Effects of packaging material on the quality of "pupuru" flour during storage.

"Pupuru" is a fermented cassava product dried by smoking and is commonly consumed by the people living in the riverine areas of the southern, eastern and the middle belts of Nigeria. The study investigated the effects of packaging material on the quality of pupuru flour stored at ambient condition (30.5 ±3°C; RH 76.5±3%) for 24 weeks. Pupuru flour was processed from cassava (TMS 30572) using the traditional method and was packaged in polyvinyl chloride container (CP), low density polyethylene film (LOPE), high density polyethylene film (HOPE) and polypropylene (PP) while uncovered polyvinyl chloride container (VCP) was used as control. Moisture content, pH, total titratable acidity (ITA), bulk density, water binding capacity, swelling power and solubility were determined at two weeks interval during storage; while amylose content, free sugar, starch, pasting properties, total plate count, fungi count, staphylococci count, E.coli count and sensory qualities were determined monthly. Regression analysis of microbial load against the storage period was also carried out. Data showed that moisture content (11.00-15.60%) and ITA (0.28-0.46%) increased significantly (P<0.01), while pH (3.74-3.21), water binding capacity (353.20-164.19%), swelling power (14.82-10.06), solubility (10.00-3.00), amylose (22.40-19.01%), free sugar (3.80-4.83%), starch content (64.86-54.10%), peak viscosity (245.25-166.64RVU), peak time (5.60-5.46mins) and pasting temperature (82.25-79.50°C) decreased significantly (P<0.01) during storage. Furthermore, most of these changes were more pronounced in samples packaged in HOPE than those in other packaging materials. Colour, texture and aroma of the samples packaged in HOPE were more acceptable than those in other packaging materials. Total plate count increased and varied linearly with period of storage (R2 =0.88-0.92). The estimated shelf life of pupuru flour packaged in LOPE, CP, PP, and VCP were found to be 12 weeks, 9 weeks, 6 weeks and 4 weeks respectively, while pupuru flour packaged in HDPE gave the longest estimated shelf life of 14 weeks at ambient condition.