Development of Ready to Eat (Rte) Pre-cooked Corn Grits and Their Quality Evaluation

Abstract

The present study was undertaken to develop ready-to eat (RTE) pre-cooked corn kernels grits and their quality analysis. The proximate composition (moisture, protein, fat, fiber, ash, pH etc); hydration characterises, sand roasting characteristics and milling characteristics, quality and yield of corn grits was also analysed. The steps involved cleaning, moisture pre-conditioning, dry conduction heating (sand roasting) and grinding of roasted corn kernels. The effect of these treatments on hardness, alkali spreading value (ASV), hydration behaviour, physico-chemical, milling, granular morphology properties and specific power consumption (SPC) were studied. The hydration characteristics and the development of stress cracks on the corn kernel was also studied by soaking corn kernels in excess water at temperature ranging from 30 to 90°C for 1 to 1440 min. The pre-conditioned corn kernels were roasted at varying roasting process variables viz., moisture content ranging from 14-22%, sand temperature ranging from 160-200°C and roasting time from 30-150 s. The response considered includes hardness. A central composite rotatable design (CCRD) was used to conduct the experiments. A response surface methodology (RSM) was used to analyze and predict the optimum conditions for corn roasting to get maximum hardness. From the results optimum parameters were found as moisture content 19.97 - 176 - (% db), sand temperature 191.89°C and roasting time 103 s, the hardness 7.6 kg and gelatinization alkali score was 7. The maximum grits yield (86.6%) and SPC (0.028 kWh/kg) were found at lower rpm 1648. Although, a significant variation was found in grinding constants with the different mill speed (rpm) and varying sand roasting temperature. Bulk density decreased from 537.86±6.3 to 484.49±5.3 kg/m3 with increase in roasting temperature from 160ºC to 200ºC. The proximate composition (moisture, protein, fat, fiber, ash, carbohydrate and energy) was found in the sand roasted corn kernels grits at 191.89°C roasting temperature and sand roasting time 1.73 minute ranged 11.6±0.15 %, 7.3±0.02 %, 3.9±0.08 %, 0.5±0.01 %, 0.4±0.03 %, 76.3±0.05% and 369.5±0.12 kcal respectively. This study also indicate that corn kernels grits prepared by using dry conduction heating (sand roasting) was nutritionally superior than native (non-roasted) sample with having good keeping quality.