Journal of Agricultural Engineering

The effect of storage period and type of packaging material on the popping behaviour of roasted makhana seeds was studied. Raw makhana seeds with a diameter of 9-10 mm were roasted using a batch-type primary roasting machine and tempered for 48 hours to bring the roasted seed moisture content to about 16% dry basis (d.b.). The roasted seeds were stored in 15, 25, and 80 μm Low-Density Polyethylene (LDPE), 110 μm Polypropylene (PP), 140 μm Biaxially Oriented Polypropylene (BOPP), and 60 μm Silver Laminate (SL) packets for six months. Popping experiment on the stored seeds was conducted at 15-days interval, and observations were made on popped makhana recovery, popping efficiency, colour of popped makhana, and expansion characteristics. The expansion ratio, expansion index, popped makhana recovery and popping efficiencies prior to storage were 2.37±0.22, 13.64±4.04, 48.53±0.50%, and 82.89±0.78%, respectively. Duncan's multiple range tests showed that the seeds packed in 15 μm LDPE packages maintained the quality and recovery up to 60 days only. The 80 μm LDPE packets, BOPP, PP, and SL packets were found effective in maintaining popping efficiency, recovery of popped makhana, and expansion ratio more than 81.44±0.70%, 47.95±0.43%, and 2.14±0.14, respectively with no significant colour change up to 135 days storage of the roasted seeds. Significant changes in colour values of popped makhana were observed after 135 days of storage and a* value increased whereas L* and b* values decreased. This study showed that makhana seeds may be popped effectively with >47% popped makhana recovery, >16 mm average diameter and acceptable colour values up to 120 days when the roasted seeds are stored at 15.53±0.49% (d.b.) moisture content in airtight packaging material.