The chemical properties that serve as major determinants for the glycemic index (GI) of starchy food and recommended low-GI, carbohydrate-based foods have remained enigmatic. This present work performed a systematic assessment of linkages between chemical properties of foods and GI, and selected low-GI starchy foods. The data were sourced from literature published in various scientific journals. In total, 57 relevant studies and 936 data points were integrated into a database. Both in vitro and in vivo studies on GI values were included. The database was subsequently subjected to a meta-analysis. Meta-analysis from in vitro studies revealed that the two significant factors responsible for the GI of starchy foods were resistant starch and phenolic content (respectively, standardized mean difference (SMD): −2.52, 95% confidence interval (95%CI): −3.29 to −1.75, p (p-value) < 0.001; SMD: −0.72, 95%CI: −1.26 to −0.17, p = 0.005), while the lowest-GI crop type was legumes. Subgroup analysis restricted to the crop species with significant low GI found two crops, i.e., sorghum (SMD: −0.69, 95%CI: −2.33 to 0.96, p < 0.001) and red kidney bean (SMD: −0.39, 95%CI: −2.37 to 1.59, p = 0.001). Meta-analysis from in vivo studies revealed that the two significant factors responsible for the GI of starchy foods were flavonoid and phenolic content (respectively, SMD: −0.67, 95%CI: −0.87 to −0.47, p < 0.001; SMD: −0.63, 95%CI: −1.15 to −0.11, p = 0.009), while the lowest-GI crop type was fruit (banana). In conclusion, resistant starch and phenolic content may have a desirable impact on the GI of starchy food, while sorghum and red kidney bean are found to have low GI.

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.

Objectives: Bioactive compounds of Piper crocatum Ruiz & Pav, which have acted as antioxidants can be used to prevent and treat degenerative diseases such as hyperglycemia, cancer, gout and hypertension. This research aimed to determine the highest antioxidant activity from extract and fractions of P. crocatum leaves and to identify the active compounds such as antioxidants. Methods: The extraction was performed by maceration with 70% ethanol and then the crude extract was fractionated with three solvents, namely n-hexane, ethyl acetate and water. The identification of antioxidant activity was carried out using Rancimat and CUPRAC. The active compounds was identified using LC-MS (liquid chromatography-mass spectrometry). Results: The highest of the Rancimat method was obtained from the ethyl acetate fraction with a protective factor value of 1.38. Ten compounds were identified in the ethyl acetate fraction of P. crocatum leaves. An antioxidant activity according to the CUPRAC method showed the highest antioxidant activity in the sample of the n-hexane fraction with a value of 31.9 µmol Trolox/g extract. Thirteen compounds were identified in the n-hexane fraction of P. crocatum leaves. Conclusions: The highest antioxidant activity was obtained from ethyl acetate and n-hexane fraction. Various active compounds was identified in the highest value sample.