Pre-treatment effect on the nutritional and functional properties of selected cassava-based composite flours

Abstract

Abstract The low protein and lack of gluten in cassava ( Manihot esculenta Crantz) are disadvantageous for its use for product development and is overcome through the use of composite flours incorporating cereal and/or legume flours. The functionality and nutritional attributes of cassava flour were altered in the present study by pre-treatment with termamyl and green gram amylase, pre-gelatinization and subsequent blending with cereals, legumes, bran sources etc. Malting of cassava flour with termamyl followed by pre-gelatinization reduced the starch and increased the sugar content of the mixes. Pre-gelatinization had little effect on the crude protein of the mixes; nevertheless, the fat content was higher by 0.15–1.0 units. Energy content was around 1176 and 1217 KJ/100 g for the rice bran added mixes from malted cassava, which slightly increased in the respective pre-gelatinized cassava mixes. The peak viscosity of termamyl treated cassava-based flour mixes was much lower than the respective gram amylase based mixes, indicating that the latter had much less amylolytic activity than termamyl and pre-gelatinization further reduced the viscosity. The very low viscosity for the enzyme treated cassava-based mixes was due to the inability for retrogradation of the hydrolyzed starch. Significant improvement in in vitro starch digestibility (IVSD) (enhancement by 5.0–16.0 units in termamyl treatment vs 5.0–9.0 units in gram amylase treatment) was observed for the pre-gelatinized mixes. Lowest IVSD (25–29 units) was for the two bran based mixes, suggesting its use in the nutrition therapy for controlling obesity linked diseases. Industrial relevance With the development in human society, the incidence of chronic diseases like diabetes, cancer, cardiovascular problems and conditions like obesity contributing to several diseases is on the increase. This has led to an increasing awareness and research efforts on the development of functional foods, pharmafoods etc, which have wide potential application in medical nutrition therapy. The present work aims at improving the nutritional and functional attributes of cassava through fortification with cereal and/ or legume flours, bran sources etc. and through pre- treatment with enzymes to improve the functionality and reduce the energy content. The study led to the development of cassava based composite flours with low starch digestibility, high protein content and low energy content which could be effectively utilized for developing designer foods for obese and diabetic people. Enhanced digestibility of pre- gelatinized malted flours from cassava finds potential application for the development of foods for geriatric and convalescent people.