Pizhūhish va Nuāvarī dar ̒Ulūm va Sanāyi̒-i Ghaz̠āyī (Mar 2014)
Effect of gelatin edible coating containing antioxidant agents on hardness, and color of roasted pistachio nuts
Abstract
The present study investigated the effect of gelatin coating, containing ascorbic-acid (AA:1% w/v) and Propyl-gallate (PG:100ppm), on the instrumental and sensory properties of roasted pistachio (hardness and color). Pistachio nuts packed and stored at 35°C and 50°C. The changes occurred in the textural properties, moisture content, color parameter (‘L’, ‘a’ and ‘b’ values) and sensory attributes of pistachio nuts were determined during 3 months of storage. The instrumental properties were correlated with sensory attributes. Gelatin-antioxidants coating significantly (P<0.05) increased instrumental and sensory hardness of pistachio. The moisture content decrease with time in gelatin-antioxidants and antioxidant-coated samples. However, this value in gelatin-coated samples was significantly lower than another sample. In sensory evaluation of color, the effect of treatments was significant. The image-processing result revealed that color parameter a* in green kernel beside L* and b* parameter in purple skin of kernel, was significantly increased in AA-gelatin coated pistachio. Using the gelatin-antioxidants coating, brought better maintenance to the green color of the kernel (the ∆E* factor lower than control sample) while it decreased the red-purple color of kernel skin (more ∆E* factor). The results indicated that there are strong relationships between the instrumental and sensory hardness values, but sensory and instrumental color values had a weak correlation with each other.
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