poly unsaturated fatty acids might be regarded as valuable oil for consumption.

Introduction: Sweeteners are one of the most important substances which are used in confectionary products such as chewing gums. Due to the problems associated with sucrose as food ingredient namely obesity, diabetic and its contribution to food properties namely texture, it is the aim of this research to examine the possibility of producing chewing gums with high fructose corn syrup (HFCS) or glucose syrups with DE42 and DE63.Materials and Methods: Sensory evaluation and tests related to the quality such as determinations of humidity, reduce sugar, sucrose, texture, taste, flavor and aroma were carried out on the samples.Results: The results were examined by using statistical pattern of random variables. In addition to compare the average variables, multi-dimensional Dunkan was applied. The results indicated that the chewing gum with HFCS might be regarded as superior while the one with glucose syrup; DE42, appeared to be in the inferior position among the samples examined.Conclusion: Application of sugar syrups beside sucrose causes a reduction in the sucrose consumption and at the same time improves quality characteristics of chewing gum.

Introduction: Meat is a rich nutrient matrix that provides a suitable environment for proliferation of meat spoilage microorganisms and common food-borne pathogens. In this study, the effect of irradiation on the meat microbiological quality and half life of minced beef during chilled storage were investigated.Materials and Methods: Samples of minced meat (n=20) were irradiated with doses of 2, 5, 7 and 10 KGy (cobalt-60, gamma cell 220) and evaluated for their microbiological quality up to 10 days.Results: The results showed that gamma irradiation reduced the number of microorganisms in all the irradiated minced meat samples, with 2, 5, 7 and 10 KGy and the half life of samples were increased considerably (p<0.01). In addition, the results indicated that there was a significant difference in the number of coliformes between untreated and irradiated samples (p<0.05). Staphylococcus aureus could not be detected in the irradiated samples with doses of 7 and 10 KGy.Conclusion: These results indicate that irradiation might be employed as an effective mean to inactivate common food-borne pathogens namely S. aureus and increases the half life of meat.