Effect of Chemical Preservative and Packaging Material during Storage

Antinutritional properties of yam flour treated with chemical preservatives during six months of storage were carried out. Yam samples were purchased from the wurukum market, processed to obtain yam flour treated with chemical preservatives and packaged in plastic and low-density polyethene. About 100 grams of each of the different samples were separated into five portions. The first portion (sample A) was treated in a water bath with 250 ml of water with 0.5% of sodium metabisulphite for 15 minutes, drained and dried in an automated drier at about 70oC until dried to brittleness, Second portion (Sample B) was immersed in a solution of 0.5% Ascorbic acid for 15 minutes respectively, Third portion(Sample C) was immersed in a solution of 0.5% of Citric acid for 15 minutes, Fourth portion ( Sample D) was immersed in a solution of 0.5% of Ascorbic and Citric Acid, Fifth portion was blanched at 70oC for 5 minutes respectively. The yam slices were dried to brittleness and milled separately with a laboratory hammer mill and sieved using a 250-um mesh to obtain yam flour referred to as high–quality yam flour. The flour samples were analyzed for antinutritional using standard laboratory procedures. The anti-nutritional factors in the high‐quality yam flour were significantly different (p ≤ 0.05) from each other in terms of pretreatment but there was no significant difference in packaging material across storage. Antinutritional factors of yam flour samples decreased as storage progressed. The alkaloid contents of the different yam flour samples ranged from 0.17mg/100 g before storage to 0.39mg/100 g two months after storage, The Tannin contents of the different yam flour samples ranged from 0.32–0.68 mg/100 g (month 0), 0.04–0.64 mg/100 g (month 2), 0.31–0.58 mg/100 g (month 4), and 0.28–0.52mg/100 g (month 6) and The saponnin contents of the different yam flour samples ranged from 0.21–0.39 mg/100 g (month 0), 0.20–0.34 mg/100 g (month 2), 0.19–0.35 mg/100 g (month 4), and 0.21–0.32 mg/100 g (month 6). The anti-nutritional factors in the treated and untreated yam flour samples were significantly (p < .05) affected by pretreatment, storage and packaging materials. Chemical preservatives used in yam processing makes treated yam flour safe for consumption after six months of storage.