EFFECT OF STORAGE TEMPERATURE ON THE EXTENT OF BALADY BREAD STALING

Abstract

The effect of storage temperature on freshness score, moisture content, alkaline water retention capacity (AWRC), the amount and composition of soluble starch as well as parting properties of balady bread were investigated. The data revealed that the temperature of storage has more important effect on the extent of bread freshness than its moisture content. The AWRC, the amount of soluble starch extracted and amylose decline sharply during the first 24hrs of storage, after which it leveled off. The component of the soluble starch was predominantly amylopectin. The amount of amylose in the soluble starch extracted from fresh bread after withdrawal from oven was small, declining sharply during the first 24hrs.of storage and this decreased slowly afterwordes. After24hrs.of storage, the decrease in soluble starch was accompanied by decreasing in amylopectin content. The refrigerator temperature is more likely to increase starch crystallization in bread and thus acceralate the rate of staling occurred than ambient temperature. No considerable changes in freshness as well as staling parameters were observed in bread stored at freezing temperature up to 72 hrs. Amylogram data showed slight decrease in the pasting temperature of bread slurries with longer storage time. The difference in peak viscosity, 15 min height, including a holding treatment at 95 C for 15 min; and after subsequent cooling to 50C (setback) gave the simillar rankings. These changes are more extensive at refrigerator temperature than at ambient temperature. Based on the data presented in this study, the AWRC, the amount of soluble starch, amylose and viscosity highly correlated with the sensory perception evaluation of bread staleness.