ORIGINAL PAPER Development of extruded fasting snacks by using vari rice, sweet potato and banana powder with applying response surface methodology Rahul P. Rathod 1 • Uday S. Annapure 1 Received: 13 September 2015 / Accepted: 24 April 2016 Ó Springer Science+Business Media New York 2016 Abstract Fasting is an integral part of the Indian culture and tradition. Traditionally, during fasting people would like to eat vari rice, sago, tubers and fruits. Vari rice (Echinochloa colonum) is the seed of a grass which fre- quently grows along with the paddy in the field. It provides the nourishment and energy equal to rice. It is rich source of minerals, vitamins, digestible fiber and starch as a major component and its products are slowly digestible. The present study was aimed to develop extrudate snacks for fasting purpose using vari rice, sweet potato and unripe banana powder and evaluate for their physicochemical and sensory properties by using response surface methodology. The die temperature has been varied from 160 to 180 °C with screw speed of 170–190 rpm at constant feed rate 16 rpm (70 g/min) and the feed moisture of the raw material was in the range of 16–21 %. The blend of vari rice, sweet potato and unripe banana powder in the ratio of (40:40:20) extruded at 180 °C die temperature, screw speed of 170 rpm with 16 % moisture content was most acceptable. Keywords Fasting Á Vari rice Á Extrudate product Á Response surface methodology Á Unripe banana powder Introduction Fasting is a ritual from many thousands of years which is a healing and a religious or spiritual process. Fasting is an integral part of the Indian culture and tradition and thought to be important as it nourishes both the physical and spiritual needs of the person. Also many religions including Christianity, Judaism and the Eastern religions have encouraged fasting for penitence, mourning, sacri- fice and union with the God. Apart from religious rea- sons fasting also has health benefits. Some researches [1, 2] observe that fasting helps to keep their metabolic rates working properly for instance. During fasting peo- ple would like to eat traditional product prepared from vari rice, sago, sweet potato, potato and fruits. Indian people are preferred vari rice khichadi, sabudana (sago) vada, sweet potato kheer, potato vada and fruit juices made traditionally at home. But there are fewer choices available for commercial product in market such as potato chips and banana chips snacks. Snacks are gen- erally consumed as light meals or a partial replacement for a regular meal. In recent years, the demand for snacks with improved nutritional and functional proper- ties has been increased. Among these, expanded product has gained preference of both consumers and producers [3]. Extrusion of food is an emerging technology for the food industries to process and produced large number of products of varying size, shape, texture and taste [4]. Extrusion cooking is used worldwide for the production of expanded snack foods, as there is a huge demand of healthy and nutritious ready-to-eat products from all age groups of consumer. Krokida [5] studied that for con- sumer acceptability structural and textural properties as well as quality of expanded products proven to be more vital. Extrusion conditions such as feed moisture content, & Rahul P. Rathod rathod.rahul7532@gmail.com & Uday S. Annapure udayannapure@gmail.com; udayannapure@ictmumbai.edu.in 1 Food Engineering and Technology Department, Institute of Chemical Technology, Matunga, Mumbai 400 019, India 123 Food Measure DOI 10.1007/s11694-016-9356-6