Iranian Food Science and Technology Research Journal
Year:2007 | Volume:2 | Issue:2|Papers Count:9

Iced tea is a world popular beverage,for example about 80% of people in Italy and United States, consume iced tea as a thirsty-quenching beverage. However, it is also believed that iced tea contains health benefit components. Process of iced tea involved tea solid extraction and then mixing with edible acids, flavors, sugar or non-nutritional sweeteners. In this research, regarding to the demand market for new beverage, the possibility of production iced tea beverage using green tea leave was investigated and was extracted under predetermined conditions. The effects of extraction temperature and time on the extractability were examined. The results of extraction at various temperatures in sample demonstrated that the extracted solid yield increased steeply during the first 5-10 min of extraction, but gradually in next 10-30 min and after 30 min the extraction continued slowly. Tea cream and haze extract was also determined using gravimetry and spectrophotometric methods, respectively. The extraction components, which cause tea cream and haze formation in extract increased with increasing of temperature. A sharp increase was observed when extraction temperature increased from 50 to 60oC. There was no significant difference (p<0.01) between treatment regarding tea cream and haze formation between temperatures 40 and 50oC, but above 50oC was different significantly. Haze was significantly correlated to the tea cream in each extract. The linear regression coefficient for green tea leave extract was R2=0.969 (p<0.01). Iced tea beverage was flavored with different essential oil and then that acceptability was evaluated by sensory panel analyzed with multiple comparison method. A standard physical and chemical experiment, haze changes for beverage during storing was monitored for 2 months. The results indicated that produced iced tea beverage (p<0.01) was stable.

Carotenoids are the main pigments of tomato, of which 93% is lycopene. Lycopene has desirable physiological effects in human sush as cancer prevention. Recent years, because of harmful side effects of synthetic colouring agents used in food products, employing of natural food colouring agents has become very important. In this research firstly, solvent extraction method was used for tomato carotenoids extraction. The optimum conditions for solvent extraction method was a mixture of solvent (n-hexan, ethanol and acetone with ratio of 1:1:2), boiling temperature (50oC), extraction time of 6 hours and equal ratio of solvent volume to tomato sqwash (crushed tomato after removing of skin and seeds). After extraction of tomato carotenoids, applicability of the extracted colour was considered by using the colour in sausage (13.977, 9.501 and 7.03 gr colour per 100 Kg sausage) and ice cream (4.21, 8.42 and 12.63 gr colour per 100 Kg ice cream). The best percentage of the added colour to those products was determined by performing of a taste panel. Finally, the stability of the colour in the products was examined by storing them at 0-4oC (for sausages) and -21oC (for ice cream) and their colour changes were measured by Hunterlab Colorimetry System. Results of sensory evaluation showed that addition of 9.501 gr of extracted colour per 100 Kg susages and 8.42 gr of extracted colour per 100 Kg ice cream are acceptable for consumers. From viewpoint of colour changes of surface and cross section of susages, there was significant difference between first and second period of storage, but there was no significant difference between third and forth period of storage (P<0.01).

The aromatic plants are rich in essential oils characterized by a notable antimicrobial activity. For this reason, these substances can be used to delay or inhibit the growth of pathogenic or spoilage microorganisms. In this study, Log Probability percentage (Log P%) of growth of the Clostridium botulinum type A spores in Brain Heart Infusion (BHI) broth as affected by various levels of Zataria multiflora boiss essential oil (0.0, 0.03 and 0.06%), pH (7.4, 6.5) and temperatures (35, 25oC) during 30 days of storage was evaluated. The Log P% of C. botulinum in BHI broth with 0, 0.03 and 0.06% essential oil , pH 7.4 at 35oC was 1.74 (CN=1.82), -1.26 (CN=1851) and –3.26 (CN=179888) and at 25oC was 1.04 (CN= 9) , -2.62 (CN=18281) and -3.26 (CN=179888) respectively and with 0, 0.03 and 0.06% essential oil, pH 6.5 at 35oC was 1.04 (CN=9), -2.26 (CN=18281) and -2.92 (CN=82419) and at 25oC was 0.73 (CN=18), -2.92 (CN=82419) and -3.26 (CN=179888) respectively. Based on these results, the Log P% of growth of C.botulinum was decreased by increasing the concentration of essential oil, decreasing the pH level and temperature.

