(P04-045-24) Effect of Varying Cooking and Storing Techniques on Resistant Starch Structure and Concentration in Cooked Starchy Foods

Objectives: Resistant Starch (RS) is not broken down by enzymes in the small intestine and is associated with improved gut health and satiety and glycemic responses. 

The objective of this study was to determine the effect of various cooking, cooling and storing techniques on the development and chemical quality of RS in cooked starchy foods.

Methods: Commonly prepared foods from rice, wheat, and potato were analyzed in this study. Rice and wheat dishes incorporated one each of steamed and stir-fried and potato dishes incorporated baked and fried cooking methods. Each dish was stored for 5 days in the refrigerator at 4⁰C, generating 6 samples - Day 0 (fresh) and Days 1-5 (refrigerated). A total of 36 food samples were analyzed. RS and amylose and amylopectin ratio (AAR) for each sample was assessed. The physicochemical properties of the RS isolates from food samples were analyzed by particle size distribution, zetapotential measurement, swelling power, and water solubility. Data analyzed using GraphPad is presented as mean ± SD.

Results: RS concentrations (per 100g) were significantly higher in potato (5.71g ± 0.89) compared to rice (2.53g ± 1.3) and wheat (2.16g ± 0.2) products (p < 0.001). Baking foods (5.96g ± 0.71) had significantly higher RS concentrations when compared to steaming (2.65g ± 1.20) and frying (3.17g ± 1.78) (p < 0.001). Amylose content was significantly high in potato (52.45% ± 7.43) compared to wheat products (43.56% ± 7.8). Storage time did not elicit significant changes in RS concentrations. There were no significant changes in the AAR in all products based on storage and cooking methods. RS isolates were found to aggregate in water, resulting in the formation of clustered particles of size ranging from 200nm to 4.0 microns. Size distribution variabilities were supported by respective zeta potentials. Zetapotential and cluster size values were highest for steamed rice (day 5) at -29.6 mV (800 nm) compared to steamed wheat (day 3) at -26.1 mV (350 nm) and baked potato (day 3) at -23.0 mV (250nm). While there were narrow differences in the zeta potential, significant differences were found in the cluster pattern of RS samples in water.

Conclusions: The cooking method and starch source significantly affects the quality and quantity of RS and can be monitored by analyzing the size of clustering aggregates and surface chemistry.

Funding Sources: ORSSP, UT-Tyler