Showing 5 results for Shelf Life
A.r. Sadeghi Mahounack, F. Shahidi,
Volume 5, Issue 1 (4-2001)
Abstract
The antifungal effect of sodium diacetate on inhibiting the growth of some bread spoiling molds was examined both in culture media and in flat bread “In situ”. In the first step, the antifungal effect of different concentrations of sodium diacetate: 0, 1000, 2000, 3000, 4000, and 5000 ppm were examined against Aspergillus sp., Aspergillus niger, Rhizopus sp., and Penicillium sp.
The results indicated that as the concentration of sodium diacetate increased, the mold growth decreased. At 5000 ppm the mold growth was inhibited up to fifth day (the last day of experiment). Based on these results, the antifungal effect of different concentrations of sodium diacetate was evaluated in bread “In situ”. In this stage Aspergillus sp. was selected as the indicator mold. The results indicated that if 3000 ppm of sodium diacetate is used, not only mold growth is inhibited but bread staling can also be prevented. This concentration of sodium diacetate does not have any harmful effect on texture and flavour, and can increase bread shelf life up to four days. Higher concentrations of sodium diacetate can inhibit mold growth completely, but have negative effects on texture and flavour. Therefore, 3000 ppm of sodium diacetate is recommended for increasing bread shelf life.
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.
N. Zamindar, M. Shahedi,
Volume 10, Issue 3 (10-2006)
Abstract
To prepare a sheetable dough, potato granule and potato puree of Agria and Marfona potato-cultivars, corn flour, emulsifier ,shortening, water,starch, salt, garlic and pepper powder were used. Dough was sheeted to thickness of 1-2 mm and formed to desirable shape. These slices were baked at 125oC for 30 minutes. Prepared potato chips were packed in air or nitrogen atmosphere and stored in dark at 25oC. Peroxide value, bending strength and color of the samples were determined in 30 day intervals. Peroxide value was detected just at the end of the third month. Peroxide value in chips packed in nitrogen atmosphere was less than that in chips packed in air atmosphere. Atmosphere of packages had a significant effect on the bending strength of the chips (p<0.01). The bending strength of chips packed in nitrogen atmosphere was more than that of chips packed in air atmosphere. Storage time had significant effect on bending strength (p<0.01). Storage time and cultivar effects on lightness and darkness of chips (L in hunter lab system) were significant (p<0.01). Storage time and cultivar effects on yellowness and blueness (b) of chips were significant (p<0.05). Storage time, cultivar and packaging atmosphere had no significant effect on redness and greenness (a) of chips (p<0.05)
F Goodarzi,
Volume 12, Issue 46 (1-2009)
Abstract
Because of its tenderness, long distance between field and consumer locations and unsuitable condition of transportation, 30 – 40 percent of strawberry fruits is wasted during the transportation between field to markets. One of the recommended ways for cutting down the wastes of strawberry is application of calcium salts after harvest stage to increase the content of Ca2+ in fruit flesh. For this reason, the selected fruits were treated by immersing them in 0, 25, 50 and or 75 mmol/lit concentrations of CaSO4, CaCl2 or Ca(NO3)2 for 4 min. After drying in atmospheric tempetature, fruits were stored at 5°C for 5 and for 10 days. To evaluate the effect of calcium solutions on fruit quality, some quantitative and qualitative tests were carried out on them. The results showed that by increasing the concentration of calcium salts, the amount of acidity and calcium of fruits is significantly increased, but the percentage of mouldy fruits is decreased. In most cases, the 50 and 75 mmol /lit concentrations of CaSO4 showed similar effects. Among the different calcium solutions, Ca(NO3)2 had the best effect on improvement of fruit quality, such as increasing the calcium and firmness of fruit , but CaSo4 prohibited the moulding of fruits better than other solutions. By increasing the period of storage from 5 to 10 days, the amount of acidity and firmness decreased significantly, while mouldness percentage increased. The organoleptic test showed that when the concentration of CaCl2 and Ca(NO3)2 solutions is increased, the acceptability of treated samples is decreased by consumers. Because of the bitter taste, the least score was given to the samples treated by 75 mmol/lit concentration of Ca (NO3)2 solution. The panelists didn’t recognize any difference in taste between control and samples treated by 25 mmol/lit concentration of CaSO4 and CaCl2 solutions. None of the treatments showed initial attributes (tenderness and shape) of fruits after storage period. This method isn't recommended to increase the strawberrys' shelf life for home use, but it can be used for the ones which are to be consumed in food processing industries.
A Shaker Ardekani, M Shahedi, G Kabir,
Volume 13, Issue 47 (4-2009)
Abstract
Pistachio processing, such as production of pistachio butter, is one of the ways to increase the added value of pistachio. Pistachio butter is a paste containing mainly milled, roasted pistachio kernel and sugar. In this investigation, the effect of two emulsifiers (lecithin and mono-di glycerids) at three levels of 0.0, 1.0, 2.0%, on the oil leakage and the effects of BHT as an antioxidant at three levels of 0.00, 0.01 and 0.02% on the peroxide values of pistachio butter and paste after 4 months storage at 20 °C were studied. Each experiment was performed in triplicates. Rheological and organoleptic tests were performed on the finished products. The results were statistically analyzed by a completely randomized Design and by making comparisons between the means via multiple range Duncan's test (P <0.05). Roasting of the pistachios at 110°C for 15 min was the best condition as determined by taste panelists. Moreover, addition of 15-25% of sugar in butter formula, received the best score by the panelists. The results of organoleptic tests showed that the sample containing lecithin and mono-diglycerides had the least leakage of oil. Based on the results, pistachio butter produced in this investigation received higher score in terms of flavor and texture than industrial pistachio butter in the market. Results also showed that addition of BHT had a significant effect on shelf life of pistachio butter. Rheological experiments showed that pistachio butter produced in this investigation was 1.5 times softer than its industrial counterpart. The results indicated that the best formula for production of pistachio butter was 72.99 - 82.99 % roasted pistachio kernels, 15-25 % sugar, 1% lecithin, 1% mono di glyceride and 0.01 % BHT.
