Showing 4 results for Fermentation
S. Saboory Halestani, S.h. Dokhani, G.h. Kabir, R. Shokrani,
Volume 4, Issue 4 (1-2001)
Abstract
Four cultivars of olive, Kalamata, Marri, Zard and Fishmi were obtained from Roodbar town and treated with two methods, natural and controlled fermentation with Lactobacillus plantarum as a starter culture at 25°C for 100 days. HPLC analysis experiments were conducted during the whole study period. A higher level (1.08% w/w) of total acidity was produced in Fishmi cultivar especially in the natural fermentation (0.8-1.1 g lactic acid/ml) than in other cultivars. Individual organic acids were determined by HPLC. Quantitative changes of organic acids in olives showed (P<0.0l) an increasing pattern of lactic and acetic acids during fermentation, but decreasing levels of malic and citric acids were revealed. The highest level of lactic acid (1.1% w/v) was observed in Zard cultivar and the type of fermentation had no effect on acid production. Malic and citric acids gradually disappeared during 50 days of fermentation period and this change was faster for citric acid during controlled fermentation. Malic acid did not follow this pattern.
J. Jamalian, Z. Sheikhol-Eslami,
Volume 8, Issue 1 (4-2004)
Abstract
Bread, the main staple food of Iran, imparts a major portion of energy and protein to urban and rural diets. Due to the use of flour with high extraction rate and improper fermentation of the corresponding dough, traditional breads have a rather high level of phytic acid. This has a detrimental effect on absorption and availability of minerals (Ca, Fe, Zn, Mg, Cr, Cu, etc.), carbohydrates, proteins and lipids, thus leading, for e.g., to iron-deficiency anemia in the present study, flours with different extraction rates (with known phytic acid content) were used for baking “Sangak” and “Lavash” breads and analyzed for phytic acid. Different levels of yeast, times of fermentation and extraction rates of flour were applied in the preparation of breads and their phytic acid levels were then estimated. Based on technological merits and residual phytic acid contents, breads prepared from two types of treatments were selected, their chemical composition, availabilities of iron and lysine as well as organoleptic characteristics were evaluated. Results indicated that under the employed conditions total destruction of phytic acid in “Sangak” and “Lavash” is rather impractical. A considerable reduction in phytic acid was noted: in “Lavash” bread using 2.5% yeast, 4 h of fermentation and a 50-50 blend of flours with 81.0 and 86.5% extraction rates and in “Sangak” bread with similar conditions (except for the flour which was a 50-50 blend of 86.5 & 97.5% extraction rates). Available lysine was similar in both of the selected breads compared to their respective references. Their available iron contents, however, were higher than their corresponding references (P ≤ 0.05 ). No significant differences were observed with regard to organoleptic evaluations of selected breads as compared to their references (P ≤ 0.05 ). Overall, the above-mentioned treatments are recommended for the baking of “Sangak” and “Lavash” breads.
R. Hojat Ansari, M. Hasanpour Asil, A. Hatamzadeh, B. Rabiei, S.h. Roofigari Haghighat,
Volume 12, Issue 43 (4-2008)
Abstract
Variations in theaflavin and thearubigin content during fermentation and the effects of these variations on brightness and total color in black tea were evaluated at the Tea Research Center in Lahijan in the year 2004. Percentages of theaflavin (TF), thearubigin (TR), total color and brightness were determined in two clones 100 and in the natural Chinese hybrid during flushing in the months of June, August and October and different fermentation time (30, 60, 90, 120 and 150 minutes). It is evident from the results obtained that apart from genetic differences in the clones under study, changes in climatic conditions during different periods of flushing and fermentation time can to a great extent influence the amount of TF, TR, total color and brightness in black tea. Results obtained also indicated significant interacting effects of clones, different flushing and fermentation times on the quality-determining characteristics of black tea. No significant correlations were found between TR and brightness however, significant correlations were found between other characteristics studied at the 1% probability level. On the basis of regression analysis with fermentation time (independent variable) and each of the characteristics studied (dependent variable), linear relationships were detected between fermentation time and brightness and TF content. Multi-variable regression analysis between brightness (dependent variable) and TF and TR (independent variables) showed that more than 56% of variations in brightness in black tea was related to TF and TR. Also multi-variable regression analysis between total color (dependent variable) and TF and TR (independent variable) indicated that more than 43% of variations in total color in black tea can be attributed to TF and TR percentages
A Kochaki, A Sadeghi, F Shahidi, A Mortazavi, M Nasiri,
Volume 13, Issue 47 (4-2009)
Abstract
This study was intended to use the sourdough LAB containing specific starter cultures for Barbari bread production and reduction of its staling. For sourdough preparation, fresh microbial cells were collected by centrifugation from LAB cultures. Then 1.5% of flour (w/w) from these washed cells with the same amounts of wheat flour and tap water and 0.25% (w/w) active dry yeast extract, containing Saccharomyces cerevisiae were mixed. The effects of fermentation time (8, 16 and 24 hours), fermentation temperature (28, 32 and 36 ºC) and type of starter culture (Lactobacillus sanfransicencis, Lactobacillus plantarum and a mixture of both LAB) were analyzed in a completely randomized design with factorial experiment with 4 replications. Bread staling was determined by its measuring crumb hardness and specific volume in 1, 24, 48 and 72 hours after baking. Correlation between variables was obtained by multivariate regression, and regression models were exhibited. The results showed that sourdough had significant effect (p≤0.05) on reduction of Barbari bread staling at 1, 24, 48 and 72 hours after baking in comparison with control sample. Moreover, the sample prepared with Lactobacillus plantarum (24 h fermentation time and 32 ºC fermentation temperature) had the maximum specific volume and the least staling, 72 hours after baking.
