Influence of Freezing-Thawing Cycles on the Glycemic Index of the Iraqi White Bread after Oral Ingestion

Abstract

Background: The quality of bread depends not only on the quality of its ingredients, proper techniques during preparation, and storage also played a role in the rate of staling. Aims: The present study aims to investigate the impact of freezing and thawing on the glycemic response of Iraqi local white bread. Methods: In this prospective cross-over study, twelve healthy subjects (seven males, five females), aged 21–53 years, were recruited from Al-Rafidain University Campus and the local community. After overnight fasting, commercial Iraqi local white bread (200 g) was administered as fresh bread, following 1-week or 2-week freezing and thawing. Peak glucose response, 2 hr incremental area under the glucose response curve (AUC0-120) was evaluated as an outcome. Results: The different freezing and thawing conditions resulted in lower blood glucose AUC values compared to fresh white bread. In particular, compared to the fresh bread (AUC 14176±1134 mg min/dl), AUC was significantly lower when the bread was 1-week frozen and thawed (13205±660 mg min/dl, P<0.01), or 2-week frozen and thawed (12828±642 mg min/dl, P<0.01). Meanwhile, compared to the 1-week frozen bread, the 2-week freezing cycle did not produce a significantly lower AUC value. Conclusion: One or two freezing and thawing cycles decreased the glycemic response of the fresh Iraqi local white bread in healthy non-obese volunteers.