Estimation of Resistant Starch Content of Selected Routinely Consumed Indian Food Preparations

Abstract

Resistant Starch, an important component of the diet, shows the potential health benefits against lifestyle diseases and many other health conditions. Resistant Starch (RS) refers to the portion of starch and starch products that resist digestion as it passes through the gastrointestinal tract, gets fermented in the colon by colonic microflora and produces short chain fatty acids which directly or indirectly help in preventing and/or controlling many diseases.Since the main sources of RS in the Indian diet are starchy foods like varieties of cereals, cereal products, roots and tubers, raw and processed legumes etc.it becomes important to determine the RS content of typical traditional Indian starchy cereal and legume preparations.Therefore the aim of this research was to estimate the RS content of selected, routinely consumed Indian food preparations and to determine the change in RS content of cereal and pulse preparations on cooking and on storage. RS content was estimated for two varieties of rice and four rice preparations, whole and refined wheat flour and four preparations made using these flours, legumes like whole moong, Kabuli chhana, Chana flour and preparations made using them. Five of these preparations were also analyzed for their RS content after an overnight storage in the refrigerator, to understand the effect of storage on their RS content.Amount of RS was estimated using the procedure given by Parchure and Kulkarni. RS content in freshly cooked preparations was compared with RS content in equivalent amount of raw ingredients. RS content of freshly cooked preparations was also compared with RS in equivalent amount of cooked and stored samples. Comparison of means was done using paired t test. One-way ANOVA was also used to compare RS content of freshly cooked rice preparations, wheat preparations and legume preparations. P ≤ 0.05 was considered statistically significant.The RS content of raw food samples ranged from as low as 0.50g% in whole wheat flour to 27.67g% in Kolam rice. The two varieties of rice, Basmati and Kolam contained 20.22g% and 27.67g% RS respectively whereas Whole wheat flour and Refined wheat flour contained 0.50g% and 0.65g% RS respectively. The RS in raw legumes was 1.93g%, 1.98g% and 4.52g% in Kabuli Chana, Chana flour and Whole Moongrespectively.Among four freshly cooked rice preparations RS varied from 0.46g% in cooked Kolam to 0.78g% in Khichdi. Among four wheat preparations (freshly cooked) RS content varied from 0.47g% in Puri to 0.61g% (food as eaten) in paratha. Chapatti and Bhatura contained 0.49g% and 0.54g% RS (food as eaten) respectively.RS in legume preparations ranged from 0.09g% in freshly cooked Pithle to 2.38g% in cooked Chole. The RS values for germinated Moong, MoongUsal, and soaked Kabuli chana were 0.79g%, 0.87g% and 0.73g% (food as eaten) respectively.In case of rice preparations RS content was significantly lower in all the four freshly cooked rice products as compared to RS in equivalent amount of raw rice. All freshly cooked wheat products showed increase in RS content after cooking as compared to their corresponding raw equivalents. Except for Bhatura, in which the increase was not significant, in the rest of wheat preparations the increase was statistically significant. In case of processed or cooked legume preparations, except for chole, significantly lower RS was found in all preparations as compared to their raw equivalent quantities.In all the preparations that were subjected to storage, RS content increased after an overnight storage. A significant increase was seen in pressure cooked and stored Kolam Rice.Comparison among freshly cooked rice preparations showed that Khichdi contained significantly higher amount of RS as compared to other rice preparations, whereasamong freshly made wheat preparations, highest RS content was observed in Paratha. The RS value for Paratha was significantly higher than chapatti and puri. Among legume preparations Chhole had significantly higher RS content than moong usal or pithle. To conclude, the findings of this research show that Resistant Starch content of food preparation is influenced by many factors such as cooking method, processing technique, storage. Considering that Indians consume a vast variety of starchy preparations, further research in this direction is needed, to create a complete database of Resistant Starch content of Indian starchy preparations, that are made using different cooking and processing techniques and stored under varied conditions.