Effect of packaging method, temperature and storage period on physicochemical and sensory properties of wild almond kernel.

This research was performed to monitor the effect of different temperatures (4, 25 and 35 °C) and atmospheres (vacuum, CO2 and normal air) on physicochemical and sensory properties of wild almond kernel during several weeks' storage. The color, moisture content and sensory analysis of the kernels, peroxide value (PV), 2-thiobarbiotic acid (TBA), conjugated dienes and trienes (CD, CT) and acid value (AV) of the oils were determined in defined time intervals. The results showed that the influence of temperature, time and type of atmosphere on the following parameters were significantly different. At all temperatures studied, AV, PV, TBA and CD/CT of oils from all samples increased with time which was less in the modified atmosphere packaging (MAP) compared with vacuum packaging (VP) and air atmosphere packaging (AAP). At the end of storage, the samples stored under AAP at 35 °C had the highest amount of PV (15.5 meq/kg), TBA (0.056 mg/kg) and CT (0.193 μmol/g), while the samples packaged under MAP at 4 °C had the lowest. Irrespective of packaging type, L* and b* values decreased during storage with a parallel increase of values a* resulting in gradual product darkening, especially in AAP. Sensory analysis also showed the decrease of overall acceptability during the storage among the three packaging systems. In conclusion, the use of MAP was the most effective method for protecting wild almond kernel from deteriorative reactions such as oxidation and hydrolysis.