Summary 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.

Autoclaving-cooling is a common starch modification method to increase the resistant starch (RS) content. The effect of this method varies depending on the type of crop and treatment condition used. The objectives of this study were to verify the autoclaving-cooling treatment based on a meta-analysis result and to evaluate the physicochemical properties of modified starches. The meta-analysis study used 10 articles from a total of 1,293 that were retrieved using the PRISMA approach. Meta-analysis showed that the optimal treatments of autoclaving-cooling process that increase the RS content significantly, was in starch samples from the cereal group (corn, oats, rice) (SMD: 19.60; 95% CI: 9.56–29.64; p < 0.001), with water ratio 1:4 (SMD: 13.69; 95% CI: 5.50–21.87; p < 0.001), using two cycles of autoclaving-cooling (SMD: 16.33; 95% CI: 6.98–25.67; p < 0.001) and 30 min of autoclaving heating (SMD: 12.97; 95% CI: 1.97–23.97; p < 0.001) at 121°C (SMD: 12.18; 95% CI: 1.88–22.47; p < 0.001). Verification using corn flour and corn starch showed a significant increase in RS contents from 15.84 to 27.78% and from 15.27 to 32.53%, respectively, and a significant decrease in starch digestibility from 67.02 to 35.74% and from 76.15 to 28.09%, respectively. Treated sample also showed the pasting profile that was stable under heating and stirring.

Summary Annealing is one of starch physical modification techniques that can increase resistant starch (RS) content. However, the effect of annealing on RS varies based on botanical sources. Starch crystal type and relative crystallinity are two important characteristics of starch. This study aimed to compare the influence of annealing on starch crystallinity and different starch crystal type (A, B and C) and investigate its effect on RS content by literature meta‐analysis study. The literature review was carried out using 22 research articles and 101 data points. The result showed relative crystallinity increase from the highest changes to the lowest, respectively; C‐type crystal (18.98%) followed by B (13.60%) and A‐type crystal (8.17%). Meta‐analysis study results showed a significant increase of RS content on starches with A‐type crystal (SMD = 6.46; 95% CI: 3.22–9.70; P < 0.01) and a positive relationship between the degree of crystallinity and RS content after annealing modification.

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