Showing 5 results for Chromatography
S.h. Dokhani, L. Rabiei Motmaen,
Volume 5, Issue 1 (4-2001)
Abstract
Physicochemical characteristics of potato (Solanum tuberosum L.) are very important for storage and processing qualities. The amount of reducing sugars (glucose and fructose) and organic acids at harvest, during and after storage is the most important factor. In this study, three potato cultivars (Moran, Marfona and Agria) were collected, dry cleaned and graded into three sizes. They were analyzed for specific gravity and dry matter content. Potato tubers were stored at 4°C and about 85% R. H. for 15 weeks and then reconditioned at room temperature (25±l)°C for 4 weeks. During the storage period of tubers, sugars (sucrose, glucose and fructose) were analyzed on a weekly basis, but citric, D-malic and D-pyroglutamic were analyzed on a monthly basis by high performance liquid chromatography (HPLC). Data were analyzed statistically in a completely randomized design with sampling and Duncans multiple range test.
The total sugar and organic acid contents of tubers significantly increased during the 15 weeks of storage at 4°C and decreased after reconditioning at room temperature. The size of tubers did not affect the accumulation of total sugars. Dry matter content and specific gravity of Agria tubers were higher than those of both Moran and Marfona. Also accumulation of reducing sugars was lower in Agria than in Moran and Morfona initially and after the storage and reconditioning periods. Therefore, Agria must be suitable for processing into chips or dry powder.
Sh. Dokhani, R. Beheshti,
Volume 7, Issue 4 (1-2004)
Abstract
The changes of main sugars and organic acids of Red delicious and Golden delicious apples from Semirom region in Isfahan Province were determined by high performance liquid chromatography (HPLC). The apples were harvested, graded and packed in three kinds of wood, car-board and perforated polyethylene film packages and stored for eight months at 0±0.5oC and 90 to 95% relative humidity for further analysis. Sucarose, glucose and fructose, as well as citric and L-malic acids were detected and quantified in all packed samples. The obtained data were analyzed with factorial experiment in completely randomized design and mean were compared by Duncan,s muliple range test. The results showed that fructose was dominant in both cultivars in all packages compared to other sugars. Golden delicious apples contained more sucrose and less glucose than Red delicious. All sugars decreased in packed apple samples during the storage period. The dominant organic acid of both cultivars was L-malic. Citric acid increased to its maximum level in Red or Golden delicious after one or two months of storage, respectively, and then decreased gradually by the end of storage period. In general, apples kept in perforated polyethylene films exhibited the best physiochemical properties during eight months of cold storage.
J. Amiri, M. Rahemi,
Volume 10, Issue 3 (10-2006)
Abstract
This research was conducted to investigate the changes of GA3-like substances in the stratified (0, 10, 20, 30 days at 10oC) and non-stratified seeds of two olive cultivars, namely ‘Arbequina’ and ‘Zard’. In the first experiment stratified seeds of these cultivars (10 g) were extracted with ethanol (80%), purified by ethyl acetate, and then separated by thin layer chromatography (TLC). To compare the biological activity of separated zones, lettuce hypocolyl assauy was used. The results obtained in this part of study indicated that the amount of GA3-like substances increased as the stratification period increased. In the second experiment extracts were made from different parts of non-stratified seeds of both cultivars. The result of the second experiment showed that the GA3–like substances of embryos of non-stratified seeds were higher than other parts of the seed.
A. Hosseinzadeh Colagar, A. Mostafaie, M. Motallebi, M.r. Zamani,
Volume 11, Issue 41 (10-2007)
Abstract
Plant pathogenic microorganisms produce a variety of enzymes capable of degrading different polysaccharides of the plant cell walls. Pathogens use these enzymes to penetrate and colonize host cells. Polygalacturonases are thought to be the first cell wall-degrading enzymes secreted by pathogens when they grow on plant cell walls. Oligogalacturonic acids with the polymerization degrees of 10 to 13 are intermediate products of pectin degradation by the action of polygalacturonases and are known to activate plant defense responses. PG- inhibiting proteins (PGIPs) present in the cell wall of many plants increase the stability of oligogalacturonic acids in the tissues by modulating fungal PG activities. These glycoproteins of the plant cell extracellular matrix retard the advancement of fungal hyphae, reduce tissue maceration, and prevent colonization of pathogen. In this study, Phaseolus vulgaris PGIPs were extracted from hypocotyle of Derakhshan and Naz bean cultivars. PvPGIPs were purified by afinity chromatography and analyzed by SDS-PAGE. Three major bands in the range of 47-55 kDa were detected. Average yield of The affinity-purified PGIPs was 1.68 mg per 100 gram of fresh bean hypocotyle. The inhibitory effect of PGIP was assayed on the PG activities of highly virulent isolates of Fusarium oxysporum (F15) and Ascochyta rabiei (IK04). The inhibitory activity of crude PGIP from Naz and Derakhshan cultivars on polygalacturonase activity of F. oxysporum was 18 and 28 units, respectively. These inhibitory activities increased to 40 units after purification. The inhibitory effect of crude PGIPs from both these two cultivars on PG activity of A. rabiei was 9 units, while purified PGIPs inhibited this PG activity to 18 and 29 units, respectively.
A. Mahmoodi Pour, M. Esna-Ashari, O. Karami, M. Hesari,
Volume 12, Issue 45 (10-2008)
Abstract
Resveratrol (5,3,4'- trihyroxystilbene) is a valuable polyphenolic compound which prevents cancer, heart and vascular diseases in human. In this research, the compound was extracted from leaf and fruit tissues of two Iranian grape cultivars (Rajabie Sefide Shiraz and Keshmeshie Ghermez) using a general extraction method with some modification, and analyzed quantitatively by High Performance Liquid Chromatography (HPLC). Resveratrol content in leaf and fruit of Rajabie Sefide Shiraz cultivar was higher than Keshmeshie Ghermez and its amount in the fruits of both cultivars was observed to be greater than their leaves. The accumulation of Resveratrol at the early stage of fruit growth (4 weeks after full bloom) was higher than the subsequent stages of fruit growth and development (8 weeks after full bloom and ripened fruit) in both cultivars. This compound gradually decreased from the beginning of fruit set to the complete stage of growth and development and reached the lowest level when the fruits were ripe. Leaves and fruits of both cultivars were treated with methyl jasmonate (1 mM), then the rate of resveratrol was measured after treatments. It was observed that the amount of this compound was significantly increased in treated samples when compared with the control however, the difference diminished later. The fruits of both cultivars responded better to the treatments 4 weeks after full bloom.