High performance liquid chromatography (HPLC) with UV-visible detection was applied to identify adulterated saffron prepared by adding styles colored with the natural colorants extracted from saffron petals, safflower, madder and red beet to the pure saffron. The chromatograms of the methanol-water (50%, v/v) extracts of pure and adulterated saffron was obtained using a Nucleosil RP C18 column (5 mm) and a linear gradient from 20 to 80% methanol in water in 60 min with the flow rate of 1 ml min-1 at temperature 30oC. Two-way analysis of variance (ANOVA) was then applied to the HPLC data of the extracts of pure and adulterated saffron at the assayed wavelengths, 520 (or 254), 402 (or 254), 260 and 535 (or 440) nm and the presence of styles colored with the colorants of saffron petals (>9.1%, w/w), styles colored with the colorants of safflower (>14.3%), styles colored with the colorants of madder (>9.1%) and styles colored with the colorants of red beet (>14.3%) in saffron were significantly identified, respectively.

In these study conditions of refinement of clarified sugarcane juice including temperature at 3 levels (50, 60 and 70oC) and pressure at 4 levels (0, 0.5, 1 and 1.5 bars) by micro-filtration membrane technology was investigated. The raw sugarcane juice primarily was pre-filtrated with lime and then the obtained juice (clarified juice) processed by ceramic micro-filter membrane (0.2 micrometer). Investigated characteristics were included purity, turbidity and color. The results shows that the effects of different conditions of process with micro-filtration in studied temperatures and pressures on reduction of turbidity and color were significant at probably < 1% and probably < 5% respectively. Finally, 70oC temperature and 1.5 bar pressure were determinate as optimum conditions for ceramic micro-filtration. Membrane process at 70oC and 1.5 bars reduced turbidity and color of clarified juice 56.25% and 6.49% respectively and increased 0.87 units of purity.

nowadays, food industries by- product is one of the best choice for functional and novel food products. Bitter compound is the main problem to use lemon juice by-product.In this study, press peel and clarifier pulp residues were used to produce marmalade and drink.The vacuum method was proved to be the best debittering process.This pulp contains considerable amount of pectin and acid which appropriate for marmalade and drink.The results showed that considerable decrease of essential oils and bitterness, which confirm noticeable efficiency of this method. Debittering for 15 and 45 minutes under vacuum conditions reduce 50% and 88% of essential oils respectively. Processing more than 45 minutes had no effect on essential oils reduction.In addition, there was no significant differences in vitamin C between various treatments. Pulps debittered were used in marmalade and soft. These products scored by taste panel groups.

In recent years immense interest has been focused on the use of solar dryers especially when taking into consideration economical and ecological aspects and increasing in fuel costs. The aim of this study was to compare the qualitative factors of raisins made by five different drying methods. At the first step, pretreatments were applied to grapes (Var. Sultanas) and then the grapes were dried by five methods, including open-sun drying, shade drying, drying by industrial cabinet dryer and two different modes of solar drying namely mixed and indirect type. The shortest drying time was obtained with industrial cabinet drying, but mixed and indirect solar drying were more effective than open-sun drying and shade drying. Moisture content, acidity, sensory properties (color, texture, flavor and overall acceptance) and microbial level of the produced raisins were determined and compared. The texture of the raisin samples was evaluated by texture analyzer device as well. The color of the samples was measured and analyzed by a novel digital imaging method for measuring color of foods.The results indicated that the solar dryers were not only able to produce raisins similar to other drying methods but also the raisins produced by these dryers were in some qualitative factors (consumers overall acceptance and color) better than the other raisins.