Pre-cooking is a thermal process to produce food ingredients to be used in a variety of products (e.g. puddings and gluten-free pasta) in which a partial gelatinization of starch is desired. In this context, turbo cooking can be applied. This technology is based on the creation of a thin film of material in high turbulence by means of a turbine rotating inside a static horizontal chamber. After cooking, the material is dried to reduce its moisture content. The objective of this study was to explore the effects of different processing conditions on the physical and chemical properties of rice flour (Carnaroli cv). A 3-factor, 3-level Box Behnken experimental design was applied to study simultaneously the main and interactions effects of cooker temperature (120, 160, 200°C), feed moisture (30, 35, 40%) and dryer temperature (160, 180, 200°C). A fixed residence time of 30 s into the cooker was applied. A commercial flour prepared in a conventional belt cooker was used as reference. According to the Response Surface Methodology elaboration, different significant effects of the experimental factors were observed for moisture and some indices for evaluating starch gelatinization level, including damaged starch (i.e. -amylase accessibility), pasting properties and viscosity at 30°C. Furthermore, lack of fit of the models was not significant, indicating an adequate fitting of the design space. A higher significance of feed moisture was observed in comparison to the other factors. In particular, the higher the feed moisture, the higher the values of moisture and starch gelatinization as indicated by damaged starch, pasting temperature and viscosity at 30°C of the treated flours. At the same time, high feed moisture lowered the final paste viscosity, indicating once again that partial gelatinization of starch occurred during turbo cooking. As expected, cooker and dryer temperatures directly affected viscosity at 30°C and final paste viscosity. Optimization of the process conditions by the desirability function demonstrated that a cooking and drying temperature of 200°C coupled with 40% of feed moisture must be applied to obtain the maximum level of damaged starch, the highest viscosity at 30°C as well as the lowest peak viscosity. In conclusion, turbo cooking modifies the physical and chemical properties of rice flour, without reaching the same starch gelatinization as in the commercial sample, probably due to the limited residence time into the cooker. This work was supported by Lombardy Region (Linea R&S per Aggregazioni; project number 145075).
|Titolo:||Modelling of rice flour turbo cooking|
CAPPA, CAROLA (Corresponding)
|Data di pubblicazione:||22-ott-2018|
|Settore Scientifico Disciplinare:||Settore AGR/15 - Scienze e Tecnologie Alimentari|
|Citazione:||Modelling of rice flour turbo cooking / C. Cappa, R. Invernizzi, A. Marti, M. Lucisano, C. Alamprese. ((Intervento presentato al convegno AACC International Annual Meeting, Cereals & Grains tenutosi a London nel 2018.|
|Appare nelle tipologie:||14 - Intervento a convegno non pubblicato|