Effect of Packaging and Storage Conditions on Quality Attributes of Amaranth Sorghum Grains Complementary Flour

Abstract

Complementary food is food meant for infant and young children with the goal of bridging the gap between their daily energy and nutrient requirement and the amount obtained from breast milk. Complementary foods are characterised by high energy and nutrient density, shelf life stability and safety.1.3 million tons of food is lost yearly in the globe, 25-50% being attributed to poor packaging and storage conditions. Amaranth sorghum grains complementary flour is a blend of 90:10 steeped and germinated amaranth to sorghum grains respectively, dried, extruded and milled. It is a dry product with 8.8% fat content, 70.4% being unsaturated. This makes the product susceptible to lipid oxidation and moisture absorption from the storage environment. Information on the quality stability of ASCF under different storage condition in different type of packaging material is limited.In this study the effect of storage condition and type of packaging on the quality of the flour were examined. The flour was packaged in kraft paper, kraft paper with laminate and aluminium pouch and were then stored at either ambient conditions, 25°C, 60% relative humidity or 35°C,75% relative humidity . Quality assessments were done every 45 days from day zero as the baseline until the 180th day. Lipid oxidation was monitored through determination of peroxide value and p-Anisidine value. Microbial quality was determined through total viable count, and yeasts and moulds counts. Moisture adsorption isotherm was determined gravimetrically and fitted in different models. Water vapour permeability of the packaging materials was determined gravimetrically at 25°C, 75% relative humidity and 35°C, 75% relative humidity. Samples stored at 35°C, 75% relative recorded the highest peroxide value of 2.3meq O2 / kg at 180th day storage period. The interaction effect between storage conditions, storage time and type of packaging significantly (p = 0.000) affected fat oxidation which was seen to increase with storage time, high-temperature storage and kraft paper package. Total microbial count detected at the baseline level and over the storage period showed an insignificant increase (p =1.000) except for samples packaged in kraft paper and stored at 35°C and 75% relative humidity where increase was by 6.6% log cfu/g at 180th day storage period. The product exhibited type two sorption isotherm according to Brunner classification, an indication of monolayer-multilayer sorption behavior. By use of Heiss-Eichner model, the flour is predicted to keep for 1991 days at 25°C and 60% relative humidity having it packaged in aluminium pouch. Based on the results, it can be concluded that aluminium pouch and low storage temperature and relative humidity favours quality stability of the flour during storage.