نشریه پژوهش های علوم و صنایع غذایی ایران
سال ششم شماره 2 (پیاپی 12، تابستان 1389)

On of the most important of sugar beets quality is amount of sodium and potassium, because this compounds are strongly molassogenic and reduction of yield. So, attention on reasons that change this compound in sugar beets and consequently in produced juice are very important. In this study, effect of size of sugar beet (obtained from different areas) on changes of sodium and potassium are investigated. Sugar beets that obtained from 3 areas, are sorted (big size, medium size, small size and mixed size) and stored during 18 days industrial silo in Shirvan sugar factory. The results shown that amount of sodium and potassium related to cultivation areas and during storage amount of this compound change with size of sugar beets inversely. Namely, increasing of this compound in small size of sugar beets were more than others.

Thymus vulgaris is a plant from Lamiasceae family. The antimicrobial activities of T. vulgaris essential oil and extract depend on the phenolic compounds like carvacrol, thymol, γ-terpinene and p-cymene, which are reported to have antibacterial properties. In this research the antimicrobial effect of different concentration (0, 0.1, 0.2, 0.4%)of Thymus vulgaris extract was studied on Salmonella enteritidise PT4 presence mayonnaise at two different temperatures (4oC and 25oC) during storage time. This test was evaluated as a completely randomized factorial design with 3 replicates and the models were shown using RSM. The results showed that the antimicrobial effect of T.vulgaris extract was higher for the mayonnaise kept at 25oC. This effect increased with increase in concentration of extract. These concentrations of T.vulgaris extract didn’t have any unfavorable effect on the sensory parameters in mayonnaise.

Novel edible emulsified films were made using pistachio globulin protein (PGP) and palmitic fatty acid at concentrations of 2, 4, and 6 % w/w protein by Tween-80 and homogenization technique. Addition of palmitic acid to the PGP filmogenic solution resulted in great reduction of WVP in the emulsified films (37-40 %). Concentration of palmitic acid did not create significant difference (P>0.05) among WVP of the emulsified films. The WVP decreased as function of palmitic acid concentration. Water solubility of PGP films was 44.8 % and slightly decreased in the emulsified films. Oxygen permeability of the emulsified films were lower than the PGP films, but the differences were not significant (P>0.05). Tensile strength and elongation at break of the emulsified films were diminished as a result of palmitic acid addition. Incorporation of palmitic acid led to produce the opaque films, which opacity increased as function of palmitic acid concentration. Glass transition temperature (Tg) was determined by differential scanning calorimetry. The Tg of the PGP film revealed at 127.19 °C and was not affected by palmitic acid.

Lysine is nutritionally essential for humans and animals. It cannot be synthesized biologically in body. Children and growing animals have a high requirement of lysine, since it is needed for bone formation. Therefore, it must be added to food and feed supplement to improve the protein quality. In addition, lysine has some pharmaceutical applications in the formulation of diets with balanced amino acid composition. Chemical, enzymatic and biotechnological processes have been used to synthesize lysine. However, biotechnological methods (fermentation) seem to be the most economical and practicable means of producing lysine. In the present study, production of lysine by Brevibacterium linens PTCC 1603 from whey and molasses medium, in the purpose of using agricultural by-products as low-cost sources for production of value-added products, was investigated. Whey medium was prepared by hydrolyzing of lactose with HCl and molasses medium was prepared by addition of some chemicals to it. The production of lysine was examined qualitatively and quantitatively using ascending thin layer chromatography (TLC) and spectrophotometry. Results showed that lysine concentration in both media was increased significantly by the time. The highest concentration of lysine produced from whey and molasses media were 11.8 and 10.5 g.L-1, respectively. Increasing lysine concentration resulted in pH increment in molasses medium, while the pH of whey medium was decreased. After 6 days of fermentation, the amount of lysine in whey medium was significantly higher than in molasses medium.

Invert sugar is the result of sucrose of hydrolysis of sucrose by acid or enzyme, that is, the splitting of sucrose molecules into their glucose and fructose components.Invert sugar is used in different industries such as; food industry, soft drinks and Pharmaceutical, due to its special characteristics such as; sweetness level, moisture ability’s property, crystallization level and special taste and flavor.The level of inversion sucrose into glucose and fructose during hydrolysis, is effected time, temperature and pH that amount of produced glucose and fructose and as well as residual sucrose, is shown physical properties of sugar solution and quality of final inverted syrup. Experimental assay of hydrolyzed sucrose level along with variable methods such as enzymatic methods, HPAEC, HPLC, need long time for testing and high cost. This paper is applied in two fields, first, usage of variation in physical properties of industrial sucrose solution during inversion process such as physical properties of solution optical action and viscosity for fast determination inversion grade level in duration industrial process. Another field is survey of achieved invert sugar quality control with respect to temperature and time of inversion process to producing this by-product industrially in Iran. Results of this article are indicated amount of residual sucrose purity grade is decrease by inversion time in constant temperature that it measured with polarimetry method for determination inversion level. As result of inversion process, amount of viscosity of solution ratio to industrial sucrose solution had lower differences after initial severe loss. Quality of liquid sugar and produced inverted syrup applied viewpoint color, amount of final invert sugar, microbial characteristics and hydroxyl methyl furfural (HMP) with respect to time (1,2 and 3 hours) and inversion temperature (60,70 and 80 ºC), had been shown desirable quality of this product was in 60 and 70 ºC.

