CHEMICAL ENGINEERING TRANSACTIONS VOL. 75, 2019 A publication of The Italian Association of Chemical Engineering Online at www.cetjournal.it Guest Editors: Sauro Pierucci, Laura Piazza Copyright © 2019, AIDIC Servizi S.r.l. I SBN 978-88-95608-72-3; I SSN 2283-9216 Influence of Acidity in Paste Properties of Modified Corn Starch Through Natural Fermentation Maiara P Mendes a , Crislayne T Vasques a , Denise M B Silva b , Claudia C F Monteiroa c ,Ivo M Demiate d , Antonio R G Monteiro b *. a Food Science Post-Graduation Program, State University of Maringá, Av Colombo, 5790.87020-900, Maringá-PR, Brazil. b Food Engineer Department, State University of Maringá, Av Colombo, 5790.87020-900, Maringá-PR, Brazil. c Department of Design, State University of Maringá, Av Colombo, 5790.87020-900, Maringá-PR, Brazil d Food Engineer Department, State University of Ponta Grossa, Av. Carlos Cavalcanti, 4747 84030-900 Ponta Grossa-PR Brazil. argmonteiro@uem.br The objective of this research was to carry out the fermentation of corn starch in the same manner as cassava starch fermentation and to study its behavior during the fermentation process, analysing acidity and paste properties. CoS (corn starch) and CaS (cassava starch) were used. The sample was analysed by paste properties and acidity, at time 0, at every 7 days until the end of fermentation and after sun-drying. Regarding viscosity peak, CaS samples showed higher values, in the resistance attribute when comparing CoS and CaS samples those that had the same fermentation time did not present significant difference between them. CoS samples showed no significant difference between break results, but they did differ when compared to CaS samples. Only NCaS (native cassava starch) had greater retrogradation compared to CoS samples. However, the initial samples NCoS (native corn starch) and NCaS did not present differences in final viscosity results. However, they presented the highest values for this parameter with results of 171.50 and 180.50 RVU (Rapid Visco Units), respectively. Correlating results of acidity with paste properties it was observed that with fermentation time and consequent acidity increase, paste properties had important changes, decreasing the values of the measured parameters, only the paste temperature remained constant. It is concluded that the natural fermentation modification of corn starch compared with cassava starch had similarities about acidity. However, for pasting properties were no significant differences and should be better clarified through functional analysis and application product. Keywords: Modified Starch; production; structure; paste properties. 1. Introduction Starch is one of the most used polymers in the food industry. Currently, it stands out for its excellent utility in various food products. Its use is prevalent among food manufacturers because of its low price and availability. The primary sources of starch are corn, cassava, wheat and rice (Waterschoot et al., 2015). During the last years, the gluten-free products market showed a remarkable expansion. This has occurred due to the demand of celiac patients, increasing digestive health issues, changes in consumer's eating habits and awareness about other food intolerance issues (Díaz et al., 2019). The starches most used in the production of gluten-free products are those of corn and some roots and tubers, such as potatoes and cassava (Masure, Fierens&Delcour, 2016). In South America, it is used very starch fermented cassava and dried in the sun. Fermentation in cassava starch is a type of enzymatic modification. The production of modified starches is an alternative that has been used to overcome one or more limitations of native starches. Native starches have unstable functional properties, i.e., low resistance to changes in pH, temperature and mechanical treatment. To avoid such undesirable changes, native starch is modified by physical, chemical or enzymatic methods (Alcázar-alay&Meireles, 2015). DOI: 10.3303/CET1975078 Paper Received: 1 July 2018; Revised: 15 October 2018; Accepted: 30 March 2019 Please cite this article as: Mendes M., Vasques C., Silva D., Monteiro C., Demiate I., Monteiro A., 2019, Influence of Acidity in Paste Properties of Modified Corn Starch Through Natural Fermentation, Chemical Engineering Transactions, 75, 463-468 DOI:10.3303/CET1975078 463