Efecto de la termosonicación sobre las propiedades termicas y la digestibilidad de las harina de arroz (paddy) y harina de trigo. (triticum durum).

Abstract

Emerging technologies such as ultrasound (US) in the food industry develop safer, more efficient, economic processes and positively impact the properties of food, compared with traditional methods. The aim of this study was to evaluate the effect of the US on the thermal properties, in vitro protein digestibility and comparison with weighted patterns established by the FAO digestibility 1991, for urban and rural adult population. These analyzes were applied to samples of wheat flour and rice flour to which were suspended in water and subjected to thermosonication (40 KHz) at temperatures of 40, 50 or 60 ° C for 15 to 30 minutes. The results obtained for the analysis of protein samples of wheat flour was of 4.90 ± 1.23% and rice flour was 8.83 ± 1.67%, which shows that the amount and composition of protein It is responsible for the marketing potential of a flour to different processing in the food industry (bread, porridge, washes, biscuits, instant puddings, soups); protein quality depends on several factors such as variety, differences in the structure of proteins, the type of grain processing technology. The in vitro protein digestibility was determined using a system trienzimático (trypsin, chymotrypsin and peptidase). A significant increase (p <0.05) treatment in which US was used at 40 KHz to 50 ° C for 15 minutes reaching a value of 85.92 ± 0.11% with respect to the other samples were found . No variation was observed in the other treatments compared to the control sample, averaging ranging from 84.50 to 86.00% of the value of the in vitro digestibility of the treated samples and not with US. The results could be due to the basic constitution of wheat flour; as grinding grains increases the surface for enzymatic attack and the cavitation phenomenon caused by the US increases the temperature of the denaturing proteins and improving the digestibility. The thermal properties of wheat flour and rice were determined by differential scanning calorimetry (DSC). Starches thermograms showed an initial endothermic peak (To) from 62 14 to 70 ° C and a second peak (Tp) between 68.19 to 74.79 ° C; at the end of the process the system reached the baseline reaching a final temperature (Te) of 75.94 to 84.81 ° C recorded the highest heat absorption values. Also, it was found that the samples treated with US 40KHz / 50 ° C / 30 min were valued at 8.47 Jul / g in the enthalpy of gelatinization (ΔHp) turned out to be higher against the determinations of all samples . For its part, the samples treated at 60 ° C / 15 to 60 ° C / 30 min showed the lowest values (3.91 and 3.15 Jul / g respectively) in the enthalpy of gelatinization against all treatments (p < 0.05). The thermal transition samples treated rice flour To in US presented a range of 66 to 71 ° C, the value was between 70,73-75,07ºC Tp and as the process ends in a range of Te 77.52 to 86.66 ° C. Most ΔHp was 9.89 Jul / g treatment 40KHz / 40 °C / 15 min, showing significant differences (p <0.05) in all treatments. This probably due to cavitation caused by the US, which disperses the starch granule agglomerates and increases the mass transfer in the boundary layer between the pellets and the aqueous phase; as depressions and cracks occur. Showing that the effect of improving the thermal stability US flour, features to reduce energy costs in different agroindustrial processes because gelatinization is quickly reached to a lower temperature, so they are easy to cook and require less power than other types of starch