Walnuts with essential and unsaturated fatty acids from omega-3 group, are considered as one of the most important dried fruits with nutritional value. Genotypes 25 and 29 (superior walnut genotypes) were selected to investigate the effect of modified atmosphere packaging on the beneficial compounds of their kernels oil. Walnut kernels were packaged under modified atmospheric conditions into a 90-μ m metalized plastic. After the oil cold extraction and purification of walnut kernels, the quantitative and qualitative composition of fatty acids was measured. The percent of fatty acids, aflatoxin content, peroxide index, iodine value, acidity and sensory evaluation of samples were determined in the 0-day and during one year storage. The results showed that the unsaturated fatty acids content are predominant in walnut kernels oil, and the linoleic acid is the dominating fatty acid. The saturated fatty acids content was less than 10%. The aflatoxin content of genotypes 25 and 29 were measured 0 and 5 ppb, respectively. The moisture content and the peroxide value were determined 1. 55-4. 32% and 0. 48-4. 65 meqO2/kg, respectively. The highest level of acidity was observed in the 25 genotypes. The peroxide index, titratable acidity, and weight loss increased with the increasing of storage time, while the iodine value decreased. Totally, the packaged genotype 25 in the PA/PE/PA/PE/Aluminum foil films under modified atmospheric containing 5-6% O2, 15% CO2 and 79-80% N2 is recommended due to the high quality of chemical and organoleptic properties and the lack of aflatoxin in the walnuts kernel.

Background: With respect to the importance of meat preservation and various reports on different types of packaging and to compare the effects of Modified Atmosphere Packaging (MAP) and Vacuum Packaging (VP) on shelf-life of fresh bull meat, the present study was conducted in National Research Institute of Food Science (NRIFS) in 1997. Materials and methods: It was an experimental study. 96 samples were randomly packed in two groups of MAP and VP, then transported in chilled condition to NRIFS. Chemical and microbial tests were carried out. These included PH, TVN, TBA, total coliform, lactic acid bacteria, and pseudomonas count and looking for clostridiums. Sensory evaluation consisted of color, odor and weep tests. Results: Results have revealed that total microbial count was in standard range within the first 6 weeks for VP and the first 5 weeks for MAP technique. Other microbial factors including coliforms, lactic acid bacteria, pseudomonas were similar to total count, however, clostridiums were not seen. Deterioration was defined as the presence of 24 milligrams of volatile nitrogen in 100 gram of sample and was occurred at 6th week for VP and 5th week for MAP technique. TBA and PH were always in normal limits. There was no significant difference in TBA except in the second week (p<0.05). Sensory evaluation showed that VP offered better condition in odor and color, however, it had a bit more weep.Conclusion: The results showed that according to our existing facilities, VP is recommended for meat packaging.