Inulin is widely distributed throughout the plant kingdom. It has been increasingly used in various foods due to its beneficial nutritional attributes as prebiotic ingredient. The Helianthus tuberosus could be a source of inulin, but scarce studies about its extraction exist. Ultrasound has attracted considerable interest in food science and technology due to its promising effects in food processing and preservation. The use of power ultrasound significantly improves the extraction of organic compounds contained within the body of plants and seeds. The mechanical effects of ultrasound provide a greater penetration of solvent into cellular materials and improve mass transfer. In some cases sonication increased the efficiency of extraction at lower temperatures producing a purer product in a shorter time. It seems that the application of ultrasound would be a promising method to enhance the extraction process. The objective of this study was to develop a set of optimum extraction conditions for Helianthus tuberosus with an aim towards improving inulin extraction yield. Experiment design employed central composite design (CCD) and response surface methodology (RSM). Determination of inulin content was measured with the difference between total carbohydrate and reducing sugars. Then, Inulin extraction yield (%) was calculated too. Based on canonical analysis, the optimal conditions for maximizing inulin extraction yield (91.26%) were at 45.95 °C for 31.44 min and amplitude of 100%.

Nowadays, using natural preservatives than synthetic ones is increasing. The present study was aimed to compare the effect of thyme (Zataria multiflora Boiss), onion (Allium cepa) and Ziziphora clinopodioides extracts on shelf-life extending of rainbow trout (Oncorhynchus mykiss) salted, vacuum packaged fillet, kept at 4°C. For this purpose fish filets were kept in 4 treatment: salted in brine 10% and vacuum packaged (V), V treatment with 1% thyme extract (T), V treatment with 1% Ziziphora clinopodioides extract (Z) and V treatment with 4% onion treatment (O) during 20 days at 4°C and were assessed by the changes of free fatty acid (FFA), tiobarbitoric acid (TBA), total volatile nitrogenic basic (TVB-N), total microbial viable count (TVC) and sensory assessments in 3 days ferequencies. In general the results showed that the value of FFA, TVB-N, TBA indices and TVC in investigated treatments was V> O> Z ≤ T during storage period

In this research the effect of substituting sugars (glucose and sucrose) by low caloric sweeteners (sorbitol and isomalt) on the physical properties of Gazz was studied. Textural properties of Gaz were investigated using Instron and micro-structure was studied by Scanning Electron Microscope (SEM). The results of texture investigation showed that the sample containing 25% of sorbitol and 65% of isomalt had the most similarity with the control sample. Increasing the content of sorbitol will soften the texture. Micro-structural studies showed that the texture of control sample has lots of bubbles inside, and this will decrease its density in comparison with dietary Gazz. No bubbles were observed when low caloric sugars were replaced which can be explained by the functional properties of sorbitol including its lubricant characteristics. This fact can led to a decrease in the density of the product in comparison with the control one.

Tofu (soy bean curd) is one of the most important vegetable protein products. It has been produced in the south-east of Asia for a long time. In the current research, the effects of pectin (0.1 and 0.2 % W/W of soya milk) and two types of coagulants (glucono delta lactone (GDL) and calcium chloride (CaCl2)) on the yield and quality parameters of Tofu were investigated. In comparison between control samples, the samples containing GDL had higher yield than those containing CaCl2. On the other hand, adding of pectin increased the yield of all samples and in contrast to control ones, in comparison between samples containing hydrocolloid, samples containing CaCl2 had higher yield in comparison to those containing GDL. There was no significant difference between control samples in L*- hunter parameter. Addition of pectin increased L* in all samples and magnitude of increase in CaCl2-Tofu was higher than GDL-Tofu samples. Compression test showed that texture of CaCl2-Tofu was firmer than GDL-Tofu. In both concentration, adding of pectin led to about a significant (P

Facultative Heterofermentative Lactobacilli (FHL) are responsible for enhancing unique flavour properties in traditional dairy products such as Lighvan cheese through biochemical mechanisms. In addition to saving domestic genetic resources, industrial production of semi-traditional dairy products is one of the major objectives of non starter microflora identification in indigenous dairy products. In this study performed on the Lighvan cheese at 4 months ripening period Based on morphologicaland biochemical methods were identified Lb. plantarum group (Lb.pentosus, Lb. plantarum, Lb. paraplantarum) and Lb. casei group (Lb. casei, Lb. paracasei). Moreove the development of the FHL in Lighvan cheese varied according to ripening time.