The effect of annealing on resistant starch content of different crop types: a systematic review and meta-analysis study

The growing demand for functional foods with a high resistant starch content (per cent RS) could be met by annealing starch modification. Through a meta-analysis, this study sought to shed light on the effect of annealing on the resistant starch content of various crop types. Twenty-one studies published between 2000 and 2020 were selected and eighty data points were extracted to be analysed using meta-essential tools. Hedge’s d Standardised Mean Difference (SMD) was designated for the effect size approach. Resistant starch content was influenced by the botanical origin of the carbohydrate source and the annealing parameters such as moisture content, incubation time and temperature. According to a meta-analysis of the data collected, the most significant increase in per cent RS is perceived on cereal (SMD: 7.58; 95% CI: 2.88–12.29; P = 0.001). Further analysis revealed that normal wheat had the highest significant per cent RS increase (SMD: 41.56; 95% CI: 19.52–63.61; P = 0.001). Annealing parameters resulted in significant %RS increase were moisture content of 80%, incubation time of 24 h and incubation temperature of 50–54 °C. These results were expected to provide data to optimise per cent RS increase through annealing efficiently